Can pelagic forage fish and spawning cisco (Coregonus artedi) biomass in the western arm of Lake Superior be assessed with a single summer survey?

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Yule, D.L.; Stockwell, J.D.; Schreiner, D.R.; Evrard, L.M.; Balge, M.; Hrabik, T.R.

2009-01-01

Management efforts to rehabilitate lake trout Salvelinus namaycush in Lake Superior have been successful and the recent increase in their numbers has led to interest in measuring biomass of pelagic prey fish species important to these predators. Lake Superior cisco Coregonus artedi currently support roe fisheries and determining the sustainability of these fisheries is an important management issue. We conducted acoustic and midwater trawl surveys of the western arm of Lake Superior during three periods: summer (July-August), October, and November 2006 to determine if a single survey can be timed to estimate biomass of both prey fish and spawning cisco. We evaluated our methods by comparing observed trawl catches of small (cisco increased substantially in November, while small bloater Coregonus hoyi biomass was lower. We compared our summer 2006 estimates of total fish biomass to the results of a summer survey in 1997 and obtained similar results. We conclude that the temporal window for obtaining biomass estimates of pelagic prey species in the western arm of Lake Superior is wide (July through October), but estimating spawning cisco abundance is best done with a November survey.

Laboratory estimation of net trophic transfer efficiencies of PCB congeners to lake trout (Salvelinus namaycush) from its prey

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Madenjian, Charles P.; Rediske, Richard R.; O'Keefe, James P.; David, Solomon R.

2014-01-01

A technique for laboratory estimation of net trophic transfer efficiency (γ) of polychlorinated biphenyl (PCB) congeners to piscivorous fish from their prey is described herein. During a 135-day laboratory experiment, we fed bloater (Coregonus hoyi) that had been caught in Lake Michigan to lake trout (Salvelinus namaycush) kept in eight laboratory tanks. Bloater is a natural prey for lake trout. In four of the tanks, a relatively high flow rate was used to ensure relatively high activity by the lake trout, whereas a low flow rate was used in the other four tanks, allowing for low lake trout activity. On a tank-by-tank basis, the amount of food eaten by the lake trout on each day of the experiment was recorded. Each lake trout was weighed at the start and end of the experiment. Four to nine lake trout from each of the eight tanks were sacrificed at the start of the experiment, and all 10 lake trout remaining in each of the tanks were euthanized at the end of the experiment. We determined concentrations of 75 PCB congeners in the lake trout at the start of the experiment, in the lake trout at the end of the experiment, and in bloaters fed to the lake trout during the experiment. Based on these measurements, γ was calculated for each of 75 PCB congeners in each of the eight tanks. Mean γ was calculated for each of the 75 PCB congeners for both active and inactive lake trout. Because the experiment was replicated in eight tanks, the standard error about mean γ could be estimated. Results from this type of experiment are useful in risk assessment models to predict future risk to humans and wildlife eating contaminated fish under various scenarios of environmental contamination.

Behavioral evidence for a role of chemoreception during reproduction in lake trout

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Buchinger, Tyler J.; Li, Weiming; Johnson, Nicholas

2015-01-01

Chemoreception is hypothesized to influence spawning site selection, mate search, and synchronization of gamete release in chars (Salvelinus spp.), but behavioral evidence is generally lacking. Here, we provide a survey of the behavioral responses of reproductive male and female lake trout (Salvelinus namaycush) to natural conspecific chemosensory stimuli. A flow-through laboratory assay with side-by-side artificial spawning reefs was used to evaluate behavioral preferences of spawning-phase males and females for chemosensory stimuli from juveniles and from spawning-phase males and females. Males and females preferred male and juvenile stimuli over no stimuli, but only had weak preferences for female stimuli. Only females had a preference for male over juvenile stimuli when given a direct choice between the two. The unexpected observation of male attraction to male stimuli, even when offered female stimuli, indicates a fundamental difference from the existing models of chemical communication in fishes. We discuss our results from the perspectives of prespawning aggregation, mate evaluation, and spawning synchronization. Identification of specific components of the stimuli will allow confirmation of the function and may have management implications for native and invasive populations of lake trout that are ecologically and economically important.

Salmon returns and consumer fitness: growth and energy storage in stream-dwelling salmonids increases with spawning salmon abundance

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We examined how biomass of marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and nitrogen stable isotope ratios (d15N) of stream-dwelling fishes. We sampled coho salmon (Oncorhynchus kisutch) parr and juvenile Dolly Varden (Salvelinus malma) d...

Changing numbers of spawning cutthroat trout in tributary streams of Yellowstone Lake and estimates of grizzly bears visiting streams from DNA

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Haroldson, M.A.; Gunther, K.A.; Reinhart, Daniel P.; Podruzny, S.R.; Cegelski, C.; Waits, L.; Wyman, T.C.; Smith, J.

2005-01-01

Spawning Yellowstone cutthroat trout (Oncorhynchus clarki) provide a source of highly digestible energy for grizzly bears (Ursus arctos) that visit tributary streams to Yellowstone Lake during the spring and early summer. During 1985–87, research documented grizzly bears fishing on 61% of the 124 tributary streams to the lake. Using track measurements, it was estimated that a minimum of 44 grizzly bears fished those streams annually. During 1994, non-native lake trout (Salvelinus namaycush) were discovered in Yellowstone Lake. Lake trout are efficient predators and have the potential to reduce the native cutthroat population and negatively impact terrestrial predators that use cutthroat trout as a food resource. In 1997, we began sampling a subset of streams (n = 25) from areas of Yellowstone Lake surveyed during the previous study to determine if changes in spawner numbers or bear use had occurred. Comparisons of peak numbers and duration suggested a considerable decline between study periods in streams in the West Thumb area of the lake. The apparent decline may be due to predation by lake trout. Indices of bear use also declined on West Thumb area streams. We used DNA from hair collected near spawning streams to estimate the minimum number of bears visiting the vicinity of spawning streams. Seventy-four individual bears were identified from 429 hair samples. The annual number of individuals detected ranged from 15 in 1997 to 33 in 2000. Seventy percent of genotypes identified were represented by more than 1 sample, but only 31% of bears were documented more than 1 year of the study. Sixty-two (84%) bears were only documented in 1 segment of the lake, whereas 12 (16%) were found in 2–3 lake segments. Twenty-seven bears were identified from hair collected at multiple streams. One bear was identified on 6 streams in 2 segments of the lake and during 3 years of the study. We used encounter histories derived from DNA and the Jolly-Seber procedure in Program MARK

Spawning and rearing behavior of bull trout in a headwaterlake ecosystem

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Lora B. Tennant,; Gresswell, Bob; Guy, Christopher S.; Michael H. Meeuwig,

2015-01-01

Numerous life histories have been documented for bull trout Salvelinus confluentus. Lacustrine-adfluvial bull trout populations that occupy small, headwater lake ecosystems and migrate short distances to natal tributaries to spawn are likely common; however, much of the research on potamodromous bull trout has focused on describing the spawning and rearing characteristics of bull trout populations that occupy large rivers and lakes and make long distance spawning migrations to natal headwater streams. This study describes the spawning and rearing characteristics of lacustrine-adfluvial bull trout in the Quartz Lake drainage, Glacier National Park, USA, a small headwater lake ecosystem. Many spawning and rearing characteristics of bull trout in the Quartz Lake drainage are similar to potamodromous bull trout that migrate long distances. For example, subadult bull trout distribution was positively associated with slow-water habitat unit types and maximum wetted width, and negatively associated with increased stream gradient. Bull trout spawning also occurred when water temperatures were between 5 and 9 °C, and redds were generally located in stream segments with low stream gradient and abundant gravel and cobble substrates. However, this study also elucidated characteristics of bull trout biology that are not well documented in the literature, but may be relatively widespread and have important implications regarding general characteristics of bull trout ecology, use of available habitat by bull trout, and persistence of lacustrine-adfluvial bull trout in small headwater lake ecosystems.

Effects of fine sediment, hyporheic flow, and spawning site characteristics on survival and development of bull trout embryos

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Bowerman, Tracy; Neilson, Bethany; Budy, Phaedra

2014-01-01

Successful spawning is imperative for the persistence of salmonid populations, but relatively little research has been conducted to evaluate factors affecting early life-stage survival for bull trout (Salvelinus confluentus), a threatened char. We conducted a field experiment to assess the relationship between site-specific environmental factors and bull trout embryo survival and fry emergence timing. Survival from egg to hatch was negatively related to percent fine sediment (construction and selection of spawning sites with strong downwelling appear to enhance hyporheic flow rates and bull trout egg survival, but early life-stage success may ultimately be limited by intrusion of fine sediment into the incubation environment.

Initial Detection and Molecular Characterization of Namaycush Herpesvirus (Salmonid Herpesvirus 5) in Lake Trout.

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Glenney, Gavin W; Barbash, Patricia A; Coll, John A

2016-03-01

A novel herpesvirus was found by molecular methods in samples of Lake Trout Salvelinus namaycush from Lake Erie, Pennsylvania, and Lake Ontario, Keuka Lake, and Lake Otsego, New York. Based on PCR amplification and partial sequencing of polymerase, terminase, and glycoprotein genes, a number of isolates were identified as a novel virus, which we have named Namaycush herpesvirus (NamHV) salmonid herpesvirus 5 (SalHV5). Phylogenetic analyses of three NamHV genes indicated strong clustering with other members of the genus Salmonivirus, placing these isolates into family Alloherpesviridae. The NamHV isolates were identical in the three partially sequenced genes; however, they varied from other salmonid herpesviruses in nucleotide sequence identity. In all three of the genes sequenced, NamHV shared the highest sequence identity with Atlantic Salmon papillomatosis virus (ASPV; SalHV4) isolated from Atlantic Salmon Salmo salar in northern Europe, including northwestern Russia. These results lead one to believe that NamHV and ASPV have a common ancestor that may have made a relatively recent host jump from Atlantic Salmon to Lake Trout or vice versa. Partial nucleotide sequence comparisons between NamHV and ASPV for the polymerase and glycoprotein genes differ by >5% and >10%, respectively. Additional nucleotide sequence comparisons between NamHV and epizootic epitheliotropic disease virus (EEDV/SalHV3) in the terminase, glycoprotein, and polymerase genes differ by >5%, >20%, and >10%, respectively. Thus, NamHV and EEDV may be occupying discrete ecological niches in Lake Trout. Even though NamHV shared the highest genetic identity with ASPV, each of these viruses has a separate host species, which also implies speciation. Additionally, NamHV has been detected over the last 4 years in four separate water bodies across two states, which suggests that NamHV is a distinct, naturally replicating lineage. This, in combination with a divergence in nucleotide sequence from EEDV

Genetic and phenotypic variation along an ecological gradient in lake trout Salvelinus namaycush

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Baillie, Shauna M.; Muir, Andrew M.; Hansen, Michael J.; Krueger, Charles C.; Bentzen, Paul

2016-01-01

BackgroundAdaptive radiation involving a colonizing phenotype that rapidly evolves into at least one other ecological variant, or ecotype, has been observed in a variety of freshwater fishes in post-glacial environments. However, few studies consider how phenotypic traits vary with regard to neutral genetic partitioning along ecological gradients. Here, we present the first detailed investigation of lake trout Salvelinus namaycushthat considers variation as a cline rather than discriminatory among ecotypes. Genetic and phenotypic traits organized along common ecological gradients of water depth and geographic distance provide important insights into diversification processes in a lake with high levels of human disturbance from over-fishing.ResultsFour putative lake trout ecotypes could not be distinguished using population genetic methods, despite morphological differences. Neutral genetic partitioning in lake trout was stronger along a gradient of water depth, than by locality or ecotype. Contemporary genetic migration patterns were consistent with isolation-by-depth. Historical gene flow patterns indicated colonization from shallow to deep water. Comparison of phenotypic (Pst) and neutral genetic variation (Fst) revealed that morphological traits related to swimming performance (e.g., buoyancy, pelvic fin length) departed more strongly from neutral expectations along a depth gradient than craniofacial feeding traits. Elevated phenotypic variance with increasing water depth in pelvic fin length indicated possible ongoing character release and diversification. Finally, differences in early growth rate and asymptotic fish length across depth strata may be associated with limiting factors attributable to cold deep-water environments.ConclusionWe provide evidence of reductions in gene flow and divergent natural selection associated with water depth in Lake Superior. Such information is relevant for documenting intraspecific biodiversity in the largest freshwater lake

Effects of fine sediment, hyporheic flow, and spawning site characteristics on survival and development of bull trout embryos

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Bowerman, Tracy; Neilson, Bethany; Budy, Phaedra

2014-01-01

Successful spawning is imperative for the persistence of salmonid populations, but relatively little research has been conducted to evaluate factors affecting early life-stage survival for bull trout (Salvelinus confluentus), a threatened char. We conducted a field experiment to assess the relationship between site-specific environmental factors and bull trout embryo survival and fry emergence timing. Survival from egg to hatch was negatively related to percent fine sediment (bull trout egg survival, but early life-stage success may ultimately be limited by intrusion of fine sediment into the incubation environment.

DECLINE AND EXTINCTION OF LAKE TROUT IN THE GREAT LAKES: CAN BIOLOGICAL INDICATORS HELP DIAGNOSE CAUSES, IDENTIFY REMEDIAL ACTIONS, AND PREDICT FUTURE CONDITIONS?

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The lake trout, Salvelinus namaycush, is the predominant top predator native fish species of the Great Lakes. Lake trout are valued for commercial and recreational use in addition to their ecological importance. In the last half of the 20th century, population declines lead to vi...

Recent changes in the deep-water fish populations of Lake Michigan

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Moffett, James W.

1957-01-01

The deep-water fish fauna of Lake Michigan consisted of lake trout (Salvelinus namaycush), burbot (Lota lota maculosa), seven species of chubs or deep-water ciscoes (Leucichthys spp.), and the deep-water sculpin (Myoxocephalus quadricornis). Other species occupied the deep-water zone but were not typically part of the fauna.

Relationships between water temperatures and upstream migration, cold water refuge use, and spawning of adult bull trout from the Lostine River, Oregon, USA

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Howell, P.J.; Dunham, J.B.; Sankovich, P.M.

2010-01-01

Understanding thermal habitat use by migratory fish has been limited by difficulties in matching fish locations with water temperatures. To describe spatial and temporal patterns of thermal habitat use by migratory adult bull trout, Salvelinus confluentus, that spawn in the Lostine River, Oregon, we employed a combination of archival temperature tags, radio tags, and thermographs. We also compared temperatures of the tagged fish to ambient water temperatures to determine if the fish were using thermal refuges. The timing and temperatures at which fish moved upstream from overwintering areas to spawning locations varied considerably among individuals. The annual maximum 7-day average daily maximum (7DADM) temperatures of tagged fish were 16-18 ??C and potentially as high as 21 ??C. Maximum 7DADM ambient water temperatures within the range of tagged fish during summer were 18-25 ??C. However, there was no evidence of the tagged fish using localized cold water refuges. Tagged fish appeared to spawn at 7DADM temperatures of 7-14 ??C. Maximum 7DADM temperatures of tagged fish and ambient temperatures at the onset of the spawning period in late August were 11-18 ??C. Water temperatures in most of the upper Lostine River used for spawning and rearing appear to be largely natural since there has been little development, whereas downstream reaches used by migratory bull trout are heavily diverted for irrigation. Although the population effects of these temperatures are unknown, summer temperatures and the higher temperatures observed for spawning fish appear to be at or above the upper range of suitability reported for the species. Published 2009. This article is a US Governmentwork and is in the public domain in the USA.

Bilan des introductions de salmonidés dans les lacs et ruisseaux d'altitude des Hautes-Pyrénées

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DELACOSTE M.

1997-01-01

Full Text Available Les introductions de Salmonidés ont été importantes au cours des 60 dernières années dans les lacs et ruisseaux d'altitude des Hautes-Pyrénées. Six espèces de Salmonidés ont été introduites dans des milieux qui, pour la plupart, étaient vierges de populations piscicoles : la truite commune (Salmo trutta L., la truite arc-en-ciel (Oncorhynchus mykiss Walbaum, l'omble de fontaine (Salvelinus fontinalis Mitchill, l'omble chevalier (Salvelinus alpinus L., le cristivomer (Salvelinus namaycush Walbaum et le splake (Salvelinus fontinalis x Salvelinus namaycush. Dans de très nombreux cas, ces introductions ont abouti à des acclimatations. En revanche, les naturalisations sont beaucoup plus rares. Seules les espèces lacustres (cristivomer et omble chevalier se sont naturalisées dans la majorité des lacs où elles ont été introduites. Les conditions de reproduction constituent le facteur clé permettant d'expliquer la naturalisation des espèces. En ruisseau, il faut y ajouter la compétition avec l'espèce indigène (la truite commune, la pression halieutique ainsi que les conditions hivernales très rigoureuses. Les incidences écologiques des introductions sur les populations de truites communes indigènes sont faibles. En revanche, elles ne sont pas négligeables pour les populations de batraciens. Cette politique d'introduction a largement participé au développement de l'halieutisme dans ces milieux d'altitude. En cela, les introductions ont parfaitement répondu aux objectifs halieutiques qu'on leur avait fixés. L'acquisition de connaissances sur l'ensemble de la chaîne pyrénéenne constitue aujourd'hui une étape incontournable pour une politique de gestion globale des introductions.

Genome Sequences of Shewanella baltica and Shewanella morhuae Strains Isolated from the Gastrointestinal Tract of Freshwater Fish.

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Castillo, Daniel; Gram, Lone; Dailey, Frank E

2018-06-21

We present here the genome sequences of Shewanella baltica strain CW2 and Shewanella morhuae strain CW7, isolated from the gastrointestinal tract of Salvelinus namaycush (lean lake trout) and Coregonus clupeaformis (whitefish), respectively. These genome sequences provide insights into the niche adaptation of these specific species in freshwater systems. Copyright © 2018 Castillo et al.

Contrasting past and current numbers of bears visiting Yellowstone cutthroat trout streams

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Haroldson, Mark A.; Schwartz, Charles C.; Teisberg, Justin E.; Gunther, Kerry A.; Fortin, Jennifer K.; Robbins, Charles T.

2014-01-01

Spawning cutthroat trout (Oncorhynchus clarkii bouvieri) were historically abundant within tributary streams of Yellowstone Lake within Yellowstone National Park and were a highly digestible source of energy and protein for Yellowstone’s grizzly bears (Ursus arctos) and black bears (U. americanus). The cutthroat trout population has subsequently declined since the introduction of non-native lake trout (Salvelinus namaycush), and in response to effects of drought and whirling disease (Myxobolus cerebralis). The trout population, duration of spawning runs, and indices of bear use of spawning streams had declined in some regions of the lake by 1997–2000. We initiated a 3-year study in 2007 to assess whether numbers of spawning fish, black bears, and grizzly bears within and alongside stream corridors had changed since 1997– 2000. We estimated numbers of grizzly bears and black bears by first compiling encounter histories of individual bears visiting 48 hair-snag sites along 35 historically fished streams.We analyzed DNA encounter histories with Pradel-recruitment and Jolly-Seber (POPAN) capture-mark-recapture models. When compared to 1997–2000, the current number of spawning cutthroat trout per stream and the number of streams with cutthroat trout has decreased. We estimated that 48 (95% CI¼42–56) male and 23 (95% CI¼21–27) female grizzly bears visited the historically fished tributary streams during our study. In any 1- year, 46 to 59 independent grizzly bears (8–10% of estimated Greater Yellowstone Ecosystem population) visited these streams. When compared with estimates from the 1997 to 2000 study and adjusted for equal effort, the number of grizzly bears using the stream corridors decreased by 63%. Additionally, the number of black bears decreased between 64% and 84%. We also document an increased proportion of bears of both species visiting front-country (i.e., near human development) streams. With the recovery of cutthroat trout, we suggest bears

Species succession and sustainability of the Great Lakes fish community

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Eshenroder, Randy L.; Burnham-Curtis, Mary K.; Taylor, William W.; Ferreri, C. Paola

1999-01-01

This article concentrates on the sustainability of the offshore pelagic and deepwater fish communities that were historically dominated by lake trout (Salvelinus namaycush). The causes of alteration in these fish communities (i.e., overfishing, introductions, and cultural eutrophication) were identified by Loftus and Regier (1972). Here we look at the ecology of these altered communities in relation to sustainability and discuss the need for restoration.

Lake trout rehabilitation in Lake Erie: a case history

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Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

1995-01-01

Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

Polychlorinated biphenyl reduction in lake trout by irradiation and broiling

International Nuclear Information System (INIS)

Cichy, R.F.; Zabik, M.E.; Weaver, C.M.

1979-01-01

The Great Lakes Environmental contaminants surveys (1974-1975) have concluded that excessive concentrations of polychlorinated biphenyls (PCBs) are present in a specific species of lake trout (Salvelinus namaycush). Over 30 ppM of PCBs have been detected in the edible fillet of this fat trout. The objective of this study was to determine the effect of gamma irradiation combined with broiling on the levels of PCBs in lake trout fillets

Ecological factors affecting Rainbow Smelt recruitment in the main basin of Lake Huron, 1976-2010

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O'Brien, Timothy P.; Taylor, William W.; Roseman, Edward F.; Madenjian, Charles P.; Riley, Stephen C.

2014-01-01

Rainbow Smelt Osmerus mordax are native to northeastern Atlantic and Pacific–Arctic drainages and have been widely introduced throughout North America. In the Great Lakes region, Rainbow Smelt are known predators and competitors of native fish and a primary prey species in pelagic food webs. Despite their widespread distribution, importance as a prey species, and potential to negatively interact with native fish species, there is limited information concerning stock–recruitment relationships for Rainbow Smelt. To better understand recruitment mechanisms, we evaluated potential ecological factors determining recruitment dynamics for Rainbow Smelt in Lake Huron using data from bottom trawl catches. We specifically evaluated influence of stock size, environmental factors (water temperature, lake levels, and precipitation), and salmonine predation on the production of age-0 recruits from 1976 to 2010. Rainbow Smelt recruitment was negatively related to stock size exceeding 10 kg/ha, indicating that compensatory, density-dependent mortality from cannibalism or intraspecific competition was an important factor related to the production of age-0 recruits. Recruitment was positively related to spring precipitation suggesting that the amount of stream-spawning habitat as determined by precipitation was important for the production of strong Rainbow Smelt recruitment. Additionally, density of age-0 Rainbow Smelt was positively related to Lake Trout Salvelinus namaycush abundance. However, spawning stock biomass of Rainbow Smelt, which declined substantially from 1989 to 2010, was negatively associated with Lake Trout catch per effort suggesting predation was an important factor related to the decline of age-2 and older Rainbow Smelt in Lake Huron. As such, we found that recruitment of Rainbow Smelt in Lake Huron was regulated by competition with or cannibalism by older conspecifics, spring precipitation influencing stream spawning habitats, and predation by Lake Trout on

First evidence of successful natural reproduction by planted lake trout in Lake Huron

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Nester, Robert T.; Poe, Thomas P.

1984-01-01

Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

Oceanic migration and spawning of anguillid eels.

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Tsukamoto, K

2009-06-01

Many aspects of the life histories of anguillid eels have been revealed in recent decades, but the spawning migrations of their silver eels in the open ocean still remains poorly understood. This paper overviews what is known about the migration and spawning of anguillid species in the ocean. The factors that determine exactly when anguillid eels will begin their migrations are not known, although environmental influences such as lunar cycle, rainfall and river discharge seem to affect their patterns of movement as they migrate towards the ocean. Once in the ocean on their way to the spawning area, silver eels probably migrate in the upper few hundred metres, while reproductive maturation continues. Although involvement of a magnetic sense or olfactory cues seems probable, how they navigate or what routes they take are still a matter of speculation. There are few landmarks in the open ocean to define their spawning areas, other than oceanographic or geological features such as oceanic fronts or seamounts in some cases. Spawning of silver eels in the ocean has never been observed, but artificially matured eels of several species have exhibited similar spawning behaviours in the laboratory. Recent collections of mature adults and newly spawned preleptocephali in the spawning area of the Japanese eel Anguilla japonica have shown that spawning occurs during new moon periods in the North Equatorial Current region near the West Mariana Ridge. These data, however, show that the latitude of the spawning events can change among months and years depending on oceanographic conditions. Changes in spawning location of this and other anguillid species may affect their larval transport and survival, and appear to have the potential to influence recruitment success. A greater understanding of the spawning migration and the choice of spawning locations by silver eels is needed to help conserve declining anguillid species.

More Than Just a Spawning Location: Examining Fine Scale Space Use of Two Estuarine Fish Species at a Spawning Aggregation Site

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Ross E. Boucek

2017-11-01

Full Text Available Many species that provide productive marine fisheries form spawning aggregations. Aggregations are predictable both in time and space and constitute nearly all of the reproductive activity for these species. For species that spend weeks to months on spawning aggregation sites, individuals may need to rely on a forage base at or near the spawning site to balance the high energetic cost associated with reproduction. Here, we ask: do spawning fish with protracted spawning seasons use spawning aggregation sites more or less than adjacent foraging habitats? To answer our research question, we tracked 30 Snook (Centropomus undecimalis and 29 Spotted Seatrout (Cynoscion nebulosus at a spawning site during the 2007 spawning season in Tampa Bay (FL, U.S. using acoustic telemetry. We quantified the amount of time both males and females of both species spent in various habitats with network analyses. Surprisingly, results from network analyses revealed that receivers with the highest edge densities for Snook and Seatrout occurred within the seagrass habitat, not the location of spawning. Likewise, we found that both Snook and Seatrout during the spawning season were using the seagrass habitat near the spawning site as much, or more than the location where spawning occurs. Our results show that if protected areas are formed based on only where spawning occurs, the reproductive stock will not be protected from fishing. Further, our results suggest that spawning aggregation sites and areas surrounding used by fishes, may have multiple ecological functions (i.e., larval dispersal and energy provisioning that may need to be considered in conservation actions. Our case study further supports hypotheses put forth in previous work that suggest we must consider more than just spawning sites in protected area development and ecological conservation.

Summer spawning of Porites lutea from north-western Australia

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Stoddart, C. W.; Stoddart, J. A.; Blakeway, D. R.

2012-09-01

Most coral species off Australia's west coast spawn in the austral autumn (March-April), with a few species also spawning in the southern spring or early summer (November-December). This is the reverse timing to spawning recorded off Australia's east coast. Porites lutea, a gonochoric broadcast spawner that is common on Australia's west coast, is shown here to spawn in the months of November or December, as it does on Australia's east coast. Spawning occurred between 2 and 5 nights after full moon, with the majority of spawning activity on night 3. Gametes developed over three to four months with rapid development in the last two weeks before spawning. Zooxanthellae were typically observed in mature oocytes, only a week before spawning so their presence may provide a useful indicator of imminent spawning.

Variability of spawning time (lunar day) in Acropora versus merulinid corals: a 7-yr record of in situ coral spawning in Taiwan

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Lin, Che-Hung; Nozawa, Yoko

2017-12-01

Despite the global accumulation of coral spawning records over the past three decades, information on inter-annual variation in spawning time is still insufficient, resulting in difficulty in predicting coral spawning time. Here, we present new information on in situ spawning times of scleractinian corals at Lyudao, Taiwan, covering their inter-annual variations over a 7-yr period (2010-2016). Spawning of 42 species from 16 genera in eight families was recorded. The majority were hermaphroditic spawners (38 of 42 species), and their spawning occurred 2-4 h after sunset on 1-11 d after the full moon (AFM), mostly in April and May. There were two distinct patterns in the two dominant taxa, the genus Acropora (14 species) and the family Merulinidae (18 species in eight genera). The annual spawning of Acropora corals mostly occurred on a single night in May with high inter-annual variation of spawning (lunar) days between 1 and 11 d AFM. In contrast, the annual spawning of merulinid corals commonly occurred over 2-3 consecutive nights in two consecutive months, April and May, with the specific range of spawning days around the last quarter moon (between 5 and 8 d AFM). The distinct spawning patterns of these taxa were also documented at Okinawa and Kochi, Japan, where similar long-term monitoring of in situ coral spawning has been conducted. This variability in spawning days implies different regulatory mechanisms of synchronous spawning where Acropora corals might be more sensitive to exogenous environmental factors (hourglass mechanism), compared to merulinid corals, which may rely more on endogenous biological rhythms (oscillator mechanism).

Genetic differentiation of spring-spawning and fall-spawning male Atlantic sturgeon in the James River, Virginia.

Directory of Open Access Journals (Sweden)

Matthew T Balazik

Full Text Available Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae populations are currently at severely depleted levels due to historic overfishing, habitat loss, and pollution. The importance of biologically correct stock structure for effective conservation and management efforts is well known. Recent improvements in our understanding of Atlantic sturgeon migrations, movement, and the occurrence of putative dual spawning groups leads to questions regarding the true stock structure of this endangered species. In the James River, VA specifically, captures of spawning Atlantic sturgeon and accompanying telemetry data suggest there are two discrete spawning groups of Atlantic sturgeon. The two putative spawning groups were genetically evaluated using a powerful microsatellite marker suite to determine if they are genetically distinct. Specifically, this study evaluates the genetic structure, characterizes the genetic diversity, estimates effective population size, and measures inbreeding of Atlantic sturgeon in the James River. The results indicate that fall and spring spawning James River Atlantic sturgeon groups are genetically distinct (overall FST = 0.048, F'ST = 0.181 with little admixture between the groups. The observed levels of genetic diversity and effective population sizes along with the lack of detected inbreeding all indicated that the James River has two genetically healthy populations of Atlantic sturgeon. The study also demonstrates that samples from adult Atlantic sturgeon, with proper sample selection criteria, can be informative when creating reference population databases. The presence of two genetically-distinct spawning groups of Atlantic sturgeon within the James River raises concerns about the current genetic assignment used by managers. Other nearby rivers may also have dual spawning groups that either are not accounted for or are pooled in reference databases. Our results represent the second documentation of genetically

Spawning of coral reef invertebrates and a second spawning season for scleractinian corals in the central Red Sea

KAUST Repository

Bouwmeester, Jessica

2016-06-22

Recent coral spawning observations in the central Red Sea show that most scleractinian species release their gametes in the spring, with a majority of species spawning in April. There is, however, a lack of reproductive data for several other coral species, as well as a general lack of data for other invertebrates. Here, we document the detailed timing of spawning for 13 scleractinian coral species, one sea anemone, and six echinoderms from an inshore reef off the coast of Thuwal, Saudi Arabia, in the spring between April and June 2014. Furthermore, inferred from the presence of mature gametes, we report the month of spawning for three additional coral species in the spring. Seven scleractinian coral species were inferred to release their gametes in a second reproductive season, in the autumn, between September and November. This is the first report of a second spawning season in the Arabian region. Biannual spawning has so far been reported on the Great Barrier Reef, in Western Australia, in Indonesia, in Malaysia, in Palau, in Thailand, in Taiwan, and in Western Samoa. © 2016, The American Microscopical Society, Inc.

Artificial reproduction of two different spawn-forms of the chub.

Science.gov (United States)

Krejszeff, Sławomir; Targońska, Katarzyna; Zarski, Daniel; Kucharczyk, Dariusz

2010-03-01

The aim of this study was to compare, under controlled conditions, reproduction results of cultured and wild stock of the chub. Wild fish spawned only once a season whereas the cultured stock spawned at least two times. In the multiple-spawn stock, fewer fish spawned and the weight of produced oocytes was reduced compared to the single-spawn stock. Larvae obtained from the multi-spawn forms were smaller than those of the single-spawn stock. The occurrence of one species with two forms of spawning performance in the same area makes it difficult to develop an efficient method for controlling the reproduction.

Dual annual spawning races in Atlantic sturgeon.

Directory of Open Access Journals (Sweden)

Matthew T Balazik

Full Text Available Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae populations in the United States were listed as either endangered or threatened under the Endangered Species Act in 2012. Because of the endangered/threatened status, a better understanding of Atlantic sturgeon life-history behavior and habitat use is important for effective management. It has been widely documented that Atlantic sturgeon reproduction occurs from late winter to early summer, varying clinally with latitude. However, recent data show Atlantic sturgeon also spawn later in the year. The group that spawns later in the year seems to be completely separate from the spring spawning run. Recognition of the later spawning season has drastically modified estimates of the population status of Atlantic sturgeon in Virginia. With the combination of new telemetry data and historical documentation we describe a dual spawning strategy that likely occurs in various degrees along most, if not all, of the Atlantic sturgeon's range. Using new data combined with historical sources, a new spawning strategy emerges which managers and researchers should note when determining the status of Atlantic sturgeon populations and implementing conservation measures.

Genet-specific spawning patterns in Acropora palmata

Science.gov (United States)

Miller, M. W.; Williams, D. E.; Fisch, J.

2016-12-01

The broadcast spawning elkhorn coral, Acropora palmata, requires outcrossing among different genets for effective fertilization. Hence, a low density of genets in parts of its range emphasizes the need for precise synchrony among neighboring genets as sperm concentration dilutes rapidly in open-ocean conditions. We documented the genet-specific nightly occurrence of spawning of A. palmata over 8 yr in a depauperate population in the Florida Keys to better understand this potential reproductive hurdle. The observed population failed to spawn within the predicted monthly window (nights 2-6 after the full moon in August) in three of the 8 yr of observation; negligible spawning was observed in a fourth year. Moreover, genet-specific patterns are evident in that (1) certain genets have significantly greater odds of spawning overall and (2) certain genets predictably spawn on the earlier and others on the later lunar nights within the predicted window. Given the already low genet density in this population, this pattern implies a substantial degree of wasted reproductive effort and supports the hypothesis that depensatory factors are impairing recovery in this species.

Using Linkage Maps as a Tool To Determine Patterns of Chromosome Synteny in the Genus Salvelinus

Directory of Open Access Journals (Sweden)

Matthew C. Hale

2017-11-01

Full Text Available Next generation sequencing techniques have revolutionized the collection of genome and transcriptome data from nonmodel organisms. This manuscript details the application of restriction site-associated DNA sequencing (RADseq to generate a marker-dense genetic map for Brook Trout (Salvelinus fontinalis. The consensus map was constructed from three full-sib families totaling 176 F1 individuals. The map consisted of 42 linkage groups with a total female map size of 2502.5 cM, and a total male map size of 1863.8 cM. Synteny was confirmed with Atlantic Salmon for 38 linkage groups, with Rainbow Trout for 37 linkage groups, Arctic Char for 36 linkage groups, and with a previously published Brook Trout linkage map for 39 linkage groups. Comparative mapping confirmed the presence of 8 metacentric and 34 acrocentric chromosomes in Brook Trout. Six metacentric chromosomes seem to be conserved with Arctic Char suggesting there have been at least two species-specific fusion and fission events within the genus Salvelinus. In addition, the sex marker (sdY; sexually dimorphic on the Y chromosome was mapped to Brook Trout BC35, which is homologous with Atlantic Salmon Ssa09qa, Rainbow Trout Omy25, and Arctic Char AC04q. Ultimately, this linkage map will be a useful resource for studies on the genome organization of Salvelinus, and facilitates comparisons of the Salvelinus genome with Salmo and Oncorhynchus.

Inter-annual variability of North Sea plaice spawning habitat

Science.gov (United States)

Loots, C.; Vaz, S.; Koubbi, P.; Planque, B.; Coppin, F.; Verin, Y.

2010-11-01

Potential spawning habitat is defined as the area where environmental conditions are suitable for spawning to occur. Spawning adult data from the first quarter (January-March) of the International Bottom Trawl Survey have been used to study the inter-annual variability of the potential spawning habitat of North Sea plaice from 1980 to 2007. Generalised additive models (GAM) were used to create a model that related five environmental variables (depth, bottom temperature and salinity, seabed stress and sediment type) to presence-absence and abundance of spawning adults. Then, the habitat model was applied each year from 1970 to 2007 to predict inter-annual variability of the potential spawning habitat. Predicted responses obtained by GAM for each year were mapped using kriging. A hierarchical classification associated with a correspondence analysis was performed to cluster spawning suitable areas and to determine how they evolved across years. The potential spawning habitat was consistent with historical spawning ground locations described in the literature from eggs surveys. It was also found that the potential spawning habitat varied across years. Suitable areas were located in the southern part of the North Sea and along the eastern coast of England and Scotland in the eighties; they expanded further north from the nineties. Annual survey distributions did not show such northward expansion and remained located in the southern North Sea. This suggests that this species' actual spatial distribution remains stable against changing environmental conditions, and that the potential spawning habitat is not fully occupied. Changes in environmental conditions appear to remain within plaice environmental ranges, meaning that other factors may control the spatial distribution of plaice spawning habitat.

Steroidogenesis in the testes and seminal vesicles of spawning and non-spawning African catfish, Clarias gariepinus

NARCIS (Netherlands)

Schoonen, W.G.E.J.; Granneman, J.C.M.; Lambert, J.G.D.; Oordt, P.G.W.J. van

1987-01-01

The in vitro biosynthesis of steroids was studied in testes as well as seminal vesicles of non-spawning pond and spawning feral African catfish, collected during the breeding season. In testes of non-spawners the conversion of [3H]-pregnenolone was directed towards 11-oxygenated androgens and

The spawning of plaice Pleuronectes platessa in the Kattegat

DEFF Research Database (Denmark)

Nielsen, Else; Støttrup, Josianne; Heilmann, Jens

2004-01-01

Cruises were carried out in the entire Kattegat in early March of 1998 and 2000 to investigate the spawning of plaice Pleuronectes platessa. The data showed that plaice still spawn in the Kattegat, with a main spawning area in the southern Kattegat and an area of less, but variable importance in ...... of the larger age groups in the catches indicate that the Kattegat plaice stock is under severe pressure today. (C) 2004 Elsevier B.V. All rights reserved......Cruises were carried out in the entire Kattegat in early March of 1998 and 2000 to investigate the spawning of plaice Pleuronectes platessa. The data showed that plaice still spawn in the Kattegat, with a main spawning area in the southern Kattegat and an area of less, but variable importance...... in the northern coastal Kattegat. The results indicate that spawning in the southern part of Kattegat occurs earlier than in the northern Kattegat. The preferred spawning depth was found to be around 30-40 m. Juvenile recruitment in the nursery areas along the Danish east coast derives mainly from the southern...

Pressure shock triploidization of Salmo trutta f. lacustris and Salvelinus umbla eggs and its impact on fish development.

Science.gov (United States)

Lahnsteiner, Franz; Kletzl, Manfred

2018-07-15

The study tested the efficiency of hydrostatic pressure triploidization methods for Salmo trutta f. lacustris and Salvelinus umbla and investigated the effects on survival rate, skeletal malformation, and on morphometrics and cellular composition of gills, spleen, liver, kidney, intestine, and blood. In Salmo trutta f. lacustris a 100% triploidy rate in combination with high larvae survival rate (80% in comparison to control) was obtained when treating eggs with a pressure of 66 × 10 3  kPa 360 °C temperature minutes (CTM) post fertilization for 5 min, in Salvelinus umbla with a similar pressure after 270 CTM. Juvenile triploid Salmo trutta f. lacustris and Salvelinus umbla (145 days post hatch) had neither an increased rate of mortality, nor an increased rate of malformations. In triploid Salmo trutta f. lacustris and Salvelinus umbla the erythrocyte volume was 50% higher and the erythrocyte concentration in peripheral blood 25-35% lower relative to diploids. In triploids also the erythrocytes surface area: volume ratio was reduced. Gills of triploid Salmo trutta f. lacustris and Salvelinus umbla had increased width of primary lamellae and increased length of secondary lamellae which might compensate for unfavorable erythrocytes surface area: volume ratio. Length of the digestive tract and histology of kidney, liver, spleen, and gills were only investigated in Salmo trutta f. lacustris. In triploids the hematopoietic tissue of the kidney was decreased by 12%, the spleen index by 53%, and the erythroblast concentrations of the spleen by 42% relative to diploids, possibly indicating reduced erythropoiesis. Length of the digestive tract and cellular arrangement of intestine, liver, and gills were not affected. In summary, the used triploidization procedure seems a reliable method not counteracting the principles of animal welfare. Copyright © 2018 Elsevier Inc. All rights reserved.

On the relative effect of spawning asynchrony, sperm quantity and sperm quality on paternity under sperm competition in an external fertilizer

Directory of Open Access Journals (Sweden)

Torvald Blikra Egeland

2015-07-01

Full Text Available How much of a fitness benefit is obtained by dominant males of external fertilizers from releasing ejaculates in synchrony with female egg-release when engaging in sperm competition, and what is the most important sperm trait for paternity in these situations? The Arctic charr (Salvelinus alpinus is an external fertilizer experiencing intense male-male competition over reproductive opportunities including sperm competition. To compensate for their disadvantage the sneaker males, which often spawn out of synchrony with the female, produce more and faster sperm than the guarding males. We used controlled in vitro fertilization trials with experimentally produced dominant and subordinate, sneaker males to test what effect relative synchrony in gamete release, sperm quality (i.e., motility and velocity and sperm quantity have on a male’s fertilization success in pair-wise sperm competitions. When the sneaker males released ejaculates after the guarding male there was no overall difference in fertilization success. The quality (i.e., motility and velocity of a male’s sperm relative to that of the competing male was the best predictor of male fertilization success regardless of their mating tactic and spawning synchrony. The relative number of sperm cells also had an effect on fertilization success, but mainly when the dominant and sneaker male ejaculated synchronously. Our close imitation of natural sperm competition in charr shows that the sneaker males of external fertilizing species may fully compensate for their disadvantaged mating role by producing ejaculates of higher quality - an adjustment strangely not met by dominants.

Spatial and temporal movement dynamics of brook Salvelinus fontinalis and brown trout Salmo trutta

Science.gov (United States)

Davis, L.A.; Wagner, Tyler; Barton, Meredith L.

2015-01-01

Native eastern brook trout Salvelinus fontinalis and naturalized brown trout Salmo trutta occur sympatrically in many streams across the brook trout’s native range in the eastern United States. Understanding within- among-species variability in movement, including correlates of movement, has implications for management and conservation. We radio tracked 55 brook trout and 45 brown trout in five streams in a north-central Pennsylvania, USA watershed to quantify the movement of brook trout and brown trout during the fall and early winter to (1) evaluate the late-summer, early winter movement patterns of brook trout and brown trout, (2) determine correlates of movement and if movement patterns varied between brook trout and brown trout, and (3) evaluate genetic diversity of brook trout within and among study streams, and relate findings to telemetry-based observations of movement. Average total movement was greater for brown trout (mean ± SD = 2,924 ± 4,187 m) than for brook trout (mean ± SD = 1,769 ± 2,194 m). Although there was a large amount of among-fish variability in the movement of both species, the majority of movement coincided with the onset of the spawning season, and a threshold effect was detected between stream flow and movement: where movement increased abruptly for both species during positive flow events. Microsatellite analysis of brook trout revealed consistent findings to those found using radio-tracking, indicating a moderate to high degree of gene flow among brook trout populations. Seasonal movement patterns and the potential for relatively large movements of brook and brown trout highlight the importance of considering stream connectivity when restoring and protecting fish populations and their habitats.

Biannual Spawning and Temporal Reproductive Isolation in Acropora Corals.

Directory of Open Access Journals (Sweden)

James P Gilmour

Full Text Available Coral spawning on the oceanic reef systems of north-western Australia was recently discovered during autumn and spring, but the degree to which species and particularly colonies participated in one or both of these spawnings was unknown. At the largest of the oceanic reef systems, the participation by colonies in the two discrete spawning events was investigated over three years in 13 species of Acropora corals (n = 1,855 colonies. Seven species spawned during both seasons; five only in autumn and one only in spring. The majority of tagged colonies (n = 218 spawned once a year in the same season, but five colonies from three species spawned during spring and autumn during a single year. Reproductive seasonality was not influenced by spatial variation in habitat conditions, or by Symbiodinium partners in the biannual spawner Acropora tenuis. Colonies of A. tenuis spawning during different seasons separated into two distinct yet cryptic groups, in a bayesian clustering analysis based on multiple microsatellite markers. These groups were associated with a major genetic divergence (G"ST = 0.469, despite evidence of mixed ancestry in a small proportion of individuals. Our results confirm that temporal reproductive isolation is a common feature of Acropora populations at Scott Reef and indicate that spawning season is a genetically determined trait in at least A. tenuis. This reproductive isolation may be punctuated occasionally by interbreeding between genetic groups following favourable environmental conditions, when autumn spawners undergo a second annual gametogenic cycle and spawn during spring.

Spawning and hatching of endangered Gila Chub in captivity

Science.gov (United States)

Schultz, Andrew A.; Bonar, Scott A.

2016-01-01

Information on reproductive characteristics of the endangered Gila Chub Gila intermedia is largely limited and qualitative, and culture techniques and requirements are virtually unknown. Here we provide the first published data on spawning and selected reproductive and developmental characteristics of Gila Chub. Fish were brought to the laboratory in March 2003 from Sabino Creek, Arizona (12.3°C). Fish were then warmed slowly and spawned at 14.9°C, 10 d after collection. Following this initial spawning, Gila Chub spawned consistently in the laboratory without hormonal, chemical, photoperiod, temperature, or substrate manipulation during all times of the year. Spawns were noted at temperatures ranging from about 15°C to 26°C; however, we noted that Gila Chub spawned less frequently at temperatures above 24°C. Multiple spawning attempts per year per individual are probable. There was a strong, inverse relationship between time to hatch and incubation temperature. The hatch rate of eggs was high (mean = 99.43%), and larval Gila Chub accepted a variety of natural and formulated diets at first feeding. The future of Gila Chub may someday depend in part on hatchery propagation to provide specimens for restocking formerly occupied habitats and establishing refuge populations. Information from our study can aid future efforts to successfully spawn and rear Gila Chub and related species.

Passive acoustic monitoring to detect spawning in large-bodied catostomids

Science.gov (United States)

Straight, Carrie A.; Freeman, Byron J.; Freeman, Mary C.

2014-01-01

Documenting timing, locations, and intensity of spawning can provide valuable information for conservation and management of imperiled fishes. However, deep, turbid or turbulent water, or occurrence of spawning at night, can severely limit direct observations. We have developed and tested the use of passive acoustics to detect distinctive acoustic signatures associated with spawning events of two large-bodied catostomid species (River Redhorse Moxostoma carinatum and Robust Redhorse Moxostoma robustum) in river systems in north Georgia. We deployed a hydrophone with a recording unit at four different locations on four different dates when we could both record and observe spawning activity. Recordings captured 494 spawning events that we acoustically characterized using dominant frequency, 95% frequency, relative power, and duration. We similarly characterized 46 randomly selected ambient river noises. Dominant frequency did not differ between redhorse species and ranged from 172.3 to 14,987.1 Hz. Duration of spawning events ranged from 0.65 to 11.07 s, River Redhorse having longer durations than Robust Redhorse. Observed spawning events had significantly higher dominant and 95% frequencies than ambient river noises. We additionally tested software designed to automate acoustic detection. The automated detection configurations correctly identified 80–82% of known spawning events, and falsely indentified spawns 6–7% of the time when none occurred. These rates were combined over all recordings; rates were more variable among individual recordings. Longer spawning events were more likely to be detected. Combined with sufficient visual observations to ascertain species identities and to estimate detection error rates, passive acoustic recording provides a useful tool to study spawning frequency of large-bodied fishes that displace gravel during egg deposition, including several species of imperiled catostomids.

Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams : 1991 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Martin, Steven W.

1992-07-01

Bull trout (Salvelinus confluentus) are native to many tributaries of the Snake River in southeast Washington. The Washington Department of Wildlife (WDW) and the American Fisheries Society (AFS) have identified bull trout as a species of special concern which means that they may become threatened or endangered by relatively, minor disturbances to their habitat. Steelhead trout/rainbow trout (Oncorhynchus mykiss) and spring chinook salmon (O.tshawytscha) are also native to several tributaries of the Snake river in southeast Washington. These species of migratory fishes are depressed, partially due to the construction of several dams on the lower Snake river. In response to decreased run size, large hatchery program were initiated to produce juvenile steelhead and salmon to supplement repressed tributary stocks, a practice known as supplementation. There is a concern that supplementing streams with artificially high numbers of steelhead and salmon may have an impact on resident bull trout in these streams. Historically, these three species of fish existed together in large numbers, however, the amount of high-quality habitat necessary for reproduction and rearing has been severely reduced in recent years, as compared to historic amounts. The findings of the first year of a two year study aimed at identifying species interactions in southeast Washington streams are presented in this report. Data was collected to assess population dynamics; habitat utilization and preference, feeding habits, fish movement and migration, age, condition, growth, and the spawning requirements of bull trout in each of four streams. A comparison of the indices was then made between the study streams to determine if bull trout differ in the presence of the putative competitor species. Bull trout populations were highest in the Tucannon River (supplemented stream), followed by Mill Creek (unsupplemented stream). Young of the year bull trout utilized riffle and cascade habitat the most in all

Coral mass spawning predicted by rapid seasonal rise in ocean temperature

KAUST Repository

Keith, Sally A.

2016-05-11

Coral spawning times have been linked to multiple environmental factors; however, to what extent these factors act as generalized cues across multiple species and large spatial scales is unknown. We used a unique dataset of coral spawning from 34 reefs in the Indian and Pacific Oceans to test if month of spawning and peak spawning month in assemblages of Acropora spp. can be predicted by sea surface temperature (SST), photosynthetically available radiation, wind speed, current speed, rainfall or sunset time. Contrary to the classic view that high mean SST initiates coral spawning, we found rapid increases in SST to be the best predictor in both cases (month of spawning: R2 = 0.73, peak: R2 = 0.62). Our findings suggest that a rapid increase in SST provides the dominant proximate cue for coral mass spawning over large geographical scales. We hypothesize that coral spawning is ultimately timed to ensure optimal fertilization success.

Coral mass spawning predicted by rapid seasonal rise in ocean temperature

KAUST Repository

Keith, Sally A.; Maynard, Jeffrey A.; Edwards, Alasdair J.; Guest, James R.; Bauman, Andrew G.; van Hooidonk, Ruben; Heron, Scott F.; Berumen, Michael L.; Bouwmeester, Jessica; Piromvaragorn, Srisakul; Rahbek, Carsten; Baird, Andrew H.

2016-01-01

Coral spawning times have been linked to multiple environmental factors; however, to what extent these factors act as generalized cues across multiple species and large spatial scales is unknown. We used a unique dataset of coral spawning from 34 reefs in the Indian and Pacific Oceans to test if month of spawning and peak spawning month in assemblages of Acropora spp. can be predicted by sea surface temperature (SST), photosynthetically available radiation, wind speed, current speed, rainfall or sunset time. Contrary to the classic view that high mean SST initiates coral spawning, we found rapid increases in SST to be the best predictor in both cases (month of spawning: R2 = 0.73, peak: R2 = 0.62). Our findings suggest that a rapid increase in SST provides the dominant proximate cue for coral mass spawning over large geographical scales. We hypothesize that coral spawning is ultimately timed to ensure optimal fertilization success.

Male reproductive competition in spawning aggregations of cod ( Gadus morhua , L.)

DEFF Research Database (Denmark)

Bekkevold, Dorte; Hansen, Michael Møller; Loeschcke, V.

2002-01-01

Reproductive competition may lead to a large skew in reproductive success among individuals. Very few studies have analysed the paternity contribution of individual males in spawning aggregations of fish species with huge census population sizes. We quantified the variance in male reproductive...... success in spawning aggregations of cod under experimental conditions over an entire spawning season. Male reproductive success was estimated by microsatellite-based parentage analysis of offspring produced in six separate groups of spawning cod. In total, 1340 offspring and 102 spawnings distributed...... across a spawning season were analysed. Our results show that multiple males contributed sperm to most spawnings but that paternity frequencies were highly skewed among males, with larger males on average siring higher proportions of offspring. It was further indicated that male reproductive success...

29 CFR 780.113 - Seeds, spawn, etc.

Science.gov (United States)

2010-07-01

....” Thus, since mushrooms and beans are considered “agricultural or horticultural commodities,” the spawn of mushrooms and bean sprouts are also so considered and the production, cultivation, growing, and harvesting of mushroom spawn or bean sprouts is “agriculture” within the meaning of section 3(f). ...

Predictions of realised fecundity and spawning time in Norwegian spring-spawning herring ( Clupea harengus)

Science.gov (United States)

Óskarsson, G. J.; Kjesbu, O. S.; Slotte, A.

2002-08-01

Maturing Norwegian spring-spawning (NSS) herring, Clupea harengus, were collected for reproductive analyses along the Norwegian coast prior to the spawning seasons of 1997-2000. Over this time period there was a marked change in weight (W) at length (TL) with 1998 showing extremely low values and 2000 high values in a historical perspective. Potential fecundity, amounting to about 20 000-100 000 developing (vitellogenic) oocytes per fish and positively related to fish size, increased significantly with fish condition. Relative somatic potential fecundity (RF P, number of oocytes per g ovary-free body weight) in NSS herring was found to vary by 35-55% between years. Unexpectedly, females in 2000 showed low RF P-values, possibly due to negative feedback from previous reproductive investments at low condition. A clear threshold value for Fulton's condition factor, K (K=100×W/TL 3), of 0.65-0.70 existed below which there was considerable atresia (resorption of vitellogenic oocytes). Thus, these components of the spawning stock, amounting to 1-46% in the period 1980-1999, obviously contributed relatively little to the total egg production. This was confirmed by low ovary weights and examples of delayed oocyte development in these individuals. An up-to-date atresia model is presented. The established oocyte growth curve, and to a lesser degree the assumed atretic oocytic turnover rate, was critical for the estimation of realised fecundity (number of eggs spawned). Modelled realised fecundity was significantly below observed potential fecundity. Females that had migrated the shortest distance from the over-wintering area, Vestfjorden, northern Norway, were in the poorest condition, had the least developed oocytes and the lowest potential and realised fecundities. In agreement with previously published studies on temporal and spatial changes in gonad weights, those females reaching the main spawning grounds in the south-western part of the coast (Møre) were the most

Evidence of deepwater spawning of fall chinook salmon (Oncorhynchus tshawytscha): spawning near Ives and Pierce Island of the Columbia River, 1999; ANNUAL

International Nuclear Information System (INIS)

Mueller, Robert P.; Dauble, Dennis D.

2000-01-01

Fall chinook salmon Oncorhynchus tshawytscha, thought to originate from Bonneville Hatchery, were first noted to be spawning downstream of Bonneville Dam by Washington Department of Fisheries and Wildlife (WDFW) biologists in 1993 (Hymer 1997). Known spawning areas include gravel beds on the Washington side of the river near Hamilton Creek and Ives island. Limited spawning ground surveys were conducted in the area around Ives and Pierce Islands during 1994-1997 and based on these surveys it was believed that fall chinook salmon successfully spawned in this area. The size of this population from 1994 to 1996 was estimated at 1,800 to 5,200 fish (Hymer 1997). Recently, chum salmon were also documented spawning downstream of Bonneville Dam. Chum salmon O. kisutch were listed as threatened under the Endangered Species Act (ESA) in March, 1999. There are several ongoing investigations to define the physical habitat characteristics associated with fall chinook and chum salmon spawning areas downstream of Bonneville Dam. A major concern is to determine what flows (i.e. surface elevations) are necessary to ensure their long-term survival. Our objective was to locate deepwater spawning locations in the main Columbia River channel and to collect additional data on physical habitat parameters at the site. This objective is consistent with the high priority that the Northwest Power Planning Council's Independent Advisory Board and the salmon managers have placed on determining the importance of mainstem habitats to the production of salmon in the Columbia River Basin

Multi-species spawning synchrony within scleractinian coral assemblages in the Red Sea

KAUST Repository

Bouwmeester, Jessica; Baird, Andrew Hamilton; Chen, C. J.; Guest, James R.; Vicentuan, Kareen C.; Berumen, Michael L.

2014-01-01

Early work on coral reproduction in the far northern Red Sea suggested that the spawning times of ecologically abundant species did not overlap, unlike on the Great Barrier Reef where many species spawn with high synchrony. In contrast, recent work in the northern and central Red Sea indicates a high degree of synchrony in the reproductive condition of Acropora species: over 90 % of species sampled in April/May contain mature gametes. However, it has yet to be determined when most Acropora release their gametes. In addition, there is a lack of data for other ecologically important scleractinian species such as merulinids and poritids. Here, we document the date and time of spawning for 51 species in the central Red Sea over three consecutive years, and the month of spawning for an additional 17 species inferred from the presence of mature gametes. Spawning occurs on nights around the full moon, the spawning season lasts at least 4 months from April until July, and observations are consistent with the few other records from the Red Sea. The number of Acropora species spawning was highest in April with 13 species spawning two nights before the full moon in 2011, 13 species spawning on the night of the full moon in 2012, and eight species spawning four nights after the full moon in 2013. The total number of species spawning was high in April, May, and June and involved 15–19 species per month in 2012. Only four species spawned in July 2012. Few regions worldwide have been similarly sampled and include the Philippines, Okinawa in Japan, and Palau, where spawning patterns are very similar to those in the central Red Sea and where corals spawn on nights around the full moon over a period of 3–4 months. In particular, in all four locations, Acropora are among the first species to spawn. Our results add to a growing body of evidence indicating that multi-species spawning synchrony is a feature of all speciose coral assemblages.

Multi-species spawning synchrony within scleractinian coral assemblages in the Red Sea

KAUST Repository

Bouwmeester, Jessica

2014-09-21

Early work on coral reproduction in the far northern Red Sea suggested that the spawning times of ecologically abundant species did not overlap, unlike on the Great Barrier Reef where many species spawn with high synchrony. In contrast, recent work in the northern and central Red Sea indicates a high degree of synchrony in the reproductive condition of Acropora species: over 90 % of species sampled in April/May contain mature gametes. However, it has yet to be determined when most Acropora release their gametes. In addition, there is a lack of data for other ecologically important scleractinian species such as merulinids and poritids. Here, we document the date and time of spawning for 51 species in the central Red Sea over three consecutive years, and the month of spawning for an additional 17 species inferred from the presence of mature gametes. Spawning occurs on nights around the full moon, the spawning season lasts at least 4 months from April until July, and observations are consistent with the few other records from the Red Sea. The number of Acropora species spawning was highest in April with 13 species spawning two nights before the full moon in 2011, 13 species spawning on the night of the full moon in 2012, and eight species spawning four nights after the full moon in 2013. The total number of species spawning was high in April, May, and June and involved 15–19 species per month in 2012. Only four species spawned in July 2012. Few regions worldwide have been similarly sampled and include the Philippines, Okinawa in Japan, and Palau, where spawning patterns are very similar to those in the central Red Sea and where corals spawn on nights around the full moon over a period of 3–4 months. In particular, in all four locations, Acropora are among the first species to spawn. Our results add to a growing body of evidence indicating that multi-species spawning synchrony is a feature of all speciose coral assemblages.

Characterization of a Neochlamydia-like Bacterium Associated with Epitheliocystis in Cultured Artic Char Salvelinus alpinus

Science.gov (United States)

Infections of branchial epithelium by intracellular gram-negative bacteria, termed epitheliocystis, have limited culture of Arctic char (Salvelinus alpinus). To characterize a bacterium associated with epitheliocystis in cultured char, gills were sampled for histopathologic examination, conventional...

How coarse is too coarse for salmon spawning substrates?

Science.gov (United States)

Wooster, J. K.; Riebe, C. S.; Ligon, F. K.; Overstreet, B. T.

2009-12-01

Populations of Pacific salmon species have declined sharply in many rivers of the western US. Reversing these declines is a top priority and expense of many river restoration projects. To help restore salmon populations, managers often inject gravel into rivers, to supplement spawning habitat that has been depleted by gravel mining and the effects of dams—which block sediment and thus impair habitat downstream by coarsening the bed where salmon historically spawned. However, there is little quantitative understanding nor a methodology for determining when a river bed has become too coarse for salmon spawning. Hence there is little scientific basis for selecting sites that would optimize the restoration benefits of gravel injection (e.g., sites where flow velocities are suitable but bed materials are too coarse for spawning). To develop a quantitative understanding of what makes river beds too coarse for salmon spawning, we studied redds and spawning use in a series of California and Washington rivers where salmon spawning ability appears to be affected by coarse bed material. Our working hypothesis is that for a given flow condition, there is a maximum “threshold” particle size that a salmon of a given size is able to excavate and/or move as she builds her redd. A second, related hypothesis is that spawning use should decrease and eventually become impossible with increasing percent coverage by immovable particles. To test these hypotheses, we quantified the sizes and spatial distributions of immovably coarse particles in a series of salmon redds in each river during the peak of spawning. We also quantified spawning use and how it relates to percent coverage by immovable particles. Results from our studies of fall-run chinook salmon (Oncorhynchus tshawytsha) in the Feather River suggest that immovable particle size varies as a function of flow velocity over the redd, implying that faster water helps fish move bigger particles. Our Feather River study also

First record of multi-species synchronous coral spawning from Malaysia

Directory of Open Access Journals (Sweden)

Alvin Chelliah

2015-02-01

Full Text Available Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta exhibited highly synchronous spawning (100% of sampled colonies, two other common species (A. hyacinthus and A. digitifera did not contain visible eggs in the majority of colonies sampled (i.e., <15% of colonies in either April or October, suggesting that these species spawn at other times of the year. To the best of our knowledge, this is the first detailed documented observation of multi-species coral spawning from reefs in Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia.

INDUCTION SPAWNING FOR THE TROPICAL ABALONE (Haliotis asinina IN THE LABORATORY

Directory of Open Access Journals (Sweden)

D.E. Djoko Setyono

2006-06-01

Full Text Available The main purpose of this study was to test and understand the effectivity of previous successful treatment to induce spawning in temperate abalone, including the use of hydrogen peroxide, vigorous aeration, desiccation, thermal shock, and UV-irradiated seawater, to induce spawning in the tropical abalone (Haliotis asinina from southern Lombok waters, NTB. Approximately 90% of mature animals conditioned in the laboratory could be spawned successfully. Wild freshly mature broodstock collected in the morning during spring low tide failed to spawn under any treatment tried, while in wild freshly mature broodstock collected in the afternoon during spring low tide, approximately 45% of the males and 37% of the females, spawned successfully under all treatments. Mature animals ready to spawn were usually found creeping up the tanks close to the water surface, and were very active but relaxed, and the foot was soft and flabby. In the laboratory, H. asinina from southern Lombok waters released gametes at night between 11:00 pm and 01:00 am. The conditioned broodstock had average batch fecundity ranged from 50,000 to 435,000 eggs and the freshly caught wild broodstock ranged from 50,000 to 105,000 eggs. Approximately 75% of spawned eggs were found to be ripe and the remaining 25% were unripe. In general, no artificial spawning induction is required to spawn tropical abalone (H. asinina in laboratory (hatchery.

Skipped spawning in fishes: More common than you might think

DEFF Research Database (Denmark)

Rideout, Rick M.; Tomkiewicz, Jonna

2011-01-01

The traditional view of iteroparity in fishes is one of an annual reproductive cycle that culminates each year in spawning. More recently, a more flexible view of fish reproduction has been adopted, including the potential for mature fish to skip spawning. Here, we review the abundance of recent...... on elemental and isotope signatures. Skipped spawning is most commonly attributed to deficient diet and poor nutritional condition. Advances made in this field of study in recent years include descriptions of hormonal changes that precede and perhaps initiate skipped spawning, the development of life history...

Environmental and biological cues for spawning in the crown-of-thorns starfish.

Directory of Open Access Journals (Sweden)

Ciemon Frank Caballes

Full Text Available Sporadic outbreaks of the coral-eating crown-of-thorns starfish are likely to be due, at least in part, to spatial and temporal variation in reproductive and settlement success. For gonochoric and broadcast spawning species such as crown-of-thorns starfish, spawning synchrony is fundamental for achieving high rates of fertilization. Highly synchronized gamete release within and among distinct populations is typically the result of the entrainment of neurohormonal endogenous rhythms by cues from the environment. In this study, we conducted multiple spawning assays to test the effects of temperature change, reduced salinity and nutrient enrichment of seawater, phytoplankton, gametes (sperm and eggs, and the combined effect of sperm and phytoplankton on the likelihood of spawning in male and female crown-of-thorns starfish. We also investigated sex-specific responses to each of these potential spawning cues. We found that (1 abrupt temperature change (an increase of 4°C induced spawning in males, but less so in females; (2 males often spawned in response to the presence of phytoplankton, but none of the females spawned in response to these cues; (3 the presence of sperm in the water column induced males and females to spawn, although additive and synergistic effects of sperm and phytoplankton were not significant; and (4 males are more sensitive to the spawning cues tested and most likely spawn prior to females. We propose that environmental cues act as spawning 'inducers' by causing the release of hormones (gonad stimulating substance in sensitive males, while biological cues (pheromones from released sperm, in turn, act as spawning 'synchronizers' by triggering a hormonal cascade resulting in gamete shedding by conspecifics. Given the immediate temporal linkage between the timing of spawning and fertilization events, variability in the extent and synchronicity of gamete release will significantly influence reproductive success and may account

Influence of Color of Polythene Container and three Spawn rates on ...

African Journals Online (AJOL)

a

2012-04-16

Apr 16, 2012 ... estimated from the barley substrate at 150 g spawn level. Therefore, this study ... Days for completion of spawn running, fruiting bodies formation and pinheads formation of .... more energy for mycelial growth. Using a spawn ...

Fall spawning of Atlantic sturgeon in the Roanoke River, North Carolina

Science.gov (United States)

Smith, Joseph A.; Hightower, Joseph E.; Flowers, H. Jared

2015-01-01

In 2012, the National Oceanic and Atmospheric Administration (NOAA) declared Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus to be threatened or endangered throughout its range in U.S. waters. Restoration of the subspecies will require much new information, particularly on the location and timing of spawning. We used a combination of acoustic telemetry and sampling with anchored artificial substrates (spawning pads) to detect fall (September–November) spawning in the Roanoke River in North Carolina. This population is included in the Carolina Distinct Population Segment, which was classified by NOAA as endangered. Sampling was done immediately below the first shoals encountered by anadromous fishes, near Weldon. Our collection of 38 eggs during the 21 d that spawning pads were deployed appears to be the first such collection (spring or fall) for wild-spawned Atlantic Sturgeon eggs. Based on egg development stages, estimated spawning dates were September 17–18 and 18–19 at water temperatures from 25.3°C to 24.3°C and river discharge from 55 to 297 m3/s. These observations about fall spawning and habitat use should aid in protecting critical habitats and planning research on Atlantic Sturgeon spawning in other rivers.

Climate change and vulnerability of bull trout (Salvelinus confluentus ) in a fire-prone landscape

Science.gov (United States)

Jeffrey A. Falke; Rebecca L. Flitcroft; Jason B. Dunham; Kristina M. McNyset; Paul F. Hessburg; Gordon H. Reeves; C. Tara Marshall

2015-01-01

Linked atmospheric and wildfire changes will complicate future management of native coldwater fishes in fire-prone landscapes, and new approaches to management that incorporate uncertainty are needed to address this challenge. We used a Bayesian network (BN) approach to evaluate population vulnerability of bull trout (Salvelinus confluentus) in the Wenatchee River...

First record of multi-species synchronous coral spawning from Malaysia.

Science.gov (United States)

Chelliah, Alvin; Amar, Halimi Bin; Hyde, Julian; Yewdall, Katie; Steinberg, Peter D; Guest, James R

2015-01-01

Knowledge about the timing and synchrony of coral spawning has important implications for both the ecology and management of coral reef ecosystems. Data on the timing of spawning and extent of synchrony, however, are still lacking for many coral reefs, particularly from equatorial regions and from locations within the coral triangle. Here we present the first documentation of a multi-species coral spawning event from reefs around Pulau Tioman, Peninsular Malaysia, a popular diving and tourist destination located on the edge of the coral triangle. At least 8 coral species from 3 genera (Acropora, Montipora and Porites) participated in multi-species spawning over five nights in April 2014, between two nights before and two nights after the full moon. In addition, two Acropora species were witnessed spawning one night prior to the full moon in October 2014. While two of the Acropora species that reproduced in April (A. millepora and A. nasuta) exhibited highly synchronous spawning (100% of sampled colonies), two other common species (A. hyacinthus and A. digitifera) did not contain visible eggs in the majority of colonies sampled (i.e., Malaysia. These data provide further support for the contention that this phenomenon is a feature of all speciose coral assemblages, including equatorial reefs. More research is needed, however, to determine the seasonal cycles and extent of spawning synchrony on these reefs and elsewhere in Malaysia.

Analysis of the association between spawning time QTL markers and the biannual spawning behavior in rainbow trout (Oncorhynchus mykiss

Directory of Open Access Journals (Sweden)

Nelson Colihueque

2010-01-01

Full Text Available The rainbow trout is a salmonid fish that occasionally exhibits broodstocks with biannual spawning behavior, a phenomenon known as a double annual reproductive cycle (DARC. Spawning time quantitative trait loci (SPT-QTLs affect the time of the year that female rainbow trout spawn and may influence expression of the DARC trait. In this study, microsatellite markers linked and unlinked to SPT-QTLs were genotyped to investigate the underlying genetics of this trait. SPT-QTLs influenced the DARC trait since in two case-control comparisons three linked markers (OmyFGT12TUF, One3ASC and One19ASC had significant levels of allelic frequency differentiation and marker-character association. Furthermore, alleles of One3ASC and One19ASC had significantly higher frequencies in populations that carried the DARC trait.

Optimisation Of Volvariella volvacea Spawn Production For High Mycelia Growth

International Nuclear Information System (INIS)

Nie, H.J.; Azhar Mohamad; Joyce, Y.S.M.; Muhamad Najmi Moin

2016-01-01

Volvariella volvacea is a tropical mushroom cultivated throughout the world mostly in Asia and Europe for its taste, nutrition, fast growing nature and simple method of cultivation. It is also widely cultivated in Malaysia and known locally as Paddy Straw Mushroom. Growers strive to obtain high quality mushroom spawn to achieve high production. High quality spawn with fast mycelia growth are achieved through strain selection and optimisation of seedling production conditions. This study aims to optimise spawn production through 3 studies along the production main stages. Firstly, comparisons were made between agar media. Mycelia grown on Malt Extract Agar (MEA) covered the agar plates 2 days faster than Potato Dextrose Agar (PDA) grown mycelia. The next stage is of mother grain spawn production by inoculating a bag of grains from mycelia agar plugs. Bags are then sealed with caps. The amount of aeration for grain spawn were studied by using two types of caps. Caps with hole allowed more aeration compared to caps without holes. Study determined bags with more aeration colonised grains 2 days faster than bags with lesser aeration. For the final stage of producing planting spawn, the growth on paddy straw substrate with and without kapok (10 %) were evaluated. Results revealed mycelia fully colonised the substrate bags without kapok 1-2 days faster than substrate bags with kapok. These findings contribute in achieving production of high quality Volvariella volvacea spawn. (author)

Temporal patterns of migration and spawning of river herring in coastal Massachusetts

Science.gov (United States)

Rosset, Julianne; Roy, Allison; Gahagan, Benjamin I.; Whiteley, Andrew R.; Armstrong, Michael P.; Sheppard, John J.; Jordaan, Adrian

2017-01-01

Migrations of springtime Alewife Alosa pseudoharengus and Blueback Herring A. aestivalis, collectively referred to as river herring, are monitored in many rivers along the Atlantic coast to estimate population sizes. While these estimates give an indication of annual differences in the number of returning adults, links to the subsequent timing and duration of spawning and freshwater juvenile productivity remain equivocal. In this study, we captured juvenile river herring at night in 20 coastal Massachusetts lakes using a purse seine and extracted otoliths to derive daily fish ages and back-calculate spawn dates. Estimates of spawning dates were compared with fishway counts of migrating adults to assess differences in migration timing and the timing and duration of spawning. We observed a distinct delay between the beginning of the adult migration run and the start of spawning, ranging from 7 to 28 d across the 20 lakes. Spawning continued 13–48 d after adults stopped migrating into freshwater, further demonstrating a pronounced delay in spawning following migration. Across the study sites the duration of spawning (43–76 d) was longer but not related to the duration of migration (29–66 d). The extended spawning period is consistent with recent studies suggesting that Alewives are indeterminate spawners. The long duration in freshwater provides the opportunity for top-down (i.e., predation on zooplankton) and bottom-up (i.e., food for avian, fish, and other predators) effects, with implications for freshwater food webs and nutrient cycling. General patterns of spawn timing and duration can be incorporated into population models and used to estimate temporal changes in productivity associated with variable timing and density of spawning river herring in lakes.

Behavioral Ecology of Coral Reef Fishes at Spawning Aggregation Sites

National Research Council Canada - National Science Library

Sancho, Gorka

1998-01-01

This thesis is an extensive investigation of the behavioral and ecological relationships between spawning reef fishes, their predators, and various environmental parameters at spawning aggregation sites...

Influence of Inoculation Method and Spawn Level on Biological ...

African Journals Online (AJOL)

ADOWIE PERE

in and layering) and spawn levels (3, 5, 7, 9, 11, and 13%) on the mushroom. The results ... grows faster and has more energy available for fruiting body formation, hence the increased .... The shortest spawn running time obtained when the.

Migration patterns of post-spawning Pacific herring in a subarctic sound

Science.gov (United States)

Bishop, Mary Anne; Eiler, John H.

2018-01-01

Understanding the distribution of Pacific herring (Clupea pallasii) can be challenging because spawning, feeding and overwintering may take place in different areas separated by 1000s of kilometers. Along the northern Gulf of Alaska, Pacific herring movements after spring spawning are largely unknown. During the fall and spring, herring have been seen moving from the Gulf of Alaska into Prince William Sound, a large embayment, suggesting that fish spawning in the Sound migrate out into the Gulf of Alaska. We acoustic-tagged 69 adult herring on spawning grounds in Prince William Sound during April 2013 to determine seasonal migratory patterns. We monitored departures from the spawning grounds as well as herring arrivals and movements between the major entrances connecting Prince William Sound and the Gulf of Alaska. Departures of herring from the spawning grounds coincided with cessation of major spawning events in the immediate area. After spawning, 43 of 69 tagged herring (62%) moved to the entrances of Prince William Sound over a span of 104 d, although most fish arrived within 10 d of their departure from the spawning grounds. A large proportion remained in these areas until mid-June, most likely foraging on the seasonal bloom of large, Neocalanus copepods. Pulses of tagged herring detected during September and October at Montague Strait suggest that some herring returned from the Gulf of Alaska. Intermittent detections at Montague Strait and the Port Bainbridge passages from September through early January (when the transmitters expired) indicate that herring schools are highly mobile and are overwintering in this area. The pattern of detections at the entrances to Prince William Sound suggest that some herring remain in the Gulf of Alaska until late winter. The results of this study confirm the connectivity between local herring stocks in Prince William Sound and the Gulf of Alaska.

Impact of Ichthyophonus infection on spawning success of Yukon River Chinook salmon Oncorhynchus tshawytscha.

Science.gov (United States)

Hamazaki, Toshihide; Kahler, Eryn; Borba, Bonnie M; Burton, Tamara

2013-11-06

We examined the impacts of Ichthyophonus infection on spawning success of Yukon River Chinook salmon Oncorhynchus tshawytscha at spawning grounds of the Chena and Salcha Rivers, Alaska, USA. During the period 2005 to 2006, 1281 salmon carcasses (628 male, 652 female) were collected throughout the spawning season and from the entire spawning reaches of the Chena and Salcha Rivers. For each fish, infection status was determined by culture method and visual inspection of lesions of heart tissue as uninfected (culture negative), infected without lesions (culture positive with no visible lesions), and infected with lesions (culture positive with visible lesions), and spawning status was determined by visually inspecting the percentage of gametes remaining as full-spawned (50%). Among the 3 groups, the proportion of full-spawned (i.e. spawning success) females was lower for those infected without lesions (69%) than those uninfected (87%) and infected with lesions (86%), but this did not apply to males (uninfected 42%, infected without lesions 38%, infected with lesions 41%). At the population level, the combined (infected and uninfected) proportion of female spawning success was 86%, compared to 87% when all females were assumed uninfected. These data suggest that while Ichthyophonus infection slightly reduces spawning success of infected females, its impact on the spawning population as a whole appears minimal.

Prediction of reef fish spawning aggregations using remote sensing: A review

International Nuclear Information System (INIS)

Rosli, M R; Ibrahim, A L; Masron, T

2014-01-01

Spawning aggregation is a very important occurrence to particular reef fish species as they use this opportunity to reproduce. However, due to their predictable nature, these aggregations have always been vulnerable to overexploitation. This problem leads to the importance of identifying the exact time and location for reef fish spawning aggregation. Thus, this paper review a little bit about spawning aggregation of reef fish as well as their characteristics, and problems regarding this phenomena. The use of remote sensing in marine applications is also described here in order to discuss how remote sensing can be utilize to predict reef fish spawning aggregation. Based on the unique geomorphological characteristics of the spawning aggregation, remote sensing seems to be a powerful tool to determine their exact times and locations. It has been proved that satellite imagery was able to delineate specific reef geomorphologies such as shelf edges and reef promontories. Despite of the widely use of remote sensing in marine applications, in fact there are still lack of studies had been carried out regarding spawning aggregations of reef fish due to the skeptical point-of-view by certain researchers over the capability of this technique. However, there is actually no doubt that the use of remote sensing will provide a better hand to the authorities in order to establish a more effective monitoring and conservation plan for these spawning aggregations

Timing and locations of reef fish spawning off the southeastern United States.

Directory of Open Access Journals (Sweden)

Nicholas A Farmer

Full Text Available Managed reef fish in the Atlantic Ocean of the southeastern United States (SEUS support a multi-billion dollar industry. There is a broad interest in locating and protecting spawning fish from harvest, to enhance productivity and reduce the potential for overfishing. We assessed spatiotemporal cues for spawning for six species from four reef fish families, using data on individual spawning condition collected by over three decades of regional fishery-independent reef fish surveys, combined with a series of predictors derived from bathymetric features. We quantified the size of spawning areas used by reef fish across many years and identified several multispecies spawning locations. We quantitatively identified cues for peak spawning and generated predictive maps for Gray Triggerfish (Balistes capriscus, White Grunt (Haemulon plumierii, Red Snapper (Lutjanus campechanus, Vermilion Snapper (Rhomboplites aurorubens, Black Sea Bass (Centropristis striata, and Scamp (Mycteroperca phenax. For example, Red Snapper peak spawning was predicted in 24.7-29.0°C water prior to the new moon at locations with high curvature in the 24-30 m depth range off northeast Florida during June and July. External validation using scientific and fishery-dependent data collections strongly supported the predictive utility of our models. We identified locations where reconfiguration or expansion of existing marine protected areas would protect spawning reef fish. We recommend increased sampling off southern Florida (south of 27° N, during winter months, and in high-relief, high current habitats to improve our understanding of timing and location of reef fish spawning off the southeastern United States.

Microphytoplankton variations during coral spawning at Los Roques, Southern Caribbean

Directory of Open Access Journals (Sweden)

Francoise Cavada-Blanco

2016-03-01

Full Text Available Phytoplankton drives primary productivity in marine pelagic systems. This is also true for the oligotrophic waters in coral reefs, where natural and anthropogenic sources of nutrients can alter pelagic trophic webs. In this study, microphytoplankton assemblages were characterized for the first time in relation to expected coral spawning dates in the Caribbean. A hierarchical experimental design was used to examine these assemblages in Los Roques archipelago, Venezuela, at various temporal and spatial scales for spawning events in both 2007 and 2008. At four reefs, superficial water samples were taken daily for 9 days after the full moon of August, including days before, during and after the expected days of coral spawning. Microphytoplankton assemblages comprised 100 microalgae taxa at up to 50 cells per mL (mean ± 8 SD and showed temporal and spatial variations related to the coral spawning only in 2007. However, chlorophyll a concentrations increased during and after the spawning events in both years, and this was better matched with analyses of higher taxonomical groups (diatoms, cyanophytes and dinoflagellates, that also varied in relation to spawning times in 2007 and 2008, but asynchronously among reefs. Heterotrophic and mixotrophic dinoflagellates increased in abundance, correlating with a decrease of the diatom Cerataulina pelagica and an increase of the diatom Rhizosolenia imbricata. These variations occurred during and after the coral spawning event for some reefs in 2007. For the first time, a fresh-water cyanobacteria species of Anabaena was ephemerally found (only 3 days in the archipelago, at reefs closest to human settlements. Variability among reefs in relation to spawning times indicated that reef-specific processes such as water residence time, re-mineralization rates, and benthic-pelagic coupling can be relevant to the observed patterns. These results suggest an important role of microheterotrophic grazers in re

Spawning Dynamics and Size Related Trends in Reproductive Parameters of Southern Bluefin Tuna, Thunnus maccoyii.

Directory of Open Access Journals (Sweden)

Jessica H Farley

Full Text Available Knowledge of spawning behaviour and fecundity of fish is important for estimating the reproductive potential of a stock and for constructing appropriate statistical models for assessing sustainable catch levels. Estimates of length-based reproductive parameters are particularly important for determining potential annual fecundity as a function of fish size, but they are often difficult to estimate reliably. Here we provide new information on the reproductive dynamics of southern bluefin tuna (SBT Thunnus maccoyii through the analysis of fish size and ovary histology collected on the spawning ground in 1993-1995 and 1999-2002. These are used to refine previous parameter estimates of spawning dynamics and investigate size related trends in these parameters. Our results suggest that the small SBT tend to arrive on the spawning ground slightly later and depart earlier in the spawning season relative to large fish. All females were mature and the majority were classed as spawning capable (actively spawning or non-spawning with a very small proportion classed as regressing. The fraction of females spawning per day decreased with fish size, but once females start a spawning episode, they spawned daily irrespective of size. Mean batch fecundity was estimated directly at 6.5 million oocytes. Analysis of ovary histology and ovary weight data indicated that relative batch fecundity, and the duration of spawning and non-spawning episodes, increased with fish size. These reproductive parameter estimates could be used with estimates of residency time on the spawning ground as a function of fish size (if known and demographic data for the spawning population to provide a time series of relative annual fecundity for SBT.

The North Sea autumn spawning herring (Clupea harengus L.) Spawning Component Abundance Index (SCAI)

DEFF Research Database (Denmark)

2013-01-01

, the sum of the fitted abundance indices across all components proves an excellent proxy for the biomass of the total stock, even though the model utilizes information at the individual-component level. The Orkney-Shetland component appears to have recovered faster from historic depletion events than......The North Sea autumn-spawning herring (Clupea harengus) stock consists of a set of different spawning components. The dynamics of the entire stock have been well characterized, but although time-series of larval abundance indices are available for the individual components, study of the dynamics...... at the component level has historically been hampered by missing observations and high sampling noise. A simple state-space statistical model is developed that is robust to these problems, gives a good fit to the data, and proves capable of both handling and predicting missing observations well. Furthermore...

Migration and spawning of female surubim (Pseudoplatystoma corruscans, Pimelodidae) in the São Francisco river, Brazil

Science.gov (United States)

Godinho, Alexandre L.; Kynard, Boyd; Godinho, Hugo P.

2007-01-01

Surubim, Pseudoplatystoma corruscans, is the most valuable commercial and recreational fish in the São Francisco River, but little is known about adult migration and spawning. Movements of 24 females (9.5–29.0 kg), which were radio-tagged just downstream of Três Marias Dam (TMD) at river kilometer 2,109 and at Pirapora Rapids (PR) 129 km downstream of TMD, suggest the following conceptual model of adult female migration and spawning. The tagged surubims used only 274 km of the main stem downstream of TMD and two tributaries, the Velhas and Abaeté rivers. Migration style was dualistic with non-migratory (resident) and migratory fish. Pre-spawning females swam at ground speeds of up to 31 km day-1 in late September–December to pre-spawning staging sites located 0–11 km from the spawning ground. In the spawning season (November–March), pre-spawning females migrated back and forth from nearby pre-spawning staging sites to PR for short visits to spawn, mostly during floods. Multiple visits to the spawning site suggest surubim is a multiple spawner. Most post-spawning surubims left the spawning ground to forage elsewhere, but some stayed at the spawning site until the next spawning season. Post-spawning migrants swam up or downstream at ground speeds up to 29 km day-1 during January–March. Construction of proposed dams in the main stem and tributaries downstream of TMD will greatly reduce surubim abundance by blocking migrations and changing the river into reservoirs that eliminate riverine spawning and non-spawning habitats, and possibly, cause extirpation of populations.

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush)

Science.gov (United States)

Ottinger, Christopher A.; Honeyfield, Dale C.; Densmore, Christine L.; Iwanowicz, Luke R.

2014-01-01

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush).

Science.gov (United States)

Ottinger, Christopher A; Honeyfield, Dale C; Densmore, Christine L; Iwanowicz, Luke R

2014-05-01

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP--biologically inactive form) to thiamine pyrophosphate (TPP--biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state. Published by Elsevier Ltd.

Using genetic and phenotypic comparisons to evaluate apparent segregation among Kokanee spawning groups

Science.gov (United States)

Whitlock, Steven L.; Campbell, Matthew R.; Quist, Michael C.; Dux, Andrew M.

2018-01-01

Genetic and phenotypic traits of spatially and temporally segregated kokanee Oncorhynchus nerka spawning groups in Lake Pend Oreille, Idaho, were compared to test for evidence of divergence on the basis of ecotype (stream spawners versus shoreline spawners) and spawn timing and to describe morphological, life history, and reproductive variation within and among groups. Early and late spawning runs were found to be reproductively isolated; however, there was no clear evidence of genetic differentiation between ecotypes. Spawning groups within the same ecotype differed in length, age distribution, mean length at age, fecundity, and egg size. Variation in reproductive attributes was due primarily to differences in length distributions. Larger‐bodied shore‐spawning kokanee were located in areas where egg survival is known to be enhanced by downwelling, suggesting that the distribution of shore‐spawning kokanee may be partly structured by competition for spawning habitats with groundwater influence. This study contributes to other research indicating that introduced kokanee populations are unlikely to undergo adaptive divergence if they have a history of population fluctuations and are supplemented regularly.

Spawning Behaviour and the Softmouth Trout Dilemma

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Esteve Manu

2014-07-01

Full Text Available Morphological, ecological and molecular data sets do not completely agree on the phylogenetic placement of the softmouth trout, Salmo (Salmothymus obtusirostris (Heckel. Molecules posit that softmouths are closely related to brown trout, Salmo trutta L. while some morphological, ecological and life history traits place them in the most basal position of the Salmoninae subfamily between grayling (Thymallus and lenok (Brachymystax. Here we add an additional source of data, behavioural characters based on the first reported observations of softmouth spawning. During spawning softmouth females present three important behaviours not found in the other Salmo members: they continually abandon their nests, rarely staying on them for periods over nine minutes; they expel different batches of eggs at the same nest at intervals of several minutes; and they do not cover their eggs immediately after spawning. These three behaviours are intriguing for two reasons: 1 they are possible homologous to behaviours found in grayling females; 2 when coupled to the nest digging behaviour-widespread in all the salmonines, including softmouths, they seem to be mal-adaptive.

Location Isn't Everything: Timing of Spawning Aggregations Optimizes Larval Replenishment.

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Megan J Donahue

Full Text Available Many species of reef fishes form large spawning aggregations that are highly predictable in space and time. Prior research has suggested that aggregating fish derive fitness benefits not just from mating at high density but, also, from oceanographic features of the spatial locations where aggregations occur. Using a probabilistic biophysical model of larval dispersal coupled to a fine resolution hydrodynamic model of the Florida Straits, we develop a stochastic landscape of larval fitness. Tracking virtual larvae from release to settlement and incorporating changes in larval behavior through ontogeny, we found that larval success was sensitive to the timing of spawning. Indeed, propagules released during the observed spawning period had higher larval success rates than those released outside the observed spawning period. In contrast, larval success rates were relatively insensitive to the spatial position of the release site. In addition, minimum (rather than mean larval survival was maximized during the observed spawning period, indicating a reproductive strategy that minimizes the probability of recruitment failure. Given this landscape of larval fitness, we take an inverse optimization approach to define a biological objective function that reflects a tradeoff between the mean and variance of larval success in a temporally variable environment. Using this objective function, we suggest that the length of the spawning period can provide insight into the tradeoff between reproductive risk and reward.

Spawning sites of the Japanese eel in relation to oceanographic structure and the West Mariana Ridge.

Science.gov (United States)

Aoyama, Jun; Watanabe, Shun; Miller, Michael J; Mochioka, Noritaka; Otake, Tsuguo; Yoshinaga, Tatsuki; Tsukamoto, Katsumi

2014-01-01

The Japanese eel, Anguilla japonica, spawns within the North Equatorial Current that bifurcates into both northward and southward flows in its westward region, so its spawning location and larval transport dynamics seem important for understanding fluctuations in its recruitment to East Asia. Intensive research efforts determined that Japanese eels spawn along the western side of the West Mariana Ridge during new moon periods, where all oceanic life history stages have been collected, including eggs and spawning adults. However, how the eels decide where to form spawning aggregations is unknown because spawning appears to have occurred at various latitudes. A salinity front formed from tropical rainfall was hypothesized to determine the latitude of its spawning locations, but an exact spawning site was only found once by collecting eggs in May 2009. This study reports on the collections of Japanese eel eggs and preleptocephali during three new moon periods in June 2011 and May and June 2012 at locations indicating that the distribution of lower salinity surface water or salinity fronts influence the latitude of spawning sites along the ridge. A distinct salinity front may concentrate spawning south of the front on the western side of the seamount ridge. It was also suggested that eels may spawn at various latitudes within low-salinity water when the salinity fronts appeared unclear. Eel eggs were distributed within the 150-180 m layer near the top of the thermocline, indicating shallow spawning depths. Using these landmarks for latitude (salinity front), longitude (seamount ridge), and depth (top of the thermocline) to guide the formation of spawning aggregations could facilitate finding mates and help synchronize their spawning.

Marked changes in neuropeptide expression accompany broadcast spawnings in the gastropod Haliotis asinina

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York Patrick S

2012-05-01

Full Text Available Abstract Introduction A huge diversity of marine species reproduce by synchronously spawning their gametes into the water column. Although this species-specific event typically occurs in a particular season, the precise time and day of spawning often can not be predicted. There is little understanding of how the environment (e.g. water temperature, day length, tidal and lunar cycle regulates a population’s reproductive physiology to synchronise a spawning event. The Indo-Pacific tropical abalone, Haliotis asinina, has a highly predictable spawning cycle, where individuals release gametes on the evenings of spring high tides on new and full moons during the warmer half of the year. These calculable spawning events uniquely allow for the analysis of the molecular and cellular processes underlying reproduction. Here we characterise neuropeptides produced in H. asinina ganglia that are known in egg-laying molluscs to control vital aspects of reproduction. Results We demonstrate that genes encoding APGWamide, myomodulin, the putative proctolin homologue whitnin, FMRFamide, a schistosomin-like peptide (SLP, a molluscan insulin-related peptide (MIP and a haliotid growth-associated peptide (HGAP all are differentially expressed in the anterior ganglia during the two week spawning cycle in both male and female abalone. Each gene has a unique and sex-specific expression profile. Despite these differences, expression levels in most of the genes peak at or within 12 h of the spawning event. In contrast, lowest levels of transcript abundance typically occurs 36 h before and 24 h after spawning, with differences in peak and low expression levels being most pronounced in genes orthologous to known molluscan reproduction neuromodulators. Conclusions Exploiting the predictable semi-lunar spawning cycle of the gastropod H. asinina, we have identified a suite of evolutionarily-conserved, mollusc-specific and rapidly-evolving neuropeptides that appear to

Spawning pattern of the neon flying squid Ommastrephes bartramii (Cephalopoda: Oegopsida around the Hawaiian Islands

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Dharmamony Vijai

2014-12-01

Full Text Available The neon flying squid, Ommastrephes bartramii, is an oceanic squid species that is widely distributed in the North Pacific, with the winter-spring cohort spawning around the Hawaiian Islands. Here, we investigated the spawning characteristics of O. bartramii by analyzing various reproductive parameters of individuals (622 males, 108 females collected in this region. Female spawning status was determined from the somatic indices and histological characteristics of the ovaries. At all developmental stages, the ovaries of spawned females contained oocytes, and oviduct fullness was not correlated with body size. Thus, because the eggs mature asynchronously, with multiple filling and evacuation events, this species is considered an intermittent spawner. Mature males with developed accessory glands were also present within the distribution range of healthy spawned females, indicating that mating occurs between spawning events. Our data indicate that the first spawning event occurs at a mantle length of ~520-540 mm for Hawaiian O. bartramii. Subsequently, the squid forage and grow, and refill the oviducts, before the second spawning event occurs.

Thermal Niche Tracking and Future Distribution of Atlantic Mackerel Spawning in response to Ocean Warming

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Antoine eBruge

2016-06-01

Full Text Available North-east Atlantic mackerel spawning distribution has shifted northward in the last three decades probably in response to global sea warming. Yet, uncertainties subsist regarding on the shift rate, causalities, and how this species will respond to future conditions. Using egg surveys, we explored the influence of temperature change on mackerel’s spawning distribution (western and southern spawning components of the stock between 1992 and 2013, and projected how it may change under future climate change scenarios. We developed three generalized additive models: (i a spatiotemporal model to reconstruct the spawning distribution for the north-east Atlantic stock over the period 1992-2013, to estimate the rate of shift; (ii a thermal habitat model to assess if spawning mackerel have tracked their thermal spawning-niche; and (iii a niche-based model to project future spawning distribution under two predicted climate change scenarios. Our findings showed that mackerel spawning activity has shifted northward at a rate of 15.9 ± 0.9 km/decade between 1992 and 2013. Similarly, using the thermal habitat model, we detected a northward shift of the thermal spawning-niche. This indicates that mackerel has spawned at higher latitudes to partially tracking their thermal spawning-niche, at a rate of 28.0 ± 9.0 km/°C of sea warming. Under future scenarios (mid and end of the century, the extrapolation of the niche-based model to coupled hydroclimatic and biogeochemical models indicates that centre of gravity of mackerel spawning distribution is expected to shift westward (32 to 117 km and northward (0.5 to 328 km, but with high variability according to scenarios and time frames. The future of the overall egg production in the area is uncertain (change from -9.3% to 12%. With the aim to allow the fishing industry to anticipate the future distribution of mackerel shoals during the spawning period, future research should focus on reducing uncertainty in

Hydrographic features of anguillid spawning areas: Potential signposts for migrating eels

DEFF Research Database (Denmark)

Schabetsberger, Robert; Miller, Michael J.; Dall'Olmo, Giorgio

2016-01-01

Catadromous anguillid eels (genus Anguilla) migrate from their freshwater or estuarine habitats to marine spawning areas. Evidence from satellite tagging studies indicates that tropical and temperate eel species exhibit pronounced diel vertical migrations, from between 150-300 m nighttime depths...... to 600-800 m during the day. Collections of eggs and larvae of Japanese eels A. japonica suggest they may spawn at these upper nighttime migration depths. How anguillid eels navigate through the ocean and find their spawning areas remains unknown; thus, this study describes the salinity, temperature...

The use of artificial spawning substrates in order to understand the factors influencing the spawning site selection, depth of egg strands deposition and hatching time of perch (Perca fluviatilis L.

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Jan Kubečka

2012-01-01

Full Text Available The distribution of egg strands of perch Perca fluviatilis and factors affecting this distribution, in terms of spawning sites and spawning depths used, was studied in spring 2010 in Chabařovice Lake, Czech Republic, using areas with an artificial spawning substrate (A.S.S. and control areas outside the A.S.S. Perch significantly preferred a calm shore instead of a windward shore for spawning. The depths at which perch egg strands were found increased significantly during the spawning period in both A.S.S. areas and in areas outside the A.S.S. (on average from 4.9 m at the beginning to 12.3 m at the end of the spawning period. With increasing depth of deposition the size of the egg strands decreased significantly. The mean depth of egg strands on individual dates corresponded to the position of 10-12°C water layers. From the third week onward, however, egg strands were deposited in much deeper and colder water. A strong relationship was found between the depth at which egg strands were deposited and the duration of the daylight period, indicating that, at the end of the spawning season, perch do not react to the actual temperature of the water column but that they follow their inner clock, assuming that "normally" the shallower depth layers are too warm for successful embryo development. Factors influencing the depth distribution of egg strands were identified as waves, temperature and duration of the daylight period. Factors influencing the selection of spawning sites were identified as wind inducing current, internal seiches and temperature instability of the water column. The first perch larvae were present in the open water of Chabařovice Lake before mid-May, and the latest larvae not earlier than the beginning of July, since warming of the water in deeper layers was very slow. It appears that with prolonged spawning and hatching periods and with spawning occurring at various depths and temperatures, perch have evolved a powerful

Bedform morphology of salmon spawning areas in a large gravel-bed river

Energy Technology Data Exchange (ETDEWEB)

Hanrahan, Timothy P.

2007-05-01

While the importance of river channel morphology to salmon spawning habitat is increasingly recognized, quantitative measures of the relationships between channel morphology and habitat use are lacking. Such quantitative measures are necessary as management and regulatory agencies within the Pacific Northwestern region of the USA, and elsewhere, seek to quantify potential spawning habitat and develop recovery goals for declining salmon populations. The objective of this study was to determine if fall Chinook salmon (Oncorhynchus tshawytscha) spawning areas in the Snake River, Idaho, USA, were correlated with specific bed form types at the pool-riffle scale. A bed form differencing technique was used to objectively quantify the longitudinal riverbed profile into four distinct pool-riffle units that were independent of discharge. The vertical location of thalweg points within these units was quantified with a riffle proximity index. Chinook salmon spawning areas were mapped and correlated with the pool-riffle units through the use of cross-tabulation tables. The results indicate that 84% of fall Chinook salmon spawning areas were correlated with riffles (Chi-square=152.1, df=3, p<0.001), with 53% of those areas located on the upstream side of riffle crests. The majority of Snake River fall Chinook salmon spawning occurred at a vertical location within 80% of the nearest riffle crest elevation. The analyses of bed form morphology will assist regional fish mangers in quantifying existing and potential fall Chinook salmon spawning habitat, and will provide a quantitative framework for evaluating general ecological implications of channel morphology in large gravel-bed rivers.

A study on the effect of low doses gamma radiation on mushroom spawn

International Nuclear Information System (INIS)

Ajlouni, Said

1993-03-01

Mushroom spawn (Hybrid-521) was irradiated at room temperature using low doses of gamma radiation (50-600 rad). The spawn was then planted at two stages; first, after 24 hours of irradiation, and second after storage for three weeks at refrigeration temperature. Results of this study showed that the applied doses of gamma radiation did not have any stimulatory effect on mushroom growth or productivity. It was also noticed that mushroom production rate decreased when irradiated spawn was stored for three weeks prior to planting, as compared with spawn planted 24 hours after irradiation. (author). 18 refs., 2 figs., 2 tabs

Differences in detection of Aeromonas salmonicida in covertly infected salmonid fishes by the stress-inducible furunculosis test and culture-based assays

Science.gov (United States)

Cipriano, R.C.; Ford, L.A.; Smith, D.R.; Schachte, J.H.; Petrie, C.J.

1997-01-01

Accurate detection of Aeromonas salmonicida subsp. salmonicida (the cause of furunculosis disease) in covertly infected salmonids is difficult and is a cause of concern for those involved in fish health inspection and resource management programs. In this study, we examined populations of brook trout Salvelinus fontinalis, Atlantic salmon Salmo salar, and lake trout Salvelinus namaycush that previously sustained natural episodes of furunculosis. Consequently, the sampled fish were presumed to harbor latent infections. Mucus, gill, liver, kidney, heart, spleen, and intestine samples (N = 100 fish per group sampled) were processed and examined by (1) direct dilution counts and (2) quadrant streaking after a 48-h pre-enrichment in trypticase soy broth (TSB). Another subsample of fish from each group was then subjected to stress-inducible furunculosis tests. Stress tests detected A. salmonicida in three of four groups of fish that were examined whereas the pathogen was detected in only two of the groups analyzed with culture-based assays. Although pre-enrichment in TSB enhanced detection within internal sampling sites including the liver, heart, spleen, and kidney, enrichment did not enhance detection from mucus, gill, or intestinal samples.

Influence of Color of Polythene Container and three Spawn rates on ...

African Journals Online (AJOL)

a

2012-04-16

Apr 16, 2012 ... and based on completely randomized design (CRD) with three replications. Factors were different colour of polythene container (blue, yellow, transparent and green) and various levels of spawn (2.5, 4 and 5% wet weight substrate bases). There was significant difference in the yields from different spawn.

Repeat surveys of spawning cisco (Coregonus artedi) in western Lake Superior: timing, distribution and composition of spawning stocks

Science.gov (United States)

Yule, Daniel L.; Schreiner, Donald R.; Addison, Peter A.; Seider, Michael J.; Evrard, Lori M.; Geving, Steven A.; Quinlan, Henry R.

2012-01-01

Acoustic (AC) and midwater trawl (MT) surveys of spawning cisco (Coregonus artedi) in Lake Superior have been combined with commercial yield to estimate exploitation. To time surveys properly, it is important to understand when adults typically arrive at spawning grounds and how numbers change as the spawning season progresses. We conducted repeat autumn surveys during nighttime hours at coastal sites where commercial roe fisheries occur. Spawner densities increased significantly from October to mid-November, but differences measured at sites sampled from mid- to late-November were comparatively small. Spawners occupied the upper 20–30 m of the water column during mid-November before utilizing a wider range of depths by late-November. We compared repeat AC densities to temporal trends of catch-per-unit-effort (CPUE) in suspended commercial gillnets and found good agreement within sites. Because different gillnet mesh sizes were used in each roe fishery. CPUE and AC density were poorly correlated among sites. We recommend that future surveys be conducted between mid- and late-November, and that MT gear be used to measure cisco densities in the uppermost 10 m of the water column where AC estimates may be conservative. Given the short temporal window for assessing spawner density, we believe both AC-MT and gillnet surveys will be needed to ensure that harvest of different stocks is kept at a sustainable level.

Hormonal changes over the spawning cycle in the female three-spined stickleback, Gasterosteus aculeatus.

Science.gov (United States)

Roufidou, Chrysoula; Schmitz, Monika; Mayer, Ian; Sebire, Marion; Katsiadaki, Ioanna; Shao, Yi Ta; Borg, Bertil

2018-02-01

Female three-spined sticklebacks are batch spawners laying eggs in a nest built by the male. We sampled female sticklebacks at different time points, when they were ready to spawn and 6, 24, 48 and 72h post-spawning (hps) with a male. Following spawning, almost all females (15 out of 19) had ovulated eggs again at Day 3 post-spawning (72hps). At sampling, plasma, brain and pituitaries were collected, and the ovary and liver were weighed. Testosterone (T) and estradiol (E2) were measured by radioimmunoassay. Moreover, the mRNA levels of follicle-stimulating hormone (fsh-β) and luteinizing hormone (lh-β) in the pituitary, and of the gonadotropin-releasing hormones (GnRHs: gnrh2, gnrh3) and kisspeptin (kiss2) and its G protein-coupled receptor (gpr54) in the brain were measured by real-time qPCR. Ovarian weights peaked in "ready to spawn" females, dropped after spawning, before again progressively increasing from 6 to 72hps. Plasma T levels showed peaks at 24 and 48hps and decreased at 72hps, while E2 levels increased already at 6hps and remained at high levels up to 48hps. There was a strong positive correlation between T and E2 levels over the spawning cycle. Pituitary lh-β mRNA levels showed a peak at 48hps, while fsh-β did not change. The neuropeptides and gpr54 did not show any changes. The changes in T and E2 over the stickleback spawning cycle were largely consistent with those found in other multiple-spawning fishes whereas the marked correlation between T and E2 does not support T having other major roles over the cycle than being a precursor for E2. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Pair replacement on the spawning success of broodstock Seahorse (Hippocampus barbouri

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. Syafiuddin

2011-01-01

Full Text Available Seahorse, (Hippocampus barbouri is one of marine living resources having high commercial values and has commonly been traded especially as live ornamental aquarium fish, raw material of traditional medicine and as souvenirs. This expriment was conducted to determine the succces of spawning rate by replacing the broodstock pair of seahorse. This study was done experimentally with treatment of replacement of broodstock pair after spawning under control condition. The experiment was designed to apply completely randomize design by using the following treatments: Treatment A, without replacement neither male nor female. Treatment B, spawned female broodstock  was being mated with her unpaired male broodstock.  Treatment C, a male broodstock that still brood was being mated with his unpaired female broodstock.  Treatment D, a spawned male broodstock that has released larva was being mated with his unpaired female broodstock.  Results showed that under control condition the replacement of broodstock pairs of seahorse had significantly influenced the spawning interval, number of eggs released and number of juveniles produced (P0,05.  It can be concluded that seahorse is not monogamous, either male or female after being spawned may accept other pair for the next spawning. Key words: pair replacement, broodstock, success spawning, Hippocampus barbouri   ABSTRAK Kuda laut, (Hippocampus barbouri merupakan salah satu sumberdaya hayati laut yang memiliki nilai komersial dan telah banyak diperdagangkan terutama sebagai ikan hias, bahan baku obat tradisional dan juga sebagai suvenir. Penelitian ini dilakukan dengan tujuan untuk mengkaji tingkat keberhasilan pemijahan dengan penggantian pasangan induk kuda laut pada wadah budidaya. Percobaan ini dilakukan secara ekperimental dengan perlakuan penggantian pasangan induk setelah pemijahan dalam wadah budidaya. Percobaan dirancang dengan menggunakan rancangan acak lengkap (RAL dengan perlakuan sebagai berikut

Lake sturgeon response to a spawning reef constructed in the Detroit river

Science.gov (United States)

Roseman, Edward F.; Manny, B.; Boase, J.; Child, M.; Kennedy, G.; Craig, J.; Soper, K.; Drouin, R.

2011-01-01

Prior to the First World War, the bi-national Detroit River provided vast areas of functional fish spawning and nursery habitat. However, ongoing conflicting human uses of these waters for activities such as waste disposal, water withdrawals, shoreline development, shipping, recreation, and fishing have altered many of the chemical, physical, and biological processes of the Detroit River. Of particular interest and concern to resource managers and stakeholders is the significant loss and impairment of fish spawning and nursery habitat that led to the decline in abundance of most fish species using this ecosystem. Lake sturgeon (Acipenser fulvescens) populations for example, were nearly extirpated by the middle of the 20th century, leaving only a small fraction of their former population. Fisheries managers recognized that the loss of suitable fish spawning habitat is a limiting factor in lake sturgeon population rehabilitation in the Detroit River. In efforts to remediate this beneficial water use impairment, a reef consisting of a mixture of natural rock and limestone was constructed at the upstream end of Fighting Island in 2008. This paper focuses on the response by lake sturgeon to the different replicates of suitable natural materials used to construct the fish spawning habitat at Fighting Island in the Detroit River. Pre-construction fisheries assessment during 2006–2008 showed that along with the presence of adult lake sturgeon, spawning conditions were favorable. However, no eggs were found in assessments conducted prior to reef construction. The 3300 m2 Fighting Island reef was placed at the upstream end of the island in October of 2008. The construction design included 12 spawning beds of three replicates each consisting of either round rock, small or large (shot-rock) diameter limestone or a mixture thereof. An observed response by spawning lake sturgeon occurred the following year when spawning-ready adults (ripe), viable eggs, and larvae were

Spawning strategies and transport of early stages of the two Cape ...

African Journals Online (AJOL)

Seasonal and short-term variability of environmental parameters influence the spawning strategies of fish species. In this study, the spawning strategies and the transport of early stages of the two Cape hake species off South Africa were investigated. Distribution of eggs and larvae of Merluccius paradoxus and M. capensis ...

Creation of artificial spawning grounds downstream of the Riviere-des-Prairies Spillway

International Nuclear Information System (INIS)

Verdon, R.

1991-01-01

The creation of artificial spawning grounds is often considered a valuable means of mitigating impact on fish populations. In 1985, following reconstruction of the Riviere-des-Prairies spillway, granular material from the access road was used to create a new spawning area for resident fish. This 0.5 hectare spawning bed was used over the following years by walleye, sauger, longnose and white suckers, and lake sturgeon for reproduction. It was also used as a fry habitat by sturgeon and sucker. Since the reproductive success of the fish depends largely on stable flow conditions, the quality of the habitat is strongly related to the spillway flow regime. Operating procedures compatible with power generation can optimize the spawning success of desirable fish species. Details are presented of site design, construction, fish monitoring, and spillway operation. 4 refs., 7 figs., 1 tab

Spawning Habitat Studies of Hanford Reach Fall Chinook Salmon (Oncorhynchus tshawytscha), Final Report.

Energy Technology Data Exchange (ETDEWEB)

Geist, David R.; Arntzen, Evan V.; Chien, Yi-Ju (Pacific Northwest National Laboratory)

2009-03-02

The Pacific Northwest National Laboratory conducted this study for the Bonneville Power Administration (BPA) with funding provided through the Northwest Power and Conservation Council(a) and the BPA Fish and Wildlife Program. The study was conducted in the Hanford Reach of the Columbia River. The goal of study was to determine the physical habitat factors necessary to define the redd capacity of fall Chinook salmon that spawn in large mainstem rivers like the Hanford Reach and Snake River. The study was originally commissioned in FY 1994 and then recommissioned in FY 2000 through the Fish and Wildlife Program rolling review of the Columbia River Basin projects. The work described in this report covers the period from 1994 through 2004; however, the majority of the information comes from the last four years of the study (2000 through 2004). Results from the work conducted from 1994 to 2000 were covered in an earlier report. More than any other stock of Pacific salmon, fall Chinook salmon (Oncorhynchus tshawytscha) have suffered severe impacts from the hydroelectric development in the Columbia River Basin. Fall Chinook salmon rely heavily on mainstem habitats for all phases of their life cycle, and mainstem hydroelectric dams have inundated or blocked areas that were historically used for spawning and rearing. The natural flow pattern that existed in the historic period has been altered by the dams, which in turn have affected the physical and biological template upon which fall Chinook salmon depend upon for successful reproduction. Operation of the dams to produce power to meet short-term needs in electricity (termed power peaking) produces unnatural fluctuations in flow over a 24-hour cycle. These flow fluctuations alter the physical habitat and disrupt the cues that salmon use to select spawning sites, as well as strand fish in near-shore habitat that becomes dewatered. The quality of spawning gravels has been affected by dam construction, flood protection, and

Changes in the timing of spawning of Baltic cod : possible causes and implications for recruitment

DEFF Research Database (Denmark)

Wieland, Kai; Jarre, Astrid; Horbowa, K.

2000-01-01

caused progressively delayed spawning since the early 1990s. Late spawning involves several processes that are detrimental to the survival of the early lire stages. Recruitment in the mid-1990s was below what could be expected from spawning stock biomass and favourable hydrographic conditions...

Variation in the Mating Systems of Wrasses (Labridae at a Spawning Aggregation Site on Guam, Mariana Islands

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Terry J. Donaldson

2015-11-01

Full Text Available The wrasses (family Labridae exhibit a diverse number of mating strategies and behaviors. This diversity is expressed not only interspecifically but also intraspecifically. At Guam, Mariana Islands, over twenty species of wrasses spawn on a small, shallow coral reef known as Finger Reef that projects outward from the main reef into Apra Harbor. Preliminary observations indicated that the mating system utilized by some wrasses varied within species. To examine why this occurs, I utilized direct visual observations supplemented by underwater video and photography. I recorded the identity of the species courting, the number of individuals participating, the distribution of male mating territories, courtship and spawning behaviors, and courtship success. Field work utilized snorkeling for several hours a day variously within the lunar month during 2013-2015. I found that courtship and spawning occurs either in temporary resident spawning aggregations or within a protogynous haremic mating system. Within spawning aggregations, mating systems include a lek-like system with paired spawning, and group or promiscuous spawning. Haremic species followed the traditional single male-multiple female model. Both group-spawning and haremic species, however, also spawned in simple male-female pairs. Sneaking or streaking behavior during pelagic spawning events were observed in all mating systems. The results of these observations found that lek-like behavior and group spawning were dependent upon higher densities of males and females at the site. At lower densities, however, some species reverted to simple paired spawning while others used a haremic system rather than a lek-like system. This suggests that some species of wrasses practice a mixed strategy that is dependent upon fish density during the courtship period.

Identification of a female spawn-associated Kazal-type inhibitor from the tropical abalone Haliotis asinina.

Science.gov (United States)

Wang, Tianfang; Nuurai, Parinyaporn; McDougall, Carmel; York, Patrick S; Bose, Utpal; Degnan, Bernard M; Cummins, Scott F

2016-07-01

Abalone (Haliotis) undergoes a period of reproductive maturation, followed by the synchronous release of gametes, called broadcast spawning. Field and laboratory studies have shown that the tropical species Haliotis asinina undergoes a two-week spawning cycle, thus providing an excellent opportunity to investigate the presence of endogenous spawning-associated peptides. In female H. asinina, we have isolated a peptide (5145 Da) whose relative abundance in hemolymph increases substantially just prior to spawning and is still detected using reverse-phase high-performance liquid chromatography chromatograms up to 1-day post-spawn. We have isolated this peptide from female hemolymph as well as samples prepared from the gravid female gonad, and demonstrated through comparative sequence analysis that it contains features characteristic of Kazal-type proteinase inhibitors (KPIs). Has-KPI is expressed specifically within the gonad of adult females. A recombinant Has-KPI was generated using a yeast expression system. The recombinant Has-KPI does not induce premature spawning of female H. asinina when administered intramuscularly. However it displays homomeric aggregations and interaction with at least one mollusc-type neuropeptide (LRDFVamide), suggesting a role for it in regulating neuropeptide endocrine communication. This research provides new understanding of a peptide that can regulate reproductive processes in female abalone, which has the potential to lead to the development of greater control over abalone spawning. The findings also highlight the need to further explore abalone reproduction to clearly define a role for novel spawning-associated peptide in sexual maturation and spawning. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters.

Directory of Open Access Journals (Sweden)

Timothy B Grabowski

Full Text Available The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15-16 April 2009. We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON, as well as a remotely operated underwater vehicle (ROV. A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1-5 m into the water column from the bottom at an average vertical swimming speed of 0.20-0.25 m s(-1 and maintained an average spacing of 1.0-1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters

Science.gov (United States)

Grabowski, Timothy B.; Boswell, Kevin M.; McAdam, Bruce J.; Wells, R. J. David; Marteinsdóttir, Gudrún

2012-01-01

The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15–16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1–5 m into the water column from the bottom at an average vertical swimming speed of 0.20–0.25 m s−1 and maintained an average spacing of 1.0–1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

Outlier Loci Detect Intraspecific Biodiversity amongst Spring and Autumn Spawning Herring across Local Scales.

Directory of Open Access Journals (Sweden)

Dorte Bekkevold

Full Text Available Herring, Clupea harengus, is one of the ecologically and commercially most important species in European northern seas, where two distinct ecotypes have been described based on spawning time; spring and autumn. To date, it is unknown if these spring and autumn spawning herring constitute genetically distinct units. We assessed levels of genetic divergence between spring and autumn spawning herring in the Baltic Sea using two types of DNA markers, microsatellites and Single Nucleotide Polymorphisms, and compared the results with data for autumn spawning North Sea herring. Temporally replicated analyses reveal clear genetic differences between ecotypes and hence support reproductive isolation. Loci showing non-neutral behaviour, so-called outlier loci, show convergence between autumn spawning herring from demographically disjoint populations, potentially reflecting selective processes associated with autumn spawning ecotypes. The abundance and exploitation of the two ecotypes have varied strongly over space and time in the Baltic Sea, where autumn spawners have faced strong depression for decades. The results therefore have practical implications by highlighting the need for specific management of these co-occurring ecotypes to meet requirements for sustainable exploitation and ensure optimal livelihood for coastal communities.

Investigations of bull trout (Salvelinus confluentus), steelhead trout (Oncorhynchus mykiss), and spring chinook salmon (O. tshawytscha) interactions in Southeast Washington streams. Final report 1992

International Nuclear Information System (INIS)

Underwood, K.D.; Martin, S.W.; Schuck, M.L.; Scholz, A.T.

1995-01-01

The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed

Investigations of Bull Trout (Salvelinus Confluentus), Steelhead Trout (Oncorhynchus Mykiss), and Spring Chinook Salmon (O. Tshawytscha) Interactions in Southeast Washington Streams. Final Report 1992.

Energy Technology Data Exchange (ETDEWEB)

Underwood, Keith D.

1995-01-01

The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed.

Spawning distribution of fall chinook salmon in the Snake River : annual report 1998.; ANNUAL

International Nuclear Information System (INIS)

Garcia, Aaron P.

1999-01-01

In 1998 data was collected on the spawning distribution of the first adult fall chinook salmon to return from releases of yearling hatchery fish upriver of Lower Granite Dam. Yearling fish were released at three locations with the intent of distributing spawning throughout the existing habitat. The project was designed to use radio-telemetry to determine if the use of multiple release sites resulted in widespread spawning

Accumulation of Sr90-Y90 by the developing spawn and larvae of Coregonus lavaretus L

International Nuclear Information System (INIS)

Kulikov, N.V.; Ozhegov, L.N.

1976-01-01

The results are given of laboratory experiments aimed at studying accumulation of Sr-90 and its daughter product Y-90 in the spawn and larvae of whitefish, a representative of autumn spawning fish species. The results are of interest for predicting possible consequences of radioactive contamination of water bodies and introduction of limits for permissible concentration of radioactive substances in aqueous medium. The accumulation coefficient of Sr-90 in the spawn reaches its maximum after the first twenty four hours of the experiment. Subsequently throughout the incubation period the accumulation coefficient (AC) of radionuclide does not undergo any changes being about 3. Besides it has been established that the equilibrium distribution of Sr-90 in whitefish spawn and the surrounding solution occurs during the first two hours. Unlike Sr-90 the accumulation of Y-90 occurs during the whole incubation period and results in the AC value of 80 by the end of the spawn incubation. The experiments aimed at determining the strength of radionuclide fixation by whitefish spawn and larvae revealed that both radionuclides in the spawn are rather mobile. Strontium separates fully from it during the first twenty four hours and yttrium marked by higher fixation strength transfers completely from the spawn into surrounding aqueous medium by the end of the experiment. In larvae the radionuclides are fixed stroger than in the spawn. The approximate radiation doses of embryos by the time of their hatching have been estimated. The estimates indicate that the total radiation dose of the spawn developing in aqueous solution of Sr-90 - Y-90 with 1.1 curie/0 -5 concentration is about 500 radl

Froude Number is the Single Most Important Hydraulic Parameter for Salmonid Spawning Habitat.

Science.gov (United States)

Gillies, E.; Moir, H. J.

2015-12-01

Many gravel-bed rivers exhibit historic straightening or embanking, reducing river complexity and the available habitat for key species such as salmon. A defensible method for predicting salmonid spawning habitat is an important tool for anyone engaged in assessing a river restoration. Most empirical methods to predict spawning habitat use lookup tables of depth, velocity and substrate. However, natural site selection is different: salmon must pick a location where they can successfully build a redd, and where eggs have a sufficient survival rate. Also, using dimensional variables, such as depth and velocity, is problematic: spawning occurs in rivers of differing size, depth and velocity range. Non-dimensional variables have proven useful in other branches of fluid dynamics, and instream habitat is no different. Empirical river data has a high correlation between observed salmon redds and Froude number, without insight into why. Here we present a physics based model of spawning and bedform evolution, which shows that Froude number is indeed a rational choice for characterizing the bedform, substrate, and flow necessary for spawning. It is familiar for Froude to characterize surface waves, but Froude also characterizes longitudinal bedform in a mobile bed river. We postulate that these bedforms and their hydraulics perform two roles in salmonid spawning: allowing transport of clasts during redd building, and oxygenating eggs. We present an example of this Froude number and substrate based habitat characterization on a Scottish river for which we have detailed topography at several stages during river restoration and subsequent evolution of natural processes. We show changes to the channel Froude regime as a result of natural process and validate habitat predictions against redds observed during 2014 and 2015 spawning seasons, also relating this data to the Froude regime in other, nearby, rivers. We discuss the use of the Froude spectrum in providing an indicator of

Installaton of a fish migration channel for spawning at Itaipu

International Nuclear Information System (INIS)

Borghetti, J.R.; Perez Chena, D.; Nogueira, S.V.G.

1993-01-01

The objective of installing a fish migration channel for spawning at the Itaipu hydroelectric station on the Parana river between Brazil and Paraguay is to improve fish recovery downstream from the dam. Preliminary data from the first phase has proved the efficiency of an experimental project, with the entry and ascendancy of fish in a migration channel ladder. These data now provide the technical basis for implementation of the complementary spawning channel stage. (author)

Characterizing and predicting the distribution of Baltic Sea flounder (Platichthys flesus) during the spawning season

Science.gov (United States)

Orio, Alessandro; Bergström, Ulf; Casini, Michele; Erlandsson, Mårten; Eschbaum, Redik; Hüssy, Karin; Lehmann, Andreas; Ložys, Linas; Ustups, Didzis; Florin, Ann-Britt

2017-08-01

Identification of essential fish habitats (EFH), such as spawning habitats, is important for nature conservation, sustainable fisheries management and marine spatial planning. Two sympatric flounder (Platichthys flesus) ecotypes are present in the Baltic Sea, pelagic and demersal spawning flounder, both displaying ecological and physiological adaptations to the low-salinity environment of this young inland sea. In this study we have addressed three main research questions: 1) What environmental conditions characterize the spatial distribution and abundance of adult flounder during the spawning season? 2) What are the main factors defining the habitats of the two flounder ecotypes during the spawning season? 3) Where are the potential spawning areas of flounder? We modelled catch per unit of effort (CPUE) of flounder from gillnet surveys conducted over the southern and central Baltic Sea in the spring of 2014 and 2015 using generalized additive models. A general model included all the stations fished during the survey while two other models, one for the demersal and one for the pelagic spawning flounder, included only the stations where each flounder ecotype should dominate. The general model captured distinct ecotype-specific signals as it identified dual salinity and water depth responses. The model for the demersal spawning flounder revealed a negative relation with the abundance of round goby (Neogobius melanostomus) and a positive relation with Secchi depth and cod abundance. Vegetation and substrate did not play an important role in the choice of habitat for the demersal ecotype. The model for the pelagic spawning flounder showed a negative relation with temperature and bottom current and a positive relation with salinity. Spatial predictions of potential spawning areas of flounder showed a decrease in habitat availability for the pelagic spawning flounder over the last 20 years in the central part of the Baltic Sea, which may explain part of the observed

Draft Genome Sequence of a Picorna-Like Virus Associated with Gill Tissue in Clinically Normal Brook Trout, Salvelinus fontinalis

OpenAIRE

Iwanowicz, Luke R.; Iwanowicz, Deborah D.; Adams, Cynthia R.; Galbraith, Heather; Aunins, Aaron; Cornman, Robert S.

2017-01-01

ABSTRACT Here, we report a draft genome sequence of a picorna-like virus associated with brook trout, Salvelinus fontinalis, gill tissue. The draft genome comprises 8,681 nucleotides, excluding the poly(A) tract, and contains two open reading frames. It is most similar to picorna-like viruses that infect invertebrates.

Draft Genome Sequence of a Picorna-Like Virus Associated with Gill Tissue in Clinically Normal Brook Trout, Salvelinus fontinalis.

Science.gov (United States)

Iwanowicz, Luke R; Iwanowicz, Deborah D; Adams, Cynthia R; Galbraith, Heather; Aunins, Aaron; Cornman, Robert S

2017-10-12

Here, we report a draft genome sequence of a picorna-like virus associated with brook trout, Salvelinus fontinalis , gill tissue. The draft genome comprises 8,681 nucleotides, excluding the poly(A) tract, and contains two open reading frames. It is most similar to picorna-like viruses that infect invertebrates.

Egg deposition by lithophilic-spawning fishes in the Detroit and Saint Clair Rivers, 2005–14

Science.gov (United States)

Prichard, Carson G.; Craig, Jaquelyn M.; Roseman, Edward F.; Fischer, Jason L.; Manny, Bruce A.; Kennedy, Gregory W.

2017-03-14

A long-term, multiseason, fish egg sampling program conducted annually on the Detroit (2005–14) and Saint Clair (2010–14) Rivers was summarized to identify where productive fish spawning habitat currently exists. Egg mats were placed on the river bottom during the spring and fall at historic spawning areas and candidate fish spawning habitat restoration sites throughout both rivers. Widespread evidence was found of lithophilic spawning by numerous native fish species, including walleye (Sander vitreus), lake whitefish (Coregonus clupeaformis), lake sturgeon (Acipenser fulvescens), suckers (Catostomidae spp.), and trout-perch (Percopsis omiscomaycus). Walleye, lake whitefish, and suckers spp. spawned in nearly every region of each river in all years on both reef and nonreef substrates. Lake sturgeon eggs were collected almost exclusively over constructed reefs. Catch-per-unit effort of walleye, lake whitefish, and sucker eggs was much greater in the Detroit River than in the Saint Clair River, while Saint Clair River sites supported the greatest collections of lake sturgeon eggs. Collections during this study of lake sturgeon eggs on man-made spawning reefs suggest that artificial reefs may be an effective tool for restoring fish populations in the Detroit and Saint Clair Rivers; however, the quick response of lake sturgeon to spawn on newly constructed reefs and the fact that walleye, lake whitefish, and sucker eggs were often collected over substrate with little interstitial space to protect eggs from siltation and predators suggests that lack of suitable spawning habitat may continue to limit reproduction of lithophilic-spawning fish species in the Saint Clair-Detroit River System.

Spawning areas of Engraulis anchoita in the Southeastern Brazilian Bight during late-spring and early summer

Science.gov (United States)

del Favero, Jana M.; Katsuragawa, Mario; Zani-Teixeira, Maria de Lourdes; Turner, Jefferson T.

2017-04-01

Analysis of fish egg density and distribution is indispensable for the understanding of the adult stock variability, and is a powerful tool for fisheries management. Thus, the objective of the present study was to characterize the spatial-temporal spawning patterns of Engraulis anchoita in the Southeastern Brazilian Bight, in terms of geographic location and abiotic factors. We analyzed data of eggs sampled during ten years, from 1974 to 1993, to create maps of the mean and the standard deviation (sd) of the estimated probability of egg presence, through indicative kriging. Preferred, tolerated and avoided temperature, salinity, local depth and distance for spawning of E. anchoita were defined by the estimation of bootstrapped confidence intervals of the quotient values (Q). Despite not having identified any recurrent spawning sites, a few occasional and unfavorable spawning sites were identified, showing that the spawning habit of E. anchoita not only varied spatially, but also temporally. The largest occasional spawning site and with the highest probability of egg presence (0.6-0.7) was located around 27°S, close to Florianópolis (Santa Catarina state). On the other hand, a well-marked unfavorable spawning site was located off São Sebastião Island (São Paulo state), with the probability of egg presence between 0-0.1. Abiotic and biotic factors that could be related to the changes in the spawning areas of E. anchoita were discussed, with shelf width, mesoscale hydrodynamic features and biological interactions apparently playing important roles in defining spawning sites.

A Sperm Spawn-Inducing Pheromone in the Silver Lip Pearl Oyster (Pinctada maxima).

Science.gov (United States)

Taylor, A; Mills, D; Wang, T; Ntalamagka, N; Cummins, S F; Elizur, A

2018-04-28

Pheromones are considered to play an important role in broadcast spawning in aquatic animals, facilitating synchronous release of gametes. In oysters, the sperm has been implicated as a carrier for the spawn-inducing pheromone (SIP). In hatchery conditions, male pearl oysters (Pinctata maxima) can be stimulated to spawn through a variety of approaches (e.g. rapid temperature change), while females can only be induced to spawn through exposure to conspecific sperm, thus limiting development of targeted pairing, required for genetic research and management. The capacity for commercial production and improvement of genetic lines of pearl oysters could be greatly improved with access to a SIP. In this study, we prepared and sequenced crude and semi-purified P. maxima sperm extracts that were used in bioassays to localise the female SIP. We report that the P. maxima SIP is proteinaceous and extrinsically associated with the sperm membrane. Bioactivity from pooled RP-HPLC fractions, but not individual fractions, suggests that the SIP is multi-component. We conclude that crude sperm preparations, as described in this study, can be used as a sperm-free inducer of female P. maxima spawning, which enables for a more efficient approach to genetic breeding.

Life-history consequences of investment in free-spawned eggs and their accessory coats.

Science.gov (United States)

Podolsky, Robert D

2004-05-01

The optimal trade-off between offspring size and number can depend on details of the mode of reproduction or development. In marine organisms, broadcast spawning is widespread, and external coats are a common feature of spawned eggs. Egg jelly coats are thought to influence several aspects of fertilization and early development, including the size of the target for sperm, fertilization efficiency, egg suspension time, polyspermy, embryo survival, and fecundity. These costs and benefits of investment in jelly result in trade-offs that can influence optimal reproductive allocation and the evolution of egg size. I develop an optimization model that sequentially incorporates assumptions about the function of egg coats in fertilization. The model predicts large variation in coat size and limited variation in ovum size under a broad range of conditions. Heterogeneity among spawning events further limits the range of ovum sizes predicted to evolve under sperm limitation. In contrast, variation in larval mortality predicts a broad range of optimal ovum sizes that more closely reflects natural variation among broadcast-spawning invertebrates. By decoupling physical and energetic size, egg coats can enhance fertilization, maintain high fecundity, and buffer the evolution of ovum size from variation in spawning conditions.

Effects of hydropeaking on the spawning behaviour of Atlantic salmon Salmo salar and brown trout Salmo trutta.

Science.gov (United States)

Vollset, K W; Skoglund, H; Wiers, T; Barlaup, B T

2016-06-01

An in situ camera set-up was used to study the spawning activity of Atlantic salmon Salmo salar and brown trout Salmo trutta throughout two consecutive seasons in a spawning area affected by hydropower-related pulse flows due to hydropeaking. The purpose was to test whether the flow variation discouraged spawning in shallow areas or motivated spawning into areas with elevated risk of incubation mortality. There were more S. salar observed on the spawning ground during days with high discharge. The presence of S. salar in the spawning grounds was not affected by the hydropeaking cycles of the preceding night. Female S. salar were observed preparing nests within the first hour after water discharge had increased to levels suitable for spawning. In contrast, the number of S. trutta was not correlated with flow and nest preparation was also observed at a discharge corresponding to the lowest discharge levels during a hydropeaking cycle. Survival was generally high in nests excavated the following winter, with only 5·4% suffering mortality due to dewatering. The results suggest that S. salar may respond rapidly to variable-flow conditions and utilize short windows with suitable flows for spawning. Smaller S. trutta may utilize low-flow conditions to spawn in areas that are not habitable by larger S. salar during low flow. © 2016 The Fisheries Society of the British Isles.

Spawning of coral reef invertebrates and a second spawning season for scleractinian corals in the central Red Sea

KAUST Repository

Bouwmeester, Jessica; Gatins, Remy; Giles, Emily; Sinclair-Taylor, Tane; Berumen, Michael L.

2016-01-01

species, as well as a general lack of data for other invertebrates. Here, we document the detailed timing of spawning for 13 scleractinian coral species, one sea anemone, and six echinoderms from an inshore reef off the coast of Thuwal, Saudi Arabia

Investigations of bull trout (Salvelinus confluentus), steelhead trout (Oncorhynchus mykiss), and spring chinook salmon (O. tshawytscha) interactions in Southeast Washington streams. Final report 1992; FINAL

International Nuclear Information System (INIS)

Underwood, K.D.; Martin, S.W.; Schuck, M.L.; Scholz, A.T.

1995-01-01

The goal of this two year study was to determine if supplementation with hatchery reared steelhead trout (Oncorhynchus mykiss) and spring chinook salmon (O. tshawytscha) negatively impacted wild native bull trout (Salvelinus confluentus) through competitive interactions. Four streams with varying levels of fish supplementation activity were sampled in Southeast Washington. Tasks performed during this study were population density, relative abundance, microhabitat utilization, habitat availability, diet analysis, bull trout spawning ground surveys, radio telemetry of adult bull trout, and growth analysis. Results indicate that bull trout overlapped geographically with the supplemented species in each of the study streams suggesting competition among species was possible. Within a stream, bull trout and the supplemented species utilized dissimilar microhabitats and microhabitat utilization by each species was the same among streams suggesting that there was no shifts in microhabitat utilization among streams. The diet of bull trout and O. mykiss significantly overlapped in each of the study streams. The stream most intensely supplemented contained bull trout with the slowest growth and the non-supplemented stream contained bull trout with the fastest growth. Conversely, the stream most intensely supplemented contain steelhead with the fastest growth and the non-supplemented stream contained steelhead with the slowest growth. Growth indicated that bull trout may have been negatively impacted from supplementation, although other factors may have contributed. At current population levels, and current habitat quantity and quality, no impacts to bull trout as a result of supplementation with hatchery reared steelhead trout and spring chinook salmon were detected. Project limitations and future research recommendations are discussed

Spawning distribution of fall chinook salmon in the Snake River: Annual report 1999

International Nuclear Information System (INIS)

Garcia, Aaron P.

2000-01-01

This report is separated into 2 chapters. The chapters are (1) Progress toward determining the spawning distribution of supplemented fall chinook salmon in the Snake River in 1999; and (2) Fall chinook salmon spawning ground surveys in the Snake River, 1999

Do Norway pout (Trisopterus esmarkii) die from spawning stress?

DEFF Research Database (Denmark)

Nielsen, J. Rasmus; Lambert, G.; Bastardie, Francois

2012-01-01

out of the area, higher predation pressure on older individuals, or differences in survey catchability by NP age from before to after spawning and that it is higher in the main spawning areas than outside. We found that natural mortality (M) is significantly correlated with sexual maturity, sex...... to analyse the natural life-history traits of cohorts in the NP stock in the North Sea. Based on the ICES trawl survey abundance indices, cohort mortality is found to significantly increase with age. We argue that this cannot be explained by selectiveness in the fishery, potential size-specific migrations...

Factors influencing the spawning migration of female anadromous brown trout

DEFF Research Database (Denmark)

Svendsen, Jon Christian; Koed, Anders; Aarestrup, Kim

2004-01-01

Radio telemetry was employed to study movements of adult female anadromous brown trout Salmo trutta (sea trout) during upstream spawning migration and following spawning in a stream with tributaries. Sea trout were monitored by manual tracking and by automatic listening stations. The latter...... suggested that initiation of upstream migration was positively correlated with stream discharge. Individual sea trout performed repeated upstream migration 'initiations' (visits) to areas where they were detected by the automatic listening stations. The first and subsequent upstream migration 'initiations...

How Well Can We Predict Salmonid Spawning Habitat with LiDAR?

Science.gov (United States)

Pfeiffer, A.; Finnegan, N. J.; Hayes, S.

2013-12-01

Suitable salmonid spawning habitat is, to a great extent, determined by physical, landscape driven characteristics such as channel morphology and grain size. Identifying reaches with high-quality spawning habitat is essential to restoration efforts in areas where salmonid species are endangered or threatened. While both predictions of suitable habitat and observations of utilized habitat are common in the literature, they are rarely combined. Here we exploit a unique combination of high-resolution LiDAR data and seven years of 387 individually surveyed Coho and Steelhead redds in Scott Creek, a 77 km2 un-glaciated coastal California drainage in the Santa Cruz Mountains, to both make and test predictions of spawning habitat. Using a threshold channel assumption, we predict grain size throughout Scott Creek via a shear stress model that incorporates channel width, instead of height, using Manning's equation (Snyder et al., 2013). Slope and drainage area are computed from a LiDAR-derived DEM, and channel width is calculated via hydraulic modeling. Our results for median grain size predictions closely match median grain sizes (D50) measured in the field, with the majority of sites having predicted D50's within a factor of two of the observed values, especially for reaches with D50 > 0.02m. This success suggests that the threshold model used to predict grain size is appropriate for un-glaciated alluvial channel systems. However, it appears that grain size alone is not a strong predictor of salmon spawning. Reaches with a high (>0.1m) average predicted D50 do have lower redd densities, as expected based on spawning gravel sizes in the literature. However, reaches with lower (<0.1m) predicted D50 have a wide range of redd densities, suggesting that reach-average grain size alone cannot explain spawning site selection in the finer-grained reaches of Scott Creek. We turn to analysis of bedform morphology in order to explain the variation in redd density in the low

Spawning of migratory fish species between two reservoirs of the upper Uruguay River, Brazil

Directory of Open Access Journals (Sweden)

David A. Reynalte-Tataje

Full Text Available This study investigated the migratory fish spawning within the reservoirs of the Machadinho and Itá dams (upper Uruguay River, Brazil and its relationship to environmental variables. Sampling was conducted in the lotic region of the river in two sites between the dams' reservoirs: Uruguay (main river and Ligeiro (tributary. Sampling included nine consecutive reproductive periods (RP spanning the period from 2001 to 2010 and was conducted at night on the water surface using cylindrical-conical plankton nets (0.5 mm mesh; environmental variables were also recorded. The spawning of the migratory species Salminus brasiliensis, Prochilodus lineatus, and Steindachneridion scriptum was registered: S. brasiliensis and P. lineatus spawned in the tributary river at the end of spring/beginning of summer, during flooding and during periods of high water temperature. Steindachneridion scriptum spawned in the main river at the beginning of spring. The study showed that S. brasiliensis, P. lineatus, and S. scriptum are able to spawn in small lotic river stretches within two reservoirs, but only under very specific and not common environmental conditions.

Radiation efficacy on oyster mushroom spawn and shelf life of its sporophores

International Nuclear Information System (INIS)

Shrivastava, Mukta; Singh, Alpana; Khatri, R.K.

2007-01-01

Investigation was conducted to increase the productivity of spawn as well as to extend the shelf life and maintain the fruit quality characteristics of oyster mushrooms under the influence of gamma radiation processing at 0.20 to 0.80 kGy for spawn and 0.50 to 2.5 kGy for sporophores. Changes in mycelial run time, appearance of fruiting body, biological efficiency (B.E.) of spawn along with physiological weight loss (PWL) and marketability of sporophores were recorded. The highest B.E. (93.66%) was recorded from P. sajorcaju spawn irradiated at 0.20 kGy. PWL of irradiated sporophores was also decreased and maximum retention of marketable mushroom was observed under 2.0 kGy radiation dose. The irradiated sporophores retained the quality attributes required for its acceptability. The shelf life of these mushroom sporophores could be extended up to 8 days when packed in non-perforated polypropylene bags and stored at refrigeration temperature. A major boost in yields could also be achieved using this technology. (author)

Migration and spawning of radio-tagged zulega Prochilodus argenteus in a dammed Brazilian river

Science.gov (United States)

Godinho, Alexandre L.; Kynard, B.

2006-01-01

It is difficult for agencies to evaluate the impacts of the many planned dams on Sa??o Francisco River, Brazil, migratory fishes because fish migrations are poorly known. We conducted a study on zulega Prochilodus argenteus, an important commercial and recreational fish in the Sa??o Francisco River, to identify migrations and spawning areas and to determine linear home range. During two spawning seasons (2001-2003), we radio-tagged fish in three main-stem reaches downstream of Tre??s Marias Dam (TMD), located at river kilometer (rkm) 2,109. We tagged 10 fish at Tre??s Marias (TM), which is 5 km downstream of TMD; 12 fish at Pontal, which is 28 km downstream of TMD and which includes the mouth of the Abaete?? River, and 10 fish at Cilga, which is 45 km downstream of TMD. Late-stage (ripe) adults tagged in each area during the spawning season remained at or near the tagging site, except for four Cilga fish that went to Pontal and probably spawned. The Pontal area at the Abaete?? River mouth was the most important spawning site we found. Prespawning fish moved back and forth between main-stem staging areas upstream of the Abaete?? River mouth and Pontal for short visits. These multiple visits were probably needed as ripe fish waited for spawning cues from a flooding Abaete?? River. Some fish homed to prespaw ning staging areas, spawning areas, and nonspawning areas. The migratory style of zulega was dualistic, with resident and migratory fish. Total linear home range was also dualistic, with small (<26-km) and large (53-127-km) ranges. The locations of spawning areas and home ranges suggest that the Pontal group (which includes Cilga fish) is one population that occupies about 110 km. The Pontal population overlaps a short distance with a population located downstream of Cilga. Movements of late-stage TM adults suggest that the TM group is a separate population, possibly with connections to populations upstream of TMD. ?? Copyright by the American Fisheries Society

Noise can affect acoustic communication and subsequent spawning success in fish.

Science.gov (United States)

de Jong, Karen; Amorim, M Clara P; Fonseca, Paulo J; Fox, Clive J; Heubel, Katja U

2018-06-01

There are substantial concerns that increasing levels of anthropogenic noise in the oceans may impact aquatic animals. Noise can affect animals physically, physiologically and behaviourally, but one of the most obvious effects is interference with acoustic communication. Acoustic communication often plays a crucial role in reproductive interactions and over 800 species of fish have been found to communicate acoustically. There is very little data on whether noise affects reproduction in aquatic animals, and none in relation to acoustic communication. In this study we tested the effect of continuous noise on courtship behaviour in two closely-related marine fishes: the two-spotted goby (Gobiusculus flavescens) and the painted goby (Pomatoschistus pictus) in aquarium experiments. Both species use visual and acoustic signals during courtship. In the two-spotted goby we used a repeated-measures design testing the same individuals in the noise and the control treatment, in alternating order. For the painted goby we allowed females to spawn, precluding a repeated-measures design, but permitting a test of the effect of noise on female spawning decisions. Males of both species reduced acoustic courtship, but only painted gobies also showed less visual courtship in the noise treatment compared to the control. Female painted gobies were less likely to spawn in the noise treatment. Thus, our results provide experimental evidence for negative effects of noise on acoustic communication and spawning success. Spawning is a crucial component of reproduction. Therefore, even though laboratory results should not be extrapolated directly to field populations, our results suggest that reproductive success may be sensitive to noise pollution, potentially reducing fitness. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ecological Effects of Re-introduction of Salmonid Spawning Gravel in Lowland Danish Streams

DEFF Research Database (Denmark)

Pedersen, Morten Lauge; Kristensen, Esben Astrup; Kronvang, Brian

2009-01-01

recently been conducted in many streams and rivers. However, systematic monitoring of these spawning gravel restoration projects is limited. The overall aim of this paper was to evaluate gravel reintroduction as a long-term salmonid rehabilitation method in 32 lowland streams. Displacement of gravel......, including both restored reaches and upstream control reaches. Downstream displacement of gravel was most common at sites where gravel was reintroduced without further improvement, although these sites exhibited the highest density of YOY brown trout (Salmo trutta), evidencing that the remaining gravel...... is still functional. The intensive study of three streams showed that spawning was enhanced by the introduction of spawning gravel at the restored sites compared to control sites and that habitat quality generally were improved. Our results also suggest complex interactions exist between spawning activity...

Radio-transmitted electromyogram signals as indicators of swimming speed in lake trout and brown trout

DEFF Research Database (Denmark)

Thorstad, E.B.; Økland, F.; Koed, Anders

2000-01-01

Swimming speed and average electromyogram (EMG) pulse intervals were highly correlated in individual lake trout Salvelinus namaycush (r(2)=0.52-0.89) and brown trout Salmo trutta (r(2)=0.45-0.96). High correlations were found also for pooled data in both lake trout (r(2)=0.90) and brown trout...... of the Ema stock (r(2)=0.96) and Laerdal stock (r(2)=0.96). The linear relationship between swimming speed and average EMG pulse intervals differed significantly among lake trout and the brown trout stocks. This successful calibration of EMGs to swimming speed opens the possibility of recording swimming...... speed of free swimming lake trout and brown trout in situ. EMGs can also be calibrated to oxygen consumption to record energy expenditure. (C) 2000 The Fisheries Society of the British Isles...

Spatial Dynamics of the Blue Crab Spawning Stock in the Gulf of Mexico: Local Processes Driving Regional Patterns.

Science.gov (United States)

Darnell, M. Z.

2016-02-01

Female blue crabs undertake a critical spawning migration seaward, migrating from low-salinity mating habitat to high-salinity waters of the lower estuaries and coastal ocean, where larval survival is highest. This migration occurs primarily through ebb tide transport, driven by an endogenous circatidal rhythm in vertical swimming that is modulated by behavioral responses to environmental cues. Blue crabs are typically considered an estuarine species and fisheries are managed on a state-by-state basis. Yet recent evidence from state and regional fishery independent survey programs suggests that the spawning migration can take females substantial distances offshore (>150 km), and that offshore waters are important spawning grounds for female blue crabs in the Gulf of Mexico. This is especially true in areas where freshwater inflow is high, resulting in low estuarine and coastal salinities. In low-salinity, high-inflow areas (e.g., Louisiana), spawning occurs further offshore while in high-salinity, low-inflow areas (e.g., South Texas), spawning takes place primarily within the estuary. Regional patterns in spawning locations both inshore and offshore are driven by interactions between behavioral mechanisms and local oceanographic conditions during the spawning migration. These environmentally driven differences in spawning locations have implications for larval survival and population connectivity, and emphasize the need for interjurisdictional assessment and management of the blue crab spawning stock.

Redd site selection and spawning habitat use by fall chinook salmon: The importance of geomorphic features in large rivers

International Nuclear Information System (INIS)

Geist, D.R.; Oregon State Univ., Corvallis, OR; Dauble, D.D.

1998-01-01

Knowledge of the three-dimensional connectivity between rivers and groundwater within the hyporheic zone can be used to improve the definition of fall chinook salmon (Oncorhynchus tshawytscha) spawning habitat. Information exists on the microhabitat characteristics that define suitable salmon spawning habitat. However, traditional spawning habitat models that use these characteristics to predict available spawning habitat are restricted because they can not account for the heterogeneous nature of rivers. The authors present a conceptual spawning habitat model for fall chinook salmon that describes how geomorphic features of river channels create hydraulic processes, including hyporheic flows, that influence where salmon spawn in unconstrained reaches of large mainstem alluvial rivers. Two case studies based on empirical data from fall chinook salmon spawning areas in the Hanford Reach of the Columbia River are presented to illustrate important aspects of the conceptual model. The authors suggest that traditional habitat models and the conceptual model be combined to predict the limits of suitable fall chinook salmon spawning habitat. This approach can incorporate quantitative measures of river channel morphology, including general descriptors of geomorphic features at different spatial scales, in order to understand the processes influencing redd site selection and spawning habitat use. This information is needed in order to protect existing salmon spawning habitat in large rivers, as well as to recover habitat already lost

Habitat selection and spawning success of walleye in a tributary to Owasco Lake, New York

Science.gov (United States)

Chalupnicki, Marc A.; Johnson, James H.; McKenna, James E.; Dittman, Dawn E.

2010-01-01

Walleyes Sander vitreus are stocked into Owasco Lake, New York, to provide a sport fishery, but the population must be sustained by annual hatchery supplementation despite the presence of appropriate habitat. Therefore, we evaluated walleye spawning success in Dutch Hollow Brook, a tributary of Owasco Lake, to determine whether early survival limited recruitment. Spawning success during spring 2006 and 2007 was evaluated by estimating egg densities from samples collected in the lower 725 m of the stream. Environmental variables were also recorded to characterize the selected spawning habitat. Drift nets were set downstream of the spawning section to assess egg survival and larval drift. We estimated that 162,596 larvae hatched in 2006. For 2007, we estimated that 360,026 eggs were deposited, with a hatch of 127,500 larvae and hatching success of 35.4%. Egg density was significantly correlated to percent cover, substrate type, and depth : velocity ratio. Two sections had significantly higher egg deposition than other areas. Adult spawning walleyes selected shallow, slow habitats with some cover and gravel substrate in the accessible reaches of Dutch Hollow Brook. Our results show that walleyes found suitable spawning habitat in Dutch Hollow Brook and that egg and larval development does not appear to limit natural reproduction.

Coral-bacterial communities before and after a coral mass spawning event on Ningaloo Reef.

Directory of Open Access Journals (Sweden)

Janja Ceh

Full Text Available Bacteria associated with three coral species, Acropora tenuis, Pocillopora damicornis and Tubastrea faulkneri, were assessed before and after coral mass spawning on Ningaloo Reef in Western Australia. Two colonies of each species were sampled before and after the mass spawning event and two additional samples were collected for P. damicornis after planulation. A variable 470 bp region of the 16 S rRNA gene was selected for pyrosequencing to provide an understanding of potential variations in coral-associated bacterial diversity and community structure. Bacterial diversity increased for all coral species after spawning as assessed by Chao1 diversity indicators. Minimal changes in community structure were observed at the class level and data at the taxonomical level of genus incorporated into a PCA analysis indicated that despite bacterial diversity increasing after spawning, coral-associated community structure did not shift greatly with samples grouped according to species. However, interesting changes could be detected from the dataset; for example, α-Proteobacteria increased in relative abundance after coral spawning and particularly the Roseobacter clade was found to be prominent in all coral species, indicating that this group may be important in coral reproduction.

Confirmation of cisco spawning in Chaumont Bay, Lake Ontario using an egg pumping device

Science.gov (United States)

George, Ellen M.; Stott, Wendylee; Young, Brian; Karboski, Curtis T.; Crabtree, Darran L.; Roseman, Edward; Rudstam, Lars G.

2017-01-01

Cisco Coregonus artedi, a historically abundant and commercially important fish in the Great Lakes, have declined drastically in the last century due to the impacts of invasive species, overfishing, and habitat degradation. Chaumont Bay, New York is believed to contain one of the last remaining spawning populations of cisco in Lake Ontario although direct evidence of spawning has remained elusive. We document cisco spawning in Chaumont Bay for the first time in decades through the use of an egg pumping device specifically developed to sample through lake ice. Forty-one eggs were identified as cisco using genetic barcoding of the mitochondrial cytochrome c oxidase I (COI) gene. Cisco eggs were associated with shallow, rocky shoals. Contemporary knowledge of spawning behavior is an important step toward the successful restoration of cisco in Lake Ontario and across the Great Lakes.

Steelhead Spawning Surveys Near Locke Island, Hanford Reach of the Columbia River; TOPICAL

International Nuclear Information System (INIS)

DR Geist; RP Mueller

1999-01-01

In 1997, the National Marine Fisheries Service (NMFS) listed upper Columbia River steelhead trout (Oncorhynchus znykiss) as endangered. This action affected management of land-use activities along and within the Hanford Reach of the Columbia River, which flows through the U.S. Department of Energy (DOE) Hanford Site. Steelhead covered in this listing include all naturally spawned populations of steel-head and their progeny in streams in the Columbia River Basin upstream from the Yakima River to the United States/Canada border. The NMFS has identified a general listing of activities that could potentially result in harm to steelhead (62 FR 43937, August 18, 1997). One of these concerns includes land-use changes resulting in mass wasting or surface erosion. Landslide activity along the White Bluffs on the east ,side of Locke Island has redirected river flow into the island where substantial erosion has occurred. This erosion has exposed important anthropological and archaeological resources that were previously buried on the island. The DOE is working with affected tribes and other agencies to develop a plan for addressing the erosion of Locke Island. As part of this effort, the U.S. Army Corps of Engineers has prepared an assessment of potential alternatives to stabilize the erosion, including a no-action alternative. Steelhead historically spawned in the vicinity of Locke Island, but recent information on the occurrence of steelhead spawning or availability of spawning habitat was lacking. Therefore, the purpose of this study was to determine if steelhead spawned in the vicinity of Locke Island erosion and to evaluate the composition of substrate in the affected area. Surveys to document the occurrence of steelheads redds were conducted in Spring 1999. The surveys were conducted from the air as well as with the use of an underwater video camera. Neither aerial nor underwater surveys documented steelhead spawning within the survey area. Habitat surveys were

Comparison of ovarian maturation and spawning after unilateral eyestalk ablation of wild-caught and pond-reared Penaeus monodon

Energy Technology Data Exchange (ETDEWEB)

Wen, W.; Yang, Q.; Ma, Z.; Jiang, S.; Qiu, L.; Huang, J.; Zhou, F.; Qin, J.G.

2015-07-01

The present study compares the efficiency of ovarian maturation and spawning success between wild-caught and pond-reared Penaeus monodon females after unilateral eyestalk ablation. The earliest spawning time after eyestalk ablation was 5.9 days in wild-caught females, which is significantly shorter than the spawning time in pond-reared females (10.5 days). Both wild-caught and pond-reared females repeatedly spawned after eyestalk ablation. On average, each wild-caught female spawned 2.94 times while each pond-reared female spawned only 1.09 times. The spawning induction rate, egg hatching rate, and the number of eggs per spawning were significantly greater in wild-caught females than in pond-reared females. However, the egg size was not significantly different between wild-caught and pond-reared females. Four shrimp sizes (60, 80, 100 and 120 (± 1.0) g) were tested in this study and body weight significantly affected ovarian induction in pond-reared females but not in wild-caught females. Within the same body-weight class, the egg number per spawn in wild-caught females was significantly greater than that in pond-reared females. The egg production per spawn of the pond-reared females in the 120-g size group was two times higher than that in the pond-reared females in the 80-g size group. In conclusion, the fecundity of wild-caught P. monodon females is significantly higher than that of pond-reared P. monodon females. In breeding pond-reared P. monodon, the recommended minimum body weight of females is over 80 g, and the desirable body weight is over 100 g. (Author)

Slaughter yield and fatty acid profiles of fillets of pike (Esox lucius L. caught before and after spawning

Directory of Open Access Journals (Sweden)

Zakęś Zdzisław

2015-12-01

Full Text Available The aim of the study was to determine the impact pike fishing season (before spawning in fall (group A and after spawning in spring (group B had on the slaughter yield and fillet fatty acid profile. The slaughter yield of fillets with skin and skinned fillets from the group B fish was significantly lower (by approximately 7.5% of body weight. The fatty acid profile of the fish meat from the groups examined differed significantly. The fillets of pike caught before spawning were dominated by unsaturated fatty acids (UFA, while those from fish caught after spawning had mainly saturated fatty acids (SFA. The share of polyunsaturated fatty acids (PUFA in the fillets of fish that had spawned was sixfold lower, and the n-3 PUFA differences were nearly ninefold. The content of eicosapentaenoic (EPA and docosahexaenoic (DHA fatty acids in fillets of fish that had spawned was ninefold lower than in those that had not yet done so. Consequently, the ratio of n-3 PUFA/n-6 PUFA in pike from group A was over three times higher than that in the fish that had spawned (2.61 vs 0.82. Fillets from pike that have spawned are a significantly poorer source of valuable fatty acids for consumers.

Quantifying the influence of geography and environment on the northeast Atlantic mackerel spawning distribution

DEFF Research Database (Denmark)

Brunel, Thomas; van Damme, Cindy J. G.; Samson, Melvin

2018-01-01

on spatial egg density data collected every third year during targeted ichthyoplankton surveys. Mackerel spawning distribution was found to depend primarily on geographical variables (coordinates and bottom depth), with preferred spawning locations on the shelf-edge from the north of the Iberian peninsula...

Enhancing effect of spawning on elimination of a persistent polychlorinated biphenyl from female yellow perch

International Nuclear Information System (INIS)

Vodicnik, M.J.; Peterson, R.E.

1985-01-01

Distribution and elimination of 2,5,2',5'-tetrachloro[14C]biphenyl (4-CB) were studied for 6 months after exposing sexually mature female yellow perch to the compound in water and transferring them to flowing 4-CB-free water. Perch that were exposed in January spawned in May, and the study was terminated in June. During the first 41/2 months after exposure, the t1/2 for whole-body elimination was 22 weeks, primarily by elimination of 4-CB from the viscera and carcass. During spawning, enhanced elimination (t1/2 less than 0.7 weeks) was due to the voiding of eggs containing 4-CB. After spawning, whole-body elimination returned to a slower rate (t1/2 = 16.3 weeks). Prior to the enhancement in 4-CB elimination rate during spawning, there was a redistribution of 4-CB residues within the body of the perch which was characterized by a transfer of 4-CB residues from primarily the carcass and viscera to eggs. Two weeks after exposure, 30% of the initial 4-CB body burden was distributed to the eggs, whereas just prior to spawning, about 50% was present in this tissue. These findings demonstrate that egg maturation and spawning result in a significant reduction in the body burden of a persistent polychlorinated biphenyl in a lean-fish species

A spatial model to assess the effects of hydropower operations on Columbia River fall Chinook Salmon spawning habitat

Science.gov (United States)

Hatten, James R.; Tiffan, Kenneth F.; Anglin, Donald R.; Haeseker, Steven L.; Skalicky, Joseph J.; Schaller, Howard

2009-01-01

Priest Rapids Dam on the Columbia River produces large daily and hourly streamflow fluctuations throughout the Hanford Reach during the period when fall Chinook salmon Oncorhynchus tshawytscha are selecting spawning habitat, constructing redds, and actively engaged in spawning. Concern over the detrimental effects of these fluctuations prompted us to quantify the effects of variable flows on the amount and persistence of fall Chinook salmon spawning habitat in the Hanford Reach. Specifically, our goal was to develop a management tool capable of quantifying the effects of current and alternative hydrographs on predicted spawning habitat in a spatially explicit manner. Toward this goal, we modeled the water velocities and depths that fall Chinook salmon experienced during the 2004 spawning season, plus what they would probably have experienced under several alternative (i.e., synthetic) hydrographs, using both one- and two-dimensional hydrodynamic models. To estimate spawning habitat under existing or alternative hydrographs, we used cell-based modeling and logistic regression to construct and compare numerous spatial habitat models. We found that fall Chinook salmon were more likely to spawn at locations where velocities were persistently greater than 1 m/s and in areas where fluctuating water velocities were reduced. Simulations of alternative dam operations indicate that the quantity of spawning habitat is expected to increase as streamflow fluctuations are reduced during the spawning season. The spatial habitat models that we developed provide management agencies with a quantitative tool for predicting, in a spatially explicit manner, the effects of different flow regimes on fall Chinook salmon spawning habitat in the Hanford Reach. In addition to characterizing temporally varying habitat conditions, our research describes an analytical approach that could be applied in other highly variable aquatic systems.

Inhibitory mechanism of l-glutamic acid on spawning of the starfish Patiria (Asterina) pectinifera.

Science.gov (United States)

Mita, Masatoshi

2017-03-01

l-Glutamic acid was previously identified as an inhibitor of spawning in the starfish Patiria (Asterina) pectinifera; this study examined how l-glutamic acid works. Oocyte release from ovaries of P. pectinifera occurred after germinal vesicle breakdown (GVBD) and follicular envelope breakdown (FEBD) when gonads were incubated ex vivo with either relaxin-like gonad-stimulating peptide (RGP) or 1-methyladenine (1-MeAde). l-Glutamic acid blocked this spawning phenotype, causing the mature oocytes to remain within the ovaries. Neither RGP-induced 1-MeAde production in ovarian follicle cells nor 1-MeAde-induced GVBD and FEBD was affected by l-glutamic acid. l-Glutamic acid may act through metabotropic receptors in the ovaries to inhibit spawning, as l-(+)-2-amino-4-phosphonobutyric acid, an agonist for metabotropic glutamate receptors, also inhibited spawning induced by 1-MeAde. Application of acetylcholine (ACH) to ovaries under inhibitory conditions with l-glutamic acid, however, brought about spawning, possibly by inducing contraction of the ovarian wall to discharge mature oocytes from the ovaries concurrently with GVBD and FEBD. Thus, l-glutamic acid may inhibit ACH secretion from gonadal nerve cells in the ovary. Mol. Reprod. Dev. 84: 246-256, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Projecting the Effects of 21st Century Climate Change on the Distribution and Phenology of Reef Fish Spawning Aggregations

Science.gov (United States)

Asch, R. G.; Erisman, B.

2016-02-01

Spawning fishes often have a narrower window of thermal tolerance than other life history stages. As a result, spawning has been hypothesized to constrain how species will respond to climate change. We assess this hypothesis by combining a global database of fish spawning aggregations with earth system and ecological niche models to project shifts in the spawning distribution and phenology of reef fishes under the RCP 8.5 climate change scenario. Nassau grouper (Epinephelus striatus) was selected as the species for a proof-of-concept analysis since it is a top predator on Caribbean coral reefs and is listed by IUCN as endangered due to overfishing at its spawning grounds. The highest probability of encountering E. striatus aggregations occurred at sea surface temperatures (SSTs) of 24.5-26.5° C and seasonal SST gradients of 0 to -1° C. Based on a 1981-2000 climatology, our model projected that the highest probability of spawning would occur around Cuba, the Mesoamerican barrier reef, the Bahamas, and other areas of the Caribbean. This coincides with the observed distribution of E. striatus aggregations. By 2081-2100, a 50% decline is projected in the number of months and locations with adequate conditions for E. striatus spawning. Potential spawning habitat for E. striatus shifts northward and eastward, with slight increases in the probability of spawning around Aruba, Curacao, and Bonaire. At spawning sites, primary production is projected to increase by a mean of 14%. Higher planktonic production could benefit larval fish growth and survival by providing a greater availability of prey. The E. striatus spawning season is projected to contract and occur later in the year. Two-month delays in phenology are projected at 78% of the sites where E. striatus populations are managed through spawning season sales bans and time/area fishing closures. This implies that adaptive management in response to climate change will be needed for these measures to remain effective.

Identification of differentially expressed reproductive and metabolic proteins in the female abalone (Haliotis laevigata) gonad following artificial induction of spawning.

Science.gov (United States)

Mendoza-Porras, Omar; Botwright, Natasha A; Reverter, Antonio; Cook, Mathew T; Harris, James O; Wijffels, Gene; Colgrave, Michelle L

2017-12-01

Inefficient control of temperate abalone spawning prevents pair-wise breeding and production of abalone with highly marketable traits. Traditionally, abalone farmers have used a combination of UV irradiation and application of temperature gradients to the tank water to artificially induce spawning. Proteins are known to regulate crucial processes such as respiration, muscle contraction, feeding, growth and reproduction. Spawning as a pre-requisite of abalone reproduction is likely to be regulated, in part, by endogenous proteins. A first step in elucidating the mechanisms that regulate spawning is to identify which proteins are directly involved during spawning. The present study examined protein expression following traditional spawning induction in the Haliotis laevigata female. Gonads were collected from abalone in the following physiological states: (1) spawning; (2) post-spawning; and (3) failed-to-spawn. Differential protein abundance was initially assessed using two-dimensional difference in-gel electrophoresis coupled with mass spectrometry for protein identification. A number of reproductive proteins such as vitellogenin, vitelline envelope zona pellucida domain 29 and prohibitin, and metabolic proteins such as thioredoxin peroxidase, superoxide dismutase and heat shock proteins were identified. Differences in protein abundance levels between physiological states were further assessed using scheduled multiple reaction monitoring mass spectrometry. Positive associations were observed between the abundance of specific proteins, such as heat shock cognate 70 and peroxiredoxin 6, and the propensity or failure to spawn in abalone. These findings have contributed to better understand both the effects of oxidative and heat stress over abalone physiology and their influence on abalone spawning. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Characterising and comparing the spawning habitats of anchovy ...

African Journals Online (AJOL)

The spawning habitats of anchovy Engraulis encrasicolus and sardine Sardinops sagax in the southern Benguela upwelling ecosystem were characterised by comparing their egg abundances with environmental variables measured concomitantly during two different survey programmes: the South African Sardine and ...

Evaluation of Fall Chinook and Chum Salmon Spawning below Bonneville Dam; 2003-2004 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

van der Naald, Wayne; Duff, Cameron; Brooks, Robert (Oregon Department of Fish and Wildlife, Columbia River Section, John Day, OR)

2005-01-01

In 2003 a total of 253 adult fall chinook and 113 chum were sampled for biological data in the Ives and Pierce islands area below Bonneville Dam. Vital statistics were developed from 221 fall chinook and 109 chum samples. The peak redd count for fall chinook was 190. The peak redd count for chum was 262. Peak spawning time for fall chinook was set at approximately 24 November. Peak spawning time for chum occurred approximately 24 November. There were estimated to be a total of 1,533 fall chinook spawning below Bonneville Dam in 2003. The study area's 2003 chum population was estimated to be 688 spawning fish. Temperature unit data suggests that below Bonneville Dam 2003 brood bright stock, fall chinook emergence began on January 6, 2004 and ended 28 April 2004, with peak emergence occurring 13 April. 2003 brood juvenile chum emergence below Bonneville Dam began 22 February and continued through 15 April 2004. Peak chum emergence took place 25 March. A total of 25,433 juvenile chinook and 4,864 juvenile chum were sampled between the dates of 20 January and 28 June 2004 below Bonneville Dam. Juvenile chum migrated from the study area in the 40-55 mm fork length range. Migration of chum occurred during the months of March, April and May. Sampling results suggest fall chinook migration from rearing areas took place during the month of June 2004 when juvenile fall chinook were in the 65 to 80 mm fork length size range. Adult and juvenile sampling below Bonneville Dam provided information to assist in determining the stock of fall chinook and chum spawning and rearing below Bonneville Dam. Based on observed spawning times, adult age and sex composition, juvenile emergence timing, juvenile migration timing and juvenile size at the time of migration, it appears that in 2003 all of the fall chinook using the area below Bonneville Dam were of a late-spawning, bright stock. Observed spawning times, adult age and sex composition, GSI and DNA analysis, juvenile emergence

Time-resolved photoelectron spectroscopy and ab initio multiple spawning studies of hexamethylcyclopentadiene

DEFF Research Database (Denmark)

Wolf, T. J. A.; Kuhlman, Thomas Scheby; Schalk, O.

2014-01-01

Time-resolved photoelectron spectroscopy and ab initio multiple spawning were applied to the ultrafast non-adiabatic dynamics of hexamethylcyclopentadiene. The high level of agreement between experiment and theory associates wavepacket motion with a distinct degree of freedom.......Time-resolved photoelectron spectroscopy and ab initio multiple spawning were applied to the ultrafast non-adiabatic dynamics of hexamethylcyclopentadiene. The high level of agreement between experiment and theory associates wavepacket motion with a distinct degree of freedom....

Striped Bass Spawning in Non-Estuarine Portions of the Savannah River

Energy Technology Data Exchange (ETDEWEB)

Martin, D.; Paller, M.

2007-04-17

Historically, the estuarine portions of the Savannah River have been considered to be the only portion of the river in which significant amounts of striped bass (Morone saxatilis) spawning normally occur. A reexamination of data from 1983 through 1985 shows a region between River Kilometers 144 and 253 where significant numbers of striped bass eggs and larvae occur with estimated total egg production near that currently produced in the estuarine reaches. It appears possible that there are two separate spawning populations of striped bass in the Savannah River.

Prey resources before spawning influence gonadal investment of female, but not male, white crappie

Science.gov (United States)

Bunnell, D.B.; Thomas, S.E.; Stein, R.A.

2007-01-01

In this study, an outdoor pool experiment was used to evaluate the effect of prey resources during 4 months before spawning on the gonadal investments of male and female white crappie Pomoxis annularis, a popular freshwater sportfish that exhibits erratic recruitment. Fish were assigned one of three feeding treatments: starved, fed once every 5 days (intermediate) or fed daily (high). All measurements of male testes (i.e. wet mass, energy density and spermatocrit) were similar across treatments. Conversely, high-fed females produced larger ovaries than those of intermediate-fed and starved fish, and invested more energy in their ovaries than starved fish. Compared to pre-experiment fish, starved and intermediate-fed females appeared to increase their ovary size by relying on liver energy stores (‘capital’ spawning). Conversely, high-fed females increased liver and gonad mass, implying an ‘income’-spawning strategy (where gonads are built from recently acquired energy). Fecundity did not differ among treatments, but high-fed fish built larger eggs than those starved. Females rarely ‘skipped’ spawning opportunities when prey resources were low, as only 8% of starved females and 8% of intermediate-fed females lacked vitellogenic eggs. These results suggest that limited prey resources during the months before spawning can limit ovary production, which, in turn, can limit reproductive success of white crappies.

Genetic diversity of wild and hatchery lake trout populations: Relevance for management and restoration in the Great Lakes

Science.gov (United States)

Page, K.S.; Scribner, K.T.; Burnham-Curtis, M.

2004-01-01

The biological diversity of lake trout Salvelinus namaycush in the upper Great Lakes was historically high, consisting of many recognizable morphological types and discrete spawning populations. During the 1950s and 1960s, lake trout populations were extirpated from much of the Great Lakes primarily as a result of overfishing and predation by the parasitic sea lamprey Petromyzon marinus. Investigations of how genetic diversity is partitioned among remnant wild lake trout populations and hatchery broodstocks have been advocated to guide lake trout management and conservation planning. Using microsatellite genetic markers, we estimated measures of genetic diversity and the apportionment of genetic variance among 6 hatchery broodstocks and 10 wild populations representing three morphotypes (lean, humper, and siscowet). Analyses revealed that different hatchery broodstocks and wild populations contributed disproportionally to the total levels of genetic diversity. The genetic affinities of hatchery lake trout reflected the lake basins of origin of the wild source populations. The variance in allele frequency over all sampled extant wild populations was apportioned primarily on the basis of morphotype (??MT = 0.029) and secondarily among geographically dispersed populations within each morphotype (??ST = 0.024). The findings suggest that the genetic divergence reflected in recognized morphotypes and the associated ecological and physiological specialization occurred prior to the partitioning of large proglacial lakes into the Great Lakes or as a consequence of higher contemporary levels of gene flow within than among morphotypes. Information on the relative contributions of different broodstocks to total gene diversity within the regional hatchery program can be used to prioritize the broodstocks to be retained and to guide future stocking strategies. The findings highlight the importance of ecological and phenotypic diversity in Great Lakes fish communities and

Effectiveness of a refuge for Lake Trout in Western Lake Superior II: Simulation of future performance

Science.gov (United States)

Akins, Andrea L; Hansen, Michael J.; Seider, Michael J.

2015-01-01

Historically, Lake Superior supported one of the largest and most diverse Lake Trout Salvelinus namaycush fisheries in the Laurentian Great Lakes, but Lake Trout stocks collapsed due to excessive fishery exploitation and predation by Sea Lampreys Petromyzon marinus. Lake Trout stocking, Sea Lamprey control, and fishery regulations, including a refuge encompassing Gull Island Shoal (Apostle Islands region), were used to enable recovery of Lake Trout stocks that used this historically important spawning shoal. Our objective was to determine whether future sustainability of Lake Trout stocks will depend on the presence of the Gull Island Shoal Refuge. We constructed a stochastic age-structured simulation model to assess the effect of maintaining the refuge as a harvest management tool versus removing the refuge. In general, median abundances of age-4, age-4 and older (age-4+), and age-8+ fish collapsed at lower instantaneous fishing mortality rates (F) when the refuge was removed than when the refuge was maintained. With the refuge in place, the F that resulted in collapse depended on the rate of movement into and out of the refuge. Too many fish stayed in the refuge when movement was low (0–2%), and too many fish became vulnerable to fishing when movement was high (≥22%); thus, the refuge was more effective at intermediate rates of movement (10–11%). With the refuge in place, extinction did not occur at any simulated level of F, whereas refuge removal led to extinction at all combinations of commercial F and recreational F. Our results indicate that the Lake Trout population would be sustained by the refuge at all simulated F-values, whereas removal of the refuge would risk population collapse at much lower F (0.700–0.744). Therefore, the Gull Island Shoal Refuge is needed to sustain the Lake Trout population in eastern Wisconsin waters of Lake Superior.

Does small-bodied salmon spawning activity enhance streambed mobility?

Science.gov (United States)

Hassan, Marwan A.; Tonina, Daniele; Buxton, Todd H.

2015-09-01

Female salmonids bury and lay their eggs in streambeds by digging a pit, which is then covered with sediment from a second pit that is dug immediately upstream. The spawning process alters streambed topography, winnows fine sediment, and mixes sediment in the active layer. The resulting egg nests (redds) contain coarser and looser sediments than those of unspawned streambed areas, and display a dune-like shape with an amplitude and length that vary with fish size, substrate conditions, and flow conditions. Redds increase local bed surface roughness (drag, resulting in lower grain shear stress and less particle mobility. Spawning, also prevents streambed armoring by mixing surface and subsurface material, potentially increasing particle mobility. Here we use two-dimensional hydraulic modeling with detailed prespawning and postspawning bathymetries and field observations to test the effect of spawning by small-bodied salmonids on sediment transport. Our results show that topographical roughness from small salmon redds has negligible effects on shear stress at the reach-unit scale, and limited effects at the local scale. Conversely, results indicate sediment mixing reduces armoring and enhances sediment mobility, which increases potential bed load transport by subsequent floods. River restoration in fish-bearing streams should take into consideration the effects of redd excavation on channel stability. This is particularly important for streams that historically supported salmonids and are the focus of habitat restoration actions.

Use of existing hydrographic infrastructure to forecast the environmental spawning conditions for Eastern Baltic cod.

Science.gov (United States)

von Dewitz, Burkhard; Tamm, Susanne; Höflich, Katharina; Voss, Rüdiger; Hinrichsen, Hans-Harald

2018-01-01

The semi-enclosed nature and estuarine characteristics, together with its strongly alternating bathymetry, make the Baltic Sea prone to much stronger interannual variations in the abiotic environment, than other spawning habitats of Atlantic cod (Gadus morhua). Processes determining salinity and oxygen conditions in the basins are influenced both by long term gradual climate change, e.g. global warming, but also by short-term meteorological variations and events. Specifically one main factor influencing cod spawning conditions, the advection of highly saline and well-oxygenated water masses from the North Sea, is observed in irregular frequencies and causes strong interannual variations in stock productivity. This study investigates the possibility to use the available hydrographic process knowledge to predict the annual spawning conditions for Eastern Baltic cod in its most important spawning ground, the Bornholm Basin, only by salinity measurements from a specific location in the western Baltic. Such a prediction could serve as an environmental early warning indicator to inform stock assessment and management. Here we used a hydrodynamic model to hindcast hydrographic property fields for the last 40+ years. High and significant correlations were found for months early in the year between the 33m salinity level in the Arkona Basin and the oxygen-dependent cod spawning environment in the Bornholm Basin. Direct prediction of the Eastern Baltic cod egg survival in the Bornholm Basin based on salinity values in the Arkona Basin at the 33 m depth level is shown to be possible for eggs spawned by mid-age and young females, which currently predominate the stock structure. We recommend to routinely perform short-term predictions of the Eastern Baltic cod spawning environment, in order to generate environmental information highly relevant for stock dynamics. Our statistical approach offers the opportunity to make best use of permanently existing infrastructure in the

Detecting the movement and spawning activity of bigheaded carps with environmental DNA

Science.gov (United States)

Erickson, Richard A.; Rees, Christopher B.; Coulter, Alison A.; Merkes, Christopher; McCalla, S. Grace; Touzinsky, Katherine F; Walleser, Liza R.; Goforth, Reuben R.; Amberg, Jon J.

2016-01-01

Bigheaded carps are invasive fishes threatening to invade the Great Lakes basin and establish spawning populations, and have been monitored using environmental DNA (eDNA). Not only does eDNA hold potential for detecting the presence of species, but may also allow for quantitative comparisons like relative abundance of species across time or space. We examined the relationships among bigheaded carp movement, hydrography, spawning and eDNA on the Wabash River, IN, USA. We found positive relationships between eDNA and movement and eDNA and hydrography. We did not find a relationship between eDNA and spawning activity in the form of drifting eggs. Our first finding demonstrates how eDNA may be used to monitor species abundance, whereas our second finding illustrates the need for additional research into eDNA methodologies. Current applications of eDNA are widespread, but the relatively new technology requires further refinement.

A scientific basis for restoring fish spawning habitat in the St. Clair and Detroit Rivers of the Laurentian Great Lakes

Science.gov (United States)

Manny, Bruce A.; Roseman, Edward F.; Kennedy, Gregory W.; Boase, James C.; Craig, Jaquelyn; Bennion, David H.; Read, Jennifer; Vaccaro, Lynn; Chiotti, Justin A.; Drouin, Richard; Ellison, Roseanne

2015-01-01

Loss of functional habitat in riverine systems is a global fisheries issue. Few studies, however, describe the decision-making approach taken to abate loss of fish spawning habitat. Numerous habitat restoration efforts are underway and documentation of successful restoration techniques for spawning habitat of desirable fish species in large rivers connecting the Laurentian Great Lakes are reported here. In 2003, to compensate for the loss of fish spawning habitat in the St. Clair and Detroit Rivers that connect the Great Lakes Huron and Erie, an international partnership of state, federal, and academic scientists began restoring fish spawning habitat in both of these rivers. Using an adaptive management approach, we created 1,100 m2 of productive fish spawning habitat near Belle Isle in the Detroit River in 2004; 3,300 m2 of fish spawning habitat near Fighting Island in the Detroit River in 2008; and 4,000 m2 of fish spawning habitat in the Middle Channel of the St. Clair River in 2012. Here, we describe the adaptive-feedback management approach that we used to guide our decision making during all phases of spawning habitat restoration, including problem identification, team building, hypothesis development, strategy development, prioritization of physical and biological imperatives, project implementation, habitat construction, monitoring of fish use of the constructed spawning habitats, and communication of research results. Numerous scientific and economic lessons learned from 10 years of planning, building, and assessing fish use of these three fish spawning habitat restoration projects are summarized in this article.

Fish resource data from the Snare River, Northwest Territories

International Nuclear Information System (INIS)

Jessop, E.F.; Chang-Kue, K.T.J.; MacDonald, G.

1994-01-01

An extensive fish sampling and tagging program was conducted on the Snare River, Northwest Territories, in order to collect baseline data on the fish populations in sections of the river altered by hydroelectric projects. Fish populations were sampled from May to July 1977 in five sections of the river that were influenced by development of hydropower at three dams currently on line; 530 tagged fish were also released. The biweekly catch composition in experimental gill nets for each study area and the catch per gill net mesh size are presented for walleye (Stizostedion vitreum), lake trout (Salvelinus namaycush), lake whitefish (Coregonus clupeaformis), lake cisco (Coregonus artedi), northern pike (Esox lucius), white sucker (Catostomus commersoni), and longnose sucker (Catostomus catostomus). Age-specific data on length, weight, age, sex, and maturity are also included. 7 refs., 12 figs., 42 tabs

Maturation, fecundity, and intertidal spawning of Pacific sand lance in the northern Gulf of Alaska

Science.gov (United States)

Robards, Martin D.; Piatt, John F.; Rose, G.A.

1999-01-01

Pacific sand lance Ammodytes hexapterus in Kachemak Bay, Alaska, showed no sexual dimorphism in length-to-weight (gonad-free) ratio or length-at-age relationship. Most matured in their second year, males earlier in the season than females, but females (31%) attained a higher gonadosomatic index than males (21%). Sand lance spawned intertidally once each year in late September and October on fine gravel or sandy beaches soon after the seasonal peak in water temperatures. Sand lance in Cook Inlet and Prince William Sound displayed similar maturation schedules. Schools were dominated 2: 1 by males as they approached the intertidal zone at a site where spawning has taken place for decades. Sand lance spawned vigorously in dense formations, leaving scoured pits in beach sediments. Fecundity of females (93–199 mm) was proportional to length, ranging from 1468 to 16 081 ova per female. About half of the overall spawning school fecundity was derived from age group 1 females (55% of the school by number). Spawned eggs were 1·02 mm in diameter, demersal, slightly adhesive, and deposited in the intertidal just below the waterline. Sand lance embryos developed over 67 days through periods of intertidal exposure and sub-freezing air temperatures.

Spatial segregation within the spawning migration of North Eastern Atlantic mackerel (Scomber scombrus as indicated by juvenile growth patterns.

Directory of Open Access Journals (Sweden)

Teunis Jansen

Full Text Available A comparison of growth data (fish length with latitude shows that southern juvenile mackerel attain a greater length than those originating from further north before growth ceases during their first winter. A similar significant relationship was found between the growth in the first year (derived from the otolith inner winter ring and latitude for adult mackerel spawning between 44°N (Bay of Biscay and 54°N (west of Ireland. These observations are consistent with spatial segregation of the spawning migration; the further north that the fish were hatched, the further north they will tend to spawn. No such relationship was found in mackerel spawning at more northerly latitudes, possibly as a consequence of increased spatial mixing in a more energetic regime with stronger currents. This study provides previously lacking support for spawning segregation behaviour among North East Atlantic mackerel--an important step towards understanding the migratory behaviour of mackerel and hence the spatiotemporal distribution dynamics around spawning time.

Do native brown trout and non-native brook trout interact reproductively?

Science.gov (United States)

Cucherousset, J.; Aymes, J. C.; Poulet, N.; Santoul, F.; Céréghino, R.

2008-07-01

Reproductive interactions between native and non-native species of fish have received little attention compared to other types of interactions such as predation or competition for food and habitat. We studied the reproductive interactions between non-native brook trout ( Salvelinus fontinalis) and native brown trout ( Salmo trutta) in a Pyrenees Mountain stream (SW France). We found evidence of significant interspecific interactions owing to consistent spatial and temporal overlap in redd localizations and spawning periods. We observed mixed spawning groups composed of the two species, interspecific subordinate males, and presence of natural hybrids (tiger trout). These reproductive interactions could be detrimental to the reproduction success of both species. Our study shows that non-native species might have detrimental effects on native species via subtle hybridization behavior.

A gonad-expressed opsin mediates light-induced spawning in the jellyfish Clytia

Science.gov (United States)

Quiroga Artigas, Gonzalo; Lapébie, Pascal; Leclère, Lucas; Takeda, Noriyo; Deguchi, Ryusaku; Jékely, Gáspár

2018-01-01

Across the animal kingdom, environmental light cues are widely involved in regulating gamete release, but the molecular and cellular bases of the photoresponsive mechanisms are poorly understood. In hydrozoan jellyfish, spawning is triggered by dark-light or light-dark transitions acting on the gonad, and is mediated by oocyte maturation-inducing neuropeptide hormones (MIHs) released from the ectoderm. We determined in Clytia hemisphaerica that blue-cyan light triggers spawning in isolated gonads. A candidate opsin (Opsin9) was found co-expressed with MIH within specialised ectodermal cells. Opsin9 knockout jellyfish generated by CRISPR/Cas9 failed to undergo oocyte maturation and spawning, a phenotype reversible by synthetic MIH. Gamete maturation and release in Clytia is thus regulated by gonadal photosensory-neurosecretory cells that secrete MIH in response to light via Opsin9. Similar cells in ancestral eumetazoans may have allowed tissue-level photo-regulation of diverse behaviours, a feature elaborated in cnidarians in parallel with expansion of the opsin gene family. PMID:29303477

Quantifying the Behavioral Response of Spawning Chum Salmon to Elevated Discharges from Bonneville Dam, Columbia River : Annual Report 2005-2006.

Energy Technology Data Exchange (ETDEWEB)

Tiffan, Kenneth F.; Haskell, Craig A.; Kock, Tobias J.

2008-12-01

In unimpounded rivers, Pacific salmon (Oncorhynchus spp.) typically spawn under relatively stable stream flows, with exceptions occurring during periodic precipitation events. In contrast, hydroelectric development has often resulted in an artificial hydrograph characterized by rapid changes in discharge and tailwater elevation that occur on a daily, or even an hourly basis, due to power generation (Cushman 1985; Moog 1993). Consequently, populations of Pacific salmon that are known to spawn in main-stem habitats below hydroelectric dams face the risks of changing habitat suitability, potential redd dewatering, and uncertain spawning success (Hamilton and Buell 1976; Chapman et al. 1986; Dauble et al. 1999; Garland et al. 2003; Connor and Pflug 2004; McMichael et al. 2005). Although the direct effects of a variable hydrograph, such as redd dewatering are apparent, specific effects on spawning behavior remain largely unexplored. Chum salmon (O. keta) that spawn below Bonneville Dam on the Columbia River are particularly vulnerable to the effects of water level fluctuations. Although chum salmon generally spawn in smaller tributaries (Johnson et al. 1997), many fish spawn in main-stem habitats below Bonneville Dam near Ives Island (Tomaro et al. 2007; Figure 1). The primary spawning area near Ives Island is shallow and sensitive to changes in water level caused by hydroelectric power generation at Bonneville Dam. In the past, fluctuating water levels have dewatered redds and changed the amount of available spawning habitat (Garland et al. 2003). To minimize these effects, fishery managers attempt to maintain a stable tailwater elevation at Bonneville Dam of 3.5 m (above mean sea level) during spawning, which ensures adequate water is provided to the primary chum salmon spawning area below the mouth of Hamilton Creek (Figure 1). Given the uncertainty of winter precipitation and water supply, this strategy has been effective at restricting spawning to a specific

Morphometric Relationship, Growth, and Condition Factor of Flyingfish, Hirundicththys oxycephalus during spawning season

Science.gov (United States)

Tuapetel, Friesland; Nessa, Natsir; Alam Ali, Syamsu; Sudirman; Hutubessy, B. G.; Mosse, J. W.

2017-10-01

Flyingfish, Hirundichthys oxycephalus together with its congener species has become a major artisanal fishery resource from the Seram Sea, an area between Seram and Papua Island. However, biological information about this species has been poorly documented. Our current study focused on the growth and morphometric relationships of spawning cohorts during spawning season (June to October 2013). Flyingfish which were trapped in bale-bale, an egg aggregation device for flying fish, were collected offshore of the Southeastern Seram Sea. Total samples of 1693 with Fork Length (FL) ranged from 156.15mm to 245.52mm and total weight from 53.15gr to 115.45gr. Von Bertalanffy growth functions (L∞) for-pooled sexes were FL = 251mm [1-e (1.82 (t+0.060)], K=1.82 and t0 = 0.060. Morphometrically, significant differences were observed for all individuals between sexes (F=14.20, P=0.0002), sampling locations (F=88.48 Pfish generally declined in July-August. During spawning season, this fish tended to form single spawning cohort. The results of this study provide a significant understanding of the life history of this valuable fish inhabiting this particular region that rarely receives scientific investigation. For management purposes, harvesting eggs including broodstocks will lead to critical population depletion.

Larval growth and drift pattern and the separation of herring spawning groups in the North Sea

DEFF Research Database (Denmark)

Munk, Peter; Christensen, Villy

1990-01-01

Data from two internationally co-ordinated survey programmes are used in an attempt to display the events in the early life that took place during the 'recovery period' of the North Sea herring stock, 1979-1986. During the period, an increasing importance of the spawning grounds off Buchan and off...... Yorkshire is evident from distributions of newly hatched herring larvae. The dramatic changes in relative importance of spawning grounds are traced in the data on both late larvae (6 months old) and juveniles (18 months old). The onset of extended spawning off Buchan and off Yorkshire was followed...... in the relative contributions from spawning grounds apparently influence the overall spatial distribution as well as size composition of larval and juvenile North Sea herring. The findings indicate that groups of larvae retain, to a large extent, separate distributions until metamorphosis, and point to larval...

Chromosomal characteristics and distribution of rDNA sequences in the brook trout Salvelinus fontinalis (Mitchill, 1814).

Science.gov (United States)

Śliwińska-Jewsiewicka, A; Kuciński, M; Kirtiklis, L; Dobosz, S; Ocalewicz, K; Jankun, Malgorzata

2015-08-01

Brook trout Salvelinus fontinalis (Mitchill, 1814) chromosomes have been analyzed using conventional and molecular cytogenetic techniques enabling characteristics and chromosomal location of heterochromatin, nucleolus organizer regions (NORs), ribosomal RNA-encoding genes and telomeric DNA sequences. The C-banding and chromosome digestion with the restriction endonucleases demonstrated distribution and heterogeneity of the heterochromatin in the brook trout genome. DNA sequences of the ribosomal RNA genes, namely the nucleolus-forming 28S (major) and non-nucleolus-forming 5S (minor) rDNAs, were physically mapped using fluorescence in situ hybridization (FISH) and primed in situ labelling. The minor rDNA locus was located on the subtelo-acrocentric chromosome pair No. 9, whereas the major rDNA loci were dispersed on 14 chromosome pairs, showing a considerable inter-individual variation in the number and location. The major and minor rDNA loci were located at different chromosomes. Multichromosomal location (3-6 sites) of the NORs was demonstrated by silver nitrate (AgNO3) impregnation. All Ag-positive i.e. active NORs corresponded to the GC-rich blocks of heterochromatin. FISH with telomeric probe showed the presence of the interstitial telomeric site (ITS) adjacent to the NOR/28S rDNA site on the chromosome 11. This ITS was presumably remnant of the chromosome rearrangement(s) leading to the genomic redistribution of the rDNA sequences. Comparative analysis of the cytogenetic data among several related salmonid species confirmed huge variation in the number and the chromosomal location of rRNA gene clusters in the Salvelinus genome.

Induced spawning, survival and growth of an African catfish hybrid ...

African Journals Online (AJOL)

Induced spawning, survival and growth of an African catfish hybrid (female Clarias gariepinus and male Clarias anguillaris ) fingerlings relative to their parental species in the mount Cameroon region.

Fine-scale habitat preference of green sturgeon (Acipenser medirostris) within three spawning locations in the Sacramento River, California

Science.gov (United States)

Wyman, Megan T.; Thomas, Michael J.; McDonald, Richard R.; Hearn, Alexander R.; Battleson, Ryan D.; Chapman, Eric D.; Kinzel, Paul J.; Minear, J. Tobey; Mora, Ethan A.; Nelson, Jonathan M.; Pagel, Matthew D.; Klimley, A. Peter

2018-01-01

Vast sections of the Sacramento River have been listed as critical habitat by the National Marine Fisheries Service for green sturgeon spawning (Acipenser medirostris), yet spawning is known to occur at only a few specific locations. This study reveals the range of physical habitat variables selected by adult green sturgeon during their spawning period. We integrated fine-scale fish positions, physical habitat characteristics, discharge, bathymetry, and simulated velocity and depth using a 2-dimensional hydraulic model (FaSTMECH). The objective was to create habitat suitability curves for depth, velocity, and substrate type within three known spawning locations over two years. An overall cumulative habitat suitability score was calculated that averaged the depth, velocity, and substrate scores over all fish, sites, and years. A weighted usable area (WUA) index was calculated throughout the sampling periods for each of the three sites. Cumulative results indicate that the microhabitat characteristics most preferred by green sturgeon in these three spawning locations were velocities between 1.0-1.1 m/s, depths of 8-9 m, and gravel and sand substrate. This study provides guidance for those who may in the future want to increase spawning habitat for green sturgeon within the Sacramento River.

Marine spawning sites of perch Perca fluviatilis revealed by oviduct-inserted acoustic transmitters

DEFF Research Database (Denmark)

Skovrind, Mikkel; Christensen, Emil A.F.; Carl, Henrik

2013-01-01

In the 1970s, a flood-protection system dramatically changed a large part of the coastal environment of Køge Bugt, a bay in the western Baltic Sea, from open coast to a brackish lagoon habitat. An anadromous stock of European perch Perca fluviatilis seems to have benefitted from this change...... a strong proof of concept of oviduct-inserted acoustic transmitters in brackish and marine fish spawning studies. The transmitter expulsions were validated using an egg map, which was based on visual observations of perch egg-strands, and 11 of the 12 expulsed transmitters (92%) were located in areas...... with eggs. Many fish spawned in the brackish water with salinities up to 9.6 PSU. These salinities are higher than those previously observed for European perch spawning in the wild, and call for further investigations of salinity tolerance in perch eggs...

Outlier loci detect intraspecific biodiversity amongst spring and autumn spawning herring across local scales

DEFF Research Database (Denmark)

Bekkevold, Dorte; Gross, Riho; Arula, Timo

2016-01-01

Herring, Clupea harengus, is one of the ecologically and commercially most important species in European northern seas, where two distinct ecotypes have been described based on spawning time; spring and autumn. To date, it is unknown if these spring and autumn spawning herring constitute genetica...... of these co-occurring ecotypes to meet requirements for sustainable exploitation and ensure optimal livelihood for coastal communities....

Predator avoidance during reproduction: diel movements by spawning sockeye salmon between stream and lake habitats.

Science.gov (United States)

Bentley, Kale T; Schindler, Daniel E; Cline, Timothy J; Armstrong, Jonathan B; Macias, Daniel; Ciepiela, Lindsy R; Hilborn, Ray

2014-11-01

Daily movements of mobile organisms between habitats in response to changing trade-offs between predation risk and foraging gains are well established; however, less in known about whether similar tactics are used during reproduction, a time period when many organisms are particularly vulnerable to predators. We investigated the reproductive behaviour of adult sockeye salmon (Oncorhynchus nerka) and the activity of their principal predator, brown bears (Ursus arctos), on streams in south-western Alaska. Specifically, we continuously monitored movements of salmon between lake habitat, where salmon are invulnerable to bears, and three small streams, where salmon spawn and are highly vulnerable to bears. We conducted our study across 2 years that offered a distinct contrast in bear activity and predation rates. Diel movements by adult sockeye salmon between stream and lake habitat were observed in 51.3% ± 17.7% (mean ± SD) of individuals among years and sites. Fish that moved tended to hold in the lake for most of the day and then migrated into spawning streams during the night, coincident with when bear activity on streams tended to be lowest. Additionally, cyclic movements between lakes and spawning streams were concentrated earlier in the spawning season. Individuals that exhibited diel movements had longer average reproductive life spans than those who made only one directed movement into a stream. However, the relative effect was dependent on the timing of bear predation, which varied between years. When predation pressure primarily occurred early in the spawning run (i.e., during the height of the diel movements), movers lived 120-310% longer than non-movers. If predation pressure was concentrated later in the spawning run (i.e. when most movements had ceased), movers only lived 10-60% longer. Our results suggest a dynamic trade-off in reproductive strategies of sockeye salmon; adults must be in the stream to reproduce, but must also avoid predation long

Consumption of coral propagules after mass spawning enhances larval quality of damselfish through maternal effects.

Science.gov (United States)

McCormick, Mark I

2003-06-01

The synchronized spawning of corals in many parts of the Indo-Pacific represents a huge injection of biological material into the waters around reefs. Much of this material is consumed by fishes and filter-feeding invertebrates in the 5 or so days following spawning. The present study is the first to document the effect of the consumption of coral propagules on a population of facultatively planktivorous fish and the transference of physiological condition across generations. The study compares two populations of the damselfish Pomacentrus amboinensis that fed to differing degrees on coral propagules for 5 days after the annual mass spawning of corals at Lizard Island, Great Barrier Reef, Australia. Wind blew coral slicks over the outer lagoon to the inner lagoon some 1.5 km away. While coral propagules were abundant in the water column in the windward location, they were scarce by the time the water mass reached the inner lagoon. Behavioral observations 2-5 days after coral spawning showed that a significantly higher proportion of P. amboinensis was feeding on coral propagules in the windward location than in the inner lagoon location. Windward location females consumed coral propagules almost exclusively and had fuller guts than females from the inner lagoonal location. Five days after the mass coral spawning, windward location females had a higher condition factor and a larger liver mass relative to body mass compared to females within the inner lagoon or females from both locations 2 months later. Fish eggs laid by the windward location females soon after coral spawning yielded larvae that had 25% larger yolk sacs and 100% larger oil globules than did larvae produced from the females from the inner lagoon location, or larvae produced at either location prior to or well after coral spawning in 2 previous years. Larger yolk sacs and oil globules have been shown to have direct survival benefits in the transition from endogenous to exogenous feeding. A feeding

An extremely sensitive nested PCR-RFLP mitochondrial marker for detection and identification of salmonids in eDNA from water samples

Directory of Open Access Journals (Sweden)

Laura Clusa

2017-02-01

Full Text Available Background Salmonids are native from the North Hemisphere but have been introduced for aquaculture and sport fishing in the South Hemisphere and inhabit most rivers and lakes in temperate and cold regions worldwide. Five species are included in the Global Invasive Species Database: rainbow trout Oncorhynchus mykiss, Atlantic salmon Salmo salar, brown trout Salmo trutta, brook trout Salvelinus fontinalis, and lake trout Salvelinus namaycush. In contrast, other salmonids are endangered in their native settings. Methods Here we have developed a method to identify salmonid species directly from water samples, focusing on the Iberian Peninsula as a case study. We have designed nested Salmonidae-specific primers within the 16S rDNA region. From these primers and a PCR-RFLP procedure the target species can be unequivocally identified from DNA extracted from water samples. Results The method was validated in aquarium experiments and in the field with water from watersheds with known salmonid populations. Finally, the method was applied to obtain a global view of the Salmonidae community in Nalón River (north coast of Spain. Discussion This new powerful, very sensitive (identifying the species down to 10 pg DNA/ml water and economical tool can be applied for monitoring the presence of salmonids in a variety of situations, from checking upstream colonization after removal of river barriers to monitoring potential escapes from fish farms.

Benchmarking pre-spawning fitness, climate preferendum of some catfishes from river Ganga and its proposed utility in climate research.

Science.gov (United States)

Sarkar, Uttam Kumar; Naskar, Malay; Roy, Koushik; Sudeeshan, Deepa; Srivastava, Pankaj; Gupta, Sandipan; Bose, Arun Kumar; Verma, Vinod Kumar; Sarkar, Soma Das; Karnatak, Gunjan; Nandy, Saurav Kumar

2017-09-07

The concept of threshold condition factor (Fulton), beyond which more than 50% of the female fish population may attain readiness for spawning coined as pre-spawning fitness (K spawn50 ), has been proposed in the present article and has been estimated by applying the non-parametric Kaplan-Meier method for fitting survival function. A binary coding strategy of gonadal maturity stages was used to classify whether a female fish is "ready to spawn" or not. The proposed K spawn50 has been generated for female Mystus tengara (1.13-1.21 units), M. cavasius (0.846-0.945 units), and Eutropiichthys vacha (0.716-0.799 units). Information on the range of egg parameters (fecundity, egg weight, egg diameter) expected at the pre-spawning stage was also generated. Additional information on species-specific thermal and precipitation window (climate preferendum) within which K spawn50 is attained was also generated through the LOESS smoothing technique. Water temperatures between 31 and 36 °C (M. tengara), 30 and 32 °C (M. cavasius), and 29.5 and 31 °C (E. vacha) and monthly rainfall between 200 and 325 mm (M. tengara), > 250 mm (M. cavasius), and around 50 mm and between 350 and 850 mm (E. vacha) were found to be optimum for attainment of K spawn50 . The importance of parameterization and benchmarking of K spawn50 in addition to other conventional reproductive biology parameters has been discussed in the present article. The purposes of the present study were fulfilled by generating baseline information and similar information may be generated for other species replicating the innovative methodology used in this study.

Spatial and Temporal Distribution of Reef Fish Spawning ...

African Journals Online (AJOL)

The spatial patterns among fish families were attributed to a combination of differences in species abundance and distribution as well as variation in fishing effort. Spawning periodicity reported by fishers indicated that for snappers and rabbitfishes, the most activity occurred across a protracted period of October to April/May, ...

Implications of fisheries during the spawning season for the sustainable management and recovery of depleted fish stocks: a conceptual framework

NARCIS (Netherlands)

Rijnsdorp, A.D.

2009-01-01

Fishing during the spawning season may negatively affects the reproductive potential and reproductive dynamics of exploited fish stocks due to a variety of mechanisms such as the disturbance of the natural spawning behaviour, effects on the age, size and sex composition of the spawning population

Redd Site Selection and Spawning Habitat Use by Fall Chinook Salmon, Hanford Reach, Columbia River : Final Report 1995 - 1998.

Energy Technology Data Exchange (ETDEWEB)

Geist, David R.

1999-05-01

This report summarizes results of research activities conducted from 1995 through 1998 on identifying the spawning habitat requirements of fall chinook salmon (Oncorhynchus tshawytscha) in the Hanford Reach of the Columbia River. The project investigated whether traditional spawning habitat models could be improved in order to make better predictions of available habitat for fall chinook salmon in the Snake River. Results suggest models could be improved if they used spawning area-specific, rather than river-specific, spawning characteristics; incorporated hyporheic discharge measurements; and gave further consideration to the geomorphic features that are present in the unconstrained segments of large alluvial rivers. Ultimately the recovery of endangered fall chinook salmon will depend on how well we are able to recreate the characteristics once common in alluvial floodplains of large rivers. The results from this research can be used to better define the relationship between these physical habitat characteristics and fall chinook salmon spawning site selection, and provide more efficient use of limited recovery resources. This report is divided into four chapters which were presented in the author's doctoral dissertation which he completed through the Department of Fisheries and Wildlife at Oregon State University. Each of the chapters has been published in peer reviewed journals or is currently under review. Chapter one is a conceptual spawning habitat model that describes how geomorphic features of river channels create hydraulic processes, including hyporheic flows, that influence where salmon spawn in unconstrained reaches of large mainstem alluvial rivers. Chapter two describes the comparison of the physical factors associated with fall chinook salmon redd clusters located at two sites within the Reach. Spatial point pattern analysis of redds showed that redd clusters averaged approximately 10 hectares in area and their locations were consistent from

Efficiency of treatments for controlling Trichoderma spp during spawning in cultivation of lignicolous mushrooms.

Science.gov (United States)

Colavolpe, María Belén; Mejía, Santiago Jaramillo; Albertó, Edgardo

2014-01-01

Trichoderma spp is the cause of the green mold disease in mushroom cultivation production. Many disinfection treatments are commonly applied to lignocellulose substrates to prevent contamination. Mushroom growers are usually worried about the contaminations that may occur after these treatments during handling or spawning. The aim of this paper is to estimate the growth of the green mold Trichoderma sp on lignocellulose substrates after different disinfection treatments to know which of them is more effective to avoid contamination during spawning phase. Three different treatments were assayed: sterilization (121 °C), immersion in hot water (60 and 80 °C), and immersion in alkalinized water. Wheat straw, wheat seeds and Eucalyptus or Populus sawdust were used separately as substrates. After the disinfection treatments, bagged substrates were sprayed with 3 mL of suspension of conidia of Trichoderma sp (10(5) conidia/mL) and then separately spawned with Pleurotus ostreatus or Gymnopilus pampeanus. The growth of Trichoderma sp was evaluated based on a qualitative scale. Trichoderma sp could not grow on non-sterilized substrates. Immersions in hot water treatments and immersion in alkalinized water were also unfavorable treatments for its growth. Co- cultivation with mushrooms favored Trichoderma sp growth. Mushroom cultivation disinfection treatments of lignocellulose substrates influence on the growth of Trichoderma sp when contaminations occur during spawning phase. The immersion in hot water at 60 °C for 30 min or in alkalinized water for 36 h, are treatments which better reduced the contaminations with Trichoderma sp during spawning phase for the cultivation of lignicolous species.

Lunar Phase Modulates Circadian Gene Expression Cycles in the Broadcast Spawning Coral Acropora millepora.

Science.gov (United States)

Brady, Aisling K; Willis, Bette L; Harder, Lawrence D; Vize, Peter D

2016-04-01

Many broadcast spawning corals in multiple reef regions release their gametes with incredible temporal precision just once per year, using the lunar cycle to set the night of spawning. Moonlight, rather than tides or other lunar-regulated processes, is thought to be the proximate factor responsible for linking the night of spawning to the phase of the Moon. We compared patterns of gene expression among colonies of the broadcast spawning coral Acropora millepora at different phases of the lunar cycle, and when they were maintained under one of three experimentally simulated lunar lighting treatments: i) lunar lighting conditions matching those on the reef, or lunar patterns mimicking either ii) constant full Moon conditions, or iii) constant new Moon conditions. Normal lunar illumination was found to shift both the level and timing of clock gene transcription cycles between new and full moons, with the peak hour of expression for a number of genes occurring earlier in the evening under a new Moon when compared to a full Moon. When the normal lunar cycle is replaced with nighttime patterns equivalent to either a full Moon or a new Moon every evening, the normal monthlong changes in the level of expression are destroyed for most genes. In combination, these results indicate that daily changes in moonlight that occur over the lunar cycle are essential for maintaining normal lunar periodicity of clock gene transcription, and this may play a role in regulating spawn timing. These data also show that low levels of light pollution may have an impact on coral biological clocks. © 2016 Marine Biological Laboratory.

Estimating spawning times of Alligator Gar (Atractosteus spatula) in Lake Texoma, Oklahoma

Science.gov (United States)

Snow, Richard A.; Long, James M.

2015-01-01

In 2013, juvenile Alligator Gar were sampled in the reservoir-river interface of the Red River arm of Lake Texoma. The Red River, which flows 860 km along Oklahoma’s border with Texas, is the primary in-flow source of Lake Texoma, and is impounded by Denison Dam. Minifyke nets were deployed using an adaptive random cluster sampling design, which has been used to effectively sample rare species. Lapilli otoliths (one of the three pair of ear stones found within the inner ear of fish) were removed from juvenile Alligator Gar collected in July of 2013. Daily ages were estimated by counting the number of rings present, and spawn dates were back-calculated from date of capture and subtracting 8 days (3 days from spawn to hatch and 5 days from hatch to swimup when the first ring forms). Alligator Gar daily age estimation ranged from 50 to 63 days old since swim-up. Spawn dates corresponded to rising pool elevations of Lake Texoma and water pulses of tributaries.

Simulating Spawning and Juvenile Rainbow Trout (Oncorhynchus mykiss Habitat in Colorado River Based on High-Flow Effects

Directory of Open Access Journals (Sweden)

Weiwei Yao

2017-02-01

Full Text Available High flow generates significant alterations in downstream river reaches, resulting in physical condition changes in the downstream regions of the river such as water depth, flow velocity, water temperature and river bed. These alterations will lead to change in fish habitat configuration in the river. This paper proposes a model system to evaluate the high flow effects on river velocity, water depth, substrates changes, temperature distribution and consequently assess the change in spawning and juvenile rainbow trout (Oncorhynchus mykiss habitats in the downstream region of the Glen Canyon Dam. Firstly, based on the 2 dimensional (2D depth-averaged CFD (Computational Fluid Dynamics model and heat transfer equation applied for simulation, three indices were simulated, namely depth, flow velocity and temperature distribution. Then, the spawning and juvenile fish preference curves were obtained based on these three indices and substrates distribution. After that, the habitat model was proposed and used to simulate the high flow effects on juvenile and spawning rainbow trout habitat structure. Finally, the weighted usable area (WUA and overall suitability index (OSI of the spawning and juvenile fish species were quantitatively simulated to estimate the habitat sensitivity. The results illustrate that the high flow effect (HFE increased the juvenile rainbow trout habitat quality but decreased the spawning rainbow trout habitat quality. The juvenile trout were mainly affected by the water depth while the spawning rainbow trout were dominated by the bed elevation.

Spawning site fidelity and apparent annual survival of walleye (Sander vitreus) differ between a Lake Huron and Lake Erie tributary

Science.gov (United States)

Hayden, Todd A.; Binder, Thomas; Holbrook, Christopher; Vandergoot, Christopher; Fielder, David G.; Cooke, Steven J.; Dettmers, John M.; Krueger, Charles C.

2018-01-01

Fidelity to spawning habitats can maximise reproductive success of fish by synchronising movements to sites of previous recruitment. To determine the role of reproductive fidelity in structuring walleye Sander vitreus populations in the Laurentian Great Lakes, we used acoustic telemetry combined with Cormack–Jolly–Seber capture–recapture models to estimate spawning site fidelity and apparent annual survival for the Tittabawassee River in Lake Huron and Maumee River in Lake Erie. Walleye in spawning condition were tagged from the Tittabawassee River in Lake Huron and Maumee River in Lake Erie in 2011–2012. Site fidelity and apparent annual survival were estimated from return of individuals to the stream where tagged. Site fidelity estimates were higher in the Tittabawassee River (95%) than the Maumee River (70%) and were not related to sex or fish length at tagging. Apparent annual survival of walleye tagged in the Tittabawassee did not differ among spawning seasons but was higher for female than male walleye and decreased linearly as fish length increased. Apparent annual survival of walleye tagged in the Maumee River did not differ among spawning seasons but was higher for female walleye than male walleye and increased linearly as fish length increased. Greater fidelity of walleye tagged in the Tittabawassee River than walleye tagged in the Maumee River may be related to the close proximity to the Maumee River of other spawning aggregations and multiple spawning sites in Lake Erie. As spawning site fidelity increases, management actions to conserve population structure require an increasing focus on individual stocks.

Toxicity of fluoride to aquatic species and evaluation of toxicity modifying factors.

Science.gov (United States)

Pearcy, Krysta; Elphick, James; Burnett-Seidel, Charlene

2015-07-01

The present study was performed to investigate the toxicity of fluoride to a variety of freshwater aquatic organisms and to establish whether water quality variables contribute substantively to modifying its toxicity. Water hardness, chloride, and alkalinity were tested as possible toxicity modifying factors for fluoride using acute toxicity tests with Hyalella azteca and Oncorhynchus mykiss. Chloride appeared to be the major toxicity modifying factor for fluoride in these acute toxicity tests. The chronic toxicity of fluoride was evaluated with a variety of species, including 3 fish (Pimephales promelas, O. mykiss, and Salvelinus namaycush), 3 invertebrates (Ceriodaphnia dubia, H. azteca, and Chironomus dilutus), 1 plant (Lemna minor), and 1 alga (Pseudokirchneriella subcapitata). Hyalella azteca was the most sensitive species overall, and O. mykiss was the most sensitive species of fish. The role of chloride as a toxicity modifying factor was inconsistent between species in the chronic toxicity tests. © 2015 SETAC.

New records of Ergasilus (Copepoda: Ergasilidae) in the Laurentian Great Lakes, including a lakewide review of records and host associations

Science.gov (United States)

Hudson, Patrick L.; Bowen, Charles A.; Stedman, Ralph M.

1994-01-01

Ergasilus nerkae was found infecting ninespine stickleback (Pungitius pungitius) in lakes Huron, Michigan, and Superior and threespine stickleback (Gasterosteus aculeatus) and round whitefish (Prosopium cylindraceum) in Lake Huron. Based upon the literature and study of archived material, we propose that E. nerkae is enzootic to the Great Lakes and that ninespine stickleback are a preferred host in Lake Huron. Prevalence of E. nerkae on ninespine stickleback increased from 17% in June to 68% in September, but mean intensity remained light. Prevalence and mean intensity increased with host length. Ergasilus luciopercarum is also reported on lake trout (Salvelinus namaycush) and largemouth bass (Micropterus salmoides) for the first time. Host-parasite records of Ergasilus spp. in North America are reviewed, biology and taxonomy are summarized, and a checklist of Great Lakes host-parasite-locality records is provided. At present, eight species of Ergasilus are known to infect 42 Great Lakes fish species.

Reproductive and life cycle strategies in egg-carrying cyclopoid and free-spawning calanoid copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas; Sabatini, Marian

1994-01-01

Egg-carrying cyclopoid copepods have lower fecundity and feeding rates, and longer egg hatching times, than free-spawning calanoid copepods. Simple demographic considerations suggest that the lower feeding and fecundity of egg-carrying cyclopoids are adaptations to the potentially elevated...... mortality of ovigerous females, while the shorter egg hatching time and higher feeding and fecundity rates found in free-spawning calanoid copepods represent adaptations to the very high mortality rates experienced by suspended eggs....

Evaluation of fall chinook salmon spawning adjacent to the In-Situ Redox Manipulation treatability test site, Hanford Site, Washington

International Nuclear Information System (INIS)

Mueller, R.P.; Geist, D.R.

1998-10-01

The In Situ Redox Manipulation (ISRM) experiment is being evaluated as a potential method to remove contaminants from groundwater adjacent to the Columbia River near the 100-D Area. The ISRM experiment involves using sodium dithionate (Na 2 O 6 S 2 ) to precipitate chromate from the groundwater. The treatment will likely create anoxic conditions in the groundwater down-gradient of the ISRM treatability test site; however, the spatial extent of this anoxic plume is not exactly known. Surveys were conducted in November 1997, following the peak spawning of fall chinook salmon. Aerial surveys documented 210 redds (spawning nests) near the downstream island in locations consistent with previous surveys. Neither aerial nor underwater surveys documented fall chinook spawning in the vicinity of the ISRM treatability test site. Based on measurements of depth, velocity, and substrate, less than 1% of the study area contained suitable fall chinook salmon spawning habitat, indicating low potential for fall chinook salmon to spawn in the vicinity of the ISRM experiment

Assessment of lake sturgeon (Acipenser fulvescens) spawning efforts in the lower St. Clair River, Michigan

Science.gov (United States)

Nichols, S. Jerrine; Kennedy, Gregory; Crawford, Eric; Allen, Jeffrey; French, John; Black, Glen; Blouin, Marc; Hickey, James P.; Chernyak, Sergei; Haas, Robert; Thomas, Michael

2003-01-01

One of the most threatened remaining populations of lake sturgeon in the Great Lakes is found in the connecting channels between Lake Huron and Lake Erie. Only two spawning grounds are presently known to be active in this region, and both are in the St. Clair River. The spawning reef in the St. Clair River delta has been recently colonized by round gobies (Neogobius melanostomus) in densities up to 25/m2, raising concerns regarding predation on the benthic-oriented eggs and larvae of the sturgeon. Investigations in 1998–1999 showed that while round goby predation does occur, a number of other factors may be equally affecting sturgeon spawning success, including few spawning adults (noted in either year. There were factors other than predation affecting larval survival in 1999. There was a higher silt load on the reef than in 1998 and large numbers of dead larvae were found. Recruitment success from this site could be improved by utilizing techniques to increase the number of eggs on the reef, such as reducing the illegal take of adult fish and by placing eggs in predator-exclusion chambers to increase hatch rate.

Spatio-temporal segregation of calling behavior at a multispecies fish spawning site in Little Cayman

Science.gov (United States)

Cameron, K. C.; Sirovic, A.; Jaffe, J. S.; Semmens, B.; Pattengill-Semmens, C.; Gibb, J.

2016-02-01

Fish spawning aggregation (FSA) sites are extremely vulnerable to over-exploitation. Accurate understanding of the spatial and temporal use of such sites is necessary for effective species management. The size of FSAs can be on the order of kilometers and peak spawning often occurs at night, posing challenges to visual observation. Passive acoustics are an alternative method for dealing with these challenges. An array of passive acoustic recorders and GoPro cameras were deployed during Nassau grouper (Epinephelus striatus) spawning from February 7th to 12th, 2015 at a multispecies spawning aggregation site in Little Cayman, Cayman Islands. In addition to Nassau grouper, at least 10 other species are known to spawn at this location including tiger grouper (Mycteroperca tigris), red hind (Epinephelus guttatus), black grouper (Mycteroperca bonaci), and yellowfin grouper (Mycteroperca venenosa). During 5 days of continuous recordings, over 21,000 fish calls were detected. These calls were classified into 15 common types. Species identification and behavioral context of unknown common call types were determined by coupling video recordings collected during this time with call localizations. There are distinct temporal patterns in call production of different species. For example, red hind and yellowfin grouper call predominately at night with yellowfin call rates increasing after midnight, and black grouper call primarily during dusk and dawn. In addition, localization methods were used to reveal how the FSA area was divided among species. These findings facilitate a better understanding of the behavior of these important reef fish species allowing policymakers to more effectively manage and protect them.

Lake Sturgeon, Lake Whitefish, and Walleye egg deposition patterns with response to fish spawning substrate restoration in the St. Clair–Detroit River system

Science.gov (United States)

Fischer, Jason L.; Pritt, Jeremy J.; Roseman, Edward; Prichard, Carson G.; Craig, Jaquelyn M.; Kennedy, Gregory W.; Manny, Bruce A.

2018-01-01

Egg deposition and use of restored spawning substrates by lithophilic fishes (e.g., Lake Sturgeon Acipenser fulvescens, Lake Whitefish Coregonus clupeaformis, and Walleye Sander vitreus) were assessed throughout the St. Clair–Detroit River system from 2005 to 2016. Bayesian models were used to quantify egg abundance and presence/absence relative to site-specific variables (e.g., depth, velocity, and artificial spawning reef presence) and temperature to evaluate fish use of restored artificial spawning reefs and assess patterns in egg deposition. Lake Whitefish and Walleye egg abundance, probability of detection, and probability of occupancy were assessed with detection-adjusted methods; Lake Sturgeon egg abundance and probability of occurrence were assessed using delta-lognormal methods. The models indicated that the probability of Walleye eggs occupying a site increased with water velocity and that the rate of increase decreased with depth, whereas Lake Whitefish egg occupancy was not correlated with any of the attributes considered. Egg deposition by Lake Whitefish and Walleyes was greater at sites with high water velocities and was lower over artificial spawning reefs. Lake Sturgeon eggs were collected least frequently but were more likely to be collected over artificial spawning reefs and in greater abundances than elsewhere. Detection-adjusted egg abundances were not greater over artificial spawning reefs, indicating that these projects may not directly benefit spawning Walleyes and Lake Whitefish. However, 98% of the Lake Sturgeon eggs observed were collected over artificial spawning reefs, supporting the hypothesis that the reefs provided spawning sites for Lake Sturgeon and could mitigate historic losses of Lake Sturgeon spawning habitat.

Evaluate the Restoration Potential of Snake River Fall Chinook Salmon Spawning Habitat, Status Report 2006.

Energy Technology Data Exchange (ETDEWEB)

Hanrahan, T.P. [Pacific Northwest National Laboratory

2009-01-08

The Bonneville Power Administration (BPA) Project 2003-038-00, Evaluate the restoration potential of Snake River fall Chinook salmon spawning habitat, began in FY04 (15 December 2003) and continues into FY06. This status report is intended to summarize accomplishments during FY04 and FY05. Accomplishments are summarized by Work Elements, as detailed in the Statement of Work (see BPA's project management database PISCES). This project evaluates the restoration potential of mainstem habitats for fall Chinook salmon. The studies address two research questions: 'Are there sections not currently used by spawning fall Chinook salmon within the impounded lower Snake River that possess the physical characteristics for potentially suitable fall Chinook spawning habitat?' and 'Can hydrosystem operations affecting these sections be adjusted such that the sections closely resemble the physical characteristics of current fall Chinook salmon spawning areas in similar physical settings?' Efforts are focused at two study sites: (1) the Ice Harbor Dam tailrace downstream to the Columbia River confluence, and (2) the Lower Granite Dam tailrace. Our previous studies indicated that these two areas have the highest potential for restoring Snake River fall Chinook salmon spawning habitat. The study sites will be evaluated under existing structural configurations at the dams (i.e., without partial removal of a dam structure), and alternative operational scenarios (e.g., varying forebay/tailwater elevations). The areas studied represent tailwater habitat (i.e., riverine segments extending from a dam downstream to the backwater influence from the next dam downstream). We are using a reference site, indicative of current fall Chinook salmon spawning areas in tailwater habitat, against which to compare the physical characteristics of each study site. The reference site for tailwater habitats is the section extending downstream from the Wanapum Dam tailrace on the

Using drift nets to capture early life stages and monitor spawning of the yangtze river chinese sturgeon (Acipenser sinensis)

Science.gov (United States)

Wei, Q.W.; Kynard, B.; Yang, D.G.; Chen, X.H.; Du, H.; Shen, L.; Zhang, H.

2009-01-01

A sampling system for capturing sturgeon eggs using a D-shaped bottom anchored drift net was used to capture early life stages (ELS) of Chinese sturgeon, Acipenser sinensis, and monitor annual spawning success at Yichang on the Yangtze River, 1996-2004, before and just after the Three Gorges Dam began operation. Captured were 96 875 ELS (early life stages: eggs, yolk-sac larvae = eleuthero embryos, and larvae); most were eggs and only 2477 were yolk-sac larvae. Most ELS were captured in the main river channel and inside the bend at the Yichang spawning reach. Yolk-sac larvae were captured for a maximum of 3 days after hatching began, indicating quick dispersal downstream. The back-calculated day of egg fertilization over the eight years indicated a maximum spawning window of 23 days (20 October-10 November). Spawning in all years was restricted temporally, occurred mostly at night and during one or two spawning periods, each lasting several days. The brief temporal spawning window may reduce egg predation by opportunistic predators by flooding the river bottom with millions of eggs. During 1996-2002, the percentage of fertilized eggs in an annual 20-egg sample was between 63.5 to 94.1%; however, in 2003 the percentage fertilized was only 23.8%. This sudden decline may be related to the altered environmental conditions at Yichang caused by operation of the Three Gorges Dam. Further studies are needed to monitor spawning and changes in egg fertilization in this threatened population. ?? 2009 Blackwell Verlag GmbH.

Identification of the Spawning, Rearing, and Migratory Requirements of Fall Chinook Salmon in the Columbia River Basin, Annual Report 1994.

Energy Technology Data Exchange (ETDEWEB)

Rondorf, Dennis W.; Tiffan, Kenneth F.

1996-08-01

Spawning ground surveys were conducted in 1994 as part of a five year study of Snake River chinook salmon Oncorhynchus tshawyacha begun in 1991. Observations of fall chinook salmon spawning in the Snake River were limited to infrequent aerial red counts in the years prior to 1987. From 1987-1990, red counts were made on a limited basis by an interagency team and reported by the Washington Department of Fisheries. Starting in 1991, the U.S. Fish and Wildlife Service (USFWS), and other cooperating agencies and organizations, expanded the scope of spawning ground surveys to include: (1) additional aerial surveys to improve red counts and provide data on the timing of spawning; (2) the validation (ground truthing) of red counts from aerial surveys to improve count accuracy; (3) underwater searches to locate reds in water too deep to allow detection from the air; and (4) bathymetric mapping of spawning sites for characterizing spawning habitat. This document is the 1994 annual progress report for selected studies of fall chinook salmon. The studies were undertaken because of the growing concern about the declining salmon population in the Snake River basin.

Spawning phenology of the white bream (Blicca bjoerkna in the "Dnieper-Orylskiy" Nature Reserve in relation to seasonal temperature dynamic

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D. L. Bondarev

2017-05-01

Full Text Available This paper examines the relationship between climatic conditions and the phenology of spawning of the white bream Blicca bjoerkna (Linnaeus, 1758 in natural habitats of the "Dnipro-Orylskiy" Nature Reserve. The characteristic of spawning distribution is symmetric, as the asymmetry coefficients do not significantly differ from zero. The distribution of the timing of spawning and its duration are also characterized by excesses, which do not significantly differ from zero alternatives. Analysis of meteorological data for the period of study allowed us to determine the trends in temperature variation, which correlate with the temperature of the water. Spawning events in any given year take place entirely within an upward temperature progression that can be accurately described by a linear equation in the form: Y = b + a · x, where Y – ten-day average temperature; x – the order of decades for I–VI months of the year, a and b – the parameters of the equation. The same equation can be used to describe downward movements in the temperature for decades during the VII–XII months of the year. Regression parameters and coefficients of determination have the following environmental sense. For the ascending temperature branch the regression coefficient b will decrease in proportion to the increase in the contrast between winter and summer temperatures. Due to the fact that linear approximation is a certain generalization of the sinusoid natural course of temperature, it should be borne in mind that the highest summer temperatures are close to the change in direction in the course of temperature from increase to decrease. Therefore, the coefficient b will largely depend on the minimum winter temperatures and should be interpreted as a marker of the coldness of the winter. This interpretation is all the more justified because we are concerned here with assessment of the impact on fish spawning, and the processes that precede spawning events clearly

The role of density-dependent and -independent processes in spawning habitat selection by salmon in an Arctic riverscape.

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Brock M Huntsman

Full Text Available Density-dependent (DD and density-independent (DI habitat selection is strongly linked to a species' evolutionary history. Determining the relative importance of each is necessary because declining populations are not always the result of altered DI mechanisms but can often be the result of DD via a reduced carrying capacity. We developed spatially and temporally explicit models throughout the Chena River, Alaska to predict important DI mechanisms that influence Chinook salmon spawning success. We used resource-selection functions to predict suitable spawning habitat based on geomorphic characteristics, a semi-distributed water-and-energy balance hydrologic model to generate stream flow metrics, and modeled stream temperature as a function of climatic variables. Spawner counts were predicted throughout the core and periphery spawning sections of the Chena River from escapement estimates (DD and DI variables. Additionally, we used isodar analysis to identify whether spawners actively defend spawning habitat or follow an ideal free distribution along the riverscape. Aerial counts were best explained by escapement and reference to the core or periphery, while no models with DI variables were supported in the candidate set. Furthermore, isodar plots indicated habitat selection was best explained by ideal free distributions, although there was strong evidence for active defense of core spawning habitat. Our results are surprising, given salmon commonly defend spawning resources, and are likely due to competition occurring at finer spatial scales than addressed in this study.

Confirmed Sighting of a Spawning Aggregation of the Brown ...

African Journals Online (AJOL)

The occurrence of spawning aggregations at fixed sites and times is well documented for several species of reef fish. These aggregations are known to attract fishers and such species may therefore be vulnerable to overfishing. This is particularly true in the case of groupers which have intrinsically vulnerable life history ...

Fatty acids in female’s gonads of the Red Sea fish Rhabdosargus sarba during the spawning season

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Suhaila Qari

2014-05-01

Full Text Available Objective: To determine the fatty acids profiles in female fish, Rhabdosargus sarba (R. sarba from the Red Sea during the spawning season. Methods: Monthly individual R. sarba were obtained from Bangalah market in Jeddah, Red Sea and transported to the laboratory in ice aquarium. The total length, standard length and weight were measured, fishes were dissected. Ovaries were removed, weighed and 10 mL of concentrated hydrochloric acid were added to 10 g of the ovary in a conical flask and immersed in boiling water until the sample was dissolved and the fat was seen to collect on the surface. The conical was cooled and the fat was extracted by shaking with 30 mL of diethyl ether. The extract was bowled after allowing the layers to separate into a weighed flask. The extraction was repeated three times more and distilled off the solvent then the fat dried at 100 °C, cooled and weighed. Then 50 mg of lipid was put in a tube, 5 mL of methanolic sulphuric acid was added and 2 mL of benzene, the tube well closed and placed in water bath at 90 °C for an hour and a half. After cooling, 8 mL water and 5 mL petroleum were added and shaked strongly and the ethereal layer was separated in a dry tube, evaporated to dryness. The fatty acid methyl esters were analyzed by using a Hewlett Packard (HP 6890 chromatography, a split/splitless injector and flame ionization detector. Results: In female R. sarba, a total of 29 fatty acids were detected in ovaries throughout the spawning season. The main fatty acid group in total lipid was saturated fatty acid (SFA, 28.9%, followed by 23.5% of polyunsaturated fatty acids (PUFA and 12.9% of monounsaturated fatty acids (MUFA. The dominant SFA were palmitic and stearic, the major MUFA were palmitoleic and oleic, and the major PUFA were C18:2 and C22:2. During spawning stages, there were no significant differences in total SFA, MUFA and PUFA. The highest value of SFA was in late spawning (36.78%. However, the highest value

Gametogenesis and spawning of Spirobranchus tetraceros (Polychaeta, Serpulidae in Abu Kir Bay, Egypt

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S. A. SELIM

2005-06-01

Full Text Available The serpulid polychaete Spirobranchus tetraceros of Red Sea / Indo-pacific origin, recently has succeeded to establish a foothold in Alexandria Mediterranean waters. Worms were monthly scraped from submerged iron substrates at Abu Kir Bay during the period December 2000 – November 2001. Both light and TEM were used to study gametogenesis and time of spawning of S. tetraceros.Gametogenesis was asynchronous and oogenesis could be divided into two previtellogenic, two vitellogenic and a spawning stage. Oocyte development took about 8 months, from October to June. Spawning occurred from late May - early June until October. Thus S. tetraceros is a long period spawner. The maximum diameter of ripe oocyte is 78 mm. The spermatogenic phase could be divided into three stages: spermatogonia, spermatocytes and spermatids (including spermatozoa. The duration of sperm development took about 8 months. Spermatocytes persist from October to March. By March the sperms grew rapidly until they became spermatozoa in May. The sperm could be considered ect-aquasperm with regard to its fertilization biology.

Temperature, pressure and light data collected by attached Archival Transmitting Tags to Salvelinus malma (Dolly Varden trout) in the Wulik River, Alaska, during 2012-06 to 2013-10 (NODC Accession 0119954)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains data collected by electronic tags (Pop-up Satellite Archival Transmitting) attached to Salvelinus malma (Dolly Varden trout) in the Wulik...

Dispersal of adult black marlin (Istiompax indica) from a Great Barrier Reef spawning aggregation.

Science.gov (United States)

Domeier, Michael L; Speare, Peter

2012-01-01

The black marlin (Istiompax indica) is one of the largest bony fishes in the world with females capable of reaching a mass of over 700 kg. This highly migratory predator occurs in the tropical regions of the Pacific and Indian Oceans, and is the target of regional recreational and commercial fisheries. Through the sampling of ichthyoplankton and ovaries we provide evidence that the relatively high seasonal abundance of black marlin off the Great Barrier Reef is, in fact, a spawning aggregation. Furthermore, through the tracking of individual black marlin via satellite popup tags, we document the dispersal of adult black marlin away from the spawning aggregation, thereby identifying the catchment area for this spawning stock. Although tag shedding is an issue when studying billfish, we tentatively identify the catchment area for this stock of black marlin to extend throughout the Coral Sea, including the waters of Papua New Guinea, the Solomon Islands, Micronesia, New Caledonia, Kiribati, Vanuatu, Fiji, Tuvalu and Nauru.

Dispersal of adult black marlin (Istiompax indica from a Great Barrier Reef spawning aggregation.

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Michael L Domeier

Full Text Available The black marlin (Istiompax indica is one of the largest bony fishes in the world with females capable of reaching a mass of over 700 kg. This highly migratory predator occurs in the tropical regions of the Pacific and Indian Oceans, and is the target of regional recreational and commercial fisheries. Through the sampling of ichthyoplankton and ovaries we provide evidence that the relatively high seasonal abundance of black marlin off the Great Barrier Reef is, in fact, a spawning aggregation. Furthermore, through the tracking of individual black marlin via satellite popup tags, we document the dispersal of adult black marlin away from the spawning aggregation, thereby identifying the catchment area for this spawning stock. Although tag shedding is an issue when studying billfish, we tentatively identify the catchment area for this stock of black marlin to extend throughout the Coral Sea, including the waters of Papua New Guinea, the Solomon Islands, Micronesia, New Caledonia, Kiribati, Vanuatu, Fiji, Tuvalu and Nauru.

The reproductive biology of an open-water spawning Lake Malawi ...

African Journals Online (AJOL)

The reproductive biology of an open-water spawning Lake Malawi cichlid, Copadichromis chrysonotus. Lance W. Smith. Abstract. Copadichromis chrysonotus is a zooplanktivorous cichlid member of the diverse fish community inhabiting Lake Malawi's rocky, littoral habitat. Like most Lake Malawi cichlids, this species' ...

Spawning and nursery habitats of neotropical fish species in the tributaries of a regulated river

Science.gov (United States)

Makrakis, Maristela Cavicchioli; da Silva, Patrícia S.; Makrakis, Sergio; de Lima, Ariane F.; de Assumpção, Lucileine; de Paula, Salete; Miranda, Leandro E.; Dias, João Henrique Pinheiro

2012-01-01

This chapter provides information on ontogenetic patterns of neotropical fish species distribution in tributaries (Verde, Pardo, Anhanduí, and Aguapeí rivers) of the Porto Primavera Reservoir, in the heavily dammed Paraná River, Brazil, identifying key spawning and nursery habitats. Samplings were conducted monthly in the main channel of rivers and in marginal lagoons from October through March during three consecutive spawning seasons in 2007-2010. Most species spawn in December especially in Verde River. Main river channels are spawning habitats and marginal lagoons are nursery areas for most fish, mainly for migratory species. The tributaries have high diversity of larvae species: a total of 56 taxa representing 21 families, dominated by Characidae. Sedentary species without parental care are more abundant (45.7%), and many long-distance migratory fish species are present (17.4%). Migrators included Prochilodus lineatus, Rhaphiodon vulpinus, Hemisorubim platyrhynchos, Pimelodus maculatus, Pseudoplatystoma corruscans, Sorubim lima, two threatened migratory species: Salminus brasiliensis and Zungaro jahu, and one endangered migratory species: Brycon orbignyanus. Most of these migratory species are vital to commercial and recreational fishing, and their stocks have decreased drastically in the last decades, attributed to habitat alteration, especially impoundments. The fish ladder at Porto Primavera Dam appears to be playing an important role in re-establishing longitudinal connectivity among critical habitats, allowing ascent to migratory fish species, and thus access to upstream reaches and tributaries. Establishment of Permanent Conservation Units in tributaries can help preserve habitats identified as essential spawning and nursery areas, and can be key to the maintenance and conservation of the fish species in the Paraná River basin.

Fall and winter survival of brook trout and brown trout in a north-central Pennsylvania watershed

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Sweka, John A.; Davis, Lori A.; Wagner, Tyler

2017-01-01

Stream-dwelling salmonids that spawn in the fall generally experience their lowest survival during the fall and winter due to behavioral changes associated with spawning and energetic deficiencies during this time of year. We used data from Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta implanted with radio transmitters in tributaries of the Hunts Run watershed of north-central Pennsylvania to estimate survival from the fall into the winter seasons (September 2012–February 2013). We examined the effects that individual-level covariates (trout species, size, and movement rates) and stream-level covariates (individual stream and cumulative drainage area of a stream) have on survival. Brook Trout experienced significantly lower survival than Brown Trout, especially in the early fall during their peak spawning period. Besides a significant species effect, none of the other covariates examined influenced survival for either species. A difference in life history between these species, with Brook Trout having a shorter life expectancy than Brown Trout, is likely the primary reason for the lower survival of Brook Trout. However, Brook Trout also spawn earlier in the fall than Brown Trout and low flows during Brook Trout spawning may have resulted in a greater risk of predation for Brook Trout compared with Brown Trout, thereby also contributing to the observed differences in survival between these species. Our estimates of survival can aid parameterization of future population models for Brook Trout and Brown Trout through the spawning season and into winter.

Bed stability in unconfined gravel bed mountain streams: With implications for salmon spawning viability in future climates

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Jim McKean; Daniele Tonina

2013-01-01

Incubating eggs of autumn-spawning Chinook salmon (Oncorhynchus tshawytscha) could be at risk of midwinter high flows and substrate scour in a changing climate. A high-spatial-resolution multidimensional hydrodynamics model was used to assess the degree of scour risk in low-gradient unconfined gravel bed channels that are the favored environment for autumn-spawning...

Batch fertility and larval parameters of the jaguar cichlid (Cichlasoma managuense spawned in the laboratory (ESP

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Jorge Günther Nonell

2016-03-01

Full Text Available Batch fertility and larval parameters of 32 spawns of the jaguar guapote (Cichlasoma managuense in the laboratory were analyzed. Batch fertility was positively correlated with the female weight with spawns between about 3000 to 6000 larvae for females between 100 and 500 g wet weight. No significant correlation was found between larval parameters (fresh weight and % dry weight and female weight.

[Spontaneous spawning, ontogeny and growth in captivity of Cynoscion squamipinnis (Perciformes: Sciaenidae)].

Science.gov (United States)

Boza-Abarca, Jorge; Ramírez-Alvarado, Marvin; Barquero-Chanto, Juan; Calvo-Vargas, Emilia; Berrocal-Artavia, Karen

2016-09-01

The croakers or drums are commercial species, which have been overfished in the Nicoya Gulf, Costa Rica. This study aimed to describe, for the first time, the reproduction and the ontogeny of weakfish, Cynoscion squamipinnis in captivity, in order to perform restocking and mariculture proyects. Wild fish (n= 6, 1-2 Kg) were captured and maintained in the Estación de Biología Marina Juan Bertoglia Richards (Puntarenas, Costa Rica) for a two years period (October 2006- December 2008). During this period, maturation stage was monitored periodically by cannula samples in the females (n= 3) and gentle massage in males (n= 3). All fish were stocked in an 18 t tank, with aeration, 33-35 ups of salinity, and a constant temperature (29 ± 1 °C). The spawning period occurred from January to March 2009, producing 162 000 eggs in three spontaneous spawns. The fertilization percentage was 50-60%, and survival after hatching was 60-85%. The egg diameter was 0.852 mm (Standard deviation (SD)= 0.039), and oil drop of 0.269 mm (SD= 0.016). In the embryonary development, the first mitotic division (MD) was observed one hour after spawning (has), the second MD was 1:30 has, the third MD was 2:00 has, the fourth MD was 2:30 has, and fifth MD at 3:00 has. Morule was observed 3:30 has, the blastule 4:30 has, the gastrule 8:30 has, C shape at 10:00 has, and C shape at 12:00 has. After 19 has hatching larvae occurred. The total length (TL) of the larvae was 2.234 mm (SD= 0.122), and the nothochordial length (NL) was 2.179 mm (SD= 0.119). Preflexion stage was observed 49 has, flexion stage was 11 days after spawn (das) (3.767 mm LT (SD= 0.209)), and postflexion stage was 14 das (4.015 mm LT (SD= 0.302)). After 45 das, the juvenile weights 3.68 g (SD= 1.09). Hatch time of the weakfish larvae was minor than of others croaker species. The stages times of embrionary development were a little different from others croaker species, and probably respond to genetic characteristics of each

Linking spawning ground extent to environmental factors - patterns and dispersal during the egg phase of four North Sea fishes

DEFF Research Database (Denmark)

Höffle, Hannes; van Damme, Cindy J. G.; Fox, Clive J.

2018-01-01

, the location of the spawning grounds appeared stable on the broad scale but centres of egg abundance varied between the surveyed years. Potential effects of long-term climate change and anthropogenic short-term disturbances, such as seismic surveys, on fish reproduction are discussed, pointing out the demand...... surveys in 2004 and 2009, the present study uses Generalized Additive Mixed Models (GAMMs) to delimit these spawning grounds using the distribution of recently spawned eggs, investigates their relationship to specific environmental conditions and examines egg dispersal during their development. Results...

Oogenesis and spawn formation in the invasive lionfish, Pterois miles and Pterois volitans

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James A. Morris, Jr

2011-02-01

Full Text Available The Indo-Pacific lionfish, Pterois miles and P. volitans, have recently invaded the U.S. east coast and the Caribbean and pose a significant threat to native reef fish communities. Few studies have documented reproduction in pteroines from the Indo-Pacific. This study provides a description of oogenesis and spawn formation in P. miles and P. volitans collected from offshore waters of North Carolina, U.S.A and the Bahamas. Using histological and laboratory observations, we found no differences in reproductive biology between P. miles and P. volitans. These lionfish spawn buoyant eggs that are encased in a hollow mass of mucus produced by specialized secretory cells of the ovarian wall complex. Oocytes develop on highly vascularized peduncles with all oocyte stages present in the ovary of spawning females and the most mature oocytes placed terminally, near the ovarian lumen. Given these ovarian characteristics, these lionfish are asynchronous, indeterminate batch spawners and are thus capable of sustained reproduction throughout the year when conditions are suitable. This mode of reproduction could have contributed to the recent and rapid establishment of these lionfish in the northwestern Atlantic and Caribbean.

Dwarf char, a new form of chars (the genus Salvelinus) in Lake Kronotskoe

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Pavlov, S.D.; Pivovarov, E.A.; Ostberg, C.O.

2012-01-01

Lake Kronotskoe is situated in the Kronotskii State Nature Reserve and is a unique natural heritage of Kamchatka. The lake–river system of the reserve includes numerous springs and small streams and three large inflowing rivers, Listvennichnaya, Unana, and Uzon, which form the main bays of Lake Kronotskoe; one river (Kronotskaya) flows from the lake. This river is characterized by several rapids, which are assumed to be unsurmountable barriers for fish migration. The ichthyofauna of the lake has been isolated for a long time, and some endemic fishes appeared, including char of the genus Salvelinus and the residential form of red salmon Oncorhynchus nerka (the local name is kokanee). These species are perfect model objects to study microevolution processes. Char of Lake Kronotskoe are characterized by significant polymorphism and plasticity [1–3]; therefore, they are extremely valuable for studying the processes of speciation and form development. That is why the populations of char in Lake Kronotskoe are unique and attract special attention of researchers. 

Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means.

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Fox, Clive J; Taylor, Martin; Dickey-Collas, Mark; Fossum, Petter; Kraus, Gerd; Rohlf, Norbert; Munk, Peter; van Damme, Cindy J G; Bolle, Loes J; Maxwell, David L; Wright, Peter J

2008-07-07

Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey to cover the whole North Sea. Also, this survey, conducted in 2004, was the first to make extensive use of DNA-based molecular methods to unambiguously identify early developmental stage cod eggs. We compare the findings from the plankton survey with estimated egg production inferred from the distribution of mature cod in contemporaneous trawl surveys. Results from both approaches were in general agreement and showed hot spots of egg production around the southern and eastern edges of the Dogger Bank, in the German Bight, the Moray Firth and to the east of the Shetlands. These areas broadly coincide with known spawning locations from the period 1940 to 1970. We were, however, unable to directly detect significant numbers of cod eggs at the historic spawning ground off Flamborough (northeast coast of England). The results demonstrate that most of the major spawning grounds of cod in the North Sea are still active but that some localized populations may have been reduced to the point where it is now difficult to detect the presence of eggs in the plankton.

Effects of dressing and cooking on DDT concentrations in certain fish from Lake Michigan

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Reinert, Robert E.; Stewart, Donald; Seagran, Harry L.

1972-01-01

Concentrations of DDT residues were highest in parts of the body with the highest oil content in four species of fish from Lake Michigan: yellow perch (Perca flavescens), bloater (Coregonus hoyi), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch). Dressing reduced the DDT residues and oil content by more than 90% in yellow perch but had little effect in the other three species. The concentration of DDT residues in bloaters was changed little by smoking but was reduced 64–72% by other methods of cooking: from 8.0 ppm (raw) to 2.2 ppm after frying in corn oil; from 10.7 to 3.9 ppm after frying in lard; and from 9.1 to 3.2 ppm after broiling. The concentration of DDT residues in fillets of yellow perch changed only from 0.3 ppm (raw) to 0.4 or 0.5 ppm after baking, frying, or broiling.

Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems

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Black, B.A.; Von Biela, V.R.; Zimmerman, C.E.; Brown, Randy J.

2013-01-01

High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval (p otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales.

Validation of a spatial model used to locate fish spawning reef construction sites in the St. Clair–Detroit River system

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Fischer, Jason L.; Bennion, David; Roseman, Edward F.; Manny, Bruce A.

2015-01-01

Lake sturgeon (Acipenser fulvescens) populations have suffered precipitous declines in the St. Clair–Detroit River system, following the removal of gravel spawning substrates and overfishing in the late 1800s to mid-1900s. To assist the remediation of lake sturgeon spawning habitat, three hydrodynamic models were integrated into a spatial model to identify areas in two large rivers, where water velocities were appropriate for the restoration of lake sturgeon spawning habitat. Here we use water velocity data collected with an acoustic Doppler current profiler (ADCP) to assess the ability of the spatial model and its sub-models to correctly identify areas where water velocities were deemed suitable for restoration of fish spawning habitat. ArcMap 10.1 was used to create raster grids of water velocity data from model estimates and ADCP measurements which were compared to determine the percentage of cells similarly classified as unsuitable, suitable, or ideal for fish spawning habitat remediation. The spatial model categorized 65% of the raster cells the same as depth-averaged water velocity measurements from the ADCP and 72% of the raster cells the same as surface water velocity measurements from the ADCP. Sub-models focused on depth-averaged velocities categorized the greatest percentage of cells similar to ADCP measurements where 74% and 76% of cells were the same as depth-averaged water velocity measurements. Our results indicate that integrating depth-averaged and surface water velocity hydrodynamic models may have biased the spatial model and overestimated suitable spawning habitat. A model solely integrating depth-averaged velocity models could improve identification of areas suitable for restoration of fish spawning habitat.

The spawning products of fish living in upwelling ecosystems have ...

African Journals Online (AJOL)

denise

Normally, hake spawn offshore near the bottom at depths of. 150–400 m. ... eyes or mouth, and display little swimming activity during their first hours, but laboratory observations have revealed subsequent ... Based on current field observations, on buoyancy measure- ...... wind-induced turbulence will not influence their ver-.

Effects of telemetry transmitter placement on egg retention in naturally spawning, captively reared steelhead

International Nuclear Information System (INIS)

Berejikian, Barry A.; Brown, Richard S.; Tatara, Chris P.; Cooke, Steven J.

2007-01-01

Maturing female anadromous salmonids receiving surgical intraperitoneally-implanted telemetry transmitters may experience difficulty depositing eggs during natural spawning. We allocated maturing adult steelhead females to three treatments: tags surgically implanted in the body cavity (internal), tags implanted between the skin and muscle tissue (subdermal), and non-tagged, and allowed them to spawn naturally in an experimental channel. Internally tagged females retained significantly more eggs than both the subdermally tagged treatment (P = 0.005) and non-tagged controls (P = 0.001); the subdermal and non-tag controls did not differ significantly (P = 0.934). The internal, subdermal and non-tag treatments retained an average of 49%, 11% and 2% of their eggs, respectively. The onset of sexual activity did not differ significantly among treatments (P = 0.413). Post-spawning mortality was 70% for both internally and subdermally tagged females and 0% for non-tagged females (P <0.01). We suggest that subdermal implantation techniques be considered in future studies during the reproductive period to reduce egg retention caused by internal implantation of transmitters

Effects of telemetry transmitter placement on egg retention in naturally spawning, captively reared steelhead

Energy Technology Data Exchange (ETDEWEB)

Berejikian, Barry A.; Brown, Richard S.; Tatara, Chris P.; Cooke, Steven J.

2007-05-01

Maturing female anadromous salmonids receiving surgical intraperitoneally-implanted telemetry transmitters may experience difficulty depositing eggs during natural spawning. We allocated maturing adult steelhead females to three treatments: tags surgically implanted in the body cavity (internal), tags implanted between the skin and muscle tissue (subdermal), and non-tagged, and allowed them to spawn naturally in an experimental channel. Internally tagged females retained significantly more eggs than both the subdermally tagged treatment (P = 0.005) and non-tagged controls (P = 0.001); the subdermal and non-tag controls did not differ significantly (P = 0.934). The internal, subdermal and non-tag treatments retained an average of 49%, 11% and 2% of their eggs, respectively. The onset of sexual activity did not differ significantly among treatments (P = 0.413). Post-spawning mortality was 70% for both internally and subdermally tagged females and 0% for non-tagged females (P <0.01). We suggest that subdermal implantation techniques be considered in future studies during the reproductive period to reduce egg retention caused by internal implantation of transmitters.

Seasonal dynamics of Atlantic herring (Clupea harengus L.) populations spawning in the vicinity of marginal habitats.

Science.gov (United States)

Eggers, Florian; Slotte, Aril; Libungan, Lísa Anne; Johannessen, Arne; Kvamme, Cecilie; Moland, Even; Olsen, Esben M; Nash, Richard D M

2014-01-01

Gillnet sampling and analyses of otolith shape, vertebral count and growth indicated the presence of three putative Atlantic herring (Clupea harengus L.) populations mixing together over the spawning season February-June inside and outside an inland brackish water lake (Landvikvannet) in southern Norway. Peak spawning of oceanic Norwegian spring spawners and coastal Skagerrak spring spawners occurred in March-April with small proportions of spawners entering the lake. In comparison, spawning of Landvik herring peaked in May-June with high proportions found inside the lake, which could be explained by local adaptations to the environmental conditions and seasonal changes of this marginal habitat. The 1.85 km(2) lake was characterized by oxygen depletion occurring between 2.5 and 5 m depth between March and June. This was followed by changes in salinity from 1-7‰ in the 0-1 m surface layer to levels of 20-25‰ deeper than 10 m. In comparison, outside the 3 km long narrow channel connecting the lake with the neighboring fjord, no anoxic conditions were found. Here salinity in the surface layer increased over the season from 10 to 25‰, whereas deeper than 5 m it was stable at around 35‰. Temperature at 0-5 m depth increased significantly over the season in both habitats, from 7 to 14 °C outside and 5 to 17 °C inside the lake. Despite differences in peak spawning and utilization of the lake habitat between the three putative populations, there was an apparent temporal and spatial overlap in spawning stages suggesting potential interbreeding in accordance with the metapopulation concept.

Seasonal dynamics of Atlantic herring (Clupea harengus L. populations spawning in the vicinity of marginal habitats.

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Florian Eggers

Full Text Available Gillnet sampling and analyses of otolith shape, vertebral count and growth indicated the presence of three putative Atlantic herring (Clupea harengus L. populations mixing together over the spawning season February-June inside and outside an inland brackish water lake (Landvikvannet in southern Norway. Peak spawning of oceanic Norwegian spring spawners and coastal Skagerrak spring spawners occurred in March-April with small proportions of spawners entering the lake. In comparison, spawning of Landvik herring peaked in May-June with high proportions found inside the lake, which could be explained by local adaptations to the environmental conditions and seasonal changes of this marginal habitat. The 1.85 km(2 lake was characterized by oxygen depletion occurring between 2.5 and 5 m depth between March and June. This was followed by changes in salinity from 1-7‰ in the 0-1 m surface layer to levels of 20-25‰ deeper than 10 m. In comparison, outside the 3 km long narrow channel connecting the lake with the neighboring fjord, no anoxic conditions were found. Here salinity in the surface layer increased over the season from 10 to 25‰, whereas deeper than 5 m it was stable at around 35‰. Temperature at 0-5 m depth increased significantly over the season in both habitats, from 7 to 14 °C outside and 5 to 17 °C inside the lake. Despite differences in peak spawning and utilization of the lake habitat between the three putative populations, there was an apparent temporal and spatial overlap in spawning stages suggesting potential interbreeding in accordance with the metapopulation concept.

Evidence for spawning aggregations of the endangered Atlantic goliath grouper Epinephelus itajara in southern Brazil.

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Bueno, L S; Bertoncini, A A; Koenig, C C; Coleman, F C; Freitas, M O; Leite, J R; De Souza, T F; Hostim-Silva, M

2016-07-01

In this study, seasonal numerical abundance of the critically endangered Atlantic goliath grouper Epinephelus itajara was estimated by conducting scuba dive surveys and calculating sightings-per-unit-effort (SPUE) at three sites in southern Brazil. Seasonal differences in size and reproductive condition of captured or confiscated specimens were compared. The SPUE differed significantly with season, increasing in late spring and peaking during the austral summer months. A significant effect was observed in the number of fish relative to the lunar cycle. All females sampled during the summer were spawning capable, while all those sampled during other seasons were either regressing or regenerating. What these data strongly infer is that the E. itajara spawning aggregation sites have been located in the southern state of Paraná and the northern state of Santa Catarina and summer is the most likely spawning season. Size frequency distributions, abundance and reproductive state were estimated and correlated with environmental variables. © 2016 The Fisheries Society of the British Isles.

Arctic Cisco, Coregonus autumnalis, distribution, migration and spawning in the Mackenzie River

International Nuclear Information System (INIS)

Dillinger, R.E. Jr.; Birt, T.P.; Green, J.M.

1992-01-01

Oil exploration along the Beaufort Sea coast of North America has raised interest in populations of Arctic Cisco. A synopsis is presented of research on Arctic Cisco distributions and spawning activities in the Mackenzie River system. The distribution, migration, and spawning activities of Arctic Cisco in the tributaries of the Mackenzie River system were found to be more extensive than previously reported. The Peel River population had the earliest migration time, mid-July; however, a small movement of mature males upriver also occurred there in mid-September. Major movements of mature males and females took place in both late July and early to mid-Spetember in the Arctic Red River. Migrations in the other river systems occurred in late August and early September. Arctic Ciscoes in the only river south of Great Bear Lake that has been found to contain this species, the Liard River, may show a mixed life history strategy. The apparently long distance the fish must swim, the lack of any known populations in any of the rivers between the Liard and the Great Bear rivers, and the lack of evidence of migrations past Fort Simpson suggest that this population may contain non-anadromous forms. No actual spawning was seen in any of the populations, but possible areas were noted, one in the Peel River and one in the Liard River. 18 refs., 3 figs., 2 tabs

GIS-BASED EXPERIENCE OF INVESTIGATING THE STATUS OF SPAWNING AREAS WITHIN THE UPPER SECTION OF THE TSIMLYANSK RESERVOIR

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N. S. Kalioujnaia

2017-01-01

Full Text Available This paper presents a GIS-based research approach to investigating the status and dynamics of spawning areas of the Tsimlyansk Reservoir (within Volgograd Region, one of the largest inland fishery water bodies in the South of Russia.The spawning areas were considered in terms of the concept of ecotone origin, of the highly dynamic aquatic-terrestrial transitional environment in which temporary flooding is the main factor determining the diversity of spawning habitats, recruitment conditions, as well as ecosystem productivity.The processing and interpretation of Landsat images for the spring and low-water seasons for years between 2005 and 2016, in combination with other data (large-scale topographic maps, fishery research, and scientific papers allowed revealing the location of main spawning areas within the reservoir’s Upper section and to calculate their areas.For three case study sites located on the left bank of the reservoir, the main natural and anthropogenic factors determining the spawning conditions were identified. Retrospective analysis and synthesis of data on young fish composition and abundance between 1980 and today confirmed the importance of these sites for fish recruitment as well as the opportunities for their improvement by means of restoration measures.The output maps present the spatial distribution of the spawning areas and the environmental factors directly or indirectly affecting fish recruitment conditions. The most impacted areas have been determined, including the areas affected by abrasion, siltation and eutrophication processes, as well as pollution of the aquatic zone and water protection zone of the reservoir.The results of the research are useful both for understanding the general environmental conditions of the Tsimlyansk Reservoir and for supporting management decisions towards its improvement. 

Novel species interactions: American black bears respond to Pacific herring spawn.

Science.gov (United States)

Fox, Caroline Hazel; Paquet, Paul Charles; Reimchen, Thomas Edward

2015-05-26

In addition to the decline and extinction of the world's species, the decline and eventual loss of species interactions is one of the major consequences of the biodiversity crisis. On the Pacific coast of North America, diminished runs of salmon (Oncorhynchus spp.) drive numerous marine-terrestrial interactions, many of which have been intensively studied, but marine-terrestrial interactions driven by other species remain relatively unknown. Bears (Ursus spp.) are major vectors of salmon into terrestrial ecosystems, but their participation in other cross-ecosystem interactions is similarly poorly described. Pacific herring (Clupea pallasii), a migratory forage fish in coastal marine ecosystems of the North Pacific Ocean and the dominant forage fish in British Columbia (BC), spawn in nearshore subtidal and intertidal zones. Spawn resources (eggs, milt, and spawning adults) at these events are available to coastal predators and scavengers, including terrestrial species. In this study, we investigated the interaction between American black bears (Ursus americanus) and Pacific herring at spawn events in Quatsino Sound, BC, Canada. Using remote cameras to monitor bear activity (1,467 camera days, 29 sites, years 2010-2012) in supratidal and intertidal zones and a machine learning approach, we determined that the quantity of Pacific herring eggs in supratidal and intertidal zones was a leading predictor of black bear activity, with bears positively responding to increasing herring egg masses. Other important predictors included day of the year and Talitrid amphipod (Traskorchestia spp.) mass. A complementary analysis of black bear scats indicated that Pacific herring egg mass was the highest ranked predictor of egg consumption by bears. Pacific herring eggs constituted a substantial yet variable component of the early springtime diet of black bears in Quatsino Sound (frequency of occurrence 0-34%; estimated dietary content 0-63%). Other major dietary items included

Optimum Pathways of Fish Spawning Migrations in Rivers

Science.gov (United States)

McElroy, B. J.; Jacobson, R. B.; Delonay, A.

2010-12-01

Many fish species migrate large distances upstream in rivers to spawn. These migrations require energetic expenditures that are inversely related to fecundity of spawners. Here we present the theory necessary to quantify relative energetic requirements of upstream migration pathways and then test the hypothesis that least-cost paths are taken by the federally endangered pallid sturgeon (Scaphyrhyncus Albus), a benthic rheophile, in the lower Missouri River, USA. Total work done by a fish through a migratory path is proportional to the size of the fish, the total drag on the fish, and the distance traversed. Normalizing by the work required to remain stationary at the beginning of a path, relative work expenditure at each point of the path is found to be the cube of the ratio of the velocity along the path to the velocity at the start of the path. This is the velocity of the fish relative to the river flow. A least-cost migratory pathway can be determined from the velocity field in a reach as the path that minimizes a fish's relative work expenditure. We combine location data from pallid sturgeon implanted with telemetric tags and pressure-sensitive data storage tags with depth and velocity data collected with an acoustic Doppler profiler. During spring 2010 individual sturgeon were closely followed as they migrated up the Missouri River to spawn. These show that, within a small margin, pallid sturgeon in the lower Missouri River select least-cost paths as they swim upstream (typical velocities near 1.0 - 1.2 m/s). Within the range of collected data, it is also seen that many alternative paths not selected for migration are two orders of magnitude more energetically expensive (typical velocities near 2.0 - 2.5 m/s). In general these sturgeon migrated along the inner banks of bends avoiding high velocities in the thalweg, crossing the channel where the thalweg crosses in the opposite direction in order to proceed up the inner bank of subsequent bends. Overall, these

Hexamethylcyclopentadiene: time-resolved photoelectron spectroscopy and ab initio multiple spawning simulations

DEFF Research Database (Denmark)

Wolf, T. J. A.; Kuhlman, Thomas Scheby; Schalk, O.

2014-01-01

comparing time-resolved photoelectron spectroscopy (TRPES) with ab initio multiple spawning (AIMS) simulations on the MS-MR-CASPT2 level of theory. We disentangle the relationship between two phenomena that dominate the immediate molecular response upon light absorption: a spectrally dependent delay...

Rearing in seawater mesocosms improves the spawning performance of growth hormone transgenic and wild-type coho salmon.

Directory of Open Access Journals (Sweden)

Rosalind A Leggatt

Full Text Available Growth hormone (GH transgenes can significantly accelerate growth rates in fish and cause associated alterations to their physiology and behaviour. Concern exists regarding potential environmental risks of GH transgenic fish, should they enter natural ecosystems. In particular, whether they can reproduce and generate viable offspring under natural conditions is poorly understood. In previous studies, GH transgenic salmon grown under contained culture conditions had lower spawning behaviour and reproductive success relative to wild-type fish reared in nature. However, wild-type salmon cultured in equal conditions also had limited reproductive success. As such, whether decreased reproductive success of GH transgenic salmon is due to the action of the transgene or to secondary effects of culture (or a combination has not been fully ascertained. Hence, salmon were reared in large (350,000 L, semi-natural, seawater tanks (termed mesocosms designed to minimize effects of standard laboratory culture conditions, and the reproductive success of wild-type and GH transgenic coho salmon from mesocosms were compared with that of wild-type fish from nature. Mesocosm rearing partially restored spawning behaviour and success of wild-type fish relative to culture rearing, but remained lower overall than those reared in nature. GH transgenic salmon reared in the mesocosm had similar spawning behaviour and success as wild-type fish reared in the mesocosm when in full competition and without competition, but had lower success in male-only competition experiments. There was evidence of genotype×environmental interactions on spawning success, so that spawning success of transgenic fish, should they escape to natural systems in early life, cannot be predicted with low uncertainty. Under the present conditions, we found no evidence to support enhanced mating capabilities of GH transgenic coho salmon compared to wild-type salmon. However, it is clear that GH transgenic

2008 Spawning Cisco Investigations in the Canadian Waters of Lake Superior

Science.gov (United States)

Yule, Daniel; Addison, Peter A.; Evrard, Lori M.; Cullis, Ken I.; Cholwek, Gary A.

2009-01-01

The Great Lakes Science Center of the United States Geological Survey (USGS) is working cooperatively with the Ontario Ministry of Natural Resources (OMNR) on a threeyear study to develop standard procedures for acoustic and midwater trawl (AC-MT) assessments of spawning cisco Coregonus artedi that the OMNR can carry forward as a management activity. In year two (2008), we conducted an AC-MT survey of the northern shore from Nipigon Bay to Thunder Bay. Spawning-cisco (> 250 mm total length) densities were lowest near Nipigon Bay (cisco in Thunder Bay during the 2008 fishery at 4% for ages 1-5, 8.7% for ages 6-12, and 4.4% for ages ≥ 13. Lake Superior fishery managers recently recommended that annual exploitation of adult female lake cisco be kept below 10-15%. Recruitment of cisco since 2003 has been low and there is a strong probability the Thunder Bay stock will decline into the future. Using a simple population dynamics approach we estimated that if the current total allowable catch (TAC) quota is held constant, exploitation fractions could exceed 10% by 2010 and 15% by 2011. Our 2008 collections suggested the survey of Black Bay was likely conducted before all spawners had returned there to spawn. Our data also suggested that cisco collected in Black Bay and east of this site in mid-November may be from the same stock. During November 2009 we will attempt to get better definition of the area occupied by cisco around Black Bay and also determine when surveys should be conducted at this location.

Characterizing and predicting the distribution of Baltic Sea flounder (Platichthys flesus) during the spawning season

DEFF Research Database (Denmark)

Orio, Alessandro; Bergström, Ulf; Casini, Michele

2017-01-01

, both displaying ecological and physiological adaptations to the low-salinity environment of this young inland sea. In this study we have addressed three main research questions: 1) What environmental conditions characterize the spatial distribution and abundance of adult flounder during the spawning...... a decrease in habitat availability for the pelagic spawning flounder over the last 20 years in the central part of the Baltic Sea, which may explain part of the observed changes in populations' biomass. We conclude that spatiotemporal modelling of habitat availability can improve our understanding of fish...

Satellite monitoring temperature conditions spawning area of the Northeast Arctic cod in the Norwegian Sea and assessment its abundance

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Vanyushin, George; Bulatova, Tatiana; Klochkov, Dmitriy; Troshkov, Anatoliy; Kruzhalov, Michail

2013-04-01

In this study, the attempt to consider the relationship between sea surface anomalies of temperature (SST anomalies °C) in spawning area of the Norwegian Arctic cod off the Lofoten islands in coastal zone of the Norwegian Sea and modern cod total stock biomass including forecasting assessment of future cod generation success. Continuous long-term database of the sea surface temperature (SST) was created on the NOAA satellites data. Mean monthly SST and SST anomalies are computed for the selected area on the basis of the weekly SST maps for the period of 1998-2012. These maps were plotted with the satellite SST data, as well as information of vessels, byoies and coastal stations. All data were classified by spawning seasons (March-April) and years. The results indicate that poor and low middle generations of cod (2001, 2006, 2007) occurred in years with negative or extremely high positive anomalies in the spawning area. The SST anomalies in years which were close to normal or some more normal significances provide conditions for appearance strong or very strong generations of cod (1998, 2000, 2002, 2004, 2005, 2006, 2008, 2009). Temperature conditions in concrete years influence on different indexes of cod directly. So, the mean temperature in spawning seasons in years 1999-2005 was ≈5,0°C and SST anomaly - +0,35°C, by the way average year significances indexes of cod were: total stock biomass - 1425,0 th.t., total spawning biomass - 460,0 th.t., recruitment (age 3+) - 535,0 mln. units and landings - 530,0 th.t. In spawning seasons 2006-2012 years the average data were following: mean SST ≈6,0°C, SST anomaly - +1,29°C, total stock biomass - 2185,0 th.t., total spawning biomass - 1211,0 th.t., recruitment (age 3+) - 821,0 mln. units and landings - 600,0 th.t. The SST and SST anomalies (the NOAA satellite data) characterize increase of decrease in input of warm Atlantic waters which form numerous eddies along the flows of the main warm currents thus creating

Identification of the Spawning, Rearing, and Migratory Requirements of Fall Chinook Salmon in the Columbia River Basin, Annual Report 1993.

Energy Technology Data Exchange (ETDEWEB)

Rondorf, Dennis W.; Tiffan, Kenneth F.

1994-12-01

Recovery efforts for the endangered fall chinook salmon necessitates knowledge of the factors limiting the various life history stages. This study attempts to identify those physical and biological factors which affect spawning of the fish in the free-flowing Snake River and their rearing seward migration through Columbia River basin reservoirs. The spawning was generally a November event in 1993, with some activity in late Oct. and early Dec. Spawning habitat availability was assessed by applying hydraulic and habitat models to known fall chinook salmon spawning sites. Juveniles were seined and PIT tagged in the free-flowing Snake River, and in the Columbia River in he Hanford Reach and in McNary Reservoir. Subyearling fish were marked at McNary Dam to relate river flow and migration patterns of juveniles to adult returns. Hydroacoustic surveys were conducted on McNary and John Day reservoirs and in net pens.

Hierarchical Bayesian Markov switching models with application to predicting spawning success of shovelnose sturgeon

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Holan, S.H.; Davis, G.M.; Wildhaber, M.L.; DeLonay, A.J.; Papoulias, D.M.

2009-01-01

The timing of spawning in fish is tightly linked to environmental factors; however, these factors are not very well understood for many species. Specifically, little information is available to guide recruitment efforts for endangered species such as the sturgeon. Therefore, we propose a Bayesian hierarchical model for predicting the success of spawning of the shovelnose sturgeon which uses both biological and behavioural (longitudinal) data. In particular, we use data that were produced from a tracking study that was conducted in the Lower Missouri River. The data that were produced from this study consist of biological variables associated with readiness to spawn along with longitudinal behavioural data collected by using telemetry and archival data storage tags. These high frequency data are complex both biologically and in the underlying behavioural process. To accommodate such complexity we developed a hierarchical linear regression model that uses an eigenvalue predictor, derived from the transition probability matrix of a two-state Markov switching model with generalized auto-regressive conditional heteroscedastic dynamics. Finally, to minimize the computational burden that is associated with estimation of this model, a parallel computing approach is proposed. ?? Journal compilation 2009 Royal Statistical Society.

Spawning segregation and philopatry are major prezygotic barriers in sympatric cryptic Mugil cephalus species.

Science.gov (United States)

Shen, Kang-Ning; Chang, Chih-Wei; Durand, Jean-Dominique

2015-12-01

The flathead mullet, Mugil cephalus, is a commercially vital fish in fisheries and aquaculture worldwide. Genetic analyses have recently revealed three cryptic species of M. cephalus in the Northwest Pacific. These species are sympatric in Taiwanese waters and specific reproductive behaviors have been suggested to be a major prezygotic barrier. Species composition was evaluated in samples of M. cephalus at different growth stages collected from various habitats (offshore spawning ground, estuarine nursery and feeding areas) over several months or years. The gonadosomatic index of adults and the body length of juveniles were recorded to determine the reproductive season and recruitment periods in estuaries. The results revealed partially temporal spawning isolation between species pairs, spatial segregation on specific spawning grounds and strong philopatry preclude hybridization. Thus, the results imply that traditional fisheries of mature fish in the Taiwan Strait target only one species, whereas aquaculture in Taiwan contain juveniles of all three species collected in estuaries. The ecological niche and demography of these species must be investigated further to estimate the impact of juvenile sources on aquaculture. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregation.

Science.gov (United States)

Karkarey, Rucha; Zambre, Amod; Isvaran, Kavita; Arthur, Rohan

2017-02-28

At high densities, terrestrial and marine species often employ alternate reproductive tactics (ARTs) to maximize reproductive benefits. We describe ARTs in a high-density and unfished spawning aggregation of the squaretail grouper (Plectropomus areolatus) in Lakshadweep, India. As previously reported for this species, territorial males engage in pair-courtship, which is associated with a pair-spawning tactic. Here, we document a previously unreported school-courtship tactic; where territorial males court multiple females in mid-water schools, which appears to culminate in a unique 'school-spawning' tactic. Courtship tactics were conditional on body size, local mate density and habitat, likely associated with changing trade-offs between potential mating opportunities and intra-sexual competition. Counter-intuitively, the aggregation showed a habitat-specific inverse size-assortment: large males courted small females on the reef slope while small males courted equal-sized or larger females on the shelf. These patterns remained stable across two years of observation at high, unfished densities. These unique density-dependent behaviours may disappear from this aggregation as overall densities decline due to increasing commercial fishing pressure, with potentially large consequences for demographics and fitness.

Predicting the Influence of Streamflow on Migration and Spawning of a Threatened Diadromous Fish, the Australian Grayling Prototroctes Maraena

Science.gov (United States)

Koster, W. M.; Crook, D. A.; Dawson, D. R.; Gaskill, S.; Morrongiello, J. R.

2018-03-01

The development of effective strategies to restore the biological functioning of aquatic ecosystems with altered flow regimes requires a detailed understanding of flow-ecology requirements, which is unfortunately lacking in many cases. By understanding the flow conditions required to initiate critical life history events such as migration and spawning, it is possible to mitigate the threats posed by regulated river flow by providing targeted environmental flow releases from impoundments. In this study, we examined the influence of hydrological variables (e.g., flow magnitude), temporal variables (e.g., day of year) and spatial variables (e.g., longitudinal position of fish) on two key life history events (migration to spawning grounds and spawning activity) for a threatened diadromous fish (Australian grayling Prototroctes maraena) using data collected from 2008 to 2015 in the Bunyip-Tarago river system in Victoria. Our analyses revealed that flow changes act as a cue to downstream migration, but movement responses differed spatially: fish in the upper catchment showed a more specific requirement for rising discharge to initiate migration than fish in the lower catchment. Egg concentrations peaked in May when weekly flows increased relative to the median flow during a given spawning period. This information has recently been incorporated into the development of targeted environmental flows to facilitate migration and spawning by Australian grayling in the Bunyip-Tarago river system and other coastal systems in Victoria.

Ecotoxicity of Lake Druksiai waters assessed by biotesting with rainbow trout spawn and larvae

International Nuclear Information System (INIS)

Kazlauskiene, N.; Cepuliene, Z.

1998-01-01

The toxicity of Lake Druksiai was assessed by testing with spawn and larvae of rainbow trout (Oncorhynchus mykiss). We sampled Ignalina NPP waste waters of various biotopes of the lake. Larvae of trout were found to be more sensitive to wastewaters than spawn. The hatching stage was one of the most sensitive stages in ontogenesis. Our data showed that the wastewater of Ignalina NPP was the most toxic, however waters of some biotopes of the lake were also toxic. That suggested that toxicants discharged into cooling reservoirs with NPP wastewater might affect test-organisms, disturbing their development and growth. The observed effects were irreversible and caused death. (author)

Mass coral spawning: A natural large-scale nutrien t addition experiment

DEFF Research Database (Denmark)

Eyre, B.D.; Glud, Ronnie Nøhr; Patten, N.

2008-01-01

A mass coral spawning event on the Heron Island reef flat in 2005 provided a unique opportunity to examine the response of a coral reef ecosystem to a large episodic nutrient addition. A post-major spawning phytoplankton bloom resulted in only a small drawdown of dissolved inorganic phosphorus (DIP......), and dissolved organic phosphorus were used in the production of biomass, and mass balance calculations highlighted the importance of organic forms of N and P for benthic and pelagic production in tropical coral reef environments characterized by low inorganic N and P. The input of N and P via the deposition...... potential N limitation of benthic coral reef communities. For example, there was sufficient bioavailable P stored in the top 10 cm of the sediment column to sustain the prespawning rates of benthic production for over 200 d. Most of the change in benthic N cycling occurred via DON and N-2 pathways, driven...

Reproduction and spawning habitat of white trevally, Pseudocaranx dentex, in the Azores, central north Atlantic

Directory of Open Access Journals (Sweden)

Pedro Afonso

2008-06-01

Full Text Available Reproductive biology and habitat preferences of the white trevally, Pseudocaranx dentex (Carangidae, were studied in the Azores islands, central north Atlantic, to determine the spatial and seasonal dynamics of habitat use of immature and mature fish. The sex ratio was close to 1:1 and fish matured at about 30 cm fork length. There were no differences in the maturation or length-weight relationships between sexes. The spawning season lasts from June to September. Underwater visual censuses showed that schools of mature individuals preferentially aggregate around the summits of offshore reefs during the spawning season. In contrast, schools of smaller, immature fish use inshore habitats all year round. Our data support the hypothesis that offshore reefs are a preferential spawning habitat of larger white trevally, and most possibly for a number of visitor pelagic predators as well. Inverse relationships between exploitation levels, abundance and size composition at the two different islands suggest that the summer fishery targeting trevally schools around offshore reefs has negatively impacted the population. These findings bring additional ecological and management relevance to offshore reefs.

Reproductive neuropeptides that stimulate spawning in the Sydney Rock Oyster (Saccostrea glomerata).

Science.gov (United States)

In, Vu Van; Ntalamagka, Nikoleta; O'Connor, Wayne; Wang, Tianfang; Powell, Daniel; Cummins, Scott F; Elizur, Abigail

2016-08-01

The Sydney Rock Oyster, Saccostrea glomerata, is a socioeconomically important species in Australia, yet little is known about the molecular mechanism that regulates its reproduction. To address this gap, we have performed a combination of high throughput transcriptomic and peptidomic analysis, to identify genes and neuropeptides that are expressed in the key regulatory tissues of S. glomerata; the visceral ganglia and gonads. Neuropeptides are known to encompass a diverse class of peptide messengers that play functional roles in many aspects of an animal's life, including reproduction. Approximately 28 neuropeptide genes were identified, primarily within the visceral ganglia transcriptome, that encode precursor proteins containing numerous neuropeptides; some were confirmed through mass spectral peptidomics analysis of the visceral ganglia. Of those, 28 bioactive neuropeptides were synthesized, and then tested for their capacity to induce gonad development and spawning in S. glomerata. Egg laying hormone, gonadotropin-releasing hormone, APGWamide, buccalin, CCAP and LFRFamide were neuropeptides found to trigger spawning in ripe animals. Additional testing of APGWa and buccalin demonstrated their capacity to advance conditioning and gonadal maturation. In summary, our analysis of S. glomerata has identified neuropeptides that can influence the reproductive cycle of this species, specifically by accelerating gonadal maturation and triggering spawning. Other molluscan neuropeptides identified in this study will enable further research into understanding the neuroendocrinology of oysters, which may benefit their cultivation. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

AFSC/ABL: Stock composition, timing, and spawning distribution of Yukon River Chinook salmon

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National Oceanic and Atmospheric Administration, Department of Commerce — Radio telemetry was used to determine the distribution, locate spawning sites, and evaluate the tagging response of wild Chinook salmon Oncorhynchus tshawytscha...

Catchment source contributions to the sediment-bound organic matter degrading salmonid spawning gravels in a lowland river, southern England

Energy Technology Data Exchange (ETDEWEB)

Collins, A.L., E-mail: adrian.collins@adas.co.uk [ADAS, Pendeford House, Wobaston Road, Wolverhampton WV9 5AP (United Kingdom); Geography and Environment, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Williams, L.J.; Zhang, Y.S. [ADAS, Pendeford House, Wobaston Road, Wolverhampton WV9 5AP (United Kingdom); Marius, M. [Civil Engineering and Environment, University of Southampton, Highfield, Southampton S017 1BJ (United Kingdom); Dungait, J.A.J. [Department of Sustainable Systems and Grassland Science, Rothamsted Research—North Wyke, Okehampton, Devon EX20 2SB (United Kingdom); Smallman, D.J. [Civil Engineering and Environment, University of Southampton, Highfield, Southampton S017 1BJ (United Kingdom); Dixon, E.R. [Department of Sustainable Systems and Grassland Science, Rothamsted Research—North Wyke, Okehampton, Devon EX20 2SB (United Kingdom); Stringfellow, A. [Civil Engineering and Environment, University of Southampton, Highfield, Southampton S017 1BJ (United Kingdom); Sear, D.A. [Geography and Environment, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Jones, J.I. [School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom); Naden, P.S. [CEH Wallingford, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB (United Kingdom)

2013-07-01

The ingress of particulate material into freshwater spawning substrates is thought to be contributing to the declining success of salmonids reported over recent years for many rivers. Accordingly, the need for reliable information on the key sources of the sediment problem has progressed up the management agenda. Whilst previous work has focussed on apportioning the sources of minerogenic fine sediment degrading spawning habitats, there remains a need to develop procedures for generating corresponding information for the potentially harmful sediment-bound organic matter that represents an overlooked component of interstitial sediment. A source tracing procedure based on composite signatures combining bulk stable {sup 13}C and {sup 15}N isotope values with organic molecular structures detected using near infrared (NIR) reflectance spectroscopy was therefore used to assess the primary sources of sediment-bound organic matter sampled from artificial spawning redds. Composite signatures were selected using a combination of the Kruskal–Wallis H-test, principal component analysis and GA-driven discriminant function analysis. Interstitial sediment samples were collected using time-integrating basket traps which were inserted at the start of the salmonid spawning season and extracted in conjunction with critical phases of fish development (eyeing, hatch, emergence, late spawning). Over the duration of these four basket extractions, the overall relative frequency-weighted average median (± 95% confidence limits) source contributions to the interstitial sediment-bound organic matter were estimated to be in the order: instream decaying vegetation (39 ± < 1%; full range 0–77%); damaged road verges (28 ± < 1%; full range 0–77%); septic tanks (22 ± < 1%; full range 0–50%), and; farm yard manures/slurries (11 ± < 1%; full range 0–61%). The reported procedure provides a promising basis for understanding the key sources of interstitial sediment-bound organic matter

Dose-dependent effect of a single GnRHa injection on the spawning of meagre (Argyrosomus regius broodstock reared in captivity

Directory of Open Access Journals (Sweden)

Hipolito Fernandez-Palacios

2014-10-01

Full Text Available The present study aimed to determine the spawning efficacy, egg quality and quantity of captive breed meagre induced with a single gonadotrophin‐releasing hormone agonist (GnRHa injection of 0, 1, 5, 10, 15, 20, 25, 30, 40 or 50 µg kg-1 to determine a recommended optimum dose to induce spawning. The doses 10, 15 and 20 μg kg-1 gave eggs with the highest quality (measured as: percentage of viability, floating, fertilisation and hatch and quantity (measured as: total number of eggs, number of viable eggs, number of floating eggs, number of hatched larvae and number of larvae that reabsorbed the yolk sac. All egg quantity parameters were described by Gaussian regression analysis with R2=0.89 or R2=0.88. The Gaussian regression analysis identified that the optimal dose used was 15 μg kg-1. The regression analysis highlighted that this comprehensive study examined doses that ranged from low doses insufficient to stimulate a high spawning response (significantly lower egg quantities, p<0.05 compared to 15 μg kg-1 through to high doses that stimulated the spawning of significantly lower egg quantities and eggs with significantly lower quality (egg viability. In addition, the latency period (time from hormone application to spawning decreased with increasing doses to give a regression (R2=0.93 which suggests that higher doses accelerated oocyte development that in turn reduced egg quality and quantity. The identification of an optimal dose for the spawning of meagre, which has high aquaculture potential, represents an important advance for the Mediterranean aquaculture industry.

Efficient induction of spawning of northern leopard frogs (Lithobates pipiens) during and outside the natural breeding season.

Science.gov (United States)

Trudeau, Vance L; Schueler, Frederick W; Navarro-Martin, Laia; Hamilton, Christine K; Bulaeva, Elizabeth; Bennett, Amanda; Fletcher, William; Taylor, Lisa

2013-02-25

Amphibian declines are now recognized globally. It is also well known that many anurans do not reproduce easily in captivity, especially when held over long periods, or if they require hibernation before breeding. A simple method to induce spawning and subsequent development of large numbers of healthy tadpoles is therefore required to meet research and conservation goals. The method is based on simultaneous injection of both female and male leopard frogs, Lithobates pipiens (formerly called Rana pipiens) with a cocktail of a gonadotropin-releasing hormone agonist (GnRH-A) and a dopamine antagonist. We call this the AMPHIPLEX method, which is derived from the combination of the words amphibian and amplexus. Following injection, the animals are thereby induced, and perform amplexus and natural fertilization under captive conditions. We tested combinations of a GnRH agonist with 2 different dopamine antagonists in L. pipiens in the breeding season. The combination of des-Gly(10), D-Ala(6), Pro-NHEt(9)-GnRH (0.4 micrograms/g body weight; GnRH-A) with metoclopramide hydrochloride (10 micrograms/g body weight; MET) or domperidone (DOM) were equally effective, producing 89% and 88% successful spawning, respectively. This yielded more than 44,000 eggs for the 16/18 females that ovulated in the GnRH-A+MET group, and more than 39,000 eggs for the 15/17 females that ovulated in the GnRH-A+DOM group. We further tested the GnRH-A+MET in frogs collected in the wild in late autumn and hibernated for a short period under laboratory conditions, and report a low spawning success (43%). However, GnRH-A priming 24 hours prior to injections of the GnRH-A+MET cocktail in animals hibernated for 5-6 weeks produced out-of-season spawning (89%) and fertilization (85%) comparable to those we observed for in-season spawning. Assessment of age and weight at metamorphosis indicated that L. pipiens tadpoles resulting from out-of-season spawning grew normally and metamorphosed successfully. We

Shelf spawning habitat of Emmelichthys nitidus in south-eastern Australia - Implications and suitability for egg-based biomass estimation

Science.gov (United States)

Neira, Francisco J.; Lyle, Jeremy M.; Keane, John P.

2009-03-01

The spawning habitat of Emmelichthys nitidus (Emmelichthyidae) in south-eastern Australia is described from vertical ichthyoplankton samples collected along the shelf region off eastern through to south-western Tasmania during peak spawning in October 2005-06. Surveys covered eastern waters in 2005 (38.8-43.5°S), and both eastern and southern waters in 2006 (40.5°S around to 43.5°S off the south-west). Eggs ( n = 10,393) and larvae ( n = 378) occurred along eastern Tasmania in both years but were rare along southern waters south and westwards of 43.5°S in 2006. Peak egg abundances (1950-2640 per m -2) were obtained off north-eastern Tasmania (40.5-41.5°S) between the shelf break and 2.5 nm inshore from the break. Eggs were up to 5-days old, while nearly 95% of larvae were at the early preflexion stage, i.e. close to newly emerged. Average abundances of aged eggs pooled across each survey declined steadily from day-1 to day-5 eggs both in 2005 (97-18) and 2006 (175-34). Moreover, day-1 egg abundances were significantly greater 2.5 nm at either side of the break, including at the break, than in waters ≥5 nm both inshore and offshore from the break. These results, complemented with egg and larval data obtained in shelf waters off New South Wales (NSW; 35.0-37.7°S) in October 2002-03, indicate that the main spawning area of E. nitidus in south-eastern Australia lies between 35.5°S off southern NSW and 43.5°S off south-eastern Tasmania, and that spawning activity declines abruptly south and westwards of 43.5°S around to the south-west coast. In addition, quotient analyses of day-1 egg abundances point to a preferred spawning habitat contained predominantly within a 5 nm corridor along the shelf break, where waters are 125-325 m deep and median temperatures 13.5-14.0 °C. Spawning off eastern Tasmania is timed with the productivity outburst typical of the region during the austral spring, and the temperature increase from the mixing between the southwards

Catchment source contributions to the sediment-bound organic matter degrading salmonid spawning gravels in a lowland river, southern England

International Nuclear Information System (INIS)

Collins, A.L.; Williams, L.J.; Zhang, Y.S.; Marius, M.; Dungait, J.A.J.; Smallman, D.J.; Dixon, E.R.; Stringfellow, A.; Sear, D.A.; Jones, J.I.; Naden, P.S.

2013-01-01

The ingress of particulate material into freshwater spawning substrates is thought to be contributing to the declining success of salmonids reported over recent years for many rivers. Accordingly, the need for reliable information on the key sources of the sediment problem has progressed up the management agenda. Whilst previous work has focussed on apportioning the sources of minerogenic fine sediment degrading spawning habitats, there remains a need to develop procedures for generating corresponding information for the potentially harmful sediment-bound organic matter that represents an overlooked component of interstitial sediment. A source tracing procedure based on composite signatures combining bulk stable 13 C and 15 N isotope values with organic molecular structures detected using near infrared (NIR) reflectance spectroscopy was therefore used to assess the primary sources of sediment-bound organic matter sampled from artificial spawning redds. Composite signatures were selected using a combination of the Kruskal–Wallis H-test, principal component analysis and GA-driven discriminant function analysis. Interstitial sediment samples were collected using time-integrating basket traps which were inserted at the start of the salmonid spawning season and extracted in conjunction with critical phases of fish development (eyeing, hatch, emergence, late spawning). Over the duration of these four basket extractions, the overall relative frequency-weighted average median (± 95% confidence limits) source contributions to the interstitial sediment-bound organic matter were estimated to be in the order: instream decaying vegetation (39 ± road verges > septic tanks > farm manures

Evidence for migratory spawning behavior by morphologically distinct Cisco (Coregonus artedi) from a small inland lake

Science.gov (United States)

Ross, Alexander J.; Weidel, Brian C.; Leneker, Mellisa; Solomon, Christopher T.

2017-01-01

Conservation and management of rare fishes relies on managers having the most informed understanding of the underlying ecology of the species under investigation. Cisco (Coregonus artedi), a species of conservation concern, is a cold-water pelagic fish that is notoriously variable in morphometry and life history. Published reports indicate, at spawning time, Cisco in great lakes may migrate into or through large rivers, whereas those in small lakes move inshore. Nonetheless, during a sampling trip to Follensby Pond, a 393 ha lake in the Adirondack Mountains, New York, we observed gravid Cisco swimming over an outlet sill from a narrow shallow stream and into the lake. We opportunistically dip-netted a small subsample of 11 individuals entering the lake from the stream (three female, eight male) and compared them to fish captured between 2013 and 2015 with gillnets in the lake. Stream-captured Cisco were considerably larger than lake-captured individuals at a given age, had significantly larger asymptotic length, and were present only as mature individuals between age of 3 and age 5. These results could suggest either Cisco are migrating from a nearby lake to spawn in Follensby Pond, or that a distinct morphotype of Cisco from Follensby Pond migrates out to the stream and then back in at spawning time. Our results appear to complement a handful of other cases in which Cisco spawning migrations have been documented and to provide the first evidence for such behavior in a small inland lake.

Effects of Hydroelectric Dam Operations on the Restoration Potential of Snake River Fall Chinook Salmon (Oncorhynchus tshawytscha) Spawning Habitat Final Report, October 2005 - September 2007.

Energy Technology Data Exchange (ETDEWEB)

Hanrahan, Timothy P.; Richmond, Marshall C.; Arntzen, Evan V. [Pacific Northwest National Laboratory

2007-11-13

This report describes research conducted by the Pacific Northwest National Laboratory for the Bonneville Power Administration (BPA) as part of the Fish and Wildlife Program directed by the Northwest Power and Conservation Council. The study evaluated the restoration potential of Snake River fall Chinook salmon spawning habitat within the impounded lower Snake River. The objective of the research was to determine if hydroelectric dam operations could be modified, within existing system constraints (e.g., minimum to normal pool levels; without partial removal of a dam structure), to increase the amount of available fall Chinook salmon spawning habitat in the lower Snake River. Empirical and modeled physical habitat data were used to compare potential fall Chinook salmon spawning habitat in the Snake River, under current and modified dam operations, with the analogous physical characteristics of an existing fall Chinook salmon spawning area in the Columbia River. The two Snake River study areas included the Ice Harbor Dam tailrace downstream to the Highway 12 bridge and the Lower Granite Dam tailrace downstream approximately 12 river kilometers. These areas represent tailwater habitat (i.e., riverine segments extending from a dam downstream to the backwater influence from the next dam downstream). We used a reference site, indicative of current fall Chinook salmon spawning areas in tailwater habitat, against which to compare the physical characteristics of each study site. The reference site for tailwater habitats was the section extending downstream from the Wanapum Dam tailrace on the Columbia River. Fall Chinook salmon spawning habitat use data, including water depth, velocity, substrate size and channelbed slope, from the Wanapum reference area were used to define spawning habitat suitability based on these variables. Fall Chinook salmon spawning habitat suitability of the Snake River study areas was estimated by applying the Wanapum reference reach habitat

Use of wild trout for PBDE assessment in freshwater environments: Review and summary of critical factors

Directory of Open Access Journals (Sweden)

Juan M. Ríos

2015-11-01

Full Text Available Certain wild animals represent sentinels to address issues related to environmental pollution, since they can provide integrative data on both pollutant exposure and biological effects. Despite their technological benefits, PBDEs are considered a threat to environmental health due to their persistence, toxicity, and capacity to be accumulated. These pollutants have been found geographically widespread in fish, particularly in predator species such as trout. The aim of this work is to critically review the applicability and usefulness of wild trout for assessing PBDEs in freshwater environments. Reviewed reports include data from highly industrialized areas as well as areas from remote regions with relatively low human activity, including European and North American great lakes and freshwater environments in Europe, Greenland, subarctic areas and Patagonia, respectively. A summary of relevant factors were grouped into organism-specific factors (food habits, age, size, lipid content, sex and reproduction, tissue type, mechanism of contaminant uptake and metabolism, and PBDE levels in the surrounding environment (sediment. Five wild trout species [rainbow trout (Oncorhynchus mykiss, brown trout (Salmo trutta, lake trout (Salvelinus namaycush, arctic char (Salvelinus alpinus, and brook trout (Salvelinus fontinalis], collected worldwide within the 1994 to present time frame, were considered. Multivariate techniques (principal component analysis-PCA and mapping approach, showed clear differences in geographic distribution patterns of PBDE levels in trout depending on the region studied: wild trout from European and North American great lakes have the highest PBDE loads. This pattern could be due to high industrial activity at these locations. A correlational approach used to explore intraspecific relationships between PBDE levels and morphometry, showed positive relationships only for brown trout. Further, brown trout showed the highest trout

Thallium in spawn, juveniles, and adult common toads (Bufo bufo) living in the vicinity of a zinc-mining complex, Poland.

Science.gov (United States)

Dmowski, Krzysztof; Rossa, Monika; Kowalska, Joanna; Krasnodębska-Ostręga, Beata

2015-01-01

A breeding population of the common toad Bufo bufo living in the vicinity of a Zn-Pb smelting works in Bukowno, Poland was studied for the presence of thallium. Tl concentration was measured in the bottom sediments of the spawning pond, in the laid eggs, in juveniles after metamorphosis, and in the selected tissues of the adult individuals. A very high concentration of Tl was detected in the spawn (13.97 ± 8.90 mg/kg d.w.). In 50% of the spawn samples, levels exceeded 20 mgTl/kg d.w. The issue of maternal transfer of thallium from females to oocytes is discussed. Due to a significant accumulation of thallium, spawn analysis can be used as a sensitive indicator of the presence of this element in the environment and may replace more invasive methods that involve the killing of adult animals. In those regions that are abundant in Zn-Pb ores, the spawn of amphibians may be a very important source of thallium contamination for predators. From among all tissues of the Bukowno adult toads, the livers have shown the highest accumulation of thallium (mean 3.98 mg/kg d.w. and maximum value--18.63). For as many as 96.5% of livers, concentrations exceeded 1.0 mgTl/kg d.w. which is treated as indicative of poisoning.

Hydrographic influence on the spawning habitat suitability of western Baltic cod (Gadus morhua)

DEFF Research Database (Denmark)

Hüssy, K.; Hinrichsen, H.-H.; Huwer, B.

2012-01-01

Hydrographic influence on the spawning habitat suitability of western Baltic cod (Gadus morhua) – ICES Journal of Marine Science, 69: 1736–1743.Recruitment variability of marine fish is influenced by the reproductive potential of the stock (i.e. stock characteristics and abundance) and the survival...... of early life stages, mediated by environmental conditions of both a physical (water temperature, salinity and oxygen conditions, ocean currents) and a biological nature (i.e. food, predators). The objective of this study is to assess the importance of variability in environmental conditions within...... allowing survival of western Baltic cod eggs indicates that favourable conditions predominantly occurred during the late spawning season in April/May, while minimum survival rates could be expected from January to March. Unsuitable time periods and habitats exhibiting the highest mortality rates...

Spawning Induction System of Puntius javanicus using Common Carp as a Trigger

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M. Zairin Junior

2007-07-01

Full Text Available This study was carried out to determine the effect of induction using common carp as a trigger on spawning of Puntius javanicus.  Mature male and female of Puntius javanicus were reared in outer of the hapa that contains mature male common carp, mature female common carp, or mature male and female common carp as a control.  Common carp broodstock was injected or not injected by ovaprim.  The result of study show that the use of male common carp injected or not injected by ovaprim could induced spawning of Puntius javanicus, without the release of sperm and eggs of common carp.   Fertilization rate of Puntius javanicus eggs was high, reached of 91.4%, by using ovaprim-injected male common carp as trigger. Keywords: Puntius javanicus, common carp, Cyprinus carpio, spawning, induction system   ABSTRAK Penelitian ini dilakukan untuk mengetahui pengaruh sistem imbas menggunakan ikan mas (Cyprinus carpio sebagai pemicu terhadap pemijahan ikan tawes (Puntius javanicus. Induk ikan tawes jantan dan betina yang telah matang gonad ditempatkan di luar hapa tempat ikan mas jantan matang gonad, ikan mas betina matang gonad, atau sepasang ikan mas matang gonad sebagai perlakuan kontrol. Induk ikan mas disuntik atau tidak dengan ovaprim.  Hasil penelitian menunjukkan bahwa penggunaan ikan mas yang disuntik ovaprim maupun tidak, dapat mengimbas ikan tawes untuk memijah meskipun tidak terjadi pengeluaran sperma dan telur ikan mas. Derajat pembuahan telur ikan tawes cukup tinggi, mencapai 91,4%, pada perlakuan induksi ikan mas jantan yang disuntik ovaprim. Kata kunci: Puntius javanicus, common carp, Cyprinus carpio, pemijahan, sistem imbas

First attempt to assess the viability of bluefin tuna spawning events in offshore cages located in an a priori favourable larval habitat

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Patricia Reglero

2013-10-01

Full Text Available Most of the Atlantic bluefin tuna caught by the purse-seine fleet in the Mediterranean Sea are transferred alive into transport cages and towed to coastal facilities where they are fattened. This major fishery is targeting aggregations of reproductive bluefin tuna that continue spawning within the transport cages. Our study is the first attempt to assess the viability of the spawning events within transport cages placed offshore in a priori favourable locations for larval survival. The study was conducted in June 2010 in the Balearic Sea, a main spawning area for bluefin tuna in the Mediterranean. The location of two transport cages, one with wild and one with captive tuna, coincide with the situation of the chlorophyll front using satellite imagery as a proxy for the salinity front between resident surface waters and those of recent Atlantic origin. The results showed that bluefin tuna eggs were spawned almost every day within the two cages but few or no larvae were found. The expected larval densities estimated after applying mortality curves to the daily egg densities observed in the cages were higher than the sampled larval densities. The trajectories of the eggs after hatching estimated from a particle tracking model based on observed geostrophic currents and a drifter deployed adjacent to the cage suggest that larvae were likely to be caught close to the cages within the sampling dates. Spawning events in captive tuna in transport cages may hatch into larvae though they may experience higher mortality rates than expected in natural populations. The causes of the larval mortality are further discussed in the text. Such studies should be repeated in other spawning areas in the Mediterranean if spawning in cages located offshore in areas favourable a priori for larval survival is likely to be considered a management measurement to minimize the impact of purse-seine fishing on tuna.

Brazilian sardine (Sardinella brasiliensis spawning in the southeast Brazilian Bight over the period 1976-1993

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Yasunobu Matsuura

1998-01-01

Full Text Available Based on sampling over the period 1976-1993 in the southeast Brazilian Bight, the distribution of spawning of the Brazilian sardine (Sardinella brasi/iensis is described in relation to environmental conditions. The area of intense spawning occurs in the southern part of the bight where coastal upwelling was less /Tequent. Spawning intensity showed high interannllal variation and the egg abundance in the survey area ranged /Tom 99 billion eggs in the January 1988 cruise to 4669 billion eggs in the January 1981 cruise. Peak spawning takes place one hour after midnight and eggs hatch . out within 19 hours with a water temperature of 24 °e.Baseado nos dados coletados durante nove cruzeiros oceanográficos realizados na região sudeste, as áreas de desova da sardinha-verdadeira (Sardinella brasiliensis foram apresentadas c discutidas em relação às condições oceanográficas. As áreas de desova intensiva foram localizadas na parte sul da área de investigação, onde a ressurgência costeira foi menos freqüente. A intensidade de desova demonstrou uma variação anual relativamente grande. A produção total de ovos da sardinha- ­verdadeira variou de 99 bilhões de ovos durante o cruzeiro de janeiro de 1988 para 4669 bilhões de ovos em janeiro de 1981. O pico de desova ocorre na camada de mistura de superfície uma hora após a meia noite e os ovos eclodem em 19 horas com a temperatura de água 24 °e.

Pacific salmon (Oncorhynchus spp.) runs and consumer fitness: growth and energy storage in stream-dwelling salmonids increase with salmon spawner density

Science.gov (United States)

Rinella, Daniel J.; Wipfli, Mark S.; Stricker, Craig A.; Heintz, Ron A.; Rinella, Matthew J.

2012-01-01

We examined how marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and δ15N of stream-dwelling fishes. We sampled juvenile coho salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) during spring and fall from 11 south-central Alaskan streams that ranged widely in spawning salmon biomass (0.1–4.7 kg·m–2). Growth rate (as indexed by RNA–DNA ratios), energy density, and δ15N enrichment in spring-sampled fishes increased with spawner biomass, indicating the persistence of spawner effects more than 6 months after salmon spawning. Point estimates suggest that spawner effects on nutrition were substantially greater for coho salmon than Dolly Varden (268% and 175% greater for growth and energy, respectively), indicating that both species benefitted physiologically, but that juvenile coho salmon accrued more benefits than Dolly Varden. Although the data were less conclusive for fall- than spring-sampled fish, they do suggest spawner effects were also generally positive during fall, soon after salmon spawned. In a follow-up analysis where growth rate and energy density were modeled as a function of δ15N enrichment, results suggested that both increased with MDN assimilation, especially in juvenile coho salmon. Our results support the importance of salmon runs to the nutritional ecology of stream-dwelling fishes.

Between-year variability in the mixing of North Sea herring spawning components leads to pronounced variation in the composition of the catch

DEFF Research Database (Denmark)

Bierman, Stijn M.; Dickey-Collas, Mark; van Damme, Cindy J.G.

2010-01-01

North Sea herring (Clupea harengus) are managed as a single stock, but maintaining a diversity of spawning components is considered important. However, the total catch from each of these components cannot be estimated easily because the components mix during the summer feeding season. The spawning......-at-age between spawning components, in particular of the 2000 year class, may have caused the observed between-year changes in mixing of components. Our results indicate that estimates of compositions change when assumptions of perfect spatial mixing and perfect classification are relaxed, and can be uncertain...

Spawning habitat unsuitability: an impediment to cisco rehabilitation in Lake Michigan?

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Madenjian, Charles P.; Rutherford, Edward S.; Blouin, Marc A.; Sederberg, Bryan J.; Elliott, Jeff R.

2011-01-01

The cisco Coregonus artedi was one of the most important native prey fishes in Lake Michigan and in the other four Laurentian Great Lakes. Most of the cisco spawning in Lake Michigan was believed to have occurred in Green Bay. The cisco population in Lake Michigan collapsed during the 1950s, and the collapse was attributed in part to habitat degradation within Green Bay. Winter water quality surveys of lower Green Bay during the 1950s and 1960s indicated that the bottom dissolved oxygen (DO) concentration was less than 2 mg/L throughout much of the lower bay, and most cisco eggs would not successfully hatch at such low DO concentrations. To determine present-day spawning habitat suitability in lower Green Bay, we compared cisco egg survival in lower Green Bay with survival at a reference site (St. Marys River, Michigan–Ontario) during 2009. We also conducted winter water quality surveys in lower Green Bay and the St. Marys River during 2009 and 2010. Cisco egg survival in lower Green Bay averaged 65.3%, which was remarkably similar to and not significantly different from the mean at the St. Marys River site (64.0%). Moreover, the lowest bottom DO concentrations recorded during the winter surveys were 11.2 mg/L in lower Green Bay and 12.7 mg/L in the St. Marys River. These relatively high DO concentrations would not be expected to have any negative effect on cisco egg survival. We conclude that winter water quality conditions in lower Green Bay were suitable for successful hatching of cisco eggs and that water quality during the egg incubation period did not represent an impediment to cisco rehabilitation in Lake Michigan. Our approach to determining spawning habitat suitability for coregonids would be applicable to other aquatic systems.

Preference and avoidance pH of brook trout Salvelinus fontinalis and brown trout Salmo trutta exposed to different holding pH.

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Fost, B A; Ferreri, C P

2015-08-01

The goal of this study was to determine if short-term exposure of brook trout Salvelinus fontinalis and brown trout Salmo trutta to a lower pH than found in their source stream results in a shift in preference or avoidance pH. The lack of a shift in preference or avoidance pH of adult S. fontinalis and S. trutta suggests that these species can be held at a pH different from the source waterbody for a short period of time without altering preference or avoidance pH behaviour. © 2015 The Fisheries Society of the British Isles.

Temperature affects the timing of spawning and migration of North Sea mackerel

DEFF Research Database (Denmark)

Jansen, Teunis; Gislason, Henrik

2011-01-01

Climate change accentuates the need for knowing how temperature impacts the life history and productivity of economically and ecologically important species of fish. We examine the influence of temperature on the timing of the spawning and migrations of North Sea Mackerel using data from larvae C...

A sound worth saving: acoustic characteristics of a massive fish spawning aggregation.

Science.gov (United States)

Erisman, Brad E; Rowell, Timothy J

2017-12-01

Group choruses of marine animals can produce extraordinarily loud sounds that markedly elevate levels of the ambient soundscape. We investigated sound production in the Gulf corvina ( Cynoscion othonopterus ), a soniferous marine fish with a unique reproductive behaviour threatened by overfishing, to compare with sounds produced by other marine animals. We coupled echosounder and hydrophone surveys to estimate the magnitude of the aggregation and sounds produced during spawning. We characterized individual calls and documented changes in the soundscape generated by the presence of as many as 1.5 million corvina within a spawning aggregation spanning distances up to 27 km. We show that calls by male corvina represent the loudest sounds recorded in a marine fish, and the spatio-temporal magnitude of their collective choruses are among the loudest animal sounds recorded in aquatic environments. While this wildlife spectacle is at great risk of disappearing due to overfishing, regional conservation efforts are focused on other endangered marine animals. © 2017 The Author(s).

Impaired swimming performance of acid-exposed Arctic charr, Salvelinus alpinus L

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Hunter, L.A. (North/South Consultants Inc., Winnipeg, MB (Canada)); Scherer, E. (Dept. of Fisheries and Oceans, Freshwater Inst. Science Lab., Winnipeg, MB (Canada))

1988-01-01

Effects of increased ambient acidity are of particular interest, as the formation of metabolic and respiratory acids and acceleration of branchial ion loss during vigorous swimming duplicates or compounds effects of exposure to environmental acidity. Three year old Arctic charr (Salvelinus alpinus L.) were exposed to five levels of acidity between pH 6 and pH 3.8. Swimming performance as determined by critical swimming speeds was 67.5 cm {center dot} s{sup -1} or 4.4 body lengths per second for untreated fish (pH 7.8). Performance declined sharply below pH 4.5; at pH 3.8 it was reduced by 35% after 7 days of exposure. Tailbeat frequencies and ventilation rates showed no dose-response effects. This would support the assumption that afferent and efferent neuromuscular functions may have remained unimpaired under increased ambient acidity so that the stimulus of directed water current continued to elicit forced swimming, causing (forcing) the fish to use the entire scope for activity available at the various pH levels. At swimming speeds between 20 and 50 cm {center dot} s{sup -1}, ventilation rates at all levels of acidity were higher than at the control level. Based on this, spontaneous, i.e., non-forced swimming activity may show a lower response threshold. 19 refs., 3 figs., 1 tab.

Climatic and anthropogenic factors changing spawning pattern and production zone of Hilsa fishery in the Bay of Bengal

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M. Shohidullah Miah

2015-03-01

Full Text Available Hilsa (Tenualosa ilisha Hamilton as a single species accounts 12% for more than half of the total marine catches. About 2% of the entire population of the country is directly or indirectly engaged with Hilsa fishing. Hilsa has a wide geographical distribution in Asia from the Persian Gulf to the South China Sea. Particularly large stocks are found in Upper Bay of Bengal (BoB region sustained by the large river systems. The global Hilsa catch is reported 75% from Bangladesh water, 15% from Myanmar, 5% from India and 5% from other countries such as Thailand and Iran. Hilsa is a highly migratory and anadromous fish with the same migratory and same breeding behavior as that of Atlantic Salmon fish (Salmo sp.. Due to various anthropogenic activities, climate change effect, increased siltation and rising of the river basins, the migratory routes as well as spawning grounds of Hilsa are disturbed, displaced or even destroyed. During last two decades hilsa production from inland water declined about 20%, whereas marine water yield increased about 3 times. Major Hilsa to catch has been gradually shifted from inland to marine water. Hilsa fish ascend for spawning migration from sea into estuaries. It has been found that the major spawning areas have been shifted to the lower estuarine regions of Hatia, Sandwip and Bhola. At the spawning ground of Hilsa, the fishing level F=1.36 yr−1, where in the river Meghna the Fmsy=0.6 yr−1 and exploitation rate E=0.70 is (Emsy>0.5. Oceanographic changes viz. high turbidity increased flooding, more tidal action and changes of salinity etc. have accelerated the change of migration patterns of spawning, growth and its production. Hilsa fecundity ranges from 1.5 to 2.0 million eggs for fish ranging in length from 35 to 50 cm. Hilsa fecundity is declining in different areas due to climate change and the declining fecundity impacting greatly on Hilsa production. Due to shifting of the spawning ground at the lower

Historical spatial reconstruction of a spawning-aggregation fishery.

Science.gov (United States)

Buckley, Sarah M; Thurstan, Ruth H; Tobin, Andrew; Pandolfi, John M

2017-12-01

Aggregations of individual animals that form for breeding purposes are a critical ecological process for many species, yet these aggregations are inherently vulnerable to exploitation. Studies of the decline of exploited populations that form breeding aggregations tend to focus on catch rate and thus often overlook reductions in geographic range. We tested the hypothesis that catch rate and site occupancy of exploited fish-spawning aggregations (FSAs) decline in synchrony over time. We used the Spanish mackerel (Scomberomorus commerson) spawning-aggregation fishery in the Great Barrier Reef as a case study. Data were compiled from historical newspaper archives, fisher knowledge, and contemporary fishery logbooks to reconstruct catch rates and exploitation trends from the inception of the fishery. Our fine-scale analysis of catch and effort data spanned 103 years (1911-2013) and revealed a spatial expansion of fishing effort. Effort shifted offshore at a rate of 9.4 nm/decade, and 2.9 newly targeted FSAs were reported/decade. Spatial expansion of effort masked the sequential exploitation, commercial extinction, and loss of 70% of exploited FSAs. After standardizing for improvements in technological innovations, average catch rates declined by 90.5% from 1934 to 2011 (from 119.4 to 11.41 fish/vessel/trip). Mean catch rate of Spanish mackerel and occupancy of exploited mackerel FSAs were not significantly related. Our study revealed a special kind of shifting spatial baseline in which a contraction in exploited FSAs occurred undetected. Knowledge of temporally and spatially explicit information on FSAs can be relevant for the conservation and management of FSA species. © 2017 Society for Conservation Biology.

Evaluation of Fall Chinook and Chum Salmon Spawning below Bonneville Dam; 2004-2005 Annual Report.

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van der Naald, Wayne; Duff, Cameron; Friesen, Thomas A. (Oregon Department of Fish and Wildlife, Clackamas, OR)

2006-02-01

Pacific salmon Oncorhynchus spp. populations have declined over the last century due to a variety of human impacts. Chum salmon O. keta populations in the Columbia River have remained severely depressed for the past several decades, while upriver bright (URB) fall Chinook salmon O. tschawytscha populations have maintained relatively healthy levels. For the past seven years we have collected data on adult spawning and juvenile emergence and outmigration of URB fall Chinook and chum salmon populations in the Ives and Pierce islands complex below Bonneville Dam. In 2004, we estimated 1,733 fall Chinook salmon and 336 chum salmon spawned in our study area. Fall Chinook salmon spawning peaked 19 November with 337 redds and chum salmon spawning peaked 3 December with 148 redds. Biological characteristics continue to suggest chum salmon in our study area are similar to nearby stocks in Hardy and Hamilton creeks, and Chinook salmon we observe are similar to upriver bright stocks. Temperature data indicated that 2004 brood URB fall Chinook salmon emergence began on 6 January and ended 27 May 2005, with peak emergence occurring 12 March. Chum salmon emergence began 4 February and continued through 2 May 2005, with peak emergence occurring on 21 March. Between 13 January and 28 June, we sampled 28,984 juvenile Chinook salmon and 1,909 juvenile chum salmon. We also released 32,642 fin-marked and coded-wire tagged juvenile fall Chinook salmon to assess survival. The peak catch of juvenile fall Chinook salmon occurred on 18 April. Our results suggested that the majority of fall Chinook salmon outmigrate during late May and early June, at 70-80 mm fork length (FL). The peak catch of juvenile chum salmon occurred 25 March. Juvenile chum salmon appeared to outmigrate at 40-55 mm FL. Outmigration of chum salmon peaked in March but extended into April and May.

The Effect of zeolite addition on viability of paddy straw mushroom spawn

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DJUMHAWAN RATMAN PERMANA

2007-01-01

Full Text Available The objective of this research was to increase the viability of the paddy straw mushroom spawn by adding natural stone on the media’s composition for the paddy straw mushroom spawn. Mycelium of the paddy straw mushroom was take from the pure development of the paddy straw mushroom which was planted on the various treatment for media e.i. 100% cotton media and rice bran + 0% zeolite (A, 75% cotton media and rice bran + 25% zeolite (B, 50% cotton media and rice bran + 50% zeolite (C, 25% cotton and rice bran + 75% zeolite (D, 0% cotton media and rice bran + 100% rice bran (E. Each treatment was observed for the length of mycelium, the concentration of reduced sugar, total carbon and water content, spawn media weight, pH and temperature. Results demonstrated that there is a positive effect of zeolite added to the paddy straw mushroom media. The zeolite able to adsorbed nutrient through its pores, so the mycelium of the paddy straw mushroom able to use the nutrient gradually and equally appropriate with its growth. Therefore the viability of the paddy straw mushroom is increase. Result showed that the B is the best viability in the Potetos Dectrose Agar (PDA media, that has viability power up to 50 days after inoculation and the temperature are 29,6 0C, then followed by treatment C, D, A and E, each has viability power up to 42; 38; 34; 22 days after inoculation and the maximum length of each mycelium are 17.5; 9.2; 0.9; 0.5 cm, but in the treatment D being contaminated by Aspergillus sp.

Climate change and vulnerability of bull trout (Salvelinus confluentus) in a fire-prone landscape.

Science.gov (United States)

Falke, Jeffrey A.; Flitcroft, Rebecca L; Dunham, Jason B.; McNyset, Kristina M.; Hessburg, Paul F.; Reeves, Gordon H.

2015-01-01

Linked atmospheric and wildfire changes will complicate future management of native coldwater fishes in fire-prone landscapes, and new approaches to management that incorporate uncertainty are needed to address this challenge. We used a Bayesian network (BN) approach to evaluate population vulnerability of bull trout (Salvelinus confluentus) in the Wenatchee River basin, Washington, USA, under current and future climate and fire scenarios. The BN was based on modeled estimates of wildfire, water temperature, and physical habitat prior to, and following, simulated fires throughout the basin. We found that bull trout population vulnerability depended on the extent to which climate effects can be at least partially offset by managing factors such as habitat connectivity and fire size. Moreover, our analysis showed that local management can significantly reduce the vulnerability of bull trout to climate change given appropriate management actions. Tools such as our BN that explicitly integrate the linked nature of climate and wildfire, and incorporate uncertainty in both input data and vulnerability estimates, will be vital in effective future management to conserve native coldwater fishes.

Summer temperature metrics for predicting brook trout (Salvelinus fontinalis) distribution in streams

Science.gov (United States)

Parrish, Donna; Butryn, Ryan S.; Rizzo, Donna M.

2012-01-01

We developed a methodology to predict brook trout (Salvelinus fontinalis) distribution using summer temperature metrics as predictor variables. Our analysis used long-term fish and hourly water temperature data from the Dog River, Vermont (USA). Commonly used metrics (e.g., mean, maximum, maximum 7-day maximum) tend to smooth the data so information on temperature variation is lost. Therefore, we developed a new set of metrics (called event metrics) to capture temperature variation by describing the frequency, area, duration, and magnitude of events that exceeded a user-defined temperature threshold. We used 16, 18, 20, and 22°C. We built linear discriminant models and tested and compared the event metrics against the commonly used metrics. Correct classification of the observations was 66% with event metrics and 87% with commonly used metrics. However, combined event and commonly used metrics correctly classified 92%. Of the four individual temperature thresholds, it was difficult to assess which threshold had the “best” accuracy. The 16°C threshold had slightly fewer misclassifications; however, the 20°C threshold had the fewest extreme misclassifications. Our method leveraged the volumes of existing long-term data and provided a simple, systematic, and adaptable framework for monitoring changes in fish distribution, specifically in the case of irregular, extreme temperature events.

Comparative mapping reveals quantitative trait loci that affect spawning time in coho salmon (Oncorhynchus kisutch

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Cristian Araneda

2012-01-01

Full Text Available Spawning time in salmonids is a sex-limited quantitative trait that can be modified by selection. In rainbow trout (Oncorhynchus mykiss, various quantitative trait loci (QTL that affect the expression of this trait have been discovered. In this study, we describe four microsatellite loci associated with two possible spawning time QTL regions in coho salmon (Oncorhynchus kisutch. The four loci were identified in females from two populations (early and late spawners produced by divergent selection from the same base population. Three of the loci (OmyFGT34TUF, One2ASC and One19ASC that were strongly associated with spawning time in coho salmon (p < 0.0002 were previously associated with QTL for the same trait in rainbow trout; a fourth loci (Oki10 with a suggestive association (p = 0.00035 mapped 10 cM from locus OmyFGT34TUF in rainbow trout. The changes in allelic frequency observed after three generations of selection were greater than expected because of genetic drift. This work shows that comparing information from closely-related species is a valid strategy for identifying QTLs for marker-assisted selection in species whose genomes are poorly characterized or lack a saturated genetic map.

Recruitment of shrimp ( Pandalus borealis) in the Barents Sea related to spawning stock and environment

Science.gov (United States)

Aschan, Michaela; Ingvaldsen, Randi

2009-10-01

The shrimp spawn in autumn, and the females carry their eggs as out roe until spring when the larvae hatch. Within a period of 2 months the shrimp larvae settle to the bottom. It has been claimed that the year-class strength probably is determined during the larval phase. Today's assessment and forecast of the shrimp stock productivity and potential fishing yields are weak. This is partly due to poor knowledge on population dynamics from hatching until the shrimp are caught in the fishery at the age of 3 or 4 years. We, therefore, here identify the most important abiotic and biotic factors that affect recruitment in addition to spawning stock biomass. Since 1995, a net attached to the underbelly of the survey trawl used at the annual cruise in the Barents Sea has caught juvenile shrimp. The abundance of settled shrimp larvae varies in time and space. The recruitment to the fishery has been quite stable with the exception of the 1996 year-class, which was observed as 1-year-olds but has not been registered since. The temporal pattern of the three youngest year-classes is studied in relation to abiotic factors such as sea temperature, ice index and North Atlantic Oscillation, as well as biotic factors such as spawning stock biomass and presence of copepods, euphausiids and predating cod. Recruitment indices and factors identified by the Spearmann correlation to be significantly correlated with recruitment were used as input in a principal component analysis (PCA) and a generalized additive model (GAM) was applied. Abundance of 1-year-old shrimp is positively correlated to spawning stock biomass the previous year and to temperature of the previous winter, and negatively correlated with the number of 1-year-old cod. Two-year-old shrimp show significant correlation with temperature, whereas there is a strong negative correlation with euphausiids. Three-year-old shrimp are significantly correlated with the number of 2-year-old shrimp the previous year but negatively

Acoustic monitoring indicates a correlation between calling and spawning in captive spotted seatrout (Cynoscion nebulosus

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Eric W. Montie

2017-02-01

Full Text Available Background Fish sound production is widespread throughout many families. Territorial displays and courtship are the most common reasons for fish sound production. Yet, there is still some questions on how acoustic signaling and reproduction are correlated in many sound-producing species. In the present study, our aim was to determine if a quantitative relationship exists between calling and egg deposition in captive spotted seatrout (Cynoscion nebulosus. This type of data is essential if passive acoustics is to be used to identify spawning aggregations over large spatial scales and monitor reproductive activity over annual and decadal timeframes. Methods Acoustic recorders (i.e., DSG-Oceans were placed in three laboratory tanks to record underwater sound over an entire, simulated reproductive season. We enumerated the number of calls, calculated the received sound pressure level, and counted the number of eggs every morning in each tank. Results Spotted seatrout produced three distinct call types characterized as “drums,” “grunts,” and “staccatos.” Spotted seatrout calling increased as the light cycle shifted from 13.5 to 14.5 h of light, and the temperature increased to 27.7 °C. Calling decreased once the temperature fell below 27.7 °C, and the light cycle shifted to 12 h of light. These temperature and light patterns followed the natural reproductive season observed in wild spotted seatrout in the Southeast United States. Spotted seatrout exhibited daily rhythms in calling. Acoustic signaling began once the lights turned off, and calling reached maximum activity approximately 3 h later. Eggs were released only on evenings in which spotted seatrout were calling. In all tanks, spotted seatrout were more likely to spawn when male fish called more frequently. A positive relationship between SPL and the number of eggs collected was found in Tanks 1 and 3. Discussion Our findings indicate that acoustic metrics can predict spawning

Kootenai River white sturgeon investigations. Chapter 1: Kootenai River white sturgeon spawning and recruitment evaluation; Annual report, January 1--December 31, 1996

International Nuclear Information System (INIS)

Paragamian, V.L.; Kruse, G.; Wakkinen, V.

1997-09-01

Test flows for Kootenai River white sturgeon Acipenser transmontanus spawning, scheduled for June 1996, were postponed until July. However, an estimated 126% snow pack and unusually heavy precipitation created conditions for sturgeon spawning that were similar to those occurring before construction of Libby Dam. Discharge in the Kootenai River at Bonners Ferry rose to nearly 1,204 m 3 /s (42,500 cfs) during May and water temperature ranged from 5.8 C to 8.4 C (42 F to 47 F). Migration of adult white sturgeon into spawning areas occurred in late May during a rising hydrograph. Discharge and water temperature were rising and had reached approximately 1,077 m 3 /s (38,000 cfs) and 8 C (46 F). Discharge at Bonners Ferry peaked at about 1,397 m 3 /s (49,300 cfs) on June 5. A total of 348 eggs (and one egg shell) were collected with 106,787 h of mat effort during the flow events. The first white sturgeon eggs were collected on June 8 and continued through June 30. Staging of eggs and back-calculating to spawning dates indicated there were at least 18 spawning episodes between June 6 and June 25. Discharge on June 6 was 1,196 m 3 /s (42,200 cfs) and decreased steadily to 850 m 3 /s (30,000 cfs) by June 26. Although sturgeon spawned in the same reach of river that they had during 1994 and 1995, the majority of eggs were found significantly (P = 0.0001) farther upstream than 1994 and 1995 and this in turn may be related to elevation of Kootenay Lake

Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems

Science.gov (United States)

Black, B.A.; Von Biela, V.R.; Zimmerman, C.E.; Brown, Randy J.

2013-01-01

High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval (p fish metabolic rate or lake productivity. Given the broad distribution of lake trout within North America, this study suggests that otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales.

Xenobiotic-induced apoptosis: significance and potential application as a general biomarker of response

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Sweet, Leonard I.; Passino-Reader, Dora R.; Meier, Peter G.; Omann, Geneva M.

1999-01-01

The process of apoptosis, often coined programmed cell death, involves cell injury induced by a variety of stimuli including xenobiotics and is morphologically, biochemically, and physiologically distinct from necrosis. Apoptotic death is characterized by cellular changes such as cytoplasm shrinkage, chromatin condensation, and plasma membrane asymmetry. This form of cell suicide is appealing as a general biomarker of response in that it is expressed in multiple cell systems (e.g. immune, neuronal, hepatal, intestinal, dermal, reproductive), is conserved phylogenetically (e.g. fish, rodents, birds, sheep, amphibians, roundworms, plants, humans), is modulated by environmentally relevant levels of chemical contaminants, and indicates a state of stress of the organism. Further, apoptosis is useful as a biomarker as it serves as a molecular control point and hence may provide mechanistic information on xenobiotic stress. Studies reviewed here suggest that apoptosis is a sensitive and early indicator of acute and chronic chemical stress, loss of cellular function and structure, and organismal health. Examples are provided of the application of this methodology in studies of health of lake trout (Salvelinus namaycush) in the Laurentian Great Lakes.

Comparison of genetic and visual identification of cisco and lake whitefish larvae from Chaumont Bay, Lake Ontario

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George, Ellen M.; Hare, Matthew P.; Crabtree, Darran L.; Lantry, Brian F.; Rudstam, Lars G.

2017-01-01

Cisco Coregonus artedi are an important component of native food webs in the Great Lakes, and their restoration is instrumental to the recovery of lake trout Salvelinus namaycush and Atlantic salmon Salmo salar. Difficulties with visual identification of larvae can confound early life history surveys, as cisco are often difficult to distinguish from lake whitefish C. clupeaformis. We compared traditional visual species identification methods to genetic identifications based on barcoding of the mitochondrial cytochrome C oxidase I gene for 726 coregonine larvae caught in Chaumont Bay, Lake Ontario. We found little agreement between the visual characteristics of cisco identified by genetic barcoding and the most widely used dichotomous key, and the considerable overlap in ranges of traditionally utilized metrics suggest that visual identification of coregonine larvae from Chaumont Bay is impractical. Coregonines are highly variable and plastic species, and often display wide variations in morphometric characteristics across their broad range. This study highlights the importance of developing accurate, geographically appropriate larval identification methods in order to best inform cisco restoration and management efforts.

Connectivity of a large embayment and coastal fishery: spawning aggregations in one bay source local and broad-scale fishery replenishment.

Science.gov (United States)

Hamer, P A; Acevedo, S; Jenkins, G P; Newman, A

2011-04-01

Ichthyoplankton sampling and otolith chemistry were used to determine the importance of transient spawning aggregations of snapper Chrysophrys auratus (Sparidae) in a large embayment, Port Phillip Bay (PPB), Australia, as a source of local and broad-scale fishery replenishment. Ichthyoplankton sampling across five spawning seasons within PPB, across the narrow entrance to the bay and in adjacent coastal waters, indicated that although spawning may occur in coastal waters, the spawning aggregations within the bay were the primary source of larval recruitment to the bay. Otolith chemical signatures previously characterized for 0+ year C. auratus of two cohorts (2000 and 2001) were used as the baseline signatures to quantify the contribution that fish derived from reproduction in PPB make to fishery replenishment. Sampling of these cohorts over a 5 year period at various widely dispersed fishery regions, combined with maximum likelihood analyses of the chemistry of the 0+ year otolith portions of these older fish, indicated that C. auratus of 1 to 3+ years of age displayed both local residency and broad-scale emigration from PPB to populate coastal waters and an adjacent bay (Western Port). While the PPB fishery was consistently dominated (>70%) by locally derived fish irrespective of cohort or age, the contribution of fish that had originated from PPB to distant populations increased with age. At 4 to 5+ years of age, when C. auratus mature and fully recruit to the fishery, populations of both cohorts across the entire central and western Victorian fishery, including two major embayments and c. 800 km of coastal waters, were dominated (>70%) by fish that had originated from the spawning aggregations and nursery habitat within PPB. Dependence of this broadly dispersed fishery on replenishment from heavily targeted spawning aggregations within one embayment has significant implications for management and monitoring programmes. © 2011 The Authors. Journal of Fish

Comparison of organotin accumulation on the white-spotted charr Salvelinus leucomaenis between sea-run and freshwater-resident types

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Ohji, Madoka; Harino, Hiroya; Arai, Takaomi

2011-01-01

To examine the accumulation pattern of organotin compounds (OTs) in relation to the migration of diadromous fish, tributyltin (TBT) and triphenyltin (TPT) compounds and their derivatives were determined in the muscle tissue of both sea-run (anadromous) and freshwater-resident (nonanadromous) types of the white-spotted charr Salvelinus leucomaenis. There were generally no significant correlations between the TBT and TPT accumulation and various biological characteristics such as the total length (TL), body weight (BW), age and sex in S. leucomaenis. It is noteworthy that the TBT and TPT concentrations in sea-run white-spotted charr were significantly higher than in freshwater-resident individuals, although they are intraspecies. These results suggest that the sea-run S. leucomaenis has a higher ecological risk of TBT and TPT exposure than the freshwater-residents during their life history.

Fish spawning in a large temperate floodplain: the role of flooding and temperature

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Górski, K.; Winter, H.V.; Leeuw, de J.J.; Minin, A.E.; Nagelkerke, L.A.J.

2010-01-01

1. Floodplains are a key habitat for foraging, spawning and as a nursery for many riverine fish species. The lower Volga floodplains (Russian Federation) are still relatively undisturbed, while in Europe and North America, about 90% of floodplains have effectively been lost. 2. We examined

Annual, lunar and diel reproductive periodicity of a spawning aggregation of snapper Pagrus auratus (Sparidae) in a marine embayment on the lower west coast of Australia.

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Wakefield, C B

2010-10-01

Ichthyoplankton sampling and ovarian characteristics were used to elucidate whether the reproductive cycles of a spawning aggregation of snapper Pagrus auratus in a nearshore marine embayment were temporally and spatially specific and related with environmental conditions. The reproductive dynamics of this aggregation were studied over four consecutive years (2001-2004). Spawning occurred between September and January each year, when water temperatures ranged from 15·8 to 23·1° C. In all 4 years, the cumulative egg densities in Cockburn Sound were highest when water temperatures were between the narrow range of 19-20° C. The spawning fraction of females was monthly bimodal and peaked during new and the full moons at 96-100% and c. 75%, respectively. The backcalculated ages of P. auratus eggs collected from 16 ichthyoplankton surveys demonstrated that P. auratus in Cockburn Sound spawn at night during the 3 h following the high tide. The spatial distributions of P. auratus eggs in Cockburn Sound during the peak reproductive period in all 4 years were consistent, further implying spawning was temporally and spatially specific. High concentrations of recently spawned eggs (8-16 h old) demonstrated spawning also occurred within the adjacent marine embayments of Owen Anchorage and Warnbro Sound. Water circulation in Cockburn and Warnbro Sounds resembled an eddy that was most prominent during the period of highest egg densities, thereby facilitating the retention of eggs in these areas. The reproductive cycles of P. auratus described in this study have assisted managers with the appropriate temporal and spatial scale for a closed fishing season to protect these spawning aggregations. © 2010 The Author. Journal compilation © 2010 The Fisheries Society of the British Isles.

The timing and location of spawning for the Euphausiid Thysanoessa spinifera off the Oregon coast, USA

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Feinberg, Leah R.; Peterson, William T.; Tracy Shaw, C.

2010-04-01

Thysanoessa spinifera eggs were sampled biweekly from 1997-2005 along a transect extending off the coast of Newport, OR, USA. T. spinifera eggs were typically found in greatest abundance at NH05, our shallower mid-shelf station, and in lowest abundance at NH25, our offshore, deep-water station beyond the shelf break. In most years small peaks in density of T. spinifera eggs were found in late winter (February-March) and/or spring (April-May) along with large, prolonged peaks in summer, from July-September. However, it was more common to find egg densities of eggs at all (58-91% of sampling dates per year had densities egg densities were significantly positively correlated with chlorophyll a concentrations during the winter and spring ( r2=0.52 and 0.55 respectively, pegg densities and female densities. When winters were stormy, as in 1998, 1999 and 2000 the first eggs of Thysanoessa spinifera were not observed at any station until after upwelling was initiated later in the spring. However, in other years eggs were likely to be found earlier in the year if there were fewer storms, or winter or spring upwelling events that were not followed by a large storm. In most years, spawning continued until the upwelling season ended in the autumn, however this trend ceased in 2003-2005 and spawning was interrupted earlier in the season. Overall, we found that chlorophyll a peaks and egg peaks increased in magnitude in the later part of our study. We have concluded that T. spinifera is likely an intermittent spawner, whose ovaries are not constantly mature and prepared for spawning, despite the presence of ocean conditions that are suitable for spawning.

Monitoring Spawning Activity in a Southern California Marine Protected Area Using Molecular Identification of Fish Eggs.

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Alice E Harada

Full Text Available In order to protect the diverse ecosystems of coastal California, a series of marine protected areas (MPAs have been established. The ability of these MPAs to preserve and potentially enhance marine resources can only be assessed if these habitats are monitored through time. This study establishes a baseline for monitoring the spawning activity of fish in the MPAs adjacent to Scripps Institution of Oceanography (La Jolla, CA, USA by sampling fish eggs from the plankton. Using vertical plankton net tows, 266 collections were made from the Scripps Pier between 23 August 2012 and 28 August 2014; a total of 21,269 eggs were obtained. Eggs were identified using DNA barcoding: the COI or 16S rRNA gene was amplified from individual eggs and sequenced. All eggs that were successfully sequenced could be identified from a database of molecular barcodes of California fish species, resulting in species-level identification of 13,249 eggs. Additionally, a surface transport model of coastal circulation driven by current maps from high frequency radar was used to construct probability maps that estimate spawning locations that gave rise to the collected eggs. These maps indicated that currents usually come from the north but water parcels tend to be retained within the MPA; eggs sampled at the Scripps Pier have a high probability of having been spawned within the MPA. The surface transport model also suggests that although larvae have a high probability of being retained within the MPA, there is also significant spillover into nearby areas outside the MPA. This study provides an important baseline for addressing the extent to which spawning patterns of coastal California species may be affected by future changes in the ocean environment.

Monitoring Spawning Activity in a Southern California Marine Protected Area Using Molecular Identification of Fish Eggs.

Science.gov (United States)

Harada, Alice E; Lindgren, Elise A; Hermsmeier, Maiko C; Rogowski, Peter A; Terrill, Eric; Burton, Ronald S

2015-01-01

In order to protect the diverse ecosystems of coastal California, a series of marine protected areas (MPAs) have been established. The ability of these MPAs to preserve and potentially enhance marine resources can only be assessed if these habitats are monitored through time. This study establishes a baseline for monitoring the spawning activity of fish in the MPAs adjacent to Scripps Institution of Oceanography (La Jolla, CA, USA) by sampling fish eggs from the plankton. Using vertical plankton net tows, 266 collections were made from the Scripps Pier between 23 August 2012 and 28 August 2014; a total of 21,269 eggs were obtained. Eggs were identified using DNA barcoding: the COI or 16S rRNA gene was amplified from individual eggs and sequenced. All eggs that were successfully sequenced could be identified from a database of molecular barcodes of California fish species, resulting in species-level identification of 13,249 eggs. Additionally, a surface transport model of coastal circulation driven by current maps from high frequency radar was used to construct probability maps that estimate spawning locations that gave rise to the collected eggs. These maps indicated that currents usually come from the north but water parcels tend to be retained within the MPA; eggs sampled at the Scripps Pier have a high probability of having been spawned within the MPA. The surface transport model also suggests that although larvae have a high probability of being retained within the MPA, there is also significant spillover into nearby areas outside the MPA. This study provides an important baseline for addressing the extent to which spawning patterns of coastal California species may be affected by future changes in the ocean environment.

Spawning areas and larval distributions of anchovy Engraulis encrasicolus in relation to environmental conditions in the Gulf of Tunis (Central Mediterranean Sea

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Rafik Zarrad

2006-10-01

Full Text Available Early life stages of anchovy were investigated in the Gulf of Tunis by means of four seasonal surveys carried out from summer 2002 to spring 2003. Anchovy eggs and larvae were found all year round, but they were much more abundant in spring and summer. In spring, the main spawning area was located in the north of the Gulf, to the west and southwest of Zembra Island. In summer, higher egg and larva abundances were also observed to the southwest of Zembra Island, but secondary spawning grounds were detected in the vicinity of the mouths of the Rivers Majreda and Meliane. No direct correlations between sea surface temperature (SST, salinity (SSS and chlorophyll a and the horizontal distribution of eggs and larvae were observed. However, egg distributions in all seasons and larval distributions in summer and autumn were significantly related to depth. The temporal variation of temperature seems to control the spawning intensity and the beginning of spawning seems to be triggered by the increase in SST.

Use of the Rigor Mortis Process as a Tool for Better Understanding of Skeletal Muscle Physiology: Effect of the Ante-Mortem Stress on the Progression of Rigor Mortis in Brook Charr (Salvelinus fontinalis).

Science.gov (United States)

Diouf, Boucar; Rioux, Pierre

1999-01-01

Presents the rigor mortis process in brook charr (Salvelinus fontinalis) as a tool for better understanding skeletal muscle metabolism. Describes an activity that demonstrates how rigor mortis is related to the post-mortem decrease of muscular glycogen and ATP, how glycogen degradation produces lactic acid that lowers muscle pH, and how…

Influence of thermal conditions on successful ide (Leuciscus idus L. artificial reproduction during spawning season

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Dariusz Kucharczyk

2011-10-01

Full Text Available Two forms of ide Leuciscus idus (L. spawners: wild-coloured and ornamental: yellow-coloured were kept at three various temperature regimes shortly before spawning at optimal temperature regimes (group 1, under natural temperature conditions (group 2 and in rapidly increasing temperature (group 3. The quality and quantity of collected semen, ovulation rate and survival rate of embryos to the eyed-egg-stage were recorded. The quality of semen from group 3 (where the temperature increased over the thermal spawning optimum was the worst (46 and 51% motility of spermatozoa for the wild-coloured and yellow form, respectively. The quantity of collected semen also was the lowest in the same groups (1.1 and 1.0 cm3 kg-1 for the wild-coloured and yellow form, respectively. Increasing the temperature to 16°C also caused a decreasing percentage of ovulated females (70% and 60% of ovulation for wild-coloured and yellow form, respectively and biological quality of eggs (48.9 and 47.8% embryo survival for wild-coloured and yellow form, respectively. Fluctuations of temperature at a level of 8-14°C (group 2 did not negatively affect spawning results, except for a longer latency time (over 44 hrs. The results suggest that the temperature regime shortly before controlled reproduction of ide plays an important role influencing reproductive success.

Spawning migration of the horseshoe crab, Tachypleus gigas (Muller), in relation to lunal cycle

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Chatterji, A.; Rathod, V.; Parulekar, A.H.

Effects of lunar phases and tidal height on the spawning migration of the horseshoe crab, Tachypleus gigas, along the northeastern coast of India were studied. Mature pairs of crabs migrate towards the shore and build their nests in sandy beaches...

Quantification of coral sperm collected during a synchronous spawning event

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Aaron Teo

2016-07-01

Full Text Available Most studies of coral reproductive biology to date have focused on oocyte numbers and sizes. Only one (ex situ study has enumerated sperm numbers, even though these data have multiple potential applications. We quantified total coral sperm and eggs per gamete bundle collected from six species in situ during a synchronous spawning event in Singapore. Egg-sperm bundles were captured midwater as they floated towards the surface after being released by the colony. For each sample, a semi-transparent soft plastic bottle was squeezed and released to create a small suction force that was used to ‘catch’ the bundles. This technique provided several advantages over traditional methods, including low cost, ease of use, no diving prior to the night of collection needed, and the ability to target specific areas of the colony. The six species sampled were Echinophyllia aspera, Favites abdita, F. chinensis, Merulina ampliata, M. scabricula and Platygyra pini. The mean number of sperm packaged within one egg-sperm bundle ranged from 2.04 × 106 to 1.93 × 107. The mean number of eggs per egg-sperm bundle ranged from 26.67 (SE ± 3.27 to 85.33 (SE ± 17.79. These data are critical for fertilisation success models, but the collection technique described could also be applied to studies requiring in situ spawning data at the polyp level.

Paternity in horseshoe crabs when spawning in multiple-male groups.

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Brockmann; Nguyen; Potts

2000-12-01

Unpaired or satellite male horseshoe crabs, Limulus polyphemus, are attracted to and often form a group around a pair (a female with an attached male) that is nesting in the high intertidal zone. These males are engaged in sperm competition. We observed nesting pairs and their associated satellites in the wild, collected and reared their eggs and used genetic markers to examine paternity. We found that the unpaired, satellite males are highly successful at fertilizing eggs; two satellites can leave the attached male with few fertilizations. Two satellites together are each as successful as one spawning with a pair. A satellite's location around the female greatly affects his success, and males compete for access to a position over the dorsal canal between the prosoma and opisthosoma of the female and under the front margin of the paired male where they are most likely to fertilize eggs. Although eggs and sperm retain their viability for some time after spawning, nearly all eggs are fertilized by the satellites that are around the nesting pair at the time of egg laying and by the attached male. A number of factors including beach current, female size and male behaviour affect the outcome of sperm competition in this externally fertilizing species. Copyright 2000 The Association for the Study of Animal Behaviour.

A snapshot of the population structure of Branchiostoma lanceolatum in the Racou beach, France, during its spawning season.

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Yves Desdevises

Full Text Available A methodology for inducing spawning in captivity of the lancelet Branchiostoma lanceolatum has been developed recently with animals collected at the Racou beach, in the southern coast of France. An increasing amount of laboratories around the world are now working on the evolution of developmental mechanisms (Evo-Devo using amphioxus collected in this site. Thus, today, the development of new aquaculture techniques for keeping amphioxus in captivity is needed and the study of the natural conditions at which amphioxus is exposed in the Racou beach during their spawning season becomes necessary. We have investigated the amphioxus distribution, size frequency, and population structure in the Racou beach during its natural spawning season using multivariate methods (redundancy analysis and multiple regression. We found a clear preference of amphioxus for sandy sites, something that seems to be a general behaviour of different amphioxus species around the world. We have also estimated the amphioxus growth rate and we show how the animals are preferentially localized in shallow waters during April and June.

Extended spawning in brown trout (Salmo trutta populations from the Southern Iberian Peninsula: the role of climate variability

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José E. Larios-López

2014-02-01

Full Text Available The reproductive periods of brown trout (Salmo trutta populations in 12 rivers in the Baetic Mountains in southern Spain were studied from 2008 to 2013. This area is an ecological and geographical limit for the distribution of this species in Europe. We found that the spawning period has been markedly extended in these fish. The mean spawning dates in the studied populations are consistent with the European trend at this latitude, but our data suggest that females from most of the populations that we studied are able to produce eggs from early October through late April or early May, yielding a reproductive period of between 150 and 170 days, the longest and most delayed brown trout reproduction periods that have been reported in the literature. We believe that such expanded spawning periods result primarily from the unpredictability of the Mediterranean climate, although it is possible that other factors may have contributed to the development of this reproductive behaviour. This hypothesis is discussed in the context of a comparison of our results with those found for other European S. trutta populations.

Multiscale Terrain Analysis of Multibeam Bathymetry Data for Lake Trout Spawning Habitat Mapping in the Drummond Island Refuge, northern Lake Huron

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Wattrus, N. J.; Binder, T.

2012-12-01

Until the 1950s, lake trout supported a valuable commercial fishery in the Great Lakes. The introduction of sea lamprey into the Great Lakes and overfishing resulted in the loss of most populations. Despite consistent stocking efforts since the 1960s, restoration of these populations has been slow. The reasons are numerous, but may be related to differences in the spawning behavior between hatchery and wild trout. A four-year study initiated in 2010, utilizes acoustic telemetry to characterize and compare the spawning behaviors of hatchery and wild lake trout in the Drummond Island Refuge in northern Lake Huron. In this project, the movement of tagged fish are monitored by an array of over 125 lake floor hydrophones during the fall spawning period. Fish behavior is overlaid over detailed bathymetric and substrate data and compared with environmental variables (e.g. water temperature, wind speed and direction, and wave height and direction) to develop a conceptual behavioral model. Sites suspected of being spawning sites based upon telemetry data are verified through the use of divers and trapping eggs and fry. Prior to this study, the factors that influenced how the spawning fish utilize the lake floor shoals have been poorly understood. Among the factors thought to impact spawning success were: bathymetry and substrate composition. Diver and telemetry data suggest that the fish(both hatchery raised and wild) are particularly attracted to rocky substrates and that fragment size is important. High resolution multibeam bathymetric surveys conducted in 2010 and 2011 have been used to characterize the shape and composition of the lake floor in the study area. Classification of the substrate is a labor intensive process requiring divers, drop cameras and sediment sampling. To improve this, the traditional approach has been to use supervised and unsupervised classification techniques that are based upon measured acoustic backscatter from an echosounder or sidescan sonar

Quantifying the influence of geography and environment on the northeast Atlantic mackerel spawning distribution

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Brunel, Thomas; Damme, Van Cindy J.G.; Samson, Melvin; Dickey-Collas, Mark

2018-01-01

Mackerel (Scomber scombrus) in the northeast Atlantic have shown changes in distribution at certain times of the year, which have impacted their exploitation and management. In this study, mackerel spawning habitat over 21 recent years was characterised using generalised additive modelling, based on

Adjustments of Protein Metabolism in Fasting Arctic Charr, Salvelinus alpinus.

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Alicia A Cassidy

Full Text Available Protein metabolism, including the interrelated processes of synthesis and degradation, mediates the growth of an animal. In ectothermic animals, protein metabolism is responsive to changes in both biotic and abiotic conditions. This study aimed to characterise responses of protein metabolism to food deprivation that occur in the coldwater salmonid, Arctic charr, Salvelinus alpinus. We compared two groups of Arctic charr: one fed continuously and the other deprived of food for 36 days. We measured the fractional rate of protein synthesis (KS in individuals from the fed and fasted groups using a flooding dose technique modified for the use of deuterium-labelled phenylalanine. The enzyme activities of the three major protein degradation pathways (ubiquitin proteasome, lysosomal cathepsins and the calpain systems were measured in the same fish. This study is the first to measure both KS and the enzymatic activity of protein degradation in the same fish, allowing us to examine the apparent contribution of different protein degradation pathways to protein turnover in various tissues (red and white muscle, liver, heart and gills. KS was lower in the white muscle and in liver of the fasted fish compared to the fed fish. There were no observable effects of food deprivation on the protease activities in any of the tissues with the exception of liver, where the ubiquitin proteasome pathway seemed to be activated during fasting conditions. Lysosomal proteolysis appears to be the primary degradation pathway for muscle protein, while the ubiquitin proteasome pathway seems to predominate in the liver. We speculate that Arctic charr regulate protein metabolism during food deprivation to conserve proteins.

Endocrine changes associated with spawning behavior and social stimuli in a wild population of rainbow trout (Salmo gairdneri). II. Females

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Liley, N.R.; Fostier, Alexis; Breton, B.; Tan, E.S.P.

1986-01-01

Rainbow trout (Salmo gairdneri) were collected from a natural spawning population at Pennask Lake, B.C. Blood samples taken from female trout at different stages of spawning were assayed by radioimmunoassay for gonadotropin (GtH), estradiol-17 beta (E2), androgens, including testosterone (T), and 17α-hydroxy-20 β-dihydroprogesterone (17,20-P). Plasma levels of androgen and estradiol were highest in females sampled shortly before ovulation (ogreeno females) and declined in ovulated and sexuall...

Spawning seasons of Rasbora tawarensis (Pisces: Cyprinidae in Lake Laut Tawar, Aceh Province, Indonesia

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Musman Musri

2010-05-01

Full Text Available Abstract Background Rasbora tawarensis is an endemic freshwater fish in Lake Laut Tawar, Aceh Province, Indonesia. Unfortunately, its status is regarded as critical endangered with populations decreasing in recent years. To date no information on the spawning activities of the fish are available. Therefore, this study provides a contribution to the knowledge on reproductive biology of R. tawarensis especially on spawning seasons as well as basic information for conservation of the species. Methods Monthly sampling was conducted from April 2008 to March 2009 by using selective gillnets. The gonadosomatic index, size composition and sex ratio were assessed. The gonadal development was evaluated based on macroscopic and microscopic examinations of the gonads. Results The gonadosomatic index (GSI varied between 6.65 to 18.16 in female and 4.94 to 8.56 for male. GSI of the female R. tawarensis was higher in March, September and December indicating the onset of reproductive seasons, the GSI and oocyte size being directly correlated with gonadal development stages. Although, a greater proportion of mature male than female was detected during the study, the sex ratio showed that the overall number of female was higher than male. The ovaries had multiple oocyte size classes at every stage of gonadal development, thus R. tawarensis can be classified as a group synchronous spawner or a fractional multiple spawner. Conclusion The spawning seasons of R. tawarensis were three times a year and September being the peak of the reproductive season and the female was the predominant sex. This species is classified as a group synchronous spawner.

Biomagnification of mercury through lake trout (Salvelinus namaycush) food webs of lakes with different physical, chemical and biological characteristics

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Kidd, Karen A., E-mail: kiddk@unbsj.ca [Canadian Rivers Institute and Biology Department, University of New Brunswick, Saint John, NB, Canada E2L 4L5 (Canada); Muir, Derek C.G., E-mail: derek.muir@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Evans, Marlene S., E-mail: marlene.evans@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Saskatoon, SK, Canada S7N 3H5 (Canada); Wang, Xioawa, E-mail: xiaowa.wang@ec.gc.ca [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Whittle, Mike [Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6 (Canada); Swanson, Heidi K., E-mail: heidikswanson@yahoo.ca [Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9 (Canada); Johnston, Tom, E-mail: tjohnston@laurentian.ca [Cooperative Freshwater Ecology Unit, Ontario Ministry of Natural Resources, and Biology Department, Laurentian University, Sudbury, ON, Canada P3E 2C6 (Canada); Guildford, Stephanie, E-mail: sguildfo@d.umn.edu [Department of Biology and Large Lakes Observatory, University of Minnesota Duluth, 2205 5th St., Duluth, MN, 55812 (United States)

2012-11-01

Mercury (Hg) biomagnification in aquatic ecosystems remains a concern because this pollutant is known to affect the health of fish-eating wildlife and humans, and the fish themselves. The 'rate' of mercury biomagnification is being assessed more frequently using stable nitrogen isotope ratios ({delta}{sup 15}N), a measure of relative trophic position of biota within a food web. Within food webs and across diverse systems, log-transformed Hg concentrations are significantly and positively related to {delta}{sup 15}N and the slopes of these models vary from one study to another for reasons that are not yet understood. Here we compared the rates of Hg biomagnification in 14 lake trout lakes from three provinces in Canada to understand whether any characteristics of the ecosystems explained this among-system variability. Several fish species, zooplankton and benthic invertebrates were collected from these lakes and analyzed for total Hg (fish only), methyl Hg (invertebrates) and stable isotopes ({delta}{sup 15}N; {delta}{sup 13}C to assess energy sources). Mercury biomagnification rates varied significantly across systems and were higher for food webs of larger (surface area), higher nutrient lakes. However, the slopes were not predictive of among-lake differences in Hg in the lake trout. Results indicate that among-system differences in the rates of Hg biomagnification seen in the literature may be due, in part, to differences in ecosystem characteristics although the mechanisms for this variability are not yet understood. -- Highlights: Black-Right-Pointing-Pointer Mercury biomagnifies through aquatic food webs to toxic levels in top predator fishes. Black-Right-Pointing-Pointer Among-system differences in mercury transfer through food webs occur but have not been explained. Black-Right-Pointing-Pointer Diverse lakes supporting lake trout were compared to understand the ecosystem processes that affect mercury biomagnification. Black-Right-Pointing-Pointer Higher biomagnification of mercury was found in larger, higher nutrient lakes. Black-Right-Pointing-Pointer Results show that the food web processing of mercury is related to ecosystem properties.

Sexual maturity cycle and spawning of Greenland halibut Reinhardtius hippoglossoides in the Davis Strait

DEFF Research Database (Denmark)

Gundersen, A. C.; Stenberg, Claus; Fossen, I.

2010-01-01

Female sexual maturation cycle and the main spawning time of Greenland halibut Reinhardtius hippoglossoides in the Davis Strait were studied through regularly collected samples during 1 year starting in spring 2003. Samples were collected from the southern slope of the Davis Strait Ridge between...

Effects of Chiloquin Dam on spawning distribution and larval emigration of Lost River, shortnose, and Klamath largescale suckers in the Williamson and Sprague Rivers, Oregon

Science.gov (United States)

Martin, Barbara A.; Hewitt, David A.; Ellsworth, Craig M.

2013-01-01

Chiloquin Dam was constructed in 1914 on the Sprague River near the town of Chiloquin, Oregon. The dam was identified as a barrier that potentially inhibited or prevented the upstream spawning migrations and other movements of endangered Lost River (Deltistes luxatusChasmistes brevirostris) suckers, as well as other fish species. In 2002, the Bureau of Reclamation led a working group that examined several alternatives to improve fish passage at Chiloquin Dam. Ultimately it was decided that dam removal was the best alternative and the dam was removed in the summer of 2008. The U.S. Geological Survey conducted a long-term study on the spawning ecology of Lost River, shortnose, and Klamath largescale suckers (Catostomus snyderi) in the Sprague and lower Williamson Rivers from 2004 to 2010. The objective of this study was to evaluate shifts in spawning distribution following the removal of Chiloquin Dam. Radio telemetry was used in conjunction with larval production data and detections of fish tagged with passive integrated transponders (PIT tags) to evaluate whether dam removal resulted in increased utilization of spawning habitat farther upstream in the Sprague River. Increased densities of drifting larvae were observed at a site in the lower Williamson River after the dam was removed, but no substantial changes occurred upstream of the former dam site. Adult spawning migrations primarily were influenced by water temperature and did not change with the removal of the dam. Emigration of larvae consistently occurred about 3-4 weeks after adults migrated into a section of river. Detections of PIT-tagged fish showed increases in the numbers of all three suckers that migrated upstream of the dam site following removal, but the increases for Lost River and shortnose suckers were relatively small compared to the total number of fish that made a spawning migration in a given season. Increases for Klamath largescale suckers were more substantial. Post-dam removal monitoring

A Quantitative Polymerase Chain Reaction Assay for the Detection and Quantification of Epizootic Epitheliotropic Disease Virus (EEDV; Salmonid Herpesvirus 3).

Science.gov (United States)

Glenney, Gavin W; Barbash, Patricia A; Coll, John A

2016-03-01

Epizootic epitheliotropic disease virus (EEDV; salmonid herpesvirus [SalHV3]; family Alloherpesviridae) causes a systemic disease of juvenile and yearling Lake Trout Salvelinus namaycush. No cell lines are currently available for the culture and propagation of EEDV, so primary diagnosis is limited to PCR and electron microscopy. To better understand the pervasiveness of EEDV (carrier or latent state of infection) in domesticated and wild Lake Trout populations, we developed a sensitive TaqMan quantitative PCR (qPCR) assay to detect the presence of the EEDV terminase gene in Lake Trout tissues. This assay was able to detect a linear standard curve over nine logs of plasmid dilution and was sensitive enough to detect single-digit copies of EEDV. The efficiency of the PCR assay was 99.4 ± 0.06% (mean ± SD), with a 95% confidence limit of 0.0296 (R(2) = 0.994). Methods were successfully applied to collect preliminary data from a number of species and water bodies in the states of Pennsylvania, New York, and Vermont, indicating that EEDV is more common in wild fish than previously known. In addition, through the development of this qPCR assay, we detected EEDV in a new salmonid species, the Cisco Coregonus artedi. The qPCR assay was unexpectedly able to detect two additional herpesviruses, the Atlantic Salmon papillomatosis virus (ASPV; SalHV4) and the Namaycush herpesvirus (NamHV; SalHV5), which both share high sequence identity with the EEDV terminase gene. With these unexpected findings, we subsequently designed three primer sets to confirm initial TaqMan qPCR assay positives and to differentiate among EEDV, ASPV, and NamHV by detecting the glycoprotein genes via SYBR Green qPCR. Received April 20, 2015; accepted November 10, 2015.

Explaining variation in life history timing across a species range: Effects of climate on spawning time in an exploited marine fish

DEFF Research Database (Denmark)

Neuheimer, Anna; MacKenzie, Brian

. Combined, these results shed light on the adaptive capacity of the species in the face of changing climate. We use our results to estimate expected spawning time under future climate regimes, and discuss the implications for codecology and management across the species’ range, and in the greater ecosystem......The capacity of a species to tolerate and/or adapt to environmental conditions will shape its response to future climate change including climate extremes. Of the many life-history processes affected by climate change, timing of reproduction greatly influences offspring success and resulting...... population production. Here we explore temporal and spatial changes in spawning time for Atlantic cod (Gadus morhua) across the species’ range (4 to 80°N). We estimate spawning time using a physiologically relevant metric that includes information on fish thermal history (degree days, DD). First, we estimate...

Seasonal and annual variation in Chilean hake Merluccius gayi spawning locations and egg size off central Chile

Science.gov (United States)

Landaeta, Mauricio F.; Castro, Leonardo R.

2012-01-01

Variability in Chilean hake reproductive tactics off central Chile was assessed by analyzing ichthyoplankton samples from nine oceanographic cruises (1996-2005) and through experimental trials with early life stages (eggs, yolk-sac larvae) during the main (austral spring) and secondary (late summer-early autumn) spawning seasons. Abundant eggs in the plankton (1300-2000 eggs per 10 m 2) and historical adult reproductive data showed the highest reproductive activity in austral spring, with large egg aggregations near shelf break (50-100 m depth). Large, recently spawned eggs (1.15-1.20 mm diameter) were advected nearshore by coastward subsurface flows in the spring upwelling season. Experimental trials indicated that recently hatched larvae (3.4-3.5 mm) consumed their yolk-sac (0.17-0.41 mm 3) in 3-4 days at 10-12 °C; plankton sampling indicated that larval hake remained at mid-depth (50-100 m) without showing daily vertical migrations until completing their caudal fin formation (∼15 mm). During the secondary reproductive peak, hake spawned nearshore, when smaller eggs (0.95-1.13 mm) and recently hatched larvae (2.2-2.6 mm notochord length) occurred in surface waters (0-10 m depth). Their relatively large yolk-sac volumes (0.57 ± 0.11 mm 3) provided endogenous nourishment for at least 5 days at 10 °C, according to experiments. In the field, preflexion larvae occurred mainly in the mixed layer (0-25 m) and started ontogenetic daily vertical migrations at 7 mm. A strong decline occurred after 2002 in the adult Chilean hake biomass (estimated by hydroacoustic surveys) and body size, coinciding with variations in spawning locations (more coastward in early spring 2004 and 2005) and decline in egg size. Thus, recent variations in Chilean hake reproductive tactics may reflect an indirect effect of declines in the parental population size.

Real-time ichthyoplankton drift in Northeast Arctic cod and Norwegian spring-spawning herring.

Science.gov (United States)

Vikebø, Frode B; Ådlandsvik, Bjørn; Albretsen, Jon; Sundby, Svein; Stenevik, Erling Kåre; Huse, Geir; Svendsen, Einar; Kristiansen, Trond; Eriksen, Elena

2011-01-01

Individual-based biophysical larval models, initialized and parameterized by observations, enable numerical investigations of various factors regulating survival of young fish until they recruit into the adult population. Exponentially decreasing numbers in Northeast Arctic cod and Norwegian Spring Spawning herring early changes emphasizes the importance of early life history, when ichthyoplankton exhibit pelagic free drift. However, while most studies are concerned with past recruitment variability it is also important to establish real-time predictions of ichthyoplankton distributions due to the increasing human activity in fish habitats and the need for distribution predictions that could potentially improve field coverage of ichthyoplankton. A system has been developed for operational simulation of ichthyoplankton distributions. We have coupled a two-day ocean forecasts from the Norwegian Meteorological Institute with an individual-based ichthyoplankton model for Northeast Arctic cod and Norwegian Spring Spawning herring producing daily updated maps of ichthyoplankton distributions. Recent years observed spawning distribution and intensity have been used as input to the model system. The system has been running in an operational mode since 2008. Surveys are expensive and distributions of early stages are therefore only covered once or twice a year. Comparison between model and observations are therefore limited in time. However, the observed and simulated distributions of juvenile fish tend to agree well during early fall. Area-overlap between modeled and observed juveniles September 1(st) range from 61 to 73%, and 61 to 71% when weighted by concentrations. The model system may be used to evaluate the design of ongoing surveys, to quantify the overlap with harmful substances in the ocean after accidental spills, as well as management planning of particular risky operations at sea. The modeled distributions are already utilized during research surveys to

Real-time ichthyoplankton drift in Northeast Arctic cod and Norwegian spring-spawning herring.

Directory of Open Access Journals (Sweden)

Frode B Vikebø

Full Text Available BACKGROUND: Individual-based biophysical larval models, initialized and parameterized by observations, enable numerical investigations of various factors regulating survival of young fish until they recruit into the adult population. Exponentially decreasing numbers in Northeast Arctic cod and Norwegian Spring Spawning herring early changes emphasizes the importance of early life history, when ichthyoplankton exhibit pelagic free drift. However, while most studies are concerned with past recruitment variability it is also important to establish real-time predictions of ichthyoplankton distributions due to the increasing human activity in fish habitats and the need for distribution predictions that could potentially improve field coverage of ichthyoplankton. METHODOLOGY/PRINCIPAL FINDINGS: A system has been developed for operational simulation of ichthyoplankton distributions. We have coupled a two-day ocean forecasts from the Norwegian Meteorological Institute with an individual-based ichthyoplankton model for Northeast Arctic cod and Norwegian Spring Spawning herring producing daily updated maps of ichthyoplankton distributions. Recent years observed spawning distribution and intensity have been used as input to the model system. The system has been running in an operational mode since 2008. Surveys are expensive and distributions of early stages are therefore only covered once or twice a year. Comparison between model and observations are therefore limited in time. However, the observed and simulated distributions of juvenile fish tend to agree well during early fall. Area-overlap between modeled and observed juveniles September 1(st range from 61 to 73%, and 61 to 71% when weighted by concentrations. CONCLUSIONS/SIGNIFICANCE: The model system may be used to evaluate the design of ongoing surveys, to quantify the overlap with harmful substances in the ocean after accidental spills, as well as management planning of particular risky operations

The effect of the interaction of various spawn grains and oil types on ...

African Journals Online (AJOL)

The results revealed that the interaction of the different spawn grains with the various oil types produced a highly significant effect (p<0.01) on the stipe length, dry weight, and stipe and pileus diameters of Lentinus squarrosulus. The interactions of corn x coconut and corn x butterfat, respectively produced stipe lengths that ...

Bacterial acquisition in juveniles of several broadcast spawning coral species.

Science.gov (United States)

Sharp, Koty H; Ritchie, Kim B; Schupp, Peter J; Ritson-Williams, Raphael; Paul, Valerie J

2010-05-28

Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and zooxanthellae. The extent to which coral-bacterial associations are specific and the mechanisms for their maintenance across generations in the environment are unknown. The high diversity of bacteria in adult coral colonies has made it challenging to identify species-specific patterns. Localization of bacteria in gametes and larvae of corals presents an opportunity for determining when bacterial-coral associations are initiated and whether they are dynamic throughout early development. This study focuses on the early onset of bacterial associations in the mass spawning corals Montastraea annularis, M. franksi, M. faveolata, Acropora palmata, A. cervicornis, Diploria strigosa, and A. humilis. The presence of bacteria and timing of bacterial colonization was evaluated in gametes, swimming planulae, and newly settled polyps by fluorescence in situ hybridization (FISH) using general eubacterial probes and laser-scanning confocal microscopy. The coral species investigated in this study do not appear to transmit bacteria via their gametes, and bacteria are not detectable in or on the corals until after settlement and metamorphosis. This study suggests that mass-spawning corals do not acquire, or are not colonized by, detectable numbers of bacteria until after larval settlement and development of the juvenile polyp. This timing lays the groundwork for developing and testing new hypotheses regarding general regulatory mechanisms that control bacterial colonization and infection of corals, and how interactions among bacteria and juvenile polyps influence the structure of bacterial assemblages in corals.

Selection by higher-order effects of salinity and bacteria on early life-stages of Western Baltic spring-spawning herring.

Science.gov (United States)

Poirier, Maude; Listmann, Luisa; Roth, Olivia

2017-07-01

Habitat stratification by abiotic and biotic factors initiates divergence of populations and leads to ecological speciation. In contrast to fully marine waters, the Baltic Sea is stratified by a salinity gradient that strongly affects fish physiology, distribution, diversity and virulence of important marine pathogens. Animals thus face the challenge to simultaneously adapt to the concurrent salinity and cope with the selection imposed by the changing pathogenic virulence. Western Baltic spring-spawning herring ( Clupea harengus ) migrate to spawning grounds characterized by different salinities to which herring are supposedly adapted. We hypothesized that herring populations do not only have to cope with different salinity levels but that they are simultaneously exposed to higher-order effects that accompany the shifts in salinity, that is induced pathogenicity of Vibrio bacteria in lower saline waters. To experimentally evaluate this, adults of two populations were caught in their spawning grounds and fully reciprocally crossed within and between populations. Larvae were reared at three salinity levels, representing the spawning ground salinity of each of the two populations, or Atlantic salinity conditions resembling the phylogenetic origin of Clupea harengus . In addition, larvae were exposed to a Vibrio spp . infection. Life-history traits and gene expression analysis served as response variables. Herring seem adapted to Baltic Sea conditions and cope better with low saline waters. However, upon a bacterial infection, herring larvae suffer more when kept at lower salinities implying reduced resistance against Vibrio or higher Vibrio virulence. In the context of recent climate change with less saline marine waters in the Baltic Sea, such interactions may constitute key future stressors.

Male size composition affects male reproductive variance in Atlantic cod Gadus morhua L. spawning aggregations

DEFF Research Database (Denmark)

Bekkevold, Dorte

2006-01-01

Estimates of Atlantic cod Gadus morhua reproductive success, determined using experimental spawning groups and genetic paternity assignment of offspring, showed that within-group variance in male size correlated positively with the degree of male mating skew, predicting a decrease in male reprodu...

The relationship between emergence from spawning gravel and growth in farmed rainbow trout Oncorhynchus mykiss

DEFF Research Database (Denmark)

Åberg Andersson, Madelene; Laursen, Danielle Caroline; SILVA, P.I.M.

2013-01-01

The relationship between the timing of emergence from spawning gravel and growth after emergence was investigated in farmed Oncorhynchus mykiss. A relationship between the time of emergence and growth became evident after 6 months of rearing, where individuals with an intermediate emergence time...

Experimental effects of immersion time and water temperature on body condition, burying depth and timing of spawning of the tellinid bivalve Macoma balthica

Science.gov (United States)

de Goeij, Petra; Honkoop, Pieter J.

2003-03-01

The burying depth of many bivalve molluscs on intertidal mudflats varies throughout the year and differs between places. Many factors are known to influence burying depth on a seasonal or spatial scale, with temperature and tidal regime probably being very important. Burying depth, body condition and gonadal development of Macoma balthica were followed throughout winter and spring in an experiment in which water temperature and immersion time were manipulated. Unexpectedly, relative water temperature, in contrast to the prediction, did not generally affect body condition or burying depth. This was probably a consequence of the exceptionally overall low water temperatures during the experimental winter. Differences in temperature did, however, result in different timing of spawning: M. balthica spawned earlier at higher spring temperatures. Longer immersion times led to higher body condition only late in spring, but led to deeper burying throughout almost the whole period. There was no effect of immersion time on the timing of spawning. We conclude that a longer immersion time leads to deeper burying, independent of body condition. We also conclude that burying behaviour of M. balthica is not determined by the moment of spawning.

Developing Baltic cod recruitment models I : Resolving spatial and temporal dynamics of spawning stock and recruitment for cod, herring, and sprat

DEFF Research Database (Denmark)

Köster, Fritz; Möllmann, C.; Neuenfeldt, Stefan

2001-01-01

The Baltic Sea comprises a heterogeneous oceanographic environment influencing the spatial and temporal potential for reproductive success of cod (Gadus morhua) and sprat (Sprattus sprattus) in the different spawning basins. Hence, to quantify stock and recruitment dynamics, it is necessary......-disaggregated multispecies virtual population analyses (MSVPA) were performed for interacting species cod, herring (Clupea harengus), and sprat in the different subdivisions of the Central Baltic. The MSVPA runs revealed distinct spatial trends in population abundance, spawning biomass, recruitment, and predation...

Hiding in Plain Sight: A Case for Cryptic Metapopulations in Brook Trout (Salvelinus fontinalis.

Directory of Open Access Journals (Sweden)

David C Kazyak

Full Text Available A fundamental issue in the management and conservation of biodiversity is how to define a population. Spatially contiguous fish occupying a stream network have often been considered to represent a single, homogenous population. However, they may also represent multiple discrete populations, a single population with genetic isolation-by-distance, or a metapopulation. We used microsatellite DNA and a large-scale mark-recapture study to assess population structure in a spatially contiguous sample of Brook Trout (Salvelinus fontinalis, a species of conservation concern. We found evidence for limited genetic exchange across small spatial scales and in the absence of barriers to physical movement. Mark-recapture and stationary passive integrated transponder antenna records demonstrated that fish from two tributaries very seldom moved into the opposite tributary, but movements between the tributaries and mainstem were more common. Using Bayesian genetic clustering, we identified two genetic groups that exhibited significantly different growth rates over three years of study, yet survival rates were very similar. Our study highlights the importance of considering the possibility of multiple genetically distinct populations occurring within spatially contiguous habitats, and suggests the existence of a cryptic metapopulation: a spatially continuous distribution of organisms exhibiting metapopulation-like behaviors.

Fish and fisher behaviour influence the vulnerability of groupers (Epinephelidae) to fishing at a multispecies spawning aggregation site

Science.gov (United States)

Robinson, J.; Graham, N. A. J.; Cinner, J. E.; Almany, G. R.; Waldie, P.

2015-06-01

Targeted fishing of spawning aggregations is a major contributor to extinction risk in numerous species of grouper (Epinephelidae). Marine reserves are often used to protect spawning aggregation sites, including multispecies sites shared by several species of grouper. However, marine reserves may be biologically, socioeconomically or culturally unviable in some fisheries, and alternative management actions must be explored. Implementing effective management actions that control rather than prohibit fishing requires an improved understanding of how species vary in their vulnerability to fishing gears and respond to changes in fishing effort. To estimate sources of variability in vulnerability to fishing (i.e. catchability), catch-per-unit-effort (CPUE) and other fisheries data were collected in parallel with underwater visual census-derived estimates of aggregation size at a multispecies spawning site of Epinephelus fuscoguttatus and E. polyphekadion. Despite having similar abundances, E. polyphekadion was eightfold more vulnerable to capture by hook-and-line gear, clearly outcompeting its congener for bait. Contrasting with the common assumption of a proportional relationship, the CPUE of both species was unrelated to the size of their respective aggregations. Moreover, the CPUE of each species was unrelated to hook size and depth fished. However, E. polyphekadion CPUE declined as the density of fishing effort increased at the site, with gear saturation identified as the likely mechanism for this effect. E. fuscoguttatus CPUE was negatively related to the size of aggregations formed by its congener, stemming from the superior competitiveness and therefore higher selectivity of the gear for E. polyphekadion. Our findings demonstrate that CPUE is an unreliable indicator of spawning aggregation status. The other sources of variation in CPUE that we identify have implications for gear-based management, which must be based on understanding of gear selectivity for

Bacterial acquisition in juveniles of several broadcast spawning coral species.

Directory of Open Access Journals (Sweden)

Koty H Sharp

Full Text Available Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and zooxanthellae. The extent to which coral-bacterial associations are specific and the mechanisms for their maintenance across generations in the environment are unknown. The high diversity of bacteria in adult coral colonies has made it challenging to identify species-specific patterns. Localization of bacteria in gametes and larvae of corals presents an opportunity for determining when bacterial-coral associations are initiated and whether they are dynamic throughout early development. This study focuses on the early onset of bacterial associations in the mass spawning corals Montastraea annularis, M. franksi, M. faveolata, Acropora palmata, A. cervicornis, Diploria strigosa, and A. humilis. The presence of bacteria and timing of bacterial colonization was evaluated in gametes, swimming planulae, and newly settled polyps by fluorescence in situ hybridization (FISH using general eubacterial probes and laser-scanning confocal microscopy. The coral species investigated in this study do not appear to transmit bacteria via their gametes, and bacteria are not detectable in or on the corals until after settlement and metamorphosis. This study suggests that mass-spawning corals do not acquire, or are not colonized by, detectable numbers of bacteria until after larval settlement and development of the juvenile polyp. This timing lays the groundwork for developing and testing new hypotheses regarding general regulatory mechanisms that control bacterial colonization and infection of corals, and how interactions among bacteria and juvenile polyps influence the structure of bacterial assemblages in corals.

Goliath catfish spawning in the far western Amazon confirmed by the distribution of mature adults, drifting larvae and migrating juveniles.

Science.gov (United States)

Barthem, Ronaldo B; Goulding, Michael; Leite, Rosseval G; Cañas, Carlos; Forsberg, Bruce; Venticinque, Eduardo; Petry, Paulo; Ribeiro, Mauro L de B; Chuctaya, Junior; Mercado, Armando

2017-02-06

We mapped the inferred long-distance migrations of four species of Amazonian goliath catfishes (Brachyplatystoma rousseauxii, B. platynemum, B. juruense and B. vaillantii) based on the presence of individuals with mature gonads and conducted statistical analysis of the expected long-distance downstream migrations of their larvae and juveniles. By linking the distribution of larval, juvenile and mature adult size classes across the Amazon, the results showed: (i) that the main spawning regions of these goliath catfish species are in the western Amazon; (ii) at least three species-B. rousseauxii, B. platynemum, and B. juruense-spawn partially or mainly as far upstream as the Andes; (iii) the main spawning area of B. rousseauxii is in or near the Andes; and (iv) the life history migration distances of B. rousseauxii are the longest strictly freshwater fish migrations in the world. These results provide an empirical baseline for tagging experiments, life histories extrapolated from otolith microchemistry interpretations and other methods to establish goliath catfish migratory routes, their seasonal timing and possible return (homing) to western headwater tributaries where they were born.

Monitoring the Reproductive Success of Naturally Spawning Hatchery and Natural Spring Chinook Salmon in the Wenatchee River, 2008-2009 Progress Report.

Energy Technology Data Exchange (ETDEWEB)

Ford, Michael J.; Williamson, Kevin S. [Northwest Fisheries Science Center

2009-05-28

We investigated differences in the statistical power to assign parentage between an artificially propagated and wild salmon population. The propagated fish were derived from the wild population, and are used to supplement its abundance. Levels of genetic variation were similar between the propagated and wild groups at 11 microsatellite loci, and exclusion probabilities were >0.999999 for both groups. The ability to unambiguously identify a pair of parents for each sampled progeny was much lower than expected, however. Simulations demonstrated that the proportion of cases the most likely pair of parents were the true parents was lower for propagated parents than for wild parents. There was a clear relationship between parentage assignment ability and the degree of linkage disequilibrium, the estimated effective number of breeders that produced the parents, and the size of the largest family within the potential parents. If a stringent threshold for parentage assignment was used, estimates of relative fitness were biased downward for the propagated fish. The bias appeared to be largely eliminated by either fractionally assigning progeny among parents in proportion to their likelihood of parentage, or by assigning progeny to the most likely set of parents without using a statistical threshold. We used a DNA-based parentage analysis to measure the relative reproductive success of hatchery- and natural-origin spring Chinook salmon in the natural environment. Both male and female hatchery-origin fish produced far fewer juvenile progeny per parent when spawning naturally than did natural origin fish. Differences in age structure, spawning location, weight and run timing were responsible for some of the difference in fitness. Male size and age had a large influence on fitness, with larger and older males producing more offspring than smaller or younger individuals. Female size had a significant effect on fitness, but the effect was much smaller than the effect of size on

Evidence from the past: exploitation as cause of commercial extinction of autumn-spawning herring in the Gulf of Riga, Baltic Sea

DEFF Research Database (Denmark)

MacKenzie, Brian R; Ojaveer, Henn

2018-01-01

Historical marine ecology has shown that many exploited animal populations declined before their abundance was quantified by scientists. This situation applies for autumn-spawning herring (Clupea harengus) in the Baltic Sea. This stock used to be the dominant spawning group of herring in the early...... and biological data and conduct population development simulations to evaluate the hypothesis that exploitation may have been sufficient to lead the stock towards commercial extinction. We found that the estimated exploitation pattern, including exploitation of juveniles, was unsustainable and led to stock...

Aloe vera bathing improved physical and humoral protection in breeding stock after induced spawning in matrinxã (Brycon amazonicus).

Science.gov (United States)

Zanuzzo, Fábio S; Zaiden, Sérgio F; Senhorini, José A; Marzocchi-Machado, Cleni M; Urbinati, Elisabeth C

2015-07-01

In this study, we show that induced spawning causes stress, an intense loss of epithelia and immunosuppression, decreasing physical and humoral protection in fish, effects that were prevented or improved in fish bathed with Aloe vera. A. vera has several medicinal properties, including wound healing and immunostimulatory effects, which we observed in this study. Fish bathed with A. vera had a higher number of epidermal goblet cells and, in general, an improved wound healing rate compared with the control after induced spawning. These effects might be related to (1) the stimulation of leukocyte activity, represented here by the increased leukocyte respiratory activity triggered by A. vera (leukocytes are recognized as playing an important role in wound repair); (2) the antimicrobial properties of A. vera, which decrease wound infection and accelerate the healing process; and (3) several mechanisms that explain the healing effect of A. vera (increased collagen synthesis, rate of epithelialization, and anti-inflammatory and moisturizing effects). Our results also suggest that caution is necessary during the induced spawning process, especially during stripping, and A. vera bathing is recommended after intensive aquaculture operations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Factors affecting competitive dominance of rainbow trout over brook trout in southern Appalachian streams: Implications of an individual-based model

Energy Technology Data Exchange (ETDEWEB)

Clark, M.E. [Univ. of Tennessee, Knoxville, TN (United States); Rose, K.A. [Oak Ridge National Lab., TN (United States)

1997-01-01

We used an individual-based model to examine possible explanations for the dominance of rainbow trout Oncorhynchus mykiss over brook trout Salvelinus fontinalis in southern Appalachian streams. Model simulations were used to quantify the effects on interspecific competition of (1) competitive advantage for feeding sites by rainbow trout, (2) latitudinal differences in stream temperatures, flows, and daylight, (3) year-class failures, (4) lower fecundity of brook trout, and (5) reductions in spawning habitat. The model tracks the daily spawning, growth, and survival of individuals of both species throughout their lifetime in a series of connected stream habitat units (pools, runs, or riffles). Average densities of each species based on 100-year simulations were compared for several levels of each of the five factors and for sympatric and allopatric conditions. Based on model results and empirical information, we conclude that more frequent year-class failures and the lower fecundity of brook trout are both possible and likely explanations for rainbow trout dominance, that warmer temperatures due to latitude and limited spawning habitat are possible but unlikely explanations, and that competitive advantage for feeding sites by rainbow trout is an unlikely explanation. Additional field work should focus on comparative studies of the reproductive success and the early life stage mortalities of brook and rainbow trout among Appalachian streams with varying rainbow trout dominance. 53 refs., 11 figs.

Studies on the maturity and spawning of silver pomfret, Pampus argenteus (Euphr.) in the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Gopalan, U.K.

Maturity and spawning of the Silver Pomfret, Pampus argenteus (Euphr.) have been studied in an area between the Gulf of Kutch and the Gulf of Cambay. The method of studying were: direct observation on the occurrence of maturity stages, measurements...

Mapping the spawning grounds of North Sea cod ( Gadus morhua ) by direct and indirect means

DEFF Research Database (Denmark)

Fox, C.J.; Taylor, M.; Dickey-Collas, M.

2008-01-01

Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey...

Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means

NARCIS (Netherlands)

Fox, C.J.; Taylor, M.; Dickey-Collas, M.; Fossum, P.; Kraus, G.; Rohlf, N.; Damme, van C.J.G.; Bolle, L.J.

2008-01-01

Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey

Lake Ontario: Food web dynamics in a changing ecosystem (1970-2000)

Science.gov (United States)

Mills, E.L.; Casselman, J.M.; Dermott, R.; Fitzsimons, J.D.; Gal, G.; Holeck, K. T.; Hoyle, J.A.; Johannsson, O.E.; Lantry, B.F.; Makarewicz, J.C.; Millard, E.S.; Munawar, I.F.; Munawar, M.; O'Gorman, R.; Owens, R.W.; Rudstam, L. G.; Schaner, T.; Stewart, T.J.

2003-01-01

We examined stressors that have led to profound ecological changes in the Lake Ontario ecosystem and its fish community since 1970. The most notable changes have been reductions in phosphorus loading, invasion by Dreissena spp., fisheries management through stocking of exotic salmonids and control of sea lamprey (Petromyzon marinus), and fish harvest by anglers and double-crested cormorants (Phalacrocorax auritus). The response to these stressors has led to (i) declines in both algal photosynthesis and epilimnetic zooplankton production, (ii) decreases in alewife (Alosa pseudoharengus) abundance, (iii) declines in native Diporeia and lake whitefish (Coregonus clupeaformis), (iv) behavioral shifts in alewife spatial distribution benefitting native lake trout (Salvelinus namaycush), threespine stickleback (Gasterosteus aculeatus), and emerald shiner (Notropis atherinoides) populations, (v) dramatic increases in water clarity, (vi) predation impacts by cormorants on select fish species, and (vii) lake trout recruitment bottlenecks associated with alewife-induced thiamine deficiency. We expect stressor responses associated with anthropogenic forces like exotic species invasions and global climate warming to continue to impact the Lake Ontario ecosystem in the future and recommend continuous long-term ecological studies to enhance scientific understanding and management of this important resource.

Geochemical pathways and biological uptake of radium in small Canadian Shield lakes

International Nuclear Information System (INIS)

Hesslein, R.H.; Slavicek, E.

1984-01-01

The sediment-water interactions and biological uptake of 226 Ra are described for four small Canadian Shield lakes at the Experimental Lakes Area, Kenora, Ontario. A single addition of 226 Ra was made to each lake between 1970 and 1976. Approximately 90 percent of the added 226 Ra initially sorbed to the sediments. Outflow from the lakes showed losses of only 5-11 percent 226 Ra per year. Models are proposed for adsorption and outflow of 226 Ra from lakes. Biological uptake and long-term 226 Ra concentrations were measured in three species of macrophytes, crayfish, and five species of fish. Bioaccumulation ranged from 1100 to 5000 in macrophytes, 705 in crayfish, from 30 to 80 in large trout (Salvelinus namaycush), white sucker (Catostomus commersoni), and lake whitefish (Coregonus clupeaformis), and from 230 to 1200 in fathead minnows (Pimephales promelas), pearl dace (Semotilus margarita), and northern redbelly dace (Chrosomus eos). The concept of Ra/Ca ratio in organisms versus water and food is used to explain the differences in bioaccumulation. 226 Ra is discriminated against versus calcium by fish but favoured by macrophytes and crayfish

Ethyl-p-aminobenzoate (Benzocaine): efficacy as an anesthetic for five species of freshwater fish

Science.gov (United States)

Dawson, V.K.; Gilderhus, P.A.

1979-01-01

Ethyl-p-aminobenzoate (benzocaine) was tested for its efficacy as an anesthetic for rainbow trout (Salmo gairdnerii, brown trout (Salmo truttas, northern pike (Esox lucius). carp (Cyprinus carpio), and largemouth bass (Mieropterus salmoidesi. Since benzocaine is not water soluble, it was applied with acetone as a carrier. Concentrations of 100 to 200 mg!l were required for large adult northern pike, compared with 50 to 100 mg/l for small fish. Rates of sedation and recovery were slower in cold water than in warm water. Water hardness had little influence on the activity of benzocaine. Fish were anesthetized faster and recovered more slowly in acid than in alkaline water. Benzocaine produced deep anesthesia, but concentrations that rendered the fish handleable within 5 min were generally not safe for exposures longer than 15 min. Concentrations of benzocaine efficacious for fish were not acutely toxic to eggs of coho salmon (Oncorhynchus kisutch), chinook salmon (Oncorhynchus tshauiytschas, rainbow trout, brown trout, or lake trout (Salvelinus namaycush). Benzocaine is not registered for fishery use and is neither more effective nor safer than the registered anesthetic, tricaine methanesulfonate (MS-222l.

Comment on linking the sex difference in PCB concentrations of fish to release of eggs at spawning: Time to jettison the dogma

Science.gov (United States)

Madenjian, Charles P.

2017-01-01

For the past 20 years or so, a commonly used explanation in the scientific literature for higher polychlorinated biphenyl (PCB) concentrations in male fish than in female fish has been that females lose a high proportion of their PCB body burden by releasing eggs at spawning time, and therefore the females undergo a substantial decrease in their PCB concentration immediately after spawning due to shedding of their eggs [1]. Indeed, this explanation can be viewed as the conventional wisdom used by toxicologists to account for differences in PCB concentrations between the sexes of fish. On the surface, this explanation seems plausible. PCBs are lipid soluble, and eggs are thought to be relatively high in lipid concentration. If a sufficiently high proportion of the PCB body burden within a female fish is transferred to the eggs, then the release of eggs at spawning would be expected to result in a dramatic decrease in the PCB concentration of the female.

Sexual maturity, spawning and fecundity of king weakfish Macrodon ancylodon, caught off Rio Grande do Sul State (southern coast of Brazil

Directory of Open Access Journals (Sweden)

Anastácio Afonso Juras

1989-01-01

Full Text Available Investigations on the sexual maturity, spawning and fecundity of king weakfish, Macrodon ancylodon, off the southern coast of Brazil (lat. 29º to 32ºS were carried out from September, 1976, to August, 1977. The sex ratio varied monthly, with slight predominance of males (51.14% over females (48.86%. The mean size at first maturity was estimated as 27.4 cm TL for females and 21.5 cm TL for males. The macroscopic examination of gonads and analysis of the gonadal index indicated that December and February were the most intensive spawning months. Fish weight proved to be the best predictor data of fecundity: F = 17056.2500 + 425.3712 Wt (r² = 0.6434 , were F is the total number of eggs in both ovaries. The number of eggs of 199 females varied from 59,850 for 33.4 cm TL fish to over 358,450 for 37.2 cm TL; the mean fecundity verified was 165,273 eggs per female. Frequency distributions of egg diameter in the ovaries were polymodal, suggesting fractional spawning during the reproduction season.

Long-term retrospective analysis of mackerel spawning in the North Sea: a new time series and modeling approach to CPR data.

Science.gov (United States)

Jansen, Teunis; Kristensen, Kasper; Payne, Mark; Edwards, Martin; Schrum, Corinna; Pitois, Sophie

2012-01-01

We present a unique view of mackerel (Scomber scombrus) in the North Sea based on a new time series of larvae caught by the Continuous Plankton Recorder (CPR) survey from 1948-2005, covering the period both before and after the collapse of the North Sea stock. Hydrographic backtrack modelling suggested that the effect of advection is very limited between spawning and larvae capture in the CPR survey. Using a statistical technique not previously applied to CPR data, we then generated a larval index that accounts for both catchability as well as spatial and temporal autocorrelation. The resulting time series documents the significant decrease of spawning from before 1970 to recent depleted levels. Spatial distributions of the larvae, and thus the spawning area, showed a shift from early to recent decades, suggesting that the central North Sea is no longer as important as the areas further west and south. These results provide a consistent and unique perspective on the dynamics of mackerel in this region and can potentially resolve many of the unresolved questions about this stock.

Long-term retrospective analysis of mackerel spawning in the North Sea: a new time series and modeling approach to CPR data.

Directory of Open Access Journals (Sweden)

Teunis Jansen

Full Text Available We present a unique view of mackerel (Scomber scombrus in the North Sea based on a new time series of larvae caught by the Continuous Plankton Recorder (CPR survey from 1948-2005, covering the period both before and after the collapse of the North Sea stock. Hydrographic backtrack modelling suggested that the effect of advection is very limited between spawning and larvae capture in the CPR survey. Using a statistical technique not previously applied to CPR data, we then generated a larval index that accounts for both catchability as well as spatial and temporal autocorrelation. The resulting time series documents the significant decrease of spawning from before 1970 to recent depleted levels. Spatial distributions of the larvae, and thus the spawning area, showed a shift from early to recent decades, suggesting that the central North Sea is no longer as important as the areas further west and south. These results provide a consistent and unique perspective on the dynamics of mackerel in this region and can potentially resolve many of the unresolved questions about this stock.

1998-1999 evaluation of fall chinook and chum salmon spawning below Bonneville, The Dalles, John Day and McNary dams

International Nuclear Information System (INIS)

Naald, W.D. van der

2001-01-01

This report describes work conducted by the Oregon Department of Fish and Wildlife (ODFW) and the Washington Department of Fish and Wildlife (WDFW) from 1 October 1998 to 30 September 1999. The work is part of studies to evaluate spawning of fall chinook salmon (Oncorhynchus tshawytscha) and chum salmon (O. keta) below the four lowermost Columbia River dams under the Bonneville Power Administration's Project 99-003. The purpose of this project is twofold: (1) Document the existence of fall chinook and chum populations spawning below Bonneville Dam (river mile (RM) 145), The Dalles Dam (RM 192), John Day Dam (RM 216), and McNary Dam (RM 292) (Figure 1) and estimate the size of these populations; and (2) Profile stocks for important population characteristics; including spawning time, genetic make-up, emergence timing, migration size and timing, and juvenile to adult survival rates. Specific tasks conducted by ODFW and WDFW during this period were: (1) Documentation of fall chinook and chum spawning below Bonneville, The Dalles, John Day and McNary dams using on-water observations; (2) Collection of biological data to profile stocks in areas described in Task 1; (3) Determination of spawning population estimates and age composition, average size at return, and sex ratios in order to profile stocks in areas described in Task 1; (4) Collection of data to determine stock origin of adult salmon found in areas described in Task 1; (5) Determination of possible stock origins of adult salmon found in areas described in Task 1 using tag rates based on coded-wire tag recoveries and genetic baseline analysis; (6) Determination of emergence timing and hatching rate of juvenile fall chinook and chum below Bonneville Dam; (7) Determination of migration time and size for juvenile fall chinook and chum rearing in the area described in Task 6; (8) Investigation of feasibility of determining stock composition of juvenile fall chinook and chum rearing in the area described in Task 6

Bioenergetic evaluation of diel vertical migration by bull trout (Salvelinus confluentus) in a thermally stratified reservoir

Science.gov (United States)

Eckmann, Madeleine; Dunham, Jason B.; Connor, Edward J.; Welch, Carmen A.

2018-01-01

Many species living in deeper lentic ecosystems exhibit daily movements that cycle through the water column, generally referred to as diel vertical migration (DVM). In this study, we applied bioenergetics modelling to evaluate growth as a hypothesis to explain DVM by bull trout (Salvelinus confluentus) in a thermally stratified reservoir (Ross Lake, WA, USA) during the peak of thermal stratification in July and August. Bioenergetics model parameters were derived from observed vertical distributions of temperature, prey and bull trout. Field sampling confirmed that bull trout prey almost exclusively on recently introduced redside shiner (Richardsonius balteatus). Model predictions revealed that deeper (>25 m) DVMs commonly exhibited by bull trout during peak thermal stratification cannot be explained by maximising growth. Survival, another common explanation for DVM, may have influenced bull trout depth use, but observations suggest there may be additional drivers of DVM. We propose these deeper summertime excursions may be partly explained by an alternative hypothesis: the importance of colder water for gametogenesis. In Ross Lake, reliance of bull trout on warm water prey (redside shiner) for consumption and growth poses a potential trade-off with the need for colder water for gametogenesis.

What is left? Macrophyte meadows and Atlantic herring (Clupea harengus) spawning sites in the Greifswalder Bodden, Baltic Sea

Science.gov (United States)

Kanstinger, Philipp; Beher, Jutta; Grenzdörffer, Görres; Hammer, Cornelius; Huebert, Klaus B.; Stepputis, Daniel; Peck, Myron A.

2018-02-01

Coastal zones are productive areas of marine ecosystems which are also hotspots of anthropogenic activities causing habitat degradation. In the southwest Baltic Sea, eutrophication is thought to have caused the massive reduction in submerged macrophytes observed in recent decades. Here, we surveyed the submarine vegetation and examined locations of spawning of herring (Clupea harengus) in the Greifswalder Bodden, one of the most important reproductive habitats of the Western Baltic Spring Spawner herring stock (WBSS). This stock deposits eggs onto submerged vegetation and changes in macrophyte coverage are expected to influence the availability of reproductive habitat. Aerial, underwater video tows and SCUBA surveys conducted in spring 2009 revealed that only ∼7% of the lagoon was vegetated. Herring eggs were observed on 12 of 32 SCUBA transects, at depths between 0.2 and 5 m and were attached to a variety of spermatophyte and algae species but not to stones or mussels. A classification tree model indicated that spawning sites were strongly associated with the vegetation cover within a 100- and 500-m radius, implying that herring schools preferentially spawn on dense and large underwater meadows. Only ∼5% of the lagoon now falls into this vegetation category. Despite 20 years of efforts to reduce eutrophication, no increase in macroalgae and spermatophyte vegetation towards the historical level of 90% coverage in the area is apparent.

Understanding environmental DNA detection probabilities: A case study using a stream-dwelling char Salvelinus fontinalis

Science.gov (United States)

Wilcox, Taylor M; Mckelvey, Kevin S.; Young, Michael K.; Sepulveda, Adam; Shepard, Bradley B.; Jane, Stephen F; Whiteley, Andrew R.; Lowe, Winsor H.; Schwartz, Michael K.

2016-01-01

Environmental DNA sampling (eDNA) has emerged as a powerful tool for detecting aquatic animals. Previous research suggests that eDNA methods are substantially more sensitive than traditional sampling. However, the factors influencing eDNA detection and the resulting sampling costs are still not well understood. Here we use multiple experiments to derive independent estimates of eDNA production rates and downstream persistence from brook trout (Salvelinus fontinalis) in streams. We use these estimates to parameterize models comparing the false negative detection rates of eDNA sampling and traditional backpack electrofishing. We find that using the protocols in this study eDNA had reasonable detection probabilities at extremely low animal densities (e.g., probability of detection 0.18 at densities of one fish per stream kilometer) and very high detection probabilities at population-level densities (e.g., probability of detection > 0.99 at densities of ≥ 3 fish per 100 m). This is substantially more sensitive than traditional electrofishing for determining the presence of brook trout and may translate into important cost savings when animals are rare. Our findings are consistent with a growing body of literature showing that eDNA sampling is a powerful tool for the detection of aquatic species, particularly those that are rare and difficult to sample using traditional methods.

Onset of maturity and cohort composition at spawning of Baltic sprat Sprattus sprattus on the basis of otolith macrostructure analysis

DEFF Research Database (Denmark)

Reglero, P.; Mosegaard, Henrik

2006-01-01

predictor of sprat total length (L-T) and mass (M) in age group 0 years. Changes in the otolith size distribution over time were related to variations in cohort composition depending on the L-T and M attained during the juvenile stage. Examination of the gonads suggested two life history patterns: 1......) individuals achieving a larger L-T and M during the first growing season may contribute at age 1 years to the spawning stock and the fishery, whereas 2) individuals attaining smaller L-T and M contribute in larger amounts to both the spawning stock and the fishery later, when they are at age 2 years. Moreover...

Spawning migrations of the endemic Labeobarbus (Cyprinidae, Teleostei) species of Lake Tana, Ethiopia, status and threats

NARCIS (Netherlands)

Anteneh, W.; Getahun, A.; Dejen, E.; Sibbing, F.A.; Nagelkerke, L.A.J.; de Graaf, M.; Wudneh, T.; Vijverberg, J.; Palstra, A.P.

2012-01-01

The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning during

Spawning migrations of the endemic Labeobarbus (Cyprinidae, Teleostei) species of Lake Tana, Ethiopia: status and threats

NARCIS (Netherlands)

Anteneh, W.; Getahun, A.; Dejen, E.; Sibbing, F.A.; Nagelkerke, L.A.J.; Graaf, de M.; Wudneh, T.; Vijverberg, J.; Palstra, A.P.

2012-01-01

The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning

Water- and sediment-quality effects on Pimephales promelas spawning vary along an agriculture-to-urban land-use gradient.

Science.gov (United States)

Corsi, Steven R; Klaper, Rebecca D; Weber, Daniel N; Bannerman, Roger T

2011-10-15

Many streams in the U.S. are "impaired" due to anthropogenic influence. For watershed managers to achieve practical understanding of these impairments, a multitude of factors must be considered, including point and nonpoint-source influence on water quality. A spawning assay was developed in this study to evaluate water- and sediment-quality effects that influenced Pimephales promelas (fathead minnow) egg production over a gradient of urban and agricultural land use in 27 small watersheds in Eastern Wisconsin. Six pairs of reproducing fathead minnows were contained in separate mesh cartridges within one larger flow-through chamber. Water- and sediment quality were sampled for an array of parameters. Egg production was monitored for each pair providing an assessment of spawning success throughout the 21-day test periods. Incidences of low dissolved oxygen (DO) in many of these streams negatively impacted spawning success. Nine of 27 streams experienced DO less than 3.1mg/L and 15 streams experienced DO less than 4.8mg/L. Low DO was observed in urban and agricultural watersheds, but the upper threshold of minimum DO decreased with increasing urban development. An increase in specific conductance was related to a decrease in spawning success. In previous studies for streams in this region, specific conductance had a linear relation with chloride, suggesting the possibility that chloride could be a factor in egg production. Egg production was lower at sites with substantial urban development, but sites with low egg production were not limited to urban sites. Degradation of water- and sediment-quality parameters with increasing urban development is indicated for multiple parameters while patterns were not detected for others. Results from this study indicate that DO must be a high priority watershed management consideration for this region, specific conductance should be investigated further to determine the mechanism of the relation with egg production, and water- and

Spawning and fertility of F1 hybrids of the coral genus Acropora in the Indo-Pacific

Science.gov (United States)

Isomura, Naoko; Iwao, Kenji; Morita, Masaya; Fukami, Hironobu

2016-09-01

The role of hybridization through multi-specific synchronous spawning in the evolution of reef-building corals has been discussed since the 1990s, particularly for the genus Acropora. However, F1 hybrids have been reported as common in only one case in the Caribbean, with no evidence of mechanisms that would allow continuous reproduction of the hybrids. In this study, we report for the first time the fecundity of two F1 hybrid colonies produced experimentally from two Indo-Pacific species, A. intermedia and A. florida. These F1 hybrids spawned at the same time as the parental corals. Backcrossing and F1 hybrid crossing were successful in both directions. Furthermore, more than 90% self-fertilization was achieved in an F1 hybrid, although it was negligible in the parental corals. While it is possible that the F1 hybrid was a chimera, these results suggest that some products of interspecific hybridization may persist as the offspring of self-fertilizing F1 hybrids.

Spatial segregation of spawning habitat limits hybridization between sympatric native Steelhead and Coastal Cutthroat Trout

Science.gov (United States)

Buehrens, T.W.; Glasgow, J.; Ostberg, Carl O.; Quinn, T.P.

2013-01-01

Native Coastal Cutthroat Trout Oncorhynchus clarkii clarkii and Coastal Steelhead O. mykiss irideus hybridize naturally in watersheds of the Pacific Northwest yet maintain species integrity. Partial reproductive isolation due to differences in spawning habitat may limit hybridization between these species, but this process is poorly understood. We used a riverscape approach to determine the spatial distribution of spawning habitats used by native Coastal Cutthroat Trout and Steelhead as evidenced by the distribution of recently emerged fry. Molecular genetic markers were used to classify individuals as pure species or hybrids, and individuals were assigned to age-classes based on length. Fish and physical habitat data were collected in a spatially continuous framework to assess the relationship between habitat and watershed features and the spatial distribution of parental species and hybrids. Sampling occurred in 35 reaches from tidewaters to headwaters in a small (20 km2) coastal watershed in Washington State. Cutthroat, Steelhead, and hybrid trout accounted for 35%, 42%, and 23% of the fish collected, respectively. Strong segregation of spawning areas between Coastal Cutthroat Trout and Steelhead was evidenced by the distribution of age-0 trout. Cutthroat Trout were located farther upstream and in smaller tributaries than Steelhead were. The best predictor of species occurrence at a site was the drainage area of the watershed that contributed to the site. This area was positively correlated with the occurrence of age-0 Steelhead and negatively with the presence of Cutthroat Trout, whereas hybrids were found in areas occupied by both parental species. A similar pattern was observed in older juveniles of both species but overlap was greater, suggesting substantial dispersal of trout after emergence. Our results offer support for spatial reproductive segregation as a factor limiting hybridization between Steelhead and Coastal Cutthroat Trout.

Sex that moves mountains: The influence of spawning fish on river profiles over geologic timescales

Science.gov (United States)

Fremier, Alexander K.; Yanites, Brian J.; Yager, Elowyn M.

2018-03-01

A key component of resilience is to understand feedbacks among components of biophysical systems, such as physical drivers, ecological responses and the subsequent feedbacks onto physical process. While physically based explanations of biological speciation are common (e.g., mountains separating a species can lead to speciation), less common is the inverse process examined: can a speciation event have significant influence on physical processes and patterns in a landscape? When such processes are considered, such as with 'ecosystem engineers', many studies have focused on the short-term physical and biological effects rather than the long-term impacts. Here, we formalized the physical influence of salmon spawning on stream beds into a model of channel profile evolution by altering the critical shear stress required to move stream bed particles. We then asked if spawning and an adaptive radiation event (similar to the one that occurred in Pacific salmon species) could have an effect on channel erosion processes and stream profiles over geological timescales. We found that spawning can profoundly influence the longitudinal profiles of stream beds and thereby the evolution of entire watersheds. The radiation of five Pacific salmon from a common ancestor, additionally, could also cause significant geomorphic change by altering a wider section of the profile for a given distribution of grain sizes. This modeling study suggests that biological evolution can impact landscape evolution by increasing the sediment transport and erosion efficiency of mountain streams. Moreover, the physical effects of a species on its environment might be a complementary explanation for rapid radiation events in species through the creation of new habitat types. This example provides an illustrative case for thinking about the long- and short-term coupling of biotic and abiotic systems.

Experimentally extending the spawning season of a marine bivalve using temperature change and fluoxetine as synergistic triggers

NARCIS (Netherlands)

Honkoop, PJC; Luttikhuizen, PC; Piersma, T; Honkoop, Pieter J.C.; Kinne, Otto

1999-01-01

Contrary to prediction, a large intraspecific variation can be observed in reproductive timing of free-spawning marine organisms. The relative contributions of heritable genetic differences and phenotypic plasticity to this variation have remained unstudied. To do so would require experimental

Influence of rearing water temperature on induced gonadal development and spawning behaviour of tropical green mussel, Perna viridis

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Parathattil Rathan Sreedevi

2014-09-01

Conclusion: According to the present study temperature induced spawning method is very simple and cost effective and can accelerate the production of mussel seeds in hatchery units and further stock improvement through genetic manipulation.

The influence of fall-spawning coho salmon (Oncorhynchus kisutch) on growth and production of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska.

Science.gov (United States)

Dirk W. Lang; Gordon H. Reeves; James D. Hall; Mark S. Wipfli

2006-01-01

This study examined the influence of fall-spawning coho salmon (Oncorhynchrcs kisutch) on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon on the Copper River Delta, Alaska, USA. During the fall of 1999 and 2000, fish rearing in beaver ponds that received spawning salmon were compared with fish from...

Macrozooplankton predation impact on anchovy (Engraulis encrasicolus) eggs mortality at the Bay of Biscay shelf break spawning centre

KAUST Repository

Albaina, Aitor; Irigoien, Xabier; Aldalur, Unai; Boyra, Guillermo; Santos, Marí a; Estonba, Andone

2014-01-01

A real-time PCR based method involving a species-specific probe was applied to detect Engraulis encrasicolus eggs predation by the macrozooplankton community during the 2011 spawning season. Three locations along the shelf break presenting

Concentrations of environmental DNA (eDNA) reflect spawning salmon abundance at fine spatial and temporal scales

Science.gov (United States)

Tillotson, Michael D.; Kelly, Ryan P.; Duda, Jeff; Hoy, Marshal S.; Kralj, James; Quinn, Thomas P.

2018-01-01

Developing fast, cost-effective assessments of wild animal abundance is an important goal for many researchers, and environmental DNA (eDNA) holds much promise for this purpose. However, the quantitative relationship between species abundance and the amount of DNA present in the environment is likely to vary substantially among taxa and with ecological context. Here, we report a strong quantitative relationship between eDNA concentration and the abundance of spawning sockeye salmon in a small stream in Alaska, USA, where we took temporally- and spatially-replicated samples during the spawning period. This high-resolution dataset suggests that (1) eDNA concentrations vary significantly day-to-day, and likely within hours, in the context of the dynamic biological event of a salmon spawning season; (2) eDNA, as detected by species-specific quantitative PCR probes, seems to be conserved over short distances (tens of meters) in running water, but degrade quickly over larger scales (ca. 1.5 km); and (3) factors other than the mere presence of live, individual fish — such as location within the stream, live/dead ratio, and water temperature — can affect the eDNA-biomass correlation in space or time. A multivariate model incorporating both biotic and abiotic variables accounted for over 75% of the eDNA variance observed, suggesting that where a system is well-characterized, it may be possible to predict species' abundance from eDNA surveys, although we underscore that species- and system-specific variables are likely to limit the generality of any given quantitative model. Nevertheless, these findings provide an important step toward quantitative applications of eDNA in conservation and management.

A Spawn Mobile Agent Itinerary Planning Approach for Energy-Efficient Data Gathering in Wireless Sensor Networks.

Science.gov (United States)

Qadori, Huthiafa Q; Zulkarnain, Zuriati A; Hanapi, Zurina Mohd; Subramaniam, Shamala

2017-06-03

Mobile agent (MA), a part of the mobile computing paradigm, was recently proposed for data gathering in Wireless Sensor Networks (WSNs). The MA-based approach employs two algorithms: Single-agent Itinerary Planning (SIP) and Multi-mobile agent Itinerary Planning (MIP) for energy-efficient data gathering. The MIP was proposed to outperform the weakness of SIP by introducing distributed multi MAs to perform the data gathering task. Despite the advantages of MIP, finding the optimal number of distributed MAs and their itineraries are still regarded as critical issues. The existing MIP algorithms assume that the itinerary of the MA has to start and return back to the sink node. Moreover, each distributed MA has to carry the processing code (data aggregation code) to collect the sensory data and return back to the sink with the accumulated data. However, these assumptions have resulted in an increase in the number of MA's migration hops, which subsequently leads to an increase in energy and time consumption. In this paper, a spawn multi-mobile agent itinerary planning (SMIP) approach is proposed to mitigate the substantial increase in cost of energy and time used in the data gathering processes. The proposed approach is based on the agent spawning such that the main MA is able to spawn other MAs with different tasks assigned from the main MA. Extensive simulation experiments have been conducted to test the performance of the proposed approach against some selected MIP algorithms. The results show that the proposed SMIP outperforms the counterpart algorithms in terms of energy consumption and task delay (time), and improves the integrated energy-delay performance.

Functional role of environmental stimuli for the spawning migration in Danube nase .i.Chondrostoma nasus ./i. (L.)

Czech Academy of Sciences Publication Activity Database

Rakowitz, G.; Berger, B.; Kubečka, Jan; Keckeis, H.

2008-01-01

Roč. 17, č. 3 (2008), s. 502-514 ISSN 0906-6691 Institutional research plan: CEZ:AV0Z60170517 Keywords : freshwater fish migration * spawning migration * environmental factors * hydroacoustics * multiple linear regression analysis Subject RIV: GL - Fishing Impact factor: 1.813, year: 2008

Sympatric spawning but allopatric distribution of Anguilla japonica and Anguilla marmorata: temperature- and oceanic current-dependent sieving.

Directory of Open Access Journals (Sweden)

Yu-San Han

Full Text Available Anguilla japonica and Anguilla marmorata share overlapping spawning sites, similar drifting routes, and comparable larval durations. However, they exhibit allopatric geographical distributions in East Asia. To clarify this ecological discrepancy, glass eels from estuaries in Taiwan, the Philippines, Indonesia, and China were collected monthly, and the survival rate of A. marmorata under varying water salinities and temperatures was examined. The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter. Both species had opposing temperature preferences for recruitment. A. marmorata prefer high water temperatures and die at low water temperatures. In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures. Thus, A. japonica glass eels, which mainly spawn in summer, are preferably recruited to Taiwan, China, Korea, and Japan by the Kuroshio and its branch waters in winter. Meanwhile, A. marmorata glass eels, which spawn throughout the year, are mostly screened out in East Asia in areas with low-temperature coastal waters in winter. During summer, the strong northward currents from the South China Sea and Changjiang River discharge markedly block the Kuroshio invasion and thus restrict the approach of A. marmorata glass eels to the coasts of China and Korea. The differences in the preferences of the recruitment temperature for glass eels combined with the availability of oceanic currents shape the real geographic distribution of Anguilla japonica and Anguilla marmorata, making them "temperate" and "tropical" eels, respectively.

Sympatric spawning but allopatric distribution of Anguilla japonica and Anguilla marmorata: temperature- and oceanic current-dependent sieving.

Science.gov (United States)

Han, Yu-San; Yambot, Apolinario V; Zhang, Heng; Hung, Chia-Ling

2012-01-01

Anguilla japonica and Anguilla marmorata share overlapping spawning sites, similar drifting routes, and comparable larval durations. However, they exhibit allopatric geographical distributions in East Asia. To clarify this ecological discrepancy, glass eels from estuaries in Taiwan, the Philippines, Indonesia, and China were collected monthly, and the survival rate of A. marmorata under varying water salinities and temperatures was examined. The composition ratio of these 2 eel species showed a significant latitude cline, matching the 24 °C sea surface temperature isotherm in winter. Both species had opposing temperature preferences for recruitment. A. marmorata prefer high water temperatures and die at low water temperatures. In contrast, A. japonica can endure low water temperatures, but their recruitment is inhibited by high water temperatures. Thus, A. japonica glass eels, which mainly spawn in summer, are preferably recruited to Taiwan, China, Korea, and Japan by the Kuroshio and its branch waters in winter. Meanwhile, A. marmorata glass eels, which spawn throughout the year, are mostly screened out in East Asia in areas with low-temperature coastal waters in winter. During summer, the strong northward currents from the South China Sea and Changjiang River discharge markedly block the Kuroshio invasion and thus restrict the approach of A. marmorata glass eels to the coasts of China and Korea. The differences in the preferences of the recruitment temperature for glass eels combined with the availability of oceanic currents shape the real geographic distribution of Anguilla japonica and Anguilla marmorata, making them "temperate" and "tropical" eels, respectively.

Ex situ protection of the European mudminnow (Umbra krameri Walbaum, 1792: Spawning substrate preference for larvae rearing under controlled conditions

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Kucska Balázs

2016-01-01

Full Text Available Captive breeding programs of endangered fish species, such as the European mudminnow Umbra krameri, are essential for population restoration. To improve captive spawning and larvae rearing under controlled conditions, two experiments were carried out. In the first, the spawning substrate preference was tested in triplicate, where five different types of artificial surface were provided for mudminnow pairs:(isand, (iiartificial plants, (iiigravel, (ivsand + artificial plants and(vgravel + artificial plants. All fish preferred the gravel + artificial plant combination, which indicates that this type of surface could be the most appropriate for spawning in captivity. In the second trial, three feeding protocols were tested in triplicate under controlled conditions. In the first treatment fish were fed exclusively with Artemia nauplii; in the second treatment fish were fed with Artemiafor the first ten days then Artemia was gradually replaced with dry feed; for the third group the transition period started after 5 days of Artemia feeding. Although the survival rate of larvae could be maintained at a high level in some of the feeding protocols, a strong decrease in the growth rate was obvious in all diets containing dry food, which means that live food is essential for the first three weeks of mudminnow larvae rearing.

Evidence from data storage tags for the presence of lunar and semilunar behavioral cycles in spawning Atlantic cod

Science.gov (United States)

Grabowski, Timothy B.; McAdam, Bruce J.; Thorsteinsson, Vilhjalmur; Marteinsdóttir, Gudrún

2015-01-01

Understanding the environmental processes determining the timing and success of reproduction is of critical importance to developing effective management strategies of marine fishes. Unfortunately it has proven difficult to comprehensively study the reproductive behavior of broadcast-spawning fishes. The use of electronic data storage tags (DSTs) has the potential to provide insights into the behavior of fishes. These tags allow for data collection over relatively large spatial and temporal scales that can be correlated to predicted environmental conditions and ultimately be used to refine predictions of year class strength. In this paper we present data retrieved from DSTs demonstrating that events putatively identified as Atlantic cod spawning behavior is tied to a lunar cycle with a pronounced semi-lunar cycle within it. Peak activity occurs around the full and new moon with no evidence of relationship with day/night cycles.

Hydroacoustic resolution of small-scale vertical distribution in Baltic cod Gadus morhua - habitat choise and limits during spawning

DEFF Research Database (Denmark)

Schaber, Matthias; Hinrichsen, Hans-Harald; Neuenfeldt, Stefan

2009-01-01

to cod. The results showed a clear influence of ambient salinity and oxygen concentration on the distribution pattern and distributional limitation of cod during spawning time, and also consistency of data storage tag-derived distribution patterns with those based on individual echotracking. We therefore...... and hence the spatial structure of the ecosystem. Our aim here is to present a method to resolve small-scale distribution on an individual level, as needed for the behaviorally-based prediction of habitat choice and limits. We focused on the small-scale vertical distribution of cod Gadus morhua L....... in the Bornholm Basin, central Baltic Sea, during spawning time in 2 years with different vertical thermohaline and oxygen stratifications. Individual cod were identified by echotracking of real-time in situ hydroacoustic distribution data. In order to resolve and identify hydrographic preferences and limits...

Breaking the speed limit--comparative sprinting performance of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta)

Science.gov (United States)

Castro-Santos, Theodore; Sanz-Ronda, Francisco Javier; Ruiz-Legazpi, Jorge

2013-01-01

Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s−1. These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s−1. This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.

Bull trout (Salvelinus confluentus) telemetry and associated habitat data collected in a geodatabase from the upper Boise River, southwestern Idaho

Science.gov (United States)

MacCoy, Dorene E.; Shephard, Zachary M.; Benjamin, Joseph R.; Vidergar, Dmitri T.; Prisciandaro, Anthony F.

2017-03-23

Bull trout (Salvelinus confluentus), listed as threatened under the Endangered Species Act, are among the more thermally sensitive of coldwater species in North America. The Boise River upstream of Arrowrock Dam in southwestern Idaho (including Arrowrock Reservoir) provides habitat for one of the southernmost populations of bull trout. The presence of the species in Arrowrock Reservoir poses implications for dam and reservoir operations. From 2011 to 2014, the Bureau of Reclamation and the U.S. Geological Survey collected fish telemetry data to improve understanding of bull trout distribution and movement in Arrowrock Reservoir and in the upper Boise River tributaries. The U.S. Geological Survey compiled the telemetry (fish location) data, along with reservoir elevation, river discharge, precipitation, and water-quality data in a geodatabase. The geodatabase includes metadata compliant with Federal Geographic Data Committee content standards. The Bureau of Reclamation plans to incorporate the data in a decision‑support tool for reservoir management.

Spawning Characteristics and Artificial Hatching of Female Mottled Skate, Beringraja pulchra in the West Coast of Korea.

Science.gov (United States)

Kang, Hee-Woong; Jo, Yeong-Rok; Kang, Duk-Yong; Jeong, Gyeong-Suk; Jo, Hyun-Su

2013-09-01

The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at 8°C, 13°C, 18°C, water temperature (12.8 to 24.2°C), and the best hatching temperature was 18°C. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate.

Genetic stock assessment of spawning arctic cisco (Coregonus autumnalis) populations by flow cytometric determination of DNA content.

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Lockwood, S F; Bickham, J W

1991-01-01

Intraspecific variation in cellular DNA content was measured in five Coregonus autumnalis spawning populations from the Mackenzie River drainage, Canada, using flow cytometry. The rivers assayed were the Peel, Arctic Red, Mountain, Carcajou, and Liard rivers. DNA content was determined from whole blood preparations of fish from all rivers except the Carcajou, for which kidney tissue was used. DNA content measurements of kidney and blood preparations of the same fish from the Mountain River revealed statistically indistinguishable results. Mosaicism was found in blood preparations from the Peel, Arctic Red, Mountain, and Liard rivers, but was not observed in kidney tissue preparations from the Mountain or Carcajou rivers. The Liard River sample had significantly elevated mean DNA content relative to the other four samples; all other samples were statistically indistinguishable. Significant differences in mean DNA content among spawning stocks of a single species reinforces the need for adequate sample sizes of both individuals and populations when reporting "C" values for a particular species.

Fish and crustaceans in northeast Greenland lakes with special emphasis on interactions between Arctic charr (Salvelinus alpinus), Lepidurus arcticus and benthic chydorids

DEFF Research Database (Denmark)

Jeppesen, E.; Christoffersen, K.; Landkildehus, F.

2001-01-01

We studied the trophic structure in the pelagial and crustacean remains in the surface 1 cm of the sediment of 13 shallow, high arctic lakes in northeast Greenland (74 N). Seven lakes were fishless, while the remaining six hosted a dwarf form of Arctic charr (Salvelinus alpinus). In fishless lakes...... sp. in lakes with Lepidurus, while they were abundant in lakes with fish. The low abundance in fishless lakes could not be explained by damage of crustacean remains caused by Lepidurus feeding in the sediment, because remains of the more soft-shelled, pelagic-living Daphnia were abundant...... in the sediment of these lakes. No significant differences between lakes with and without fish were found in chlorophyll a, total phosphorus, total nitrogen, conductivity or temperature, suggesting that the observed link between Lepidurus arcticus and the benthic crustacean community is causal. Consequently...

Predicting recolonization patterns and interactions between potamodromous and anadromous salmonids in response to dam removal in the Elwha River, Washington State, USA

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Brenkman, S.J.; Pess, G.R.; Torgersen, C.E.; Kloehn, K.K.; Duda, J.J.; Corbett, S.C.

2008-01-01

The restoration of salmonids in the Elwha River following dam removal will cause interactions between anadromous and potamodromous forms as recolonization occurs in upstream and downstream directions. Anadromous salmonids are expected to recolonize historic habitats, and rainbow trout (Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) isolated above the dams for 90 years are expected to reestablish anadromy. We summarized the distribution and abundance of potamodromous salmonids, determined locations of spawning areas, and mapped natural barriers to fish migration at the watershed scale based on data collected from 1993 to 2006. Rainbow trout were far more abundant than bull trout throughout the watershed and both species were distributed up to river km 71. Spawning locations for bull trout and rainbow trout occurred in areas where we anticipate returning anadromous fish to spawn. Nonnative brook trout were confined to areas between and below the dams, and seasonal velocity barriers are expected to prevent their upstream movements. We hypothesize that the extent of interaction between potamodromous and anadromous salmonids will vary spatially due to natural barriers that will limit upstream-directed recolonization for some species of salmonids. Consequently, most competitive interactions will occur in the main stem and floodplain downstream of river km 25 and in larger tributaries. Understanding future responses of Pacific salmonids after dam removal in the Elwha River depends upon an understanding of existing conditions of the salmonid community upstream of the dams prior to dam removal.

Differences in organotin accumulation in relation to life history in the white-spotted charr Salvelinus leucomaenis

International Nuclear Information System (INIS)

Ohji, Madoka; Harino, Hiroya; Arai, Takaomi

2011-01-01

Research highlights: → Otolith Sr:Ca ratios in sea-run type were higher than those in freshwater-residents. → TBT and TPT concentrations in sea-run type were higher than those in freshwater-residents. → Sea-run type have higher risk of TBT and TPT than freshwater-residents in white-spotted charr. - Abstract: To examine the accumulation pattern of organotins (OTs) in relation to the migration of diadromous fish, tributyltin (TBT) and triphenyltin (TPT) and their derivatives were determined in the muscle tissue of both sea-run (anadromous) and freshwater-resident (nonanadromous) types of the white-spotted charr Salvelinus leucomaenis. Ontogenic changes in otolith strontium (Sr) and calcium (Ca) concentrations were examined along life history transect to discriminate migration type. Mean Sr:Ca ratio from the core to the edge of the otolith in sea-run individuals was significantly higher than those in freshwater-resident one. There were no significant correlations in S. leucomaenis between OT accumulation and various biological characteristics. It is noteworthy that TBT and TPT concentrations in sea-run type were significantly higher than those in freshwater-resident individuals, although they are both of the same species. These results suggest that sea-run S. leucomaenis have a higher ecological risk of OT exposure than freshwater-residents during their life histories.

Induced spawning and reproductive variables of the catfish Lophiosilurus alexandri Steindachner, 1876 (Siluriformes: Pseudopimelodidae

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Hélio Batista dos Santos

Full Text Available Lophiosilurus alexandri is an endemic fish from the São Francisco River basin, Brazil. The aim of this study was to induce L. alexandri to spawn and to obtain data on several reproductive variables for this species. For induced spawning, adults were submitted to Cyprinus carpio pituitary homogenate (CPH. Nine of the 12 females (75% responded positively to the treatment. The stripping of oocytes was performed 8.4 h after the second dose of CPH with the water temperature maintained at 26ºC. The number of stripped oocytes per gram of ova was 74 ± 5 oocytes g-1, and the mean oocyte diameter was 3.1 ± 0.2 and 3.6 ± 0.2 mm, before and after hydration, respectively. The oocytes were opaque, yellowish, demersal, highly adhesive, and covered by a gelatinous coat. The total fecundity was 4,534 ± 671 oocytes, and the fertilization rate was 59%. The initial and final fertilities were 2,631 ± 740 and 1,542 ± 416 embryos, respectively. Larval hatching occurred up to 56 h after fertilization, and the larvae had a total length of 8.4 ± 0.1 mm. This work provides important biological information for L. alexandri that can be used for management and conservation of this species.

Differential metabolite levels in response to spawning-induced inappetence in Atlantic salmon Salmo salar.

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Cipriano, Rocco C; Smith, McKenzie L; Vermeersch, Kathleen A; Dove, Alistair D M; Styczynski, Mark P

2015-03-01

Atlantic salmon Salmo salar undergo months-long inappetence during spawning, but it is not known whether this inappetence is a pathological state or one for which the fish are adapted. Recent work has shown that inappetent whale sharks can exhibit circulating metabolite profiles similar to ketosis known to occur in humans during starvation. In this work, metabolite profiling was used to explore differences in analyte profiles between a cohort of inappetent spawning run Atlantic salmon and captively reared animals that were fed up to and through the time of sampling. The two classes of animals were easily distinguished by their metabolite profiles. The sea-run fish had elevated ɷ-9 fatty acids relative to the domestic feeding animals, while other fatty acid concentrations were reduced. Sugar alcohols were generally elevated in inappetent animals, suggesting potentially novel metabolic responses or pathways in fish that feature these compounds. Compounds expected to indicate a pathological catabolic state were not more abundant in the sea-run fish, suggesting that the animals, while inappetent, were not stressed in an unnatural way. These findings demonstrate the power of discovery-based metabolomics for exploring biochemistry in poorly understood animal models. Copyright © 2015 Elsevier Inc. All rights reserved.

Physical characteristics of the lower San Joaquin River, California, in relation to white sturgeon spawning habitat, 2011–14

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Marineau, Mathieu D.; Wright, Scott A.; Whealdon-Haught, Daniel R.; Kinzel, Paul J.

2017-07-19

The U.S. Fish and Wildlife Service confirmed that white sturgeon (Acipenser transmontanus) recently spawned in the lower San Joaquin River, California. Decreases in the San Francisco Bay estuary white sturgeon population have led to an increased effort to understand their migration behavior and habitat preferences. The preferred spawning habitat of other white sturgeon (for example, those in the Columbia and Klamath Rivers) is thought to be areas that have high water velocity, deep pools, and coarse bed material. Coarse bed material (pebbles and cobbles), in particular, is important for the survival of white sturgeon eggs and larvae. Knowledge of the physical characteristics of the lower San Joaquin River can be used to preserve sturgeon spawning habitat and lead to management decisions that could help increase the San Francisco Bay estuary white sturgeon population.Between 2011 and 2014, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, assessed selected reaches and tributaries of the lower river in relation to sturgeon spawning habitat by (1) describing selected spawning reaches in terms of habitat-related physical characteristics (such as water depth and velocity, channel slope, and bed material) of the lower San Joaquin River between its confluences with the Stanislaus and Merced Rivers, (2) describing variations in these physical characteristics during wet and dry years, and (3) identifying potential reasons for these variations.The lower San Joaquin River was divided into five study reaches. Although data were collected from all study reaches, three subreaches where the USFWS collected viable eggs at multiple sites in 2011–12 from Orestimba Creek to Sturgeon Bend were of special interest. Water depth and velocity were measured using two different approaches—channel cross sections and longitudinal profiles—and data were collected using an acoustic Doppler current profiler.During the first year of data collection (water

Spatial ecological processes and local factors predict the distribution and abundance of spawning by steelhead (Oncorhynchus mykiss across a complex riverscape.

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Jeffrey A Falke

Full Text Available Processes that influence habitat selection in landscapes involve the interaction of habitat composition and configuration and are particularly important for species with complex life cycles. We assessed the relative influence of landscape spatial processes and local habitat characteristics on patterns in the distribution and abundance of spawning steelhead (Oncorhynchus mykiss, a threatened salmonid fish, across ∼15,000 stream km in the John Day River basin, Oregon, USA. We used hurdle regression and a multi-model information theoretic approach to identify the relative importance of covariates representing key aspects of the steelhead life cycle (e.g., site access, spawning habitat quality, juvenile survival at two spatial scales: within 2-km long survey reaches (local sites and ecological neighborhoods (5 km surrounding the local sites. Based on Akaike's Information Criterion, models that included covariates describing ecological neighborhoods provided the best description of the distribution and abundance of steelhead spawning given the data. Among these covariates, our representation of offspring survival (growing-season-degree-days, °C had the strongest effect size (7x relative to other predictors. Predictive performances of model-averaged composite and neighborhood-only models were better than a site-only model based on both occurrence (percentage of sites correctly classified = 0.80±0.03 SD, 0.78±0.02 vs. 0.62±0.05, respectively and counts (root mean square error = 3.37, 3.93 vs. 5.57, respectively. The importance of both temperature and stream flow for steelhead spawning suggest this species may be highly sensitive to impacts of land and water uses, and to projected climate impacts in the region and that landscape context, complementation, and connectivity will drive how this species responds to future environments.

Macrozooplankton predation impact on anchovy (Engraulis encrasicolus) eggs mortality at the Bay of Biscay shelf break spawning centre

KAUST Repository

Albaina, Aitor

2014-11-23

A real-time PCR based method involving a species-specific probe was applied to detect Engraulis encrasicolus eggs predation by the macrozooplankton community during the 2011 spawning season. Three locations along the shelf break presenting contrasting but high prey densities were sampled. A total of 840 individuals from 38 taxa of potential macrozooplankton predators were assayed for E. encrasicolus DNA presence and 27 presented at least one positive signal. Carnivorous copepods were responsible for the most predation events (66%) followed by euphausiids (16%), chaetognaths (5%), and myctophid fish (4%). Macrozooplankton predation on anchovy eggs followed a type-I functional response with daily mortalities <4% of available prey abundance suggesting a negligible impact on the species recruitment at the shelf break spawning centre. © 2014 International Council for the Exploration of the Sea 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Evaluation of the Potential Use of Agricultural and Forestial Waste in Spawn Production of Medicinal Mushroom (Ganoderma lucidum

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M Tavana

2013-10-01

Full Text Available Spawn quality plays an important role in successful production of medicinal mushrooms. In this study, firstly, to determine the optimum temperature for mycelia growth of G. lucidum, four basal media, including seeds of wheat, barley, millet and Abies sp. wood chip were studied separately at 25±1˚C and 29±1˚C. In the second section, in order to achieve suitable the mycelia growth, barley, wheat and millet seeds were mixed with different ratios of agriculture waste including wheat bran (10, 20 and 30% dry weight and millet peel (20, 40 and 60% dry weight and also Abies sp wood chips (20, 30, 50 and 60% dry weight as forestial waste. In the final section, several forestial waste including sawdusts (Platanus orientalis, Acer sp, Robinia peseudoacacia, Ailanthus altissima, Fagus orientals, Alnus subcordata and Populas alba were used as medium for spawn production. In the first experiment, a higher mycelia growth rate (8.92 mm/day was obtained by applying wheat seed at 29±1˚C. In the second experiment, the results showed that higher mycelia growth rate was obtained by using wheat with 10% wheat bran (9.66 mm/day. In the final section of spawn production, R. peseudoacacia sawdust (C/N=25.84 was generated higher growth rate (9.36 mm/day. Also, using supplements containing nitrogen (N such as sawdust and bran, encourage mycelium growth and with increasing C/N ratios more than 61.3 decreased growth rate due to reduce N amount.

Clonal structure and variable fertilization success in Florida Keys broadcast-spawning corals

Science.gov (United States)

Miller, M. W.; Baums, I. B.; Pausch, R. E.; Bright, A. J.; Cameron, C. M.; Williams, D. E.; Moffitt, Z. J.; Woodley, C. M.

2018-03-01

Keystone reef-building corals in the Caribbean are predominantly self-incompatible broadcast spawners and a majority are threatened due to both acute adult mortality and poor recruitment. As population densities decline, concerns about fertilization limitation and effective population size in these species increase and would be further exacerbated by either high clonality or gametic incompatibility of parental genotypes. This study begins to address these concerns for two Caribbean broadcasting species by characterizing clonal structure and quantifying experimental pairwise fertilization success. Orbicella faveolata showed surprisingly high and contrasting levels of clonality between two sampled sites; Acropora palmata was previously known to be highly clonal. Individual pairwise crosses of synchronously spawning genotypes of each species were conducted by combining aliquots of gamete bundles immediately after spawning, and showed high and significant variability in fertilization success. Over half of the individual crosses of O. faveolata and about one-third of A. palmata crosses yielded ≤ 40% fertilization. Total sperm concentration was quantified in only a subset of O. faveolata crosses (range of 1-6 × 107 mL-1), but showed no correlation with fertilization success. We interpret that both parental incompatibility and individual genotypes with low-quality gametes are likely to have contributed to the variable fertilization observed with important implications for conservation. Differential fertilization success implies effective population size may be considerably smaller than hoped and population enhancement efforts need to incorporate many more parental genotypes at the patch scale to ensure successful larval production than indicated by estimates based simply on preserving levels of standing genetic diversity.

Some considerations in applying stock-recruitment models to multiple-age spawning populations

International Nuclear Information System (INIS)

Lawler, P.J.

1988-01-01

Several approaches used during the Hudson River power plant hearings (1977-1980) to permit quantitative estimation of the impact of power plant operation on the river's striped bass population are presented. The Ricker stock-recruitment model was adopted as a starting point to provide a reasonable working conceptualization of the stock-recruitment processes operating in this river. This model was then modified in a variety of ways to reflect multiple-age spawning by striped bass, and the results were fit to data on the river's commercial striped bass catch and effort, organized to reflect certain average age distribution parameters. Environmental variation in the system, represented in an overall fashion by the spring and summer variation in the river's freshwater flow, and the effect of certain assumed modes of cannibalism were also included in these analyses. Quantitative estimates of the Ricker parameters alpha and beta representing compensatory reserve and density dependent mortality, respectively, in the system were extracted from these fits. In addition, an approach to modeling the influence of certain density-dependent and density-independent growth factors on the various modes of mortality is presented. All of the above procedures are directed toward estimating the change a given impact may induce on the stock-recruitment model parameters alpha and beta. These changes in alpha and beta are used in various equilibrium reduction models to estimate the percentage change in the equilibrium spawning population that, all other things remaining equal, can be expected in the presence of the impact under study. 15 refs., 3 tabs

Spawning and nursery habitat of the wedge sole Dicologlossa cuneata (Moreau, 1881 in the Gulf of Cádiz (SW Spain

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Eva García-Isarch

2006-10-01

Full Text Available Ichthyoplankton samples and hydrological data were obtained in an inshore area, between the mouths of the Rivers Guadalquivir and Guadiana (Gulf of Cádiz, SW Spain during monthly surveys carried out from March 2002 to March 2003. Horizontal and temporal distributions of wedge sole (Dicologlossa cuneata egg and larval abundances were analysed during this annual cycle in relation to environmental parameters. This area proved to be an important spawning and nursery ground for the species, which showed a winter-spring reproductive strategy with a long reproductive period lasting from autumn until early summer. Spawning areas were located in the shallowest waters (above 30 m depth between the mouths of the Rives Guadiana and Tinto-Odiel, and to a lesser extent in the coastal zone between the mouths of the Rivers Tinto-Odiel and Guadalquivir. The spawning habitat was mainly determined by the distribution of the adults, the bathymetry and the temperature, and a preference for shallow and colder waters was observed. The inshore zone between the mouths of the Rivers Tinto-Odiel and Guadalquivir is the main nursery ground, with the greatest larval concentration and productivity in the area, due to the influence of the River Guadalquivir. The presence of recruits in this area may be linked to these favourable conditions for larval growth and survival.

Extensive feeding on sockeye salmon Oncorhynchus nerka smolts by bull trout Salvelinus confluentus during initial outmigration into a small, unregulated and inland British Columbia river

Science.gov (United States)

Furey, Nathan B.; Hinch, Scott G.; Lotto, A.G.; Beauchamp, David A.

2015-01-01

Stomach contents were collected and analysed from 22 bull trout Salvelinus confluentus at the edge of the Chilko Lake and Chilko River in British Columbia, Canada, during spring outmigration of sockeye salmon Oncorhynchus nerka smolts. Twenty of the 22 (>90%) stomachs contained prey items, virtually all identifiable prey items were outmigrant O. nerka smolts and stomach contents represented a large portion (0·0–12·6%) of estimated S. confluentus mass. The results demonstrate nearly exclusive and intense feeding by S. confluentus on outmigrant smolts, and support recent telemetry observations of high disappearance rates of O. nerka smolts leaving large natural lake systems prior to entering high-order unregulated river systems.

Ecological Flow Assessment to Improve the Spawning Habitat for the Four Major Species of Carp of the Yangtze River: A Study on Habitat Suitability Based on Ultrasonic Telemetry

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Lixiong Yu

2018-05-01

Full Text Available Four major species of Chinese carp, namely black carp (Mylopharyngodon piceus, grass carp (Ctenopharyngodon idellus, silver carp (Hypophthalmichthys molitrix and bighead carp (Hypophthalmichthys nobilis, are important economic freshwater fish varieties in China. They primarily inhabit and breed in the Yangtze River. Unfortunately, the construction and operation of the Gezhouba Dam and the Three Gorges Dam have dramatically changed the hydrodynamic conditions in the middle reaches of the Yangtze River, leading to a sharp decline in the reproduction rates of these carp. The egg abundance of the four species of carp downstream from the Three Gorges Dam reached 8.35 billion in 1965, but abundance during 2005–2012 was only 0.25 billion. One of the main reasons was that the hydrodynamic conditions of the spawning ground could not meet the four species’ breeding requirements. However, due to the limitations of traditional detection tools, the spawning characteristics of these four species of carp were still unclear. In this study, the ultrasonic telemetry and a three–dimensional hydrodynamic model were utilized to build the habitat suitability index (HSI curves for the four species of carp. The habitat suitability model was then built based on HSI curves to assess spawning habitat quantity under different flow conditions. Finally, the habitat suitability model in the Yidu spawning ground was validated using 32 groups of sampling data in 2015 and 2017. The statistical results showed that the most suitable velocity ranged from 0.78 m/s to 0.93 m/s. The most suitable water depth ranged from 14.56 m to 16.35 m, and the most suitable Froude number ranged from 0.049 to 0.129. The habitat suitability model simulation results indicated that when the discharge was between 15,000 m3/s and 21,300 m3/s, the weighted usable area (WUA values in both the Yidu and Zhicheng spawning grounds would remain at a high level. The validation results showed that most

Spawning Cisco investigations in Canada waters of Lake Superior during 2007

Science.gov (United States)

Yule, Daniel L.; Evrard, Lori M.; Cholwek, Gary A.; Addison, Peter A.; Cullis, Ken I.

2008-01-01

Cisco Coregonus artedi form pre-spawning aggregations in Lake Superior during November with the bulk of spawning occurring during late November through early December (Dryer and Beil 1964). Eggs are broadcast into open water (Smith 1956) with fertilized eggs settling to the lakebed (Dryer and Beil 1964). Peak hatching occurs the following May (United States Geological Survey – Great Lakes Science Center, GLSC, unpublished data). Interannual variability in year class strength is high, but tends to be synchronous across different regions of Lake Superior (Bronte et al. 2003). November 2005 sampling of Thunder Bay showed 14 year-classes were present with the oldest fish being from the 1984 year-class (Yule et al. 2008). The ciscoes sampled were predominantly from five year classes that hatched during 1988, 1989, 1990, 1998, and 2003. These same strong year-classes were found in the western arm of Lake Superior during November 2006 (GLSC, unpublished data). Growth is rapid in the first few years of life with minimal growth after age-8 (Yule et al. 2008). Ciscoes exceeding 250 mm total length (TL) are typically sexually mature (Yule et al. 2006b, 2008). Thunder Bay ciscoes have high annual survival with rates for females and males averaging 0.80 and 0.75, respectively; females have higher rates of fishing-induced mortality compared to males but lower rates of natural mortality (Yule et al. 2008). Some Lake Superior stocks are currently commercially fished with the bulk of harvest occurring during November when fishers target females for their roe. The bulk of fish are harvested from Thunder Bay using suspended gillnets with mesh sizes ranging from 79-89 mm stretch measure. Ciscoes younger then age-5 make up a very small proportion (<0.1%) of the harvest (Yule, et al. 2008).

A COMPARATIVE-STUDY OF STIMULUS SELECTION IN THE FILIAL FOLLOWING RESPONSE OF FRY OF SUBSTRATE SPAWNING CICHLID FISH

NARCIS (Netherlands)

BAERENDS, GP

This paper reports on experimental research undertaken to analyse the information processing mechanism by which the fry of substrate spawning cichlid fish visually recognise their guarding parent(s), already from the earliest time they are able to swim. The study is inspired by LORENZ' concept of

Do predators influence the distribution of age-0 kokanee in a Colorado Reservoir?

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Hardiman, J.M.; Johnson, B.M.; Martinez, P.J.

2004-01-01

Seasonal changes in reservoir conditions such as productivity, light, and temperature create spatiotemporal variation in habitat that may segregate or aggregate predators and prey, producing implications for the distribution, growth, and survival of fishes. We used hydroacoustics to document the diel vertical distribution of age-0 kokanee Oncorhynchus nerka relative to environmental gradients at Blue Mesa Reservoir, Colorado, during May-August of 2002. Temperature, light, and zooplankton density profiles were examined relative to foraging conditions for kokanee and their primary predator, lake trout Salvelinus namaycush. Age-0 kokanee displayed large diel vertical migrations in May despite the lack of an energetic advantage before reservoir stratification. Age-0 kokanee minimized near-surface foraging at this time, perhaps to avoid predation by visual predators, such as lake trout, in the well-lit surface waters. Strong reservoir stratification in midsummer appeared to provide a thermal refuge from lake trout that the kokanee exploited. By August vertical migrations were shallow and most kokanee remained in the epilimnion throughout the day. Although the energetic implications of the late-summer strategy are unclear, it appears that kokanee were responding to changes in their predator environment. A robust model for kokanee diel vertical migration across a range of systems should include a predator avoidance component.

Challenge to the model of lake charr evolution: Shallow- and deep-water morphs exist within a small postglacial lake

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Chavarie, Louise; Muir, Andrew M.; Zimmerman, Mara S.; Baillie, Shauna M.; Hansen, Michael J.; Nate, Nancy A.; Yule, Daniel L.; Middel, Trevor; Bentzen, Paul; Krueger, Charles C.

2016-01-01

All examples of lake charr (Salvelinus namaycush) diversity occur within the largest, deepest lakes of North America (i.e. > 2000 km2). We report here Rush Lake (1.3 km2) as the first example of a small lake with two lake charr morphs (lean and huronicus). Morphology, diet, life history, and genetics were examined to demonstrate the existence of morphs and determine the potential influence of evolutionary processes that led to their formation or maintenance. Results showed that the huronicus morph, caught in deep-water, had a deeper body, smaller head and jaws, higher eye position, greater buoyancy, and deeper peduncle than the shallow-water lean morph. Huronicus grew slower to a smaller adult size, and had an older mean age than the lean morph. Genetic comparisons showed low genetic divergence between morphs, indicating incomplete reproductive isolation. Phenotypic plasticity and differences in habitat use between deep and shallow waters associated with variation in foraging opportunities seems to have been sufficient to maintain the two morphs, demonstrating their important roles in resource polymorphism. Rush Lake expands previous explanations for lake charr intraspecific diversity, from large to small lakes and from reproductive isolation to the presence of gene flow associated with strong ecological drivers.

Angler-caught piscivore diets reflect fish community changes in Lake Huron

Science.gov (United States)

Roseman, Edward F.; Schaeffer, Jeff; Bright, Ethan; Fielder, David G.

2014-01-01

Examination of angler-caught piscivore stomachs revealed that Lake Trout Salvelinus namaycush, Chinook Salmon Oncorhynchus tshawytscha, and Walleyes Sander vitreus altered theirdiets in response to unprecedented declines in Lake Huron's main-basin prey fish community.Diets varied by predator species, season, and location but were nearly always dominated numerically by some combination of Alewife Alosa pseudoharengus, Rainbow Smelt Osmerus mordax, Emerald Shiner Notropis atherinoides, Round Goby Neogobius melanostomus, or terrestrial insects. Rainbow Trout Oncorhynchus mykiss (steelhead), Coho Salmon Oncorhynchus kisutch, and Atlantic Salmon Salmo salar had varied diets that reflected higher contributions of insects. Compared with an earlier (1983–1986) examination of angler-caught predator fishes from Lake Huron, the contemporary results showed an increase in consumption of nontraditional prey (including conspecifics), use of smaller prey, and an increase in insects in the diet, suggesting that piscivores were faced with chronic prey limitation during this study. The management of all piscivores in Lake Huron will likely require consideration of the pervasive effects of changes in food webs, especially if prey fish remain at low levels.

Maintenance of Genetic Diversity in Natural Spawning of Captively-Reared Endangered Sockeye Salmon, Oncorhynchus nerka

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Ruth E. Withler

2014-06-01

Full Text Available Captive propagation of Pacific salmon is routine, but few captive breeding programs have been conducted to successfully re-establish extirpated wild populations. A captive breeding program for endangered Sakinaw Lake sockeye salmon was established from 84 adults between 2002 and 2005, just prior to extirpation of the wild population. After several years of absence, sockeye salmon released from captivity returned to spawn in Sakinaw Lake in 2010 and in all years thereafter. Freshwater survival rates of released hatchery fry and naturally produced progeny of reintroduced sockeye salmon have not limited abundance of the reintroduced population. In contrast, marine survival rates for Sakinaw sockeye salmon have been <1%, a level that precludes population restoration in the absence of supplementation. Genetic diversity commensurate with the number of parental founders has been maintained in captivity. The 517 adult second-generation captive fish that spawned in Sakinaw Lake in 2011 produced a smolt emigration of almost 28,000 juvenile fish with an effective population size of 132. Allelic richness and gene diversity levels in the smolts were similar to those observed in captivity. This indicates genetic contributions from all or most founding parents have been retained both in captivity and in the nascent reintroduced natural population.

Reproductive investment and multiple spawning evidence in the redfinger rubble crab Eriphia gonagra (Brachyura, Eriphioidea

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Gustavo M. Teixeira

Full Text Available Abstract The variation in reproductive investment (RI and the hypothesis of multiple spawning were evaluated in the redfinger rubble crab Eriphia gonagra (Fabricius, 1781. The gonads and embryos showed synchronous development, and fecundity and RI varied widely among females of the same size class. The mean RI value recorded was 11.31%, with no significant differences among the means for different size classes. The allometric analysis of fecundity indicated RI decrease while body size increase, but we suggested that this occurs due to size overestimation where the largest width of carapace was used as body size reference in these analyzes. In addition, we found an isometric relationship for “female weight vs. egg number”, and also for “female weight vs. egg weight”, indicating that RI increased proportionally with size of females. Relatively high frequencies both of smaller females with rudimentary gonads, and of larger females with developed gonads were observed. This indicates that larger females take place more frequently in the population reproductive output over time. This difference could not be observed by means of RI analyses of captured and fixed crabs, for which only one stage of gonad development and/or one spawning is usually recorded.

Spawning areas, dispersion and microhabitats of fish larvae in the Anavilhanas Ecological Station, rio Negro, Amazonas State, Brazil

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Edinbergh C. de Oliveira

Full Text Available The abundance and distribution of ichthyoplankton and their relationships to current velocity, temperature, dissolved oxygen, pH and electrical conductivity of the water in the Anavilhanas Ecological Station, Negro River, Amazonas State, Brazil, were analyzed. Preferred microhabitats for spawning, dispersion and nursery were also verified. Sampling was undertaken during the falling water period of 2001 and the rising water period of 2002, in a section of 100 km subdivided into 5 subsections, with a total of 20 stations (5 beaches, 5 ravines, 5 channels, and 5 lake channels at night and during the day at the surface and at the bottom. 647 eggs and 4,187 larvae were captured, belonging to 10 families and four orders: Characiformes (6, Siluriformes (2, Perciformes (1, and Clupeiformes (1. Engraulidae (55.39%, Pimelodidae (30.45%, Auchenipteridae (5.23% and Sciaenidae (5.13% were the dominant families. The hierarchical statistical model (ANOVA with three factors (microhabitat, depth and period was applied to the environmental variables and the larval abundance, showing greater abundances of sciaenids in the ravines and lower abundances of engraulids in the channels. The highest captures were obtained at lower temperature values, at the bottom during the day and at the surface at night, suggesting an active larval behavior. The presence of the four larval development stages in all subsection for pimelodids and sciaenids, and in three subsections for engraulids, indicates that the Anavilhanas Ecological Station is an important spawning and nursery area for species of these groups in the Negro River. Larvae abundance of all characiform families was extremely low (from 0.1 to 1.17%, suggesting that they do not spawn in this system.

Snake River sockeye salmon habitat and limnological research: Annual report 1997

International Nuclear Information System (INIS)

Taki, D.; Lewis, B.; Griswold, B.

1999-01-01

Since the late 1980's, Snake River sockeye Oncorhynchus nerka adults have only returned to Redfish Lake, one of five lakes in the Sawtooth Basin which historically reared sockeye. 1997 project objectives included (1) characterization of the limnology of Sawtooth Valley lakes; (2) fertilization of Redfish, Pettit, and Alturas lakes; (3) O.nerka lake population surveys; (4) estimation of kokanee escapement and fry production in Alturas Lake Creek, Stanley Lake Creek, and Fishhook Creek; (5) reduce the number of spawning kokanee in Fishook Creek; (6) evaluate hatchery rainbow trout overwinter survival and potential competition and predation interactions with O.nerka in Pettit Lake; (7) assess predation from bull trout Salvelinus malma, brook trout S.fontinalis, and northern squawfish Ptychocheilus oregonsis on lentic O.nerka; (8) establish screw tap and weir sites to monitor smolt emigration

Effects of increased discharge on spawning and age-0 recruitment of rainbow trout in the Colorado River at Lees Ferry, Arizona

Science.gov (United States)

Avery, Luke A.; Korman, Josh; Persons, William R.

2015-01-01

Negative interactions of Rainbow Trout Oncorhynchus mykiss with endangered Humpback Chub Gila cypha pose challenges to the operation of Glen Canyon Dam (GCD) to manage for both species in the Colorado River. Operations to enhance the Rainbow Trout tailwater fishery may lead to an increase in downstream movement of the trout to areas where they are likely to interact with Humpback Chub. We evaluated the effects of dam operations on age-0 Rainbow Trout in the tailwater fishery to inform managers about how GCD operations could benefit a tailwater fishery for Rainbow Trout; although this could affect a Humpback Chub population farther downstream. A near year-long increase in discharge at GCD in 2011 enabled us to evaluate whether high and stable flows led to increased spawning and production of age-0 Rainbow Trout compared with other years. Rainbow Trout spawning was monitored by fitting a model to observed redd counts to estimate the number of redds created over a spawning season. Data collected during electrofishing trips in July–September and November were used to acquire age-0 trout population and mortality rate estimates. We found that high and stable flows in 2011 resulted in 3,062 redds (1.7 times the mean of all survey years) and a population estimate of 686,000 age-0 Rainbow Trout (second highest on record). Despite high initial abundance, mortality remained low through the year (0.0043%/d) resulting in significant recruitment with a record high November population estimate of 214,000 age-0 Rainbow Trout. Recent monitoring indicates this recruitment event was followed by an increase in downstream migration, which may lead to increased interactions with downstream populations of Humpback Chub. Consequently, while our results indicate that manipulating flow at GCD can be used to manage Rainbow Trout spawning and recruitment, fisheries managers should use flow manipulation in moderation to minimize downstream migration in order to reduce negative

Genetically based population divergence in overwintering energy mobilization in brook charr (Salvelinus fontinalis).

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Crespel, Amélie; Bernatchez, Louis; Garant, Dany; Audet, Céline

2013-03-01

Investigating the nature of physiological traits potentially related to fitness is important towards a better understanding of how species and/or populations may respond to selective pressures imposed by contrasting environments. In northern species in particular, the ability to mobilize energy reserves to compensate for the low external energy intake during winter is crucial. However, the phenotypic and genetic bases of energy reserve accumulation and mobilization have rarely been investigated, especially pertaining to variation in strategy adopted by different populations. In the present study, we documented variation in several energy reserve variables and estimated their quantitative genetic basis to test the null hypothesis of no difference in variation at those traits among three strains of brook charr (Salvelinus fontinalis) and their reciprocal hybrids. Our results indicate that the strategy of winter energy preparation and mobilization was specific to each strain, whereby (1) domestic fish accumulated a higher amount of energy reserves before winter and kept accumulating liver glycogen during winter despite lower feeding; (2) Laval fish used liver glycogen and lipids during winter and experienced a significant decrease in condition factor; (3) Rupert fish had relatively little energy reserves accumulated at the end of fall and preferentially mobilized visceral fat during winter. Significant heritability for traits related to the accumulation and use of energy reserves was found in the domestic and Laval but not in the Rupert strain. Genetic and phenotypic correlations also varied among strains, which suggested population-specific genetic architecture underlying the expression of these traits. Hybrids showed limited evidence of non-additive effects. Overall, this study provides the first evidence of a genetically based-and likely adaptive-population-specific strategy for energy mobilization related to overwinter survival.

Captive Rearing Initiative for Salmon River Chinook Salmon, 1998-1999 Progress Report.

Energy Technology Data Exchange (ETDEWEB)

Hassemer, Peter F.

2001-04-01

these five were spawned out, one was partially spawned, and three died before depositing eggs. However, much of the spawning related behavior observed involved female chinook salmon paired with male bull trout Salvelinus confluentus. Two female carcasses from the East Fork Salmon River were recovered and examined for egg retention. One of these had spawned and one had not.

Captive Rearing Initiative for Salmon River Chinook Salmon, 1999 Progress Report.

Energy Technology Data Exchange (ETDEWEB)

Hassemer, Peter F.

2001-04-01

these five were spawned out, one was partially spawned, and three died before depositing eggs. However, much of the spawning related behavior observed involved female chinook salmon paired with male bull trout Salvelinus confluentus. Two female carcasses from the East Fork Salmon River were recovered and examined for egg retention. One of these had spawned and one had not.

A Bayesian spawning habitat suitability model for American shad in southeastern United States rivers

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Hightower, Joseph E.; Harris, Julianne E.; Raabe, Joshua K.; Brownell, Prescott; Drew, C. Ashton

2012-01-01

Habitat suitability index models for American shad Alosa sapidissima were developed by Stier and Crance in 1985. These models, which were based on a combination of published information and expert opinion, are often used to make decisions about hydropower dam operations and fish passage. The purpose of this study was to develop updated habitat suitability index models for spawning American shad in the southeastern United States, building on the many field and laboratory studies completed since 1985. We surveyed biologists who had knowledge about American shad spawning grounds, assembled a panel of experts to discuss important habitat variables, and used raw data from published and unpublished studies to develop new habitat suitability curves. The updated curves are based on resource selection functions, which can model habitat selectivity based on use and availability of particular habitats. Using field data collected in eight rivers from Virginia to Florida (Mattaponi, Pamunkey, Roanoke, Tar, Neuse, Cape Fear, Pee Dee, St. Johns), we obtained new curves for temperature, current velocity, and depth that were generally similar to the original models. Our new suitability function for substrate was also similar to the original pattern, except that sand (optimal in the original model) has a very low estimated suitability. The Bayesian approach that we used to develop habitat suitability curves provides an objective framework for updating the model as new studies are completed and for testing the model's applicability in other parts of the species' range.

Annual variation of hematology and plasma chemistry in shortnose sturgeon, Acipenser brevirostrum, during a dam-impeded spawning run.

Science.gov (United States)

Matsche, Mark A; Gibbons, Jarrett

2012-12-01

Shortnose sturgeon (Acipenser brevirostrum) spawning migrations on the Cooper River are impeded by Pinopolis Dam, Lake Moultrie, South Carolina. Sturgeon and other species aggregate below the dam in late winter/early spring and are subjected to a variety of stressors stemming from crowding, poor habitat quality, and injuries that appear to be caused by boat propeller or turbine strikes. Spawning has been documented in the tailrace, but reproductive success has not been verified as no juveniles have been captured. Fish within the dam tailrace were captured by gill net during winter, 2005 and 2007-2011, and physiological condition was assessed using a panel of hematologic and biochemical indices. Plasma phosphorus and calcium were significantly higher in females, while PCV and aspartate aminotransferase were significantly higher in males, indicating sex-specific physiological changes triggered during maturity. A marked leucopenia, accompanied by lymphopenia and neutrophilia, was evident in both sexes and was consistent across years, indicating that these fish were under chronic stress. Testosterone and estradiol levels and hematologic and biochemical reference intervals are provided for comparative purposes.

Biochemical characterization of the Arctic char (Salvelinus alpinus ovarian progestin membrane receptor

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Thomas Peter

2005-11-01

Full Text Available Abstract Membrane progestin receptors are involved in oocyte maturation in teleosts. However, the maturation-inducing steroid (MIS does not appear to be conserved among species and several progestins may fulfill this function. So far, complete biochemical characterization has only been performed on a few species. In the present study we have characterized the membrane progestin receptor in Arctic char (Salvelinus alpinus and show that the 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P receptor also binds several xenobiotics, thus rendering oocyte maturation sensitive to environmental pollutants. We identified a single class of high affinity (Kd, 13.8 ± 1.1 nM, low capacity (Bmax, 1.6 ± 0.6 pmol/g ovary binding sites by saturation and Scatchard analyses. Receptor binding displayed rapid association and dissociation kinetics typical of steroid membrane receptors, with t1/2 s of less than 1 minute. The 17,20beta-P binding also displayed tissue specificity with high, saturable, and specific 17,20beta-P binding detected in ovaries, heart and gills while no specific binding was observed in muscle, brain or liver. Changes in 17,20beta-P binding during oocyte maturation were consistent with its identity as the oocyte MIS membrane receptor. Incubation of fully-grown ovarian follicles with gonadotropin induced oocyte maturation, which was accompanied by a five-fold increase in 17,20beta-P receptor binding. In addition, competition studies with a variety of steroids revealed that receptor binding is highly specific for 17,20beta-P, the likely maturation-inducing steroid (MIS in Arctic char. The relative-binding affinities of all the other progestogens and steroids tested were less than 5% of that of 17,20beta-P for the receptor. Several ortho, para derivatives of DDT also showed weak binding affinity for the 17,20beta-P receptor supporting the hypothesis that xenobiotics may bind steroid receptors on the oocyte's surface and might thereby interfere

The final spawning ground of Tachypleus gigas (Muller, 1785) on the east Peninsular Malaysia is at risk: A call for action.

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Nelson, B.R.; Satyanarayan, B.; Moh, J.H.Z.; Ikhwanuddin, M.; Chatterji, A.; Shaharom, F.

Tanjung Selongor and Pantai Balok (State Pahang) are the only two places known for spawning activity of the Malaysian horseshoe crab - Tachypleus gigas (Muller, 1785) on the east coast of Peninsular Malaysia. While the former beach has been...

2009 Spawning cisco investigations in the Canadian waters of Lake Superior

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Yule, Daniel L.; Cholwek, Gary A.; Evrard, Lori M.; E. Berglund,; K.I. Cullis,

2010-01-01

We sampled with acoustics (AC) and midwater trawls (MT) to determine cisco abundance in Lake Superior’s Thunder and Black bays during 8-14 November, 2009. Total abundance of spawning-size (≥ 250 mm total length) ciscoes was estimated at 6.25 million in Thunder Bay and 1.12 million in Black Bay. Exploitation fractions of market-size (≥ age 6) females from Thunder and Black bays for 2009 were estimated at 7.1% and 11.3%, respectively; below the recommended maximum annual harvest of 15% recently adopted by Lake Superior fisheries managers. Given Thunder Bay spawner densities are on a downward trajectory, and recruitment since the 2003 year-class has been low, it is likely the exploitation fractions will increase in the future. After 2010, the Ontario Ministry of Natural Resources (OMNR) will carry on the AC program as a management activity. It is likely suspended experimental gill net (GN) samples will be used to ground truth future AC samples. In 2009, we characterized the length and age structure of Thunder Bay ciscoes using both MT samples and GN samples. Females represented 49% of the MT catch, but only 39% in GN samples. Catching a smaller proportion of females in GN samples resulted in a lower female population estimate and a higher estimated exploitation fraction (10.4%) compared to MT samples (7.1%). Experimental gill net effort was limited to 10-11.8 m water column depths where midwater trawl samples also caught roughly 40% females. Ciscoes ≥ age 17 (≥ 1992 year class) were common in Black Bay, but rare in Thunder Bay suggesting: 1) the stocks may be distinct; and 2) total mortality of ciscoes returning to spawn in Black Bay in recent years has been lower than ciscoes returning to Thunder Bay. Our mid-November 2009 effort to assess the Black Bay stock by sampling outside of the 3 bay in the lake proper was deemed successful, but this should be confirmed by sampling the Black Bay region during both mid- and late-November 2010.

Evaluation of glutamic acid and glycine as sources of nonessential amino acids for lake trout (Salvelinus namaycush) and rainbow trout (Salmo gairdnerii)

Science.gov (United States)

Hughes, S.G.

1985-01-01

1. A semi-purified test diet which contained either glutamic acid or glycine as the major source of nonessential amino acids (NEAA) was fed to lake and rainbow trout.2. Trout fed the diet containing glutamic acid consistently showed better growth and feed conversion efficiencies than those fed the diets containing glycine.3. The data indicate that these trout utilize glutamic acid more efficiently than glycine when no other major sources of NEAA are present.

Spawning habitat of the Peruvian anchovy, Engraulis ringens

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Walsh, J.J. (Brookhaven National Lab., Upton, NY); Whitledge, T.E.; Esaias, W.E.; Smith, R.L.; Huntsman, S.A.; Santander, H.; De Mendiola, B.R.

1980-01-01

Individual larvae of the anchovy Engraulis ringens appear to survive better off the northern coast of Peru during the austral winter season when a motile algal food supply is available. Concentrations of the dinoflagellate food of the first feeding anchovy larvae may be reduced less often by wind events in the north than in the south. Under El Nino conditions, more of the adult anchovy are found south within a less favorable spawning habitat, in terms of dilution and food quality, where there is evidently less larval survival and subsequent recruitment to adult stocks. Increased mortality of the larvae during 1965, 1972, and 1976 El Ninos and of the adults during the 20-y fishery has reduced the present stock to less than 20% of its biomass in times of peak yield. Such a change in food chain dynamics is reflected in transients of oxygen demand at the decadal scale of variability. Associated with an increase in zooplankton biomass and a decline of the anchovy fishery, the sardine species of the clupeid pair off Peru may also be increasing in number, implying that natural oscillations of clupeoids may be accelerated by overfishing.

The final spawning ground of Tachypleus gigas (Müller, 1785) on the east Peninsular Malaysia is at risk: a call for action.

Science.gov (United States)

Nelson, Bryan Raveen; Satyanarayana, Behara; Moh, Julia Hwei Zhong; Ikhwanuddin, Mhd; Chatterji, Anil; Shaharom, Faizah

2016-01-01

Tanjung Selongor and Pantai Balok (State Pahang) are the only two places known for spawning activity of the Malaysian horseshoe crab - Tachypleus gigas (Müller, 1785) on the east coast of Peninsular Malaysia. While the former beach has been disturbed by several anthropogenic activities that ultimately brought an end to the spawning activity of T. gigas, the status of the latter remains uncertain. In the present study, the spawning behavior of T. gigas at Pantai Balok (Sites I-III) was observed over a period of thirty six months, in three phases, between 2009 and 2013. Every year, the crab's nesting activity was found to be high during Southwest monsoon (May-September) followed by Northeast (November-March) and Inter monsoon (April and October) periods. In the meantime, the number of female T. gigas in 2009-2010 (Phase-1) was higher (38 crabs) than in 2010-2011 (Phase-2: 7 crabs) and 2012-2013 (Phase-3: 9 crabs) for which both increased overexploitation (for edible and fishmeal preparations) as well as anthropogenic disturbances in the vicinity (sand mining since 2009, land reclamation for wave breaker/parking lot constructions in 2011 and fishing jetty construction in 2013) are responsible. In this context, the physical infrastructure developments have altered the sediment close to nesting sites to be dominated by fine sand (2.5Xφ ) with moderately-well sorted (0.6-0.7σφ), very-coarse skewed (-2.4SKφ), and extremely leptokurtic (12.6Kφ) properties. Also, increased concentrations of Cadmium (from 4.2 to 13.6 mg kg(-1)) and Selenium (from 11.5 to 23.3 mg kg(-1)) in the sediment, and Sulphide (from 21 to 28 µg l(-1)) in the water were observed. In relation to the monsoonal changes affecting sheltered beach topography and sediment flux, the spawning crabs have shown a seasonal nest shifting behaviour in-between Sites I-III during 2009-2011. However, in 2012-2013, the crabs were mostly restricted to the areas (i.e., Sites I and II) with high oxygen (5.5-8.0 mg l

The final spawning ground of Tachypleus gigas (Müller, 1785 on the east Peninsular Malaysia is at risk: a call for action

Directory of Open Access Journals (Sweden)

Bryan Raveen Nelson

2016-07-01

Full Text Available Tanjung Selongor and Pantai Balok (State Pahang are the only two places known for spawning activity of the Malaysian horseshoe crab - Tachypleus gigas (Müller, 1785 on the east coast of Peninsular Malaysia. While the former beach has been disturbed by several anthropogenic activities that ultimately brought an end to the spawning activity of T. gigas, the status of the latter remains uncertain. In the present study, the spawning behavior of T. gigas at Pantai Balok (Sites I-III was observed over a period of thirty six months, in three phases, between 2009 and 2013. Every year, the crab’s nesting activity was found to be high during Southwest monsoon (May–September followed by Northeast (November–March and Inter monsoon (April and October periods. In the meantime, the number of female T. gigas in 2009–2010 (Phase-1 was higher (38 crabs than in 2010–2011 (Phase-2: 7 crabs and 2012–2013 (Phase-3: 9 crabs for which both increased overexploitation (for edible and fishmeal preparations as well as anthropogenic disturbances in the vicinity (sand mining since 2009, land reclamation for wave breaker/parking lot constructions in 2011 and fishing jetty construction in 2013 are responsible. In this context, the physical infrastructure developments have altered the sediment close to nesting sites to be dominated by fine sand (2.5Xφ with moderately-well sorted (0.6–0.7σφ, very-coarse skewed (−2.4SKφ, and extremely leptokurtic (12.6Kφ properties. Also, increased concentrations of Cadmium (from 4.2 to 13.6 mg kg−1 and Selenium (from 11.5 to 23.3 mg kg−1 in the sediment, and Sulphide (from 21 to 28 µg l−1 in the water were observed. In relation to the monsoonal changes affecting sheltered beach topography and sediment flux, the spawning crabs have shown a seasonal nest shifting behaviour in-between Sites I-III during 2009–2011. However, in 2012–2013, the crabs were mostly restricted to the areas (i.e., Sites I and II with high

Reproductive physiology of Missouri River gravid pallid sturgeon and shovelnose sturgeon during the 2005 and 2006 spawning seasons: Chapter C in Factors affecting the reproduction, recruitment, habitat, and population dynamics of pallid sturgeon and shovelnose sturgeon in the Missouri River

Science.gov (United States)

Papoulias, Diana M.; Annis, Mandy L.; Delonay, Aaron J.; Tillitt, Donald E.

2007-01-01

In a natural, unaltered river, the location and timing of sturgeon spawning will be dictated by the prevailing environmental conditions to which the sturgeon have adapted. A goal of the Comprehensive Sturgeon Research Program (CSRP; see chap. A) at the U.S. Geological Survey Columbia Environmental Research Center is to identify where, when, and under what conditions shovelnose sturgeon (Scaphirhynchus platorynchus) and pallid sturgeon (S. albus) spawn in the altered Missouri River so that those conditions necessary for spawning success can be defined. One approach to achieving this goal is to exploit what is known about fish reproductive physiology to develop and apply a suite of diagnostic indicators of readiness to spawn. In 2005 and 2006, gravid shovelnose sturgeon and a limited number of pallid sturgeon were fitted with transmitters and tracked on their spawning migration. A suite of physiological indicators of reproductive state such as reproductive hormones and oocyte development were measured. These same measurements were made on tissues collected from additional fish, presumably migrating to spawn, that were not tagged or tracked. The data presented here indicating the sturgeons’ readiness to spawn are to be evaluated together with their behavior and the environmental conditions. The U.S. Army Corps of Engineers (ACOE) Sturgeon Response to Flow Modification (SRFM; see chap. A) study, initiated in 2006, provides additional opportunities to experimentally evaluate the sturgeon reproductive response indicators relative to changes in flow. In this chapter, we report progress made on identifying and developing the physiological indicators and summarize 2 years’ worth of indicator data collected thus far.

Traveling around Cape Horn: Otolith chemistry reveals a mixed stock of Patagonian hoki with separate Atlantic and Pacific spawning grounds

Science.gov (United States)

Schuchert, P.C.; Arkhipkin, A.I.; Koenig, A.E.

2010-01-01

Trace element fingerprints of edge and core regions in otoliths from 260 specimens of Patagonian hoki, Macruronus magellanicus L??nnberg, 1907, were analyzed by LA-ICPMS to reveal whether this species forms one or more population units (stocks) in the Southern Oceans. Fish were caught on their spawning grounds in Chile and feeding grounds in Chile and the Falkland Islands. Univariate and multivariate analyses of trace element concentrations in the otolith edges, which relate to the adult life of fish, could not distinguish between Atlantic (Falkland) and Pacific (Chile) hoki. Cluster analyses of element concentrations in the otolith edges produced three different clusters in all sample areas indicating high mixture of the stocks. Cluster analysis of trace element concentrations in the otolith cores, relating to juvenile and larval life stages, produced two separate clusters mainly distinguished by 137Ba concentrations. The results suggest that Patagonian hoki is a highly mixed fish stock with at least two spawning grounds around South America. ?? 2009 Elsevier B.V.

Booming Asia-Pacific oil trade spawns regional storage projects

International Nuclear Information System (INIS)

Land, R.

1992-01-01

This paper reports that surging oil trade in the Asia-Pacific region is spawning a number of big petroleum storage projects there. Among the biggest are those in Indonesia and Singapore. A group led by Singapore's Sembawang Group plans to build a $272 million (Singapore) oil storage terminal on Karimun Island in Riau province, Indonesia. Other participants include Kuo International, Hong Kong, and likely companies from Japan, Europe, and the U.S. According to press reports from Jakarta and Singapore, Van Ommeren Terminals of Netherlands was also reportedly involved in negotiations on the projects. A joint venture agreement was expected to be signed by the third quarter. Plans call for building a terminal with a capacity of 1.5 million cu m on the island, where Sembawang has a 100 year lease. Ultimately, Sembawang and Indonesian company Bangun Cipta want to develop the site as an industrial city with petrochemical plants, engineering and manufacturing industries, and shipyards. Semabawang Project Engineering recently completed a feasibility study of the Karimun storage project

Influences of spawning timing, water temperature, and climatic warming on early life history phenology in western Alaska sockeye salmon

Science.gov (United States)

Sparks, Morgan M.; Falke, Jeffrey A.; Quinn, Thomas P.; Adkison, Milo D.; Schindler, Daniel E.; Bartz, Krista K.; Young, Daniel B.; Westley, Peter A. H.

2018-01-01

We applied an empirical model to predict hatching and emergence timing for 25 western Alaska sockeye salmon (Oncorhynchus nerka) populations in four lake-nursery systems to explore current patterns and potential responses of early life history phenology to warming water temperatures. Given experienced temperature regimes during development, we predicted hatching to occur in as few as 58 d to as many as 260 d depending on spawning timing and temperature. For a focal lake spawning population, our climate-lake temperature model predicted a water temperature increase of 0.7 to 1.4 °C from 2015 to 2099 during the incubation period, which translated to a 16 d to 30 d earlier hatching timing. The most extreme scenarios of warming advanced development by approximately a week earlier than historical minima and thus climatic warming may lead to only modest shifts in phenology during the early life history stage of this population. The marked variation in the predicted timing of hatching and emergence among populations in close proximity on the landscape may serve to buffer this metapopulation from climate change.

Kootenai River White Sturgeon Investigations; White Sturgeon Spawning and Recruitment Evaluation, 2003-2004 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Rust, Pete; Wakkinen, Virginia (Idaho Department of Fish and Game, Boise, ID)

2005-06-01

The objective of this research was to determine the environmental requirements for successful spawning and recruitment of the Kootenai River white sturgeon Acipenser transmontanus population. Annual tasks include monitoring and evaluating the various life stages of Kootenai River white sturgeon. Sampling for adult Kootenai River white sturgeon in 2003 began in March and continued through April. Eighty-one adult white sturgeon were captured with 3,576 hours of angling and set-lining effort in the Kootenai River. Discharge from Libby Dam and river stage at Bonners Ferry in 2003 peaked in May and early June. Flows remained above 500 m{sup 3}/s throughout June, decreased rapidly through mid July, and increased back to near 500 m{sup 3}/s after mid July and through mid August. By late August, flows had decreased to below 400 m{sup 3}/s. We monitored the movements of 24 adult sturgeon in Kootenay Lake, British Columbia (BC) and the Kootenai River from March 15, 2003 to August 31, 2003. Some of the fish were radio or sonic tagged in previous years. Twelve adult white sturgeon were moved upstream to the Hemlock Bar reach (rkm 260.0) and released as part of the Set and Jet Program. Transmitters were attached to seven of these fish, and their movements were monitored from the time of release until they moved downstream of Bonners Ferry. Eight additional radio-tagged white sturgeon adults were located in the traditional spawning reach (rkm 228-240) during May and June. Sampling with artificial substrate mats began May 21, 2003 and ended June 30, 2003. We sampled 717 mat d (a mat d is one 24 h set) during white sturgeon spawning. Three white sturgeon eggs were collected near Shortys Island on June 3, 2003, and five eggs were collected from the Hemlock Bar reach on June 5, 2003. Prejuvenile sampling began June 17, 2003 and continued until July 31, 2003. Sampling occurred primarily at Ambush Rock (rkm 244.0) in an attempt to document any recruitment that might have occurred from

Diverse juvenile life-history behaviours contribute to the spawning stock of an anadromous fish population

Science.gov (United States)

Walsworth, Timothy E.; Schindler, Daniel E.; Griffiths, Jennifer R.; Zimmerman, Christian E.

2015-01-01

Habitat quality often varies substantially across space and time, producing a shifting mosaic of growth and mortality trade-offs across watersheds. Traditional studies of juvenile habitat use have emphasised the evolution of single optimal strategies that maximise recruitment to adulthood and eventual fitness. However, linking the distribution of individual behaviours that contribute to recruitment at the population level has been elusive, particularly for highly fecund aquatic organisms. We examined juvenile habitat use within a population of sockeye salmon (Oncorhynchus nerka) that spawn in a watershed consisting of two interconnected lakes and a marine lagoon. Otolith microchemical analysis revealed that the productive headwater lake accounted for about half of juvenile growth for those individuals surviving to spawn in a single river in the upper watershed. However, 47% of adults had achieved more than half of their juvenile growth in the downstream less productive lake, and 3% of individuals migrated to the estuarine environment during their first summer and returned to freshwater to overwinter before migrating back to sea. These results describe a diversity of viable habitat-use strategies by juvenile sockeye salmon that may buffer the population against poor conditions in any single rearing environment, reduce density-dependent mortality and have implications for the designation of critical habitat for conservation purposes. A network of accessible alternative habitats providing trade-offs in growth and survival may be important for long-term viability of populations.

Sex Chromosome Evolution, Heterochiasmy, and Physiological QTL in the Salmonid Brook Charr Salvelinus fontinalis

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Ben J.G. Sutherland

2017-08-01

Full Text Available Whole-genome duplication (WGD can have large impacts on genome evolution, and much remains unknown about these impacts. This includes the mechanisms of coping with a duplicated sex determination system and whether this has an impact on increasing the diversity of sex determination mechanisms. Other impacts include sexual conflict, where alleles having different optimums in each sex can result in sequestration of genes into nonrecombining sex chromosomes. Sex chromosome development itself may involve sex-specific recombination rate (i.e., heterochiasmy, which is also poorly understood. The family Salmonidae is a model system for these phenomena, having undergone autotetraploidization and subsequent rediploidization in most of the genome at the base of the lineage. The salmonid master sex determining gene is known, and many species have nonhomologous sex chromosomes, putatively due to transposition of this gene. In this study, we identify the sex chromosome of Brook Charr Salvelinus fontinalis and compare sex chromosome identities across the lineage (eight species and four genera. Although nonhomology is frequent, homologous sex chromosomes and other consistencies are present in distantly related species, indicating probable convergence on specific sex and neo-sex chromosomes. We also characterize strong heterochiasmy with 2.7-fold more crossovers in maternal than paternal haplotypes with paternal crossovers biased to chromosome ends. When considering only rediploidized chromosomes, the overall heterochiasmy trend remains, although with only 1.9-fold more recombination in the female than the male. Y chromosome crossovers are restricted to a single end of the chromosome, and this chromosome contains a large interspecific inversion, although its status between males and females remains unknown. Finally, we identify quantitative trait loci (QTL for 21 unique growth, reproductive, and stress-related phenotypes to improve knowledge of the genetic

Efficient induction of spawning of Northern leopard frogs (Lithobates pipiens) during and outside the natural breeding season

OpenAIRE

Trudeau, Vance L; Schueler, Frederick W; Navarro-Martin, Laia; Hamilton, Christine K; Bulaeva, Elizabeth; Bennett, Amanda; Fletcher, William; Taylor, Lisa

2013-01-01

Background Amphibian declines are now recognized globally. It is also well known that many anurans do not reproduce easily in captivity, especially when held over long periods, or if they require hibernation before breeding. A simple method to induce spawning and subsequent development of large numbers of healthy tadpoles is therefore required to meet research and conservation goals. Methods The method is based on simultaneous injection of both female and male leopard frogs, Lithobates pipien...

Variability in oocyte size and batch fecundity in anchoveta (Engraulis ringens, Jenyns 1842 from two spawning areas off the Chilean coast

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Elson M. Leal

2009-03-01

Full Text Available Utilising histological preparations of ovaries from Engraulis ringens females collected in two contrasting spawning habitats along the Chilean coast, we assess the variability in oocyte size and batch fecundity during the peak spawning seasons in three years. The effects of female size (length and weight, batch fecundity and mean sea surface temperature on oocyte size were also examined. Results showed larger oocytes and lower batch fecundity in females from the southern area. Oocyte volume differences persisted inter-annually and were not explained by differences in female sizes. Since ovary weight was similar between areas, the cost of producing larger oocytes in the south population seems to be a fecundity reduction. The latitudinal variations in oocyte number and size seem to be determined by the predominant environmental conditions in each habitat. Hence, female E. ringens seem to adapt their reproductive tactics by producing eggs sizes and quantities that favour survival of their offspring under the environmental conditions in which they are to develop.

Radiocaesium turnover in Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in a Norwegian lake

International Nuclear Information System (INIS)

Forseth, T.; Ugedal, O.; Jonsson, B.; Langeland, A.; Njaastad, O.

1991-01-01

The radioactivity of brown trout (Salmo trutta L.) and Arctic charr (Salvelinus alpinus (L.)) was monitored in a Norwegian lake from 1986 to 1989. A distinct difference was observed between brown trout and Arctic charr in the accumulation of radiocaesium ( 134 Cs and 137 Cs) from the Chernobyl fallout, and the study focused on the understanding of this difference. Brown trout had a large food consumption and a corresponding high intake of radiocaesium. Excretion was 20% faster in brown trout than Arctic charr as brown trout lived at high temperatures in epilimnic water. Arctic charr had a lower food consumption (less than one-third of trout) and lived in colder meta-and hypolimnic water. Arctic charr therefore had a lower intake and slower excretion of radiocaesium. Brown trout an Arctic charr had different diets. For brown trout zoobenthos was the dominant food item, whereas Artic charr mainly fed on zooplankton. The radioactivity in the stomach contents of the two species was different in 1986, but similar for the rest of the period. Higher levels of radiocaesium in brown trout than Arctic charr in 1986 were due to a higher food consumption and more radioactive food items in its diet. The parallel development in accumulated radiocaesium through summer 1987 was probably formed by brown trout balancing a higher intake with a faster excretion. The ecological half-lives of radiocaesium in brown trout (357 days) and Arctic charr (550 days) from Lake Hoeysjoeen indicated a slow removal of the isotopes from the food webs. (author)

Characterization of channel substrate, and changes in suspended-sediment transport and channel geometry in white sturgeon spawning habitat in the Kootenai River near Bonners Ferry, Idaho, following the closure of Libby Dam

Science.gov (United States)

Barton, Gary J.

2004-01-01

Many local, State, and Federal agencies have concerns over the declining population of white sturgeon (Acipenser transmontanus) in the Kootenai River and the possible effects of the closure and subsequent operation of Libby Dam in 1972. In 1994, the Kootenai River white sturgeon was listed as an Endangered Species. A year-long field study was conducted in cooperation with the Kootenai Tribe of Idaho along a 21.7-kilometer reach of the Kootenai River including the white sturgeon spawning reach near Bonners Ferry, Idaho, approximately 111 to 129 kilometers below Libby Dam. During the field study, data were collected in order to map the channel substrate in the white sturgeon spawning reach. These data include seismic subbottom profiles at 18 cross sections of the river and sediment cores taken at or near the seismic cross sections. The effect that Libby Dam has on the Kootenai River white sturgeon spawning substrate was analyzed in terms of changes in suspended-sediment transport, aggradation and degradation of channel bed, and changes in the particle size of bed material with depth below the riverbed. The annual suspended-sediment load leaving the Kootenai River white sturgeon spawning reach decreased dramatically after the closure of Libby Dam in 1972: mean annual pre-Libby Dam load during 1966–71 was 1,743,900 metric tons, and the dam-era load during 1973–83 was 287,500 metric tons. The amount of sand-size particles in three suspended-sediment samples collected at Copeland, Idaho, 159 kilometers below Libby Dam, during spring and early summer high flows after the closure of Libby Dam is less than in four samples collected during the pre-Libby Dam era. The supply of sand to the spawning reach is currently less due to the reduction of high flows and a loss of 70 percent of the basin after the closure of Libby Dam. The river's reduced capacity to transport sand out of the spawning reach is compensated to an unknown extent by a reduced load of sand entering the

Total Dissolved Gas Monitoring in Chum Salmon Spawning Gravels Below Bonneville Dam

Energy Technology Data Exchange (ETDEWEB)

Arntzen, Evan V.; Geist, David R.; Panther, Jennifer L.; Dawley, Earl

2007-01-30

At the request of the U.S. Army Corps of Engineers (Portland District), Pacific Northwest National Laboratory (PNNL) conducted research to determine whether total dissolved gas concentrations are elevated in chum salmon redds during spring spill operations at Bonneville Dam. The study involved monitoring the total dissolved gas levels at egg pocket depth and in the river at two chum salmon spawning locations downstream from Bonneville Dam. Dissolved atmospheric gas supersaturation generated by spill from Bonneville Dam may diminish survival of chum (Oncorhynchus keta) salmon when sac fry are still present in the gravel downstream from Bonneville Dam. However, no previous work has been conducted to determine whether total dissolved gas (TDG) levels are elevated during spring spill operations within incubation habitats. The guidance used by hydropower system managers to provide protection for pre-emergent chum salmon fry has been to limit TDG to 105% after allowing for depth compensation. A previous literature review completed in early 2006 shows that TDG levels as low as 103% have been documented to cause mortality in sac fry. Our study measured TDG in the incubation environment to evaluate whether these levels were exceeded during spring spill operations. Total dissolved gas levels were measured within chum salmon spawning areas near Ives Island and Multnomah Falls on the Columbia River. Water quality sensors screened at egg pocket depth and to the river were installed at both sites. At each location, we also measured dissolved oxygen, temperature, specific conductance, and water depth to assist with the interpretation of TDG results. Total dissolved gas was depth-compensated to determine when levels were high enough to potentially affect sac fry. This report provides detailed descriptions of the two study sites downstream of Bonneville Dam, as well as the equipment and procedures employed to monitor the TDG levels at the study sites. Results of the monitoring at

Visual sensitivity of deepwater fishes in Lake Superior.

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Kelly A Harrington

Full Text Available The predator-prey interactions in the offshore food web of Lake Superior have been well documented, but the sensory systems mediating these interactions remain unknown. The deepwater sculpin, (Myoxocephalus thompsoni, siscowet (Salvelinus namaycush siscowet, and kiyi (Coregonus kiyi inhabit low light level environments. To investigate the potential role of vision in predator-prey interactions, electroretinography was used to determine visual sensitivity for each species. Spectral sensitivity curves revealed peak sensitivity at 525 nm for each species which closely corresponds to the prevalent downwelling light spectrum at depth. To determine if sufficient light was available to mediate predator-prey interactions, visual sensitivity was correlated with the intensity of downwelling light in Lake Superior to construct visual depth profiles for each species. Sufficient daytime irradiance exists for visual interactions to approximately 325 m for siscowet and kiyi and 355 m for the deepwater sculpin during summer months. Under full moon conditions, sufficient irradiance exists to elicit ERG response to light available at approximately 30 m for the siscowet and kiyi and 45 m for the deepwater sculpin. Visual interactions are therefore possible at the depths and times when these organisms overlap in the water column indicating that vision may play a far greater role at depth in deep freshwater lakes than had been previously documented.

Factors Affecting Mercury Stable Isotopic Distribution in Piscivorous Fish of the Laurentian Great Lakes.

Science.gov (United States)

Lepak, Ryan F; Janssen, Sarah E; Yin, Runsheng; Krabbenhoft, David P; Ogorek, Jacob M; DeWild, John F; Tate, Michael T; Holsen, Thomas M; Hurley, James P

2018-03-06

Identifying the sources of methylmercury (MeHg) and tracing the transformations of mercury (Hg) in the aquatic food web are important components of effective strategies for managing current and legacy Hg sources. In our previous work, we measured stable isotopes of Hg (δ 202 Hg, Δ 199 Hg, and Δ 200 Hg) in the Laurentian Great Lakes and estimated source contributions of Hg to bottom sediment. Here, we identify isotopically distinct Hg signatures for Great Lakes trout ( Salvelinus namaycush) and walleye ( Sander vitreus), driven by both food-web and water-quality characteristics. Fish contain high values for odd-isotope mass independent fractionation (MIF) with averages ranging from 2.50 (western Lake Erie) to 6.18‰ (Lake Superior) in Δ 199 Hg. The large range in odd-MIF reflects variability in the depth of the euphotic zone, where Hg is most likely incorporated into the food web. Even-isotope MIF (Δ 200 Hg), a potential tracer for Hg from precipitation, appears both disconnected from lake sedimentary sources and comparable in fish among the five lakes. We suggest that similar to the open ocean, water-column methylation also occurs in the Great Lakes, possibly transforming recently deposited atmospheric Hg deposition. We conclude that the degree of photochemical processing of Hg is controlled by phytoplankton uptake rather than by dissolved organic carbon quantity among lakes.

BTU convergence spawning gas market opportunities in North America

International Nuclear Information System (INIS)

Anon.

1998-01-01

The so-called BTU convergence of US electric power and natural gas sectors is spawning a boom in market opportunities in the US Northeast that ensures the region will be North America's fastest growing gas market. That's the view of Catherine Good Abbott, CEO of Columbia Gas Transmission Corp., who told a Ziff Energy conference in Calgary that US Northeast gas demand is expected to increase to almost 10 bcfd in 2000 and more than 12 bcfd in 2010 from about 8 bcfd in 1995 and only 3 bcfd in 1985. The fastest growth will be in the US Northeast's electrical sector, where demand for gas is expected to double to 4 bcfd in 2010 from about 2 bcfd in 1995. In other presentations at the Ziff Energy conference, speakers voiced concerns about the complexity and speed of the BTU convergence phenomenon and offered assurances about the adequacy of gas supplies in North American to meet demand growth propelled by the BTU convergence boom. The paper discusses the gas demand being driven by power utilities, the BTU convergence outlook, electric power demand, Canadian production and supply, and the US overview

Early life history of three pelagic-spawning minnows Macrhybopsis spp. in the lower Missouri River

Science.gov (United States)

Long, James M.; Starks, Trevor A.; Miller, M.L.

2016-01-01

Life-history characteristics of age-0 sturgeon chub Macrhybopsis gelida, shoal chub Macrhybopsis hyostoma and sicklefin chub Macrhybopsis meeki were compared using several methods. AllMacrhybopsis species consumed mostly midge pupae, but M. meeki had the most general diet (Levins' index, B = 0·22) compared with M. hyostoma (B = 0·02) and M. gelida (B = 0·09). Morisita's diet overlap index among species pairs ranged from 0·62 to 0·97 and was highest between M. hyostoma and M. gelida. Daily ages estimated from lapilli otoliths for each species ranged from 15 to 43 days for M. gelida, 19 to 44 for M. hyostoma and from 16 to 64 days for M. meeki. Mean growth rates ranged from 0·79 mm day−1 for M. meeki to 1·39 mm day−1 for M. gelida. Mortality estimates indicated high daily survivorship rates for M. meeki (0·985), but could not be estimated for the other two species. Hatch date histograms were congruent with the belief that M. hyostoma and M. gelida spawn periodically from June to September. Macrhybopsis meeki, however, appeared to respond to a specific spawning cue as hatch dates were unimodal with a peak in July. These results fill a gap in current knowledge of these imperilled species that can be used to guide management decisions.

Marine nutrient contributions to tidal creeks in Virginia: spawning marine fish as nutrient vectors to freshwater ecosystems

Science.gov (United States)

Macavoy, S. E.; Garman, G. C.

2006-12-01

Coastal freshwater streams are typically viewed as conduits for the transport of sediment and nutrients to the coasts. Some coastal streams however experience seasonal migrations of anadromous fish returning to the freshwater to spawn. The fish may be vectors for the delivery of marine nutrients to nutrient poor freshwater in the form of excreted waste and post-spawning carcasses. Nutrients derived from marine sources are 13C, 15N and 34S enriched relative to nutrients in freshwater. Here we examine sediment, particulate organic matter (POM), invertebrates and fish in two tidal freshwater tributaries of the James River USA. The d15N of POM became elevated (from 3.8 to 6.5%), coincident with the arrival of anadromous river herring (Alosa sp), indicating a pulse of marine nitrogen. However, the elevated 15N was not observed in sediment samples or among invertebrates, which did not experience a seasonal isotopic shift (there were significant differences however among the guilds of invertebrate). Anadromous Alosa aestivalis captured within the tidal freshwater were 13C and 34S enriched (-19.3 and 17.2%, respectively) relative to resident freshwater fishes (-26.4 and 3.6% respectively) captured within 2 weeks of the Alosa. Although it is likely that marine derived nitrogen was detected in the tidal freshwater, it was not in sufficient abundance to change the isotope signature of most ecosystem components.

Spawning and multiple end points of the embryo-larval bioassay of the blue mussel Mytilus galloprovincialis (Lmk).

Science.gov (United States)

Resgalla, Charrid

2016-10-01

Since the 1960s, little has been done to improve and simulate the use of short-duration chronic bioassays of bivalve embryos, particularly in mussels. However, these test organisms offer great advantages in relation to other groups, due to the ease of obtaining breeders in cultivation systems, in the environment and any time, and due to their high sensitivity to chemicals or contaminants. To contribute some methodological aspects, this study uses techniques to stimulate spawning or improve the obtaining of gametes for use in bioassays with the mussel Mytilus galloprovincialis. It also evaluates different criteria for determining the effect on the larvae, for estimation of EC 50 and NOEC values, based on morphological analysis of developmental delay and the biometrics of the larvae. KCl proved to be a reliable inducer of spawning, with positive responses in 10 of the 12 months of the year tested. Moreover, this chemical, in association with NH 4 Cl, demonstrated the capacity to activate immature oocytes obtained from extirpated gonads, enabling an improvement in fertilization rates. The different criteria adopted to determine the effects on the larvae in the assays with reference toxicants (SDS and K 2 Cr 2 O 7 ) resulted in EC 50 and NOEC values without significant differences, indicating reliability in the results and freedom in the choice of criteria of effect to be adopted in the trials.

Proteomic Changes between Male and Female Worms of the Polychaetous Annelid Neanthes arenaceodentata before and after Spawning

KAUST Repository

Chandramouli, Kondethimmanahalli; Ravasi, Timothy; Reish, Donald; Qian, Pei-Yuan

2013-01-01

The Neanthes acuminata species complex (Polychaeta) are cosmopolitan in distribution. Neanthes arenaceodentata, complex, has been widely used as toxicological test animal in the marine environment. Method of reproduction is unique in this polychaete complex. Same sexes fight and opposite sexes lie side by side until egg laying. Females lose about 75% of their weight and die after laying eggs. The male, capable of reproducing up to nine times, fertilizes the eggs and incubates the embryos for 3-4 weeks. The objective of this study was to determine if there is any set of proteins that influences this unique pattern of reproduction. Gel-based two-dimensional electrophoresis (2-DE) and gel-free quantitative proteomics methods were used to identify differential protein expression patterns before and after spawning in both male and female N. arenaceodentata. Males showed a higher degree of similarity in protein expression patterns but females showed large changes in phosphoproteme before and after spawning. There was a decrease (about 70%) in the number of detected phosphoproteins in spent females. The proteins involved in muscular development, cell signaling, structure and integrity, and translation were differentially expressed. This study provides proteomic insights of the male and female worms that may serve as a foundation for better understanding of unusual reproductive patterns in polychaete worms. © 2013 Chandramouli et al.

Proteomic Changes between Male and Female Worms of the Polychaetous Annelid Neanthes arenaceodentata before and after Spawning

KAUST Repository

Chandramouli, Kondethimmanahalli

2013-08-30

The Neanthes acuminata species complex (Polychaeta) are cosmopolitan in distribution. Neanthes arenaceodentata, complex, has been widely used as toxicological test animal in the marine environment. Method of reproduction is unique in this polychaete complex. Same sexes fight and opposite sexes lie side by side until egg laying. Females lose about 75% of their weight and die after laying eggs. The male, capable of reproducing up to nine times, fertilizes the eggs and incubates the embryos for 3-4 weeks. The objective of this study was to determine if there is any set of proteins that influences this unique pattern of reproduction. Gel-based two-dimensional electrophoresis (2-DE) and gel-free quantitative proteomics methods were used to identify differential protein expression patterns before and after spawning in both male and female N. arenaceodentata. Males showed a higher degree of similarity in protein expression patterns but females showed large changes in phosphoproteme before and after spawning. There was a decrease (about 70%) in the number of detected phosphoproteins in spent females. The proteins involved in muscular development, cell signaling, structure and integrity, and translation were differentially expressed. This study provides proteomic insights of the male and female worms that may serve as a foundation for better understanding of unusual reproductive patterns in polychaete worms. © 2013 Chandramouli et al.

Behavioural and physiological responses of brook trout Salvelinus fontinalis to midwinter flow reduction in a small ice-free mountain stream.

Science.gov (United States)

Krimmer, A N; Paul, A J; Hontela, A; Rasmussen, J B

2011-09-01

This study presents an experimental analysis of the effects of midwinter flow reduction (50-75%, reduction in discharge in 4 h daily pulses) on the physical habitat and on behaviour and physiology of overwintering brook trout Salvelinus fontinalis in a small mountain stream. Flow reduction did not result in significant lowering of temperature or formation of surface or subsurface ice. The main findings were (1) daily movement by S. fontinalis increased (c. 2·5-fold) during flow reduction, but was limited to small-scale relocations (reduced during flow reduction. (3) Although both experimental and reference fish did lose mass and condition during the experiment, no effects of flow reduction on stress indicators (blood cortisol or glucose) or bioenergetics (total body fat, water content or mass loss) were detected, probably because access to the preferred type of cover remained available. Like other salmonids, S. fontinalis moves little and seeks physical cover during winter. Unlike many of the more studied salmonids, however, this species overwinters successfully in small groundwater-rich streams that often remain ice-free, and this study identifies undercut banks as the critical winter habitat rather than substratum cover. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Feeding habits of the alien brook trout Salvelinus fontinalis and the native brown trout Salmo trutta in Czech mountain streams

Directory of Open Access Journals (Sweden)

Horká Petra

2017-01-01

Full Text Available Quantifying patterns of prey resource use is fundamental to identify mechanisms enabling the coexistence of related fish species. Trophic interactions between the native brown trout, Salmo trutta, and the introduced brook trout, Salvelinus fontinalis, were studied monthly from May to October in three mountain streams in Central Europe (Czech Republic. To evaluate whether the feeding habits differ between separated and coexisting populations of these species, one locality where both species coexist, and two allopatric populations of either species were studied. Across the study period, the mean stomach fullness of fish varied, being highest in spring and declining through autumn. The diet overlap (Schoener's overlap index between the species increased through the studied season (from 54.5% in July to 81.5% in October. In allopatry, both species had nearly the same feeding habits. However, in sympatry, brook trout consumed higher proportion of terrestrial invertebrates, while brown trout showed no changes either in the proportions of aquatic and terrestrial prey utilized or in the selectivity for prey categories in comparison to allopatric conditions. The dietary shift observed for brook trout, but not for brown trout, suggests that brown trout is a stronger competitor in the studied sympatric locality, leading the brook trout to change its feeding habits to reduce interspecific competition.

Comparative Use of a Caribbean Mesophotic Coral Ecosystem and Association with Fish Spawning Aggregations by Three Species of Shark.

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Alexandria E Pickard

Full Text Available Understanding of species interactions within mesophotic coral ecosystems (MCEs; ~ 30-150 m lags well behind that for shallow coral reefs. MCEs are often sites of fish spawning aggregations (FSAs for a variety of species, including many groupers. Such reproductive fish aggregations represent temporal concentrations of potential prey that may be drivers of habitat use by predatory species, including sharks. We investigated movements of three species of sharks within a MCE and in relation to FSAs located on the shelf edge south of St. Thomas, United States Virgin Islands. Movements of 17 tiger (Galeocerdo cuvier, seven lemon (Negaprion brevirostris, and six Caribbean reef (Carcharhinus perezi sharks tagged with acoustic transmitters were monitored within the MCE using an array of acoustic receivers spanning an area of 1,060 km2 over a five year period. Receivers were concentrated around prominent grouper FSAs to monitor movements of sharks in relation to these temporally transient aggregations. Over 130,000 detections of telemetered sharks were recorded, with four sharks tracked in excess of 3 years. All three shark species were present within the MCE over long periods of time and detected frequently at FSAs, but patterns of MCE use and orientation towards FSAs varied both spatially and temporally among species. Lemon sharks moved over a large expanse of the MCE, but concentrated their activities around FSAs during grouper spawning and were present within the MCE significantly more during grouper spawning season. Caribbean reef sharks were present within a restricted portion of the MCE for prolonged periods of time, but were also absent for long periods. Tiger sharks were detected throughout the extent of the acoustic array, with the MCE representing only portion of their habitat use, although a high degree of individual variation was observed. Our findings indicate that although patterns of use varied, all three species of sharks repeatedly

Comparative Use of a Caribbean Mesophotic Coral Ecosystem and Association with Fish Spawning Aggregations by Three Species of Shark.

Science.gov (United States)

Pickard, Alexandria E; Vaudo, Jeremy J; Wetherbee, Bradley M; Nemeth, Richard S; Blondeau, Jeremiah B; Kadison, Elizabeth A; Shivji, Mahmood S

2016-01-01

Understanding of species interactions within mesophotic coral ecosystems (MCEs; ~ 30-150 m) lags well behind that for shallow coral reefs. MCEs are often sites of fish spawning aggregations (FSAs) for a variety of species, including many groupers. Such reproductive fish aggregations represent temporal concentrations of potential prey that may be drivers of habitat use by predatory species, including sharks. We investigated movements of three species of sharks within a MCE and in relation to FSAs located on the shelf edge south of St. Thomas, United States Virgin Islands. Movements of 17 tiger (Galeocerdo cuvier), seven lemon (Negaprion brevirostris), and six Caribbean reef (Carcharhinus perezi) sharks tagged with acoustic transmitters were monitored within the MCE using an array of acoustic receivers spanning an area of 1,060 km2 over a five year period. Receivers were concentrated around prominent grouper FSAs to monitor movements of sharks in relation to these temporally transient aggregations. Over 130,000 detections of telemetered sharks were recorded, with four sharks tracked in excess of 3 years. All three shark species were present within the MCE over long periods of time and detected frequently at FSAs, but patterns of MCE use and orientation towards FSAs varied both spatially and temporally among species. Lemon sharks moved over a large expanse of the MCE, but concentrated their activities around FSAs during grouper spawning and were present within the MCE significantly more during grouper spawning season. Caribbean reef sharks were present within a restricted portion of the MCE for prolonged periods of time, but were also absent for long periods. Tiger sharks were detected throughout the extent of the acoustic array, with the MCE representing only portion of their habitat use, although a high degree of individual variation was observed. Our findings indicate that although patterns of use varied, all three species of sharks repeatedly utilized the MCE and

Coastal oceanographic processes associated with blood cockle (Anadara granosa induce spawning season in Kapar, Selangor, Malaysia

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Hadzley Harith

2016-12-01

Full Text Available Study on coastal processes in Kapar waters was conducted from 2008–2016. The aim of this study is to identify potential blood cockle (Anadara granosa induce spawning ground based on physical intermittency. A total of 132 sampling stations were recorded. A thermal power station situated 2km away is discharging treated warm water (3m MSL which prevents cockle farmers from harvesting due to their maximum of 3m long hand dredge. Thus, this information could be useful for cockle sustainable management plan in near future.

Chinook salmon use of spawning patches: relative roles of habitat quality, size, and connectivity.

Science.gov (United States)

Isaak, Daniel J; Thurow, Russell F; Rieman, Bruce E; Dunham, Jason B

2007-03-01

Declines in many native fish populations have led to reassessments of management goals and shifted priorities from consumptive uses to species preservation. As management has shifted, relevant environmental characteristics have evolved from traditional metrics that described local habitat quality to characterizations of habitat size and connectivity. Despite the implications this shift has for how habitats may be prioritized for conservation, it has been rare to assess the relative importance of these habitat components. We used an information-theoretic approach to select the best models from sets of logistic regressions that linked habitat quality, size, and connectivity to the occurrence of chinook salmon (Oncorhynchus tshawytscha) nests. Spawning distributions were censused annually from 1995 to 2004, and data were complemented with field measurements that described habitat quality in 43 suitable spawning patches across a stream network that drained 1150 km2 in central Idaho. Results indicated that the most plausible models were dominated by measures of habitat size and connectivity, whereas habitat quality was of minor importance. Connectivity was the strongest predictor of nest occurrence, but connectivity interacted with habitat size, which became relatively more important when populations were reduced. Comparison of observed nest distributions to null model predictions confirmed that the habitat size association was driven by a biological mechanism when populations were small, but this association may have been an area-related sampling artifact at higher abundances. The implications for habitat management are that the size and connectivity of existing habitat networks should be maintained whenever possible. In situations where habitat restoration is occurring, expansion of existing areas or creation of new habitats in key areas that increase connectivity may be beneficial. Information about habitat size and connectivity also could be used to strategically

Hydraulic and water-quality data collection for the investigation of Great Lakes tributaries for Asian carp spawning and egg-transport suitability

Science.gov (United States)

Murphy, Elizabeth A.; Jackson, P. Ryan

2013-01-01

If the invasive Asian carps (bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix) migrate to the Great Lakes, in spite of the efforts to stop their advancement, these species will require the fast-flowing water of the Great Lakes tributaries for spawning and recruitment in order to establish a growing population. Two Lake Michigan tributaries (the Milwaukee and St. Joseph Rivers) and two Lake Erie tributaries (the Maumee and Sandusky Rivers) were investigated to determine if these tributaries possess the hydraulic and water-quality characteristics to allow successful spawning of Asian carps. To examine this issue, standard U.S. Geological Survey sampling protocols and instrumentation for discharge and water-quality measurements were used, together with differential global positioning system data for georeferencing. Non-standard data-processing techniques, combined with detailed laboratory analysis of Asian carp egg characteristics, allowed an assessment of the transport capabilities of each of these four tributaries. This assessment is based solely on analysis of observed data and did not utilize the collected data for detailed transport modeling.

Distribution of Po-210 and Pb-210 in Arctic Char (Salvelinus alpinus) from an Arctic freshwater lake

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Gwynn, J.P.; Rudolfsen, G. [Norwegian Radiation Protection Authority, The Fram Centre, Tromsoe (Norway)

2014-07-01

There is little information available with regard to the accumulation of Po-210 and Pb-210 by freshwater fish in natural freshwater systems despite the potential for relevant ingestion doses to man. This is maybe of particular pertinence for certain population groups where freshwater fish are an important dietary food item. Equally, it is important to understand the body distributions of these naturally occurring radionuclides to quantify the resulting doses to different tissues and organs of freshwater fish. With regard to the latter, it is important to consider not only the doses arising from bio-accumulated Po-210 and Pb-210 in various body compartments but additionally the internal dose from unabsorbed Po-210 and Pb-210 in the digestive tract. In this study, activity concentrations of Po-210 and Pb-210 were determined in muscle and various internal organs of Arctic Charr (Salvelinus alpinus) sampled from a lake in the Norwegian Arctic (69 deg. 4' N, 19 deg. 20' E). Observed activity concentrations of Po-210 and Pb-210 in different tissues will be discussed in relation to physiological parameters and ambient lake water activity concentrations. Results from this study will be compared to two similar studies conducted in freshwater systems where elevated activity concentrations of these radionuclides have been observed. Ingestion dose rates to man and effective absorbed dose rates to different tissues and organs of Arctic Charr from Po-210 and Pb-210 will be derived and compared to those from observed activity concentrations of the anthropogenic radionuclide Cs-137. (authors)

Spawning chronology, nest site selection and nest success of smallmouth bass during benign streamflow conditions

Science.gov (United States)

Dauwalter, D.C.; Fisher, W.L.

2007-01-01

We documented the nesting chronology, nest site selection and nest success of smallmouth bass Micropterus dolomieu in an upstream (4th order) and downstream (5th order) reach of Baron Fork Creek, Oklahoma. Males started nesting in mid-Apr. when water temperatures increased to 16.9 C upstream, and in late-Apr. when temperatures increased to 16.2 C downstream. Streamflows were low (77% upstream to 82% downstream of mean Apr. streamflow, and 12 and 18% of meanjun. streamflow; 47 and 55 y of record), and decreased throughout the spawning period. Larger males nested first upstream, as has been observed in other populations, but not downstream. Upstream, progeny in 62 of 153 nests developed to swim-up stage. Downstream, progeny in 31 of 73 nests developed to swim-up. Nesting densities upstream (147/km) and downstream (100/km) were both higher than any densities previously reported. Males selected nest sites with intermediate water depths, low water velocity and near cover, behavior that is typical of smallmouth bass. Documented nest failures resulted from human disturbance, angling, and longear sunfish predation. Logistic exposure models showed that water velocity at the nest was negatively related and length of the guarding male was positively related to nest success upstream. Male length and number of degree days were both positively related to nest success downstream. Our results, and those of other studies, suggest that biological factors account for most nest failures during benign (stable, low flow) streamflow conditions, whereas nest failures attributed to substrate mobility or nest abandonment dominate when harsh streamflow conditions (spring floods) coincide with the spawning season.

Hydroacoustics for the discovery and quantification of Nassau grouper ( Epinephelus striatus) spawning aggregations

Science.gov (United States)

Egerton, J. P.; Johnson, A. F.; Le Vay, L.; McCoy, C. M.; Semmens, B. X.; Heppell, S. A.; Turner, J. R.

2017-06-01

Fish spawning aggregations (FSAs) are vital life-history events that need to be monitored to determine the health of aggregating populations; this is especially true of the endangered Nassau grouper ( Epinephelus striatus). Hydroacoustics were used to locate Nassau grouper FSAs at sites on the west end of Little Cayman (LCW), and east ends of Grand Cayman (GCE) and Cayman Brac (CBE). Fish abundance and biomass at each FSA were estimated via echo integration and FSA extent. Acoustic mean fish abundance estimates (±SE) on the FSA at LCW (893 ± 459) did not differ significantly from concurrent SCUBA estimates (1150 ± 75). Mean fish densities (number 1000 m-3) were significantly higher at LCW (33.13 ± 5.62) than at the other sites (GCE: 7.01 ± 2.1, CBE: 4.61 ± 1.16). We investigate different acoustic post-processing options to obtain target strength (TS), and we examine the different TS to total length (TL) formulas available. The SCUBA surveys also provided measures of TL through the use of laser callipers allowing development of an in situ TS to TL formula for Nassau grouper at the LCW FSA. Application of this formula revealed mean fish TL was significantly higher at LCW (65.4 ± 0.7 cm) than GCE (60.7 ± 0.4 cm), but not CBE (61.1 ± 2.5 cm). Use of the empirical TS to TL formula resulted in underestimation of fish length in comparison with diver measurements, highlighting the benefits of secondary length data and deriving specific TS to TL formulas for each population. FSA location examined with reference to seasonal marine protected areas (Designated Grouper Spawning Areas) showed FSAs were partially outside these areas at GCE and very close to the boundary at CBE. As FSAs often occur at the limits of safe diving operations, hydroacoustic technology provides an alternative method to monitor and inform future management of aggregating fish species.

Perturbation in protein expression of the sterile salmonid hybrids between female brook trout Salvelinus fontinalis and male masu salmon Oncorhynchus masou during early spermatogenesis.

Science.gov (United States)

Zheng, Liang; Senda, Yoshie; Abe, Syuiti

2013-05-01

Most males and females of intergeneric hybrid (BM) between female brook trout (Bt) Salvelinus fontinalis and male masu salmon (Ms) Oncorhynchus masou had undeveloped gonads, with abnormal germ cell development shown by histological examination. To understand the cause of this hybrid sterility, expression profiles of testicular proteins in the BM and parental species were examined with 2-DE coupled with MALDI-TOF/TOF MS. Compared with the parental species, more than 60% of differentially expressed protein spots were down-regulated in BM. A total of 16 up-regulated and 48 down-regulated proteins were identified in BM. Up-regulated were transferrin and other somatic cell-predominant proteins, whereas down-regulated were some germ cell-specific proteins such as DEAD box RNA helicase Vasa. Other pronouncedly down-regulated proteins included tubulins and heat shock proteins that are supposed to have roles in spermatogenesis. The present findings suggest direct association of the observed perturbation in protein expression with the failure of spermatogenesis and the sterility in the examined salmonid hybrids. Copyright © 2013 Elsevier B.V. All rights reserved.

Using remotely sensed imagery and GIS to monitor and research salmon spawning: A case study of the Hanford Reach fall chinook (Oncorhynchus Tshawytscha)

International Nuclear Information System (INIS)

RH Visser

2000-01-01

The alteration of ecological systems has greatly reduced salmon populations in the Pacific Northwest. The Hanford Reach of the Columbia River, for example, is a component of the last ecosystem in eastern Washington State that supports a relatively healthy population of fall chinook salmon ([Oncorhynchus tshawytscha], Huntington et al. 1996). This population of fall chinook may function as a metapopulation for the Mid-Columbia region (ISG 1996). Metapopulations can seed or re-colonize unused habitat through the mechanism of straying (spawning in non-natal areas) and may be critical to the salmon recovery process if lost or degraded habitat is restored (i.e., the Snake, Upper Columbia, and Yakima rivers). For these reasons, the Hanford Reach fall chinook salmon population is extremely important for preservation of the species in the Columbia River Basin. Because this population is important to the region, non-intrusive techniques of analysis are essential for researching and monitoring population trends and spawning activities

Optimum swimming pathways of fish spawning migrations in rivers

Science.gov (United States)

McElroy, Brandon; DeLonay, Aaron; Jacobson, Robert

2012-01-01

Fishes that swim upstream in rivers to spawn must navigate complex fluvial velocity fields to arrive at their ultimate locations. One hypothesis with substantial implications is that fish traverse pathways that minimize their energy expenditure during migration. Here we present the methodological and theoretical developments necessary to test this and similar hypotheses. First, a cost function is derived for upstream migration that relates work done by a fish to swimming drag. The energetic cost scales with the cube of a fish's relative velocity integrated along its path. By normalizing to the energy requirements of holding a position in the slowest waters at the path's origin, a cost function is derived that depends only on the physical environment and not on specifics of individual fish. Then, as an example, we demonstrate the analysis of a migration pathway of a telemetrically tracked pallid sturgeon (Scaphirhynchus albus) in the Missouri River (USA). The actual pathway cost is lower than 105 random paths through the surveyed reach and is consistent with the optimization hypothesis. The implication—subject to more extensive validation—is that reproductive success in managed rivers could be increased through manipulation of reservoir releases or channel morphology to increase abundance of lower-cost migration pathways.

Mudpuppy (Necturus maculosus maculosus ) spatial distribution, breeding water depth, and use of artificial spawning habitat in the Detroit River

Science.gov (United States)

Craig, Jaquelyn M.; Mifsud, David A.; Briggs, Andrew S.; Boase, James C.; Kennedy, Gregory W.

2015-01-01

Mudpuppy (Necturus maculosus maculosus) populations have been declining in the Great Lakes region of North America. However, during fisheries assessments in the Detroit River, we documented Mudpuppy reproduction when we collected all life stages from egg through adult as by-catch in fisheries assessments. Ten years of fisheries sampling resulted in two occurrences of Mudpuppy egg collection and 411 Mudpuppies ranging in size from 37–392 mm Total Length, collected from water 3.5–15.1 m deep. Different types of fisheries gear collected specific life stages; spawning females used cement structures for egg deposition, larval Mudpuppies found refuge in eggmats, and we caught adults with baited setlines and minnow traps. Based on logistic regression models for setlines and minnow traps, there was a higher probability of catching adult Mudpuppies at lower temperatures and in shallower water with reduced clarity. In addition to documenting the presence of all life stages of this sensitive species in a deep and fast-flowing connecting channel, we were also able to show that standard fisheries research equipment can be used for Mudpuppy research in areas not typically sampled in herpetological studies. Our observations show that typical fisheries assessments and gear can play an important role in data collection for Mudpuppy population and spawning assessments.

Oceanic and atmospheric patterns during spawning periods prior to extreme catches of the Brazilian sardine (Sardinella brasiliensis in the southwest Atlantic

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Helena Cachanhuk Soares

2011-07-01

Full Text Available Relative maxima and minima of landings of Brazilian sardine captured in the Southeast Brazil Bight (SBB were compared with oceanic and atmospheric composites relative to the spawning period in December and January, prior to these landings. Atmospheric and oceanic variables such as wind stress, Ekman transport, mixing index, sea surface temperature (SST, precipitation, outgoing long wave radiation and geopotential height were analyzed, revealing distinct climatological patterns in the SBB for these extreme catches that have not been described before. The system could be characterized by cooler SST composite anomaly (SSTA along the SBB as a response to increased cloud cover and reduced incidence of short-wave radiation, predominating one year before the Brazilian sardine catch maxima. This system can take on a different configuration in which positive SSTA condition in the SBB is associated with a less intense South Atlantic Convergence Zone displaced southwards one year before the period of minimum catch. Our results indicate that the spatial structure of the spawning habitat is influenced by specific ocean-atmosphere interactions rather than simply resulting from the choice of a stable environment. This climatic constraint strongly affects the interannual variability of the Brazilian sardine production.

Does the Beach-Spawning Grunion Eat Its Own Eggs? Eighth Graders Use Inquiry-Based Investigation to Collect Real Data in a University Laboratory

Science.gov (United States)

Cavanagh, J. William; Martinez, Kimberly M.; Higgins, Benjamin A.; Horn, Michael H.

2014-01-01

A collaborative effort between a junior high school and a nearby university allowed 40 eighth-grade honors students to engage in a scientific investigation within a university laboratory. These students, with their science teachers and university researchers, gathered data on egg cannibalism in a beach-spawning fish and thereby contributed to an…

Role of cortisol in stocking density-induced changes in growth and metabolism of brook charr (Salvelinus fontinalis)

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Vijayan, M.M.

1990-01-01

Brook charr (Salvelinus fontinalis) held at high stocking density (SD) (120 kg/m{sup 3}) had a lower growth rate, food consumption and food conversion efficiency, and plasma thyroxine (T4) than those held at low SD (30 kg/m{sup 3}). SD had no effect on plasma triiodothyronine (T3) levels. Plasma cortisol levels in fish maintained at high SD were variable, being either lower with increased SD or not different from the low SD group. Head kidney tissue (containing the interrenal cells) preparations of brook charr held at high SD showed a higher spontaneous cortisol secretion rate. There was no difference in the clearance rate of ({sup 3}H)-cortisol from plasma, but liver from fish held at high SD showed higher cortisol uptake and catabolism, indicative of altered hepatic metabolic activity. High SD appears to alter the energy metabolism of brook charr. This was evident from significant changes between densities in levels of metabolites (plasma glucose and liver glycogen) and activities of key hepatic enzymes (PFK, HK, FBPase, G6PDH, HOAD, GK and G3PDH). These results suggests that high SD has the effect of mobilizing triglycerides, and promoting gluconeogenesis from glycerol, but has little effect on protein metabolism. When cortisol was administered to brook charr in the form of slow release intraperitoneal implants, the metabolic changes evident were similar to those observed in fish held at high SD. There was no consistent increase in plasma cortisol levels of cortisol implanted fish over a 90 day period. Nevertheless, there were significant effects, apparently cortisol-related, on certain metabolite levels (plasma glycerol, plasma glucose, hepatic glycogen), and activities of key hepatic enzymes.

Ocean acidification affects fish spawning but not paternity at CO2 seeps.

Science.gov (United States)

Milazzo, Marco; Cattano, Carlo; Alonzo, Suzanne H; Foggo, Andrew; Gristina, Michele; Rodolfo-Metalpa, Riccardo; Sinopoli, Mauro; Spatafora, Davide; Stiver, Kelly A; Hall-Spencer, Jason M

2016-07-27

Fish exhibit impaired sensory function and altered behaviour at levels of ocean acidification expected to occur owing to anthropogenic carbon dioxide emissions during this century. We provide the first evidence of the effects of ocean acidification on reproductive behaviour of fish in the wild. Satellite and sneaker male ocellated wrasse (Symphodus ocellatus) compete to fertilize eggs guarded by dominant nesting males. Key mating behaviours such as dominant male courtship and nest defence did not differ between sites with ambient versus elevated CO2 concentrations. Dominant males did, however, experience significantly lower rates of pair spawning at elevated CO2 levels. Despite the higher risk of sperm competition found at elevated CO2, we also found a trend of lower satellite and sneaker male paternity at elevated CO2 Given the importance of fish for food security and ecosystem stability, this study highlights the need for targeted research into the effects of rising CO2 levels on patterns of reproduction in wild fish. © 2016 The Author(s).

Effect of stress during handling, seawater acclimation, confinement, and induced spawning on plasma ion levels and somatolactin-expressing cells in mature female Liza ramada.

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Khalil, Noha A; Hashem, Amal M; Ibrahim, Amal A E; Mousa, Mostafa A

2012-08-01

The present experiments were designed to determine the effect of different stress factors; handling, seawater acclimation, confinement, and induced spawning on plasma cortisol, hydro mineral balance as well as changes in size, number and integrated intensity of somatolactin (SL)-expressing cells in Liza ramada mature females confined to fresh water ponds. The plasma levels of cortisol, PO(4)(3-), Na(+), and K(+) were higher, while Ca(2+) and Mg(2+) were lower than controls during transportation without anesthesia. By using clove oil (5 mg L(-1)) as an anesthetic during transportation, the plasma cortisol, PO(4) (3-), Na(+), and K(+) were similar to controls, while Ca(2+) and Mg(2+) were higher. During seawater acclimation, the plasma cortisol and minerals were significantly higher except Na(+) which was lower than controls. In addition, during induction of spawning, the plasma levels of cortisol, PO(4)(3-), Na(+), K(+), and Mg(2+) were significantly higher than controls. The SL-producing cells are located in the pars intermedia (PI) bordering the neurohypophysis. The stress affected the number, size, and immunostaining of SL-expressing cells. During seawater acclimation, the size and the integrated intensity of SL immunoreactivity were lower, but the number of these cells was higher than controls. Furthermore, the number, size, and the integrated intensity of SL immunoreactivity were significantly lower than controls during handling and after spawning, which was opposite to confinement. The response of SL-expressing cells in PI in parallel with changes in cortisol and hydro mineral balance induced by stress support the possible role of SL in the adaptive response of fish to stress. © 2012 WILEY PERIODICALS, INC.

Variability in stream discharge and temperature: a preliminary assessment of the implications for juvenile and spawning Atlantic salmon

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D. Tetzlaff

2005-01-01

Full Text Available This study focuses on understanding the temporal variability in hydrological and thermal conditions in a small mountain stream and its potential implication for two life stages of Atlantic salmon (Salmo salar – stream resident juveniles and returning adult spawners. Stream discharge and temperature in the Girnock Burn, NE Scotland, were characterised over ten hydrological years (1994/1995–2003/2004. Attention was focussed on assessing variations during particular ecologically 'sensitive' time periods when selected life-stages of salmon behaviour may be especially influenced by hydrological and thermal conditions. Empirical discharge data were used to derive hydraulic parameters to predict the Critical Displacement Velocity (CDV of juvenile salmon. This is the velocity above which fish may no longer be able to hold station in the water column and thus can be used as an index of time periods where feeding behaviour might be constrained. In the Girnock Burn, strong inter- and intra-annual variability in hydrological and thermal conditions may have important implications for feeding opportunities for juvenile fish; both during important growth periods in late winter and early spring, and the emergence of fry in the late spring. Time periods when foraging behaviour of juvenile salmon may be constrained by hydraulic conditions were assessed as the percentage time when CDV for 0+ and 1+ fish were exceeded by mean daily stream velocities. Clear seasonal patterns of CDV were apparent, with higher summer values driven by higher stream temperatures and fish length. Inter-annual variability in the time when mean stream velocity exceeded CDV for 0+ fish ranged between 29.3% (1997/1998 and 44.7% (2000/2001. For 1+ fish mean stream velocity exceeded CDV between 14.5% (1997/1998 and 30.7% (2000/2001 of the time. The movement of adult spawners into the Girnock Burn in preparation for autumn spawning (late October to mid-November exhibited a complex

Determining Adult Pacific Lamprey Abundance and Spawning Habitat in the Lower Deschutes River Sub-Basin, Oregon, 2008 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Fox, Matt; Graham, Jennifer C. [Confederated Tribes of the Warm Springs Reservation, Oregon

2009-04-30

An adult Pacific lamprey (Lampetra tridentata) escapement estimate was generated in the lower Deschutes River during run year 2008. This included a mark-recapture study to determine adult abundance and a tribal subsistence creel. Fish measuring less than 10.5 cm received two marks for the mark-recapture estimate while those measuring greater than 10.5 cm were surgically implanted with radio transmitters to monitor migration upstream of Sherars Falls (rkm 70.4). Radio telemetry was used to determine habitat, focal spawning areas and spawn timing. All fish were collected at the Sherars Falls fish ladder from July-October 2008 using a long handled dip-net. Escapement was generated using a two event mark-recapture experiment. Adult lamprey populations were estimated at 3,471 (95% CI = 2,384-5,041; M = 101; C = 885 R = 25) using Chapman's modification of the Peterson estimate. The relative precision around the estimate was 31.42. Tribal harvest was approximately 806 adult lamprey (95% CI = +/- 74) with a total escapement of 2,669. Fourteen lamprey received radio tags and were released at Lower Blue Hole recreation site (rkm 77.3). Movement was recorded by mobile, fixed site and aerial telemetry methods. Upstream movements of lamprey were documented from July through December 2008 with most lamprey over-wintering in the mainstem Deschutes River.

Chinook salmon use of spawning patches: Relative roles of habitat quality, size, and connectivity

Science.gov (United States)

Isaak, D.J.; Thurow, R.F.; Rieman, B.E.; Dunham, J.B.

2007-01-01

Declines in many native fish populations have led to reassessments of management goals and shifted priorities from consumptive uses to species preservation. As management has shifted, relevant environmental characteristics have evolved from traditional metrics that described local habitat quality to characterizations of habitat size and connectivity. Despite the implications this shift has for how habitats may be prioritized for conservation, it has been rare to assess the relative importance of these habitat components. We used an information-theoretic approach to select the best models from sets of logistic regressions that linked habitat quality, size, and connectivity to the occurrence of chinook salmon (Oncorhynchus tshawytscha) nests. Spawning distributions were censused annually from 1995 to 2004, and data were complemented with field measurements that described habitat quality in 43 suitable spawning patches across a stream network that drained 1150 km 2 in central Idaho. Results indicated that the most plausible models were dominated by measures of habitat size and connectivity, whereas habitat quality was of minor importance. Connectivity was the strongest predictor of nest occurrence, but connectivity interacted with habitat size, which became relatively more important when populations were reduced. Comparison of observed nest distributions to null model predictions confirmed that the habitat size association was driven by a biological mechanism when populations were small, but this association may have been an area-related sampling artifact at higher abundances. The implications for habitat management are that the size and connectivity of existing habitat networks should be maintained whenever possible. In situations where habitat restoration is occurring, expansion of existing areas or creation of new habitats in key areas that increase connectivity may be beneficial. Information about habitat size and connectivity also could be used to strategically

The diet of introduced brook trout (Salvelinus fontinalis; Mitchill, 1814 in an alpine area and a literature review on its feeding ecology

Directory of Open Access Journals (Sweden)

Rocco Tiberti

2016-05-01

Full Text Available Introduced fish are a major threat for high altitude aquatic habitats and Salvelinus fontinalis have been widely used throughout the Alps for stocking lakes and rivers. Understanding its feeding ecology is a basic, but essential tool for interpreting its impact. To assess which factors determine the diet of S. fontinalis we analyzed more than 500 stomachs from several introduced populations from the Gran Paradiso National Park (GPNP, Western Italian Alps and we measured the availability of several prey groups (zooplankton, aquatic invertebrates, terrestrial invertebrates. We complemented the study with a short, but exhaustive literature review on the S. fontinalis feeding ecology. In general the food composition reflected the availability of prey -confirming that S. fontinalis is an opportunistic predator- and was influenced by habitat type (stream vs lake, fish size, and seasonality. The obtained results were discussed in the light of the existing literature on the feeding ecology and ecological impact of S. fontinalis. Large benthonic insects account for a substantial part of  the diet of stream dwelling brook trout, while they are almost absent both in the diet and in the prey species pool of lake-dwelling brook trout, probably reflecting a stronger ecological impact in the lakes.

Effectiveness of egg immersion in aqueous solutions of thiamine and thiamine analogs for reducing early mortality syndrome

Science.gov (United States)

Brown, S.B.; Brown, L.R.; Brown, M.; Moore, K.; Villella, M.; Fitzsimons, J.D.; Williston, B.; Honeyfield, D.C.; Hinterkopf, J.P.; Tillitt, D.E.; Zajicek, J.L.; Wolgamood, M.

2005-01-01

Protocols used for therapeutic thiamine treatments in salmonine early mortality syndrome (EMS) were investigated in lake trout Salvelinus namaycush and coho salmon Oncorhynchus kisutch to assess their efficacy. At least 500 mg of thiamine HCl/L added to egg baths was required to produce a sustained elevation of thiamine content in lake trout eggs. Thiamine uptake from egg baths was not influenced by a pH ranging from 5.5 to 7.5 or by a water hardness between 2 and 200 mg CaCO3/L. There was poorer thiamine uptake when initial thiamine levels were low, suggesting that current treatment regimes may not be as effective when thiamine levels are severely depressed and that higher treatment doses are necessary. Exposure of eggs to the more lipid-soluble thiamine analog allithiamine (1,000 mg/L) during water hardening increased egg thiamine levels by 1.5-2.5 nmol/g and was completely effective at reversing EMS. Another more lipid-soluble thiamine analog, benfotiamine (100 mg/L), reduced EMS but did not produce detectable increases in egg thiamine content. Although benfotiamine may be more effective than thiamine at mitigating EMS, it is more expensive than thiamine HCl or allithiamine. In addition, there still needs to be a more thorough examination of dose-response relationships. We conclude that allithiamine is an alternative to the use of thiamine in egg baths as a therapeutic treatment for salmonid EMS. ?? Copyright by the American Fisheries Society 2005.

Seasonal patterns in growth, blood consumption, and effects on hosts by parasitic-phase sea lampreys in the Great Lakes: an individual-based model approach

Science.gov (United States)

Madenjian, Charles P.; Cochran, Philip A.; Bergstedt, Roger A.

2003-01-01

An individual-based model (IBM) was developed for sea lamprey (Petromyzon marinus) populations in the Laurentian Great Lakes. The IBM was then calibrated to observed growth, by season, for sea lampreys in northern Lake Huron under two different water temperature regimes: a regime experienced by Seneca-strain lake trout (Salvelinus namaycush) and a regime experienced by Marquettestrain lake trout. Modeling results indicated that seasonal blood consumption under the Seneca regime was very similar to that under the Marquette regime. Simulated mortality of lake trout directly due to blood removal by sea lampreys occurred at nearly twice the rate during August and September under the Marquette regime than under the Seneca regime. However, cumulative sea lamprey-induced mortality on lake trout over the entire duration of the sea lamprey's parasitic phase was only 7% higher for the Marquette regime compared with the Seneca regime. Thus, these modeling results indicated that the strain composition of the host (lake trout) population was not important in determining total number of lake trout deaths or total blood consumption attributable to the sea lamprey population, given the sea lamprey growth pattern. Regardless of water temperature regime, both blood consumption rate by sea lampreys and rate of sea lamprey-induced mortality on lake trout peaked in late October. Elevated blood consumption in late October appeared to be unrelated to changes in water temperature. The IBM approach should prove useful in optimizing control of sea lampreys in the Laurentian Great Lakes.

Effects of exotic species on Yellowstone's grizzly bears

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Reinhart, Daniel P.; Haroldson, Mark A.; Mattson, D.J.; Gunther, Kerry A.

2001-01-01

Humans have affected grizzly bears (Ursus arctos horribilis) by direct mortality, competition for space and resources, and introduction of exotic species. Exotic organisms that have affected grizzly bears in the Greater Yellowstone Area include common dandelion (Taraxacum officinale), nonnative clovers (Trifolium spp.), domesticated livestock, bovine brucellosis (Brucella abortus), lake trout (Salvelinus namaycush), and white pine blister rust (Cronartium ribicola). Some bears consume substantial amounts of dandelion and clover. However, these exotic foods provide little digested energy compared to higher-quality bear foods. Domestic livestock are of greater energetic value, but use of this food by bears often leads to conflicts with humans and subsequent increases in bear mortality. Lake trout, blister rust, and brucellosis diminish grizzly bears foods. Lake trout prey on native cutthroat trout (Oncorhynchus clarkii) in Yellowstone Lake; white pine blister rust has the potential to destroy native whitebark pine (Pinus albicaulis) stands; and management response to bovine brucellosis, a disease found in the Yellowstone bison (Bison bison) and elk (Cervus elaphus), could reduce populations of these 2 species. Exotic species will likely cause more harm than good for Yellowstone grizzly bears. Managers have few options to mitigate or contain the impacts of exotics on Yellowstone's grizzly bears. Moreover, their potential negative impacts have only begun to unfold. Exotic species may lead to the loss of substantial highquality grizzly bear foods, including much of the bison, trout, and pine seeds that Yellowstone grizzly bears currently depend upon.

Impact of thiamine deficiency on T-cell dependent and T-cell independent antibody production in lake trout

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Ottinger, Christopher A.; Honeyfield, Dale C.; Densmore, Christine L.; Iwanowicz, Luke R.

2012-01-01

Lake trout Salvelinus namaycush on thiamine-replete and thiamine-depleted diets were evaluated for the effects of thiamine status on in vivo responses to the T-dependent antigen trinitophenol (TNP)-keyhole limpet hemocyanin (TNP-KLH), the T-independent antigen trinitrophenol-lipolysaccaharide (TNP-LPS), or Dulbecco's phosphate-buffered saline (DPBS; negative control fish). Plasma antibody concentrations were evaluated for possible differences in total anti-TNP activity as well as differences in response kinetics. Associations between anti-TNP activity and muscle and liver thiamine concentrations as well as ratios of muscle-to-liver thiamine to anti-TNP activity were also examined. Thiamine-depleted lake trout that were injected with TNP-LPS exhibited significantly more anti-TNP activity than thiamine-replete fish. The depleted fish injected with TNP-LPS also exhibited significantly different response kinetics relative to thiamine-replete lake trout. No differences in activity or kinetics were observed between the thiamine-replete and -depleted fish injected with TNP-KLH or in the DPBS negative controls. Anti-TNP activity in thiamine-depleted lake trout injected with TNP-KLH was positively associated with muscle thiamine pyrophosphate (thiamine diphosphate; TPP) concentration. A negative association was observed between the ratio of muscle-to-liver TPP and T-independent responses. No significant associations between anti-TNP activity and tissue thiamine concentration were observed in the thiamine-replete fish. We demonstrated that thiamine deficiency leads to alterations in both T-dependent and T-independent immune responses in lake trout.

Impact of thiamine deficiency on T-cell dependent and T-cell independent antibody production in lake trout.

Science.gov (United States)

Ottinger, Christopher A; Honeyfield, Dale C; Densmore, Christine L; Iwanowicz, Luke R

2012-12-01

Lake trout Salvelinus namaycush on thiamine-replete and thiamine-depleted diets were evaluated for the effects of thiamine status on in vivo responses to the T-dependent antigen trinitophenol (TNP)-keyhole limpet hemocyanin (TNP-KLH), the T-independent antigen trinitrophenol-lipolysaccaharide (TNP-LPS), or Dulbecco's phosphate-buffered saline (DPBS; negative control fish). Plasma antibody concentrations were evaluated for possible differences in total anti-TNP activity as well as differences in response kinetics. Associations between anti-TNP activity and muscle and liver thiamine concentrations as well as ratios of muscle-to-liver thiamine to anti-TNP activity were also examined. Thiamine-depleted lake trout that were injected with TNP-LPS exhibited significantly more anti-TNP activity than thiamine-replete fish. The depleted fish injected with TNP-LPS also exhibited significantly different response kinetics relative to thiamine-replete lake trout. No differences in activity or kinetics were observed between the thiamine-replete and -depleted fish injected with TNP-KLH or in the DPBS negative controls. Anti-TNP activity in thiamine-depleted lake trout injected with TNP-KLH was positively associated with muscle thiamine pyrophosphate (thiamine diphosphate; TPP) concentration. A negative association was observed between the ratio of muscle-to-liver TPP and T-independent responses. No significant associations between anti-TNP activity and tissue thiamine concentration were observed in the thiamine-replete fish. We demonstrated that thiamine deficiency leads to alterations in both T-dependent and T-independent immune responses in lake trout.

Effect of rearing density on poststocking survival of lake trout in Lake Ontario

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Elrod, Joseph H.; Ostergaard, David E.; Schneider, Clifford P.

1989-01-01

Six paired lots of yearling lake trout (Salvelinus namaycush) reared at densities of 41,000 and 51,000 fish per raceway during their last 9 months in the hatchery were stocked in Lake Ontario. Poststocking survival of the high-density (HD) and low-density (LD) fish was not different for the 1982 year-class. However, for the 1983 year-class, mean survival was significantly different between HD and LD fish (P Mean survival of HD fish was only 76% that of LD fish (P Mean size at stocking was not different for HD and LD fish of the 1982 year-class, but for the 1983 year-class, the LD fish were 6% longer and 22% heavier than the HD fish. Mean lengths and weights of LD and HD fish were not different in samples collected in Lake Ontario at age 2 and older. Size at stocking was not likely the factor that caused the difference in survival. Rather, the rearing conditions (probably water exchange rate in relation to number of fish in the raceway) that resulted in slower growth of the HD fish of the 1983 year-class also caused them to be poorer physiologically than the LD fish. The number of yearling lake trout per rearing unit that will result in maximum contribution to populations in the Great Lakes after stocking may be lower than the rearing densities customarily used at some hatcheries.

Particle-tracking investigation of the retention of sucker larvae emerging from spawning grounds in Upper Klamath Lake, Oregon

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Wood, Tamara M.; Wherry, Susan A.; Simon, David C.; Markle, Douglas F.

2014-01-01

This study had two objectives: (1) to use the results of an individual-based particle-tracking model of larval sucker dispersal through the Williamson River delta and Upper Klamath Lake, Oregon, to interpret field data collected throughout Upper Klamath and Agency Lakes, and (2) to use the model to investigate the retention of sucker larvae in the system as a function of Williamson River flow, wind, and lake elevation. This is a follow-up study to work reported in Wood and others (2014) in which the hydrodynamic model of Upper Klamath Lake was combined with an individual-based, particle-tracking model of larval fish entering the lake from spawning areas in the Williamson River. In the previous study, the performance of the model was evaluated through comparison with field data comprising larval sucker distribution collected in 2009 by The Nature Conservancy, Oregon State University (OSU), and the U.S. Geological Survey, primarily from the (at that time) recently reconnected Williamson River Delta and along the eastern shoreline of Upper Klamath Lake, surrounding the old river mouth. The previous study demonstrated that the validation of the model with field data was moderately successful and that the model was useful for describing the broad patterns of larval dispersal from the river, at least in the areas surrounding the river channel immediately downstream of the spawning areas and along the shoreline where larvae enter the lake. In this study, field data collected by OSU throughout the main body of Upper Klamath Lake, and not just around the Williamson River Delta, were compared to model simulation results. Because the field data were collected throughout the lake, it was necessary to include in the simulations larvae spawned at eastern shoreline springs that were not included in the earlier studies. A complicating factor was that the OSU collected data throughout the main body of the lake in 2011 and 2012, after the end of several years of larval drift

pH preference and avoidance responses of adult brook trout Salvelinus fontinalis and brown trout Salmo trutta.

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Fost, B A; Ferreri, C P

2015-03-01

The pH preferred and avoided by wild, adult brook trout Salvelinus fontinalis and brown trout Salmo trutta was examined in a series a laboratory tests using gradual and steep-gradient flow-through aquaria. The results were compared with those published for the observed segregation patterns of juvenile S. fontinalis and S. trutta in Pennsylvania streams. The adult S. trutta tested showed a preference for pH 4·0 while adult S. fontinalis did not prefer any pH within the range tested. Salmo trutta are not found in Pennsylvania streams with a base-flow pH < 5·8 which suggests that S. trutta prefer pH well above 4·0. Adult S. trutta displayed a lack of avoidance at pH below 5·0, as also reported earlier for juveniles. The avoidance pH of wild, adult S. fontinalis (between pH 5·5 and 6·0) and S. trutta (between pH 6·5 and 7·0) did not differ appreciably from earlier study results for the avoidance pH of juvenile S. fontinalis and S. trutta. A comparison of c.i. around these avoidance estimates indicates that avoidance pH is similar among adult S. fontinalis and S. trutta in this study. The limited overlap of c.i. for avoidance pH values for the two species, however, suggests that some S. trutta will display avoidance at a higher pH when S. fontinalis will not. The results of this study indicate that segregation patterns of adult S. fontinalis and S. trutta in Pennsylvania streams could be related to pH and that competition with S. trutta could be mediating the occurrence of S. fontinalis at some pH levels. © 2015 The Fisheries Society of the British Isles.

17beta-estradiol induced vitellogenesis is inhibited by cortisol at the post-transcriptional level in Arctic char (Salvelinus alpinus

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Modig Carina

2004-09-01

Full Text Available Abstract This study was performed to investigate stress effects on the synthesis of egg yolk precursor, vitellogenin (Vtg in Arctic char (Salvelinus alpinus. In particular the effect of cortisol (F was determined since this stress hormone has been suggested to interfere with vitellogenesis and is upregulated during sexual maturation in teleosts. Arctic char Vtg was purified and polyclonal antibodies were produced in order to develop tools to study regulation of vitellogenesis. The Vtg antibodies were used to develop an enzyme-linked immunosorbent assay. The corresponding Vtg cDNA was cloned from a hepatic cDNA library in order to obtain DNA probes to measure Vtg mRNA expression. Analysis of plasma from juvenile Arctic char, of both sexes, exposed to different steroids showed that production of Vtg was induced in a dose dependent fashion by 17β-estradiol (E2, estrone and estriol. Apart from estrogens a high dose of F also upregulated Vtg. In addition, F, progesterone (P and tamoxifen were tested to determine these compounds ability to modulate E2 induced Vtg synthesis at both the mRNA and protein level. Tamoxifen was found to inhibit E2 induced Vtg mRNA and protein upregulation. P did not alter the Vtg induction while F reduced the Vtg protein levels without affecting the Vtg mRNA levels. Furthermore the inhibition of Vtg protein was found to be dose dependent. Thus, the inhibitory effect of F on Vtg appears to be mediated at the post-transcriptional level.

Fine-scale population structure and riverscape genetics of brook trout (Salvelinus fontinalis) distributed continuously along headwater channel networks

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Kanno, Yoichiro; Vokoun, Jason C.; Letcher, Benjamin H.

2011-01-01

Linear and heterogeneous habitat makes headwater stream networks an ideal ecosystem in which to test the influence of environmental factors on spatial genetic patterns of obligatory aquatic species. We investigated fine-scale population structure and influence of stream habitat on individual-level genetic differentiation in brook trout (Salvelinus fontinalis) by genotyping eight microsatellite loci in 740 individuals in two headwater channel networks (7.7 and 4.4 km) in Connecticut, USA. A weak but statistically significant isolation-by-distance pattern was common in both sites. In the field, many tagged individuals were recaptured in the same 50-m reaches within a single field season (summer to fall). One study site was characterized with a hierarchical population structure, where seasonal barriers (natural falls of 1.5–2.5 m in height during summer base-flow condition) greatly reduced gene flow and perceptible spatial patterns emerged because of the presence of tributaries, each with a group of genetically distinguishable individuals. Genetic differentiation increased when pairs of individuals were separated by high stream gradient (steep channel slope) or warm stream temperature in this site, although the evidence of their influence was equivocal. In a second site, evidence for genetic clusters was weak at best, but genetic differentiation between individuals was positively correlated with number of tributary confluences. We concluded that the population-level movement of brook trout was limited in the study headwater stream networks, resulting in the fine-scale population structure (genetic clusters and clines) even at distances of a few kilometres, and gene flow was mitigated by ‘riverscape’ variables, particularly by physical barriers, waterway distance (i.e. isolation-by-distance) and the presence of tributaries.

Spawning of the chilean hake (Merluccius gayi in the upwelling system off Talcahuano in relation to oceanographic features

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Cristian A. Vargas

2001-06-01

Full Text Available Previous studies have shown that the upwelling area off Talcahuano, in central-south Chile, is an important spawning zone for the hake Merluccius gayi. We document the results of a study designed to assess the importance of oceanographic features on the horizontal and vertical distribution of hake eggs and larvae. Ichthyoplankton samples and oceanographic data (CTDO casts, and wind speed and direction were collected during a cruise carried out off Talcahuano (36º22´S-37º10´S in early spring (October 1996, which included a grid of 61 stations up to 60 nm offshore. The oceanographic information obtained revealed the presence of an upwelling plume at Lavapie Point (southern zone extending northward over the shelf, and the presence of a warmer water parcel close to shore in the northern area. Peak egg densities occurred in this northern area over the shelf, in a nucleus located at the shoreward moving deeper layer (40-100 m deep and associated with the upwelling front about 20-30 nm from shore. The highest larval abundance also occurred in the northern area over the shelf and in the deeper layer but closer to shore than the egg nucleus. Because the timing (early spring and location of spawning (at depth, over the shelf and in association with frontal structures are also shared by other hake species in upwelling areas, we propose that they may be part of a more commonly developed strategy to enhance offspring survival in coastal upwelling areas of eastern boundary currents.

Comparison of the Northeast Arctic cod year class strength (at the age of 3+) with the SST anomalies in main spawning ground (the Norwegian Shelf Waters) by results of analysis satellite monitoring data during last years.

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Vanyushin, George

2015-04-01

Continuous long-term database (1998-2014) on the sea surface temperature (SST) comprising results of regional satellite monitoring (the Norwegian and the Barents seas) is used to resolve several applied problems. Authors have analyzed indirect influence the SST (the NOAA satellite data) on modern cod total stock biomass (abundance of the Northeast Arctic cod at age 3+). In this study, we went on the consideration of the relationship between the SST anomalies for March-April in the main spawning ground of the cod off the Lofoten islands in the Norwegian Shelf Waters and forecasting assessment of future cod generation success and its future abundance of 3 year old. Mean monthly SST and SST anomalies are computed for the selected area on the basis of the weekly SST maps which made by using the NOAA satellites data for the period 1998-2014. Comparison of the SST anomalies in the main spawning ground with abundance of the cod year class at age 3+ shows that survival of the cod generations was inhibited on the whole as negative (below -0,1C) well as positive SST anomalies (above +1,3C) during March and April. Finally, the results indicate that poor and low middle generations of cod at age 3+ (2002, 2004, 2010) occurred in years with negative or extremely high positive the SST anomalies in the spawning area. The SST anomalies in years which were close to normal significances provide conditions for appearance middle or strong generations of cod (2001-2003, 2005-2009, 2011-2013). So, the SST and SST anomalies (by the NOAA satellite data) characterize of increase in input of warm Atlantic waters which form numerous eddies along the main stream thus creating favorable conditions for spawning and development of the cod larvae and fry and provide them with food stock, finally direct influence on forming total stock biomass of cod and helping its population forecast. Key words: satellite monitoring of SST, the Northeast Arctic cod, spawning ground, forecast of the cod year class

Using of gamma rays in stimulation and improvement of mushroom spawns plerotus ostreatus

International Nuclear Information System (INIS)

Hussein, O.S.; Atia, A.I.

2009-01-01

The objective of this work was activation and stimulation of plerotus ostreatus growth and increasing their yields by using of gamma rays, in addition to improvement of mushroom quality and shelf life.Exposing plerotus ostreatus to different doses of gamma rays 2.5, 5, 10 and 15 Gy to determine some of the basic composition of mushroom fruits achieved significant increase in yields and basic composition of resulted mushrooms. Also, increase in carbohydrates content, most of amino acids content and fatty acids content, mainly unsaturated fatty acid i.e., (C 16:1) and (C 18:1,2), which are essential for human nutrition as antioxidant. Whereas, there was a significant decrease in the total phenols content of the resulted fruits, which affected the quality and shelf life of mushroom fruits. All gamma rays doses used increased mushroom yield in fresh and dry wt basis. The recommended dose for spawn irradiation was 10 Gy to increase mushroom yields and its chemical components

Tracing Dietary Mercury Histochemically, with Autometallography, through the Liver to the Ovaries and Spawned Eggs of the Spot, a Temperate Coastal Marine Fish.

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Govoni, John J; Morris, James A; Evans, David W

2017-09-01

Exposure to mercury (Hg) results in reproductive abnormalities and deficiencies in female fish. We traced the maternal assimilation and redistribution of dietary inorganic (HgII) and organic (MeHg) forms of Hg in a coastal marine fish, the Spot Leiostomus xanthurus. We conducted a 90-d laboratory experiment in which treatment Spot were fed muscle of Blue Marlin Makaira nigricans with elevated concentrations of Hg mixed with a commercial fish food, while control Spot were fed only commercial food pellets. Gonadal maturation was induced by shortening the photoperiod and increasing the temperature. Spawning was induced by intramuscular injection of human chorionic gonadotropin at 100 IU/kg. Solid-sampling atomic absorption spectrophotometry measured the total Hg (THg), HgII, and MeHg in Blue Marlin muscle. Autometallography located Hg-sulfide granules in the liver, ovaries, and spawned eggs, and densitometry provided comparisons of Hg-sulfide granules in the ovaries of treatment and control Spot. Overall, the intensity and prevalence of Hg-sulfide granules were greater in the liver, ovaries, and eggs from treatment Spot than in those from controls. The tissue and cellular distribution of Hg-sulfide granules differed. Received November 18, 2016; accepted June 18, 2017.

Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

Science.gov (United States)

Peterson, D.P.; Rieman, B.E.; Dunham, J.B.; Fausch, K.D.; Young, M.K.

2008-01-01

Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropriate action. We developed a Bayesian belief network as a tool for such analyses. We focused on native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative brook trout (Salvelinus fontinalis) and considered the environmental factors influencing both species, their potential interactions, and the effects of isolation on the persistence of local cutthroat trout populations. The trade-offs between isolation and invasion were strongly influenced by size and habitat quality of the stream network to be isolated and existing demographic linkages within and among populations. An application of the model in several sites in western Montana (USA) showed the process could help clarify management objectives and options and prioritize conservation actions among streams. The approach can also facilitate communication among parties concerned with native salmonids, nonnative fish invasions, barriers and intentional isolation, and management of the associated habitats and populations. ?? 2008 NRC.

Aspectos da biologia reprodutiva de fêmeas de Etropus longimanus Norman, 1933 (Bothidae da região de Cabo Frio, Rio de Janeiro: 1. Tamanho da primeira maturação, tipo e época de desova Reproductive bioIogy aspects of female Etropus longimanus Norman, 1933 (Bothldae In cabo Frio region, Rio de Janeiro: 1. Mean size at frist spawning, of type of spawning and sapwning seasons

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Adriana Miguel Saad

1992-01-01

Full Text Available Durante o período de novembro de 1986 a outubro de 1988 foram realizados estudos sobre a ictiofauna demersal na região de ocorrência do fenômeno da ressurgência em Cabo Frio, pelo Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM. A partir de coletas mensais da ictiofauna, efetuadas com arrasto de porta, e da água, para a obtenção dos valores da temperatura, constatou-se a abundância de Etropus longimanus na região. Foram obtidas 653 fêmeas, em diferentes tamanhos e fases de desenvolvimento gonadal, o que nos permitiu a realização de um estudo sobre alguns aspectos da biologia reprodutiva desta espécie, como o tamanho da primeira maturação, o tipo de desova e a época de reprodução na região. Estimou-se um comprimento padrão médio em que a população das fêmeas apresentam 50% de probabilidade de estarem sexualmente maduras, de 75 mm; e o comprimento padrão médio em que todas estão aptas à reprodução, de 95 mm. Verificou-se que E. longimanus apresenta um desenvolvimento ovacitório sincrónico em mais de dois grupos, sugerindo a ocorrência de desova múltipla. Os resultados obtidos indicaram que a desova ocorreu desde o final da primavera, até o início do outono, com picos máximos no verão, quando registrou-se os valores da temperatura da água entre 13,3ºC a 18.7ºC, época predominante de ressurgência na região.As part of upwelling ecosystem project of the Cabo Frio region, 653 female of E. longimanus were obtained by monthly sampling from November 1986 to October 1988. Histological analyses were done in order to verify the type of spawning. Mean size at first spawning and the spawning season was determined The results indicate that mean size at first maturation is 75 mm standard length and all females were ready for reproduction at 95 mm Multiple spawning for the species was estimated, occurring from end of spring until the beginning of Fall, with peak spawning summer at water temperature between

The abiotic environment of the interstitial of a small Swiss river in the foothills of the Alps and its influence on gravel spawning brown trout (Salmo trutta L.)

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Schindler, Yael; Michel, Christian; Holm, Patricia; Alewell, Christine

2010-05-01

The hyporheic zone can be characterized by multiple abiotic parameters (e.g. bulk density, texture, temperature, oxygen, ammonium, nitrate) which are all influenced directly or indirectly by the exchange processes between surface water and groundwater. These processes can vary both in time and space and are mainly driven by river discharge, ground water level and flow patterns. The input of fine sediment particles can change water-riverbed interactions through river bed clogging potentially affecting the embryonal development and survival of gravel spawning fish, such as brown trout (Salmo trutta L.). With our investigations we aim to understand these complex interactions spatially and temporally on a relevant small scale, i.e. within individual artificial brown trout redds. We designed an experimental field setup to directly investigate i) the influence of the abiotic river and redd environment on brown trout embryo development and ii) the hydrological dynamics affecting the abiotic environment in artificial brown trout. Additionally, our setup allows investigating the temporal dynamics of i) fine-sediment infiltration into the artificial redds and ii) embryo survival to two distinct developmental stages (i.e. eyed stage and hatch) The experiment was conducted in three sites of a typical Swiss river (Enziwigger, Canton of Luzern) with a strongly modified morphology. Individual sites represented a high, medium and low fine-sediment load. In each site, six artificial redds (18 in total) were built and data were collected during the entire incubation phase. Redds were located in places where natural spawning of brown trout is present. We adapted multiple established methods to the smaller scale of our river to study the dynamics of the most relevant abiotic parameters potentially affecting embryo development: Oxygen content and temperature was monitored continuously in different depths, fine sediment (bedload, suspended sediment load and its input in the river bed

Broad-scale climate influences on spring-spawning herring (Clupea harengus, L.) recruitment in the Western Baltic Sea.

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Gröger, Joachim P; Hinrichsen, Hans-Harald; Polte, Patrick

2014-01-01

Climate forcing in complex ecosystems can have profound implications for ecosystem sustainability and may thus challenge a precautionary ecosystem management. Climatic influences documented to affect various ecological functions on a global scale, may themselves be observed on quantitative or qualitative scales including regime shifts in complex marine ecosystems. This study investigates the potential climatic impact on the reproduction success of spring-spawning herring (Clupea harengus) in the Western Baltic Sea (WBSS herring). To test for climate effects on reproduction success, the regionally determined and scientifically well-documented spawning grounds of WBSS herring represent an ideal model system. Climate effects on herring reproduction were investigated using two global indices of atmospheric variability and sea surface temperature, represented by the North Atlantic Oscillation (NAO) and the Atlantic Multi-decadal Oscillation (AMO), respectively, and the Baltic Sea Index (BSI) which is a regional-scale atmospheric index for the Baltic Sea. Moreover, we combined a traditional approach with modern time series analysis based on a recruitment model connecting parental population components with reproduction success. Generalized transfer functions (ARIMAX models) allowed evaluating the dynamic nature of exogenous climate processes interacting with the endogenous recruitment process. Using different model selection criteria our results reveal that in contrast to NAO and AMO, the BSI shows a significant positive but delayed signal on the annual dynamics of herring recruitment. The westward influence of the Siberian high is considered strongly suppressing the influence of the NAO in this area leading to a higher explanatory power of the BSI reflecting the atmospheric pressure regime on a North-South transect between Oslo, Norway and Szczecin, Poland. We suggest incorporating climate-induced effects into stock and risk assessments and management strategies as part

Broad-scale climate influences on spring-spawning herring (Clupea harengus, L. recruitment in the Western Baltic Sea.

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Joachim P Gröger

Full Text Available Climate forcing in complex ecosystems can have profound implications for ecosystem sustainability and may thus challenge a precautionary ecosystem management. Climatic influences documented to affect various ecological functions on a global scale, may themselves be observed on quantitative or qualitative scales including regime shifts in complex marine ecosystems. This study investigates the potential climatic impact on the reproduction success of spring-spawning herring (Clupea harengus in the Western Baltic Sea (WBSS herring. To test for climate effects on reproduction success, the regionally determined and scientifically well-documented spawning grounds of WBSS herring represent an ideal model system. Climate effects on herring reproduction were investigated using two global indices of atmospheric variability and sea surface temperature, represented by the North Atlantic Oscillation (NAO and the Atlantic Multi-decadal Oscillation (AMO, respectively, and the Baltic Sea Index (BSI which is a regional-scale atmospheric index for the Baltic Sea. Moreover, we combined a traditional approach with modern time series analysis based on a recruitment model connecting parental population components with reproduction success. Generalized transfer functions (ARIMAX models allowed evaluating the dynamic nature of exogenous climate processes interacting with the endogenous recruitment process. Using different model selection criteria our results reveal that in contrast to NAO and AMO, the BSI shows a significant positive but delayed signal on the annual dynamics of herring recruitment. The westward influence of the Siberian high is considered strongly suppressing the influence of the NAO in this area leading to a higher explanatory power of the BSI reflecting the atmospheric pressure regime on a North-South transect between Oslo, Norway and Szczecin, Poland. We suggest incorporating climate-induced effects into stock and risk assessments and management

Seawater acidification affects the physiological energetics and spawning capacity of the Manila clam Ruditapes philippinarum during gonadal maturation.

Science.gov (United States)

Xu, Xian; Yang, Feng; Zhao, Liqiang; Yan, Xiwu

2016-06-01

Ocean acidification is predicted to have widespread implications for marine bivalve mollusks. While our understanding of its impact on their physiological and behavioral responses is increasing, little is known about their reproductive responses under future scenarios of anthropogenic climate change. In this study, we examined the physiological energetics of the Manila clam Ruditapes philippinarum exposed to CO 2 -induced seawater acidification during gonadal maturation. Three recirculating systems filled with 600 L of seawater were manipulated to three pH levels (8.0, 7.7, and 7.4) corresponding to control and projected pH levels for 2100 and 2300. In each system, temperature was gradually increased ca. 0.3°C per day from 10 to 20°C for 30days and maintained at 20°C for the following 40days. Irrespective of seawater pH levels, clearance rate (CR), respiration rate (RR), ammonia excretion rate (ER), and scope for growth (SFG) increased after a 30-day stepwise warming protocol. When seawater pH was reduced, CR, ratio of oxygen to nitrogen, and SFG significantly decreased concurrently, whereas ammonia ER increased. RR was virtually unaffected under acidified conditions. Neither temperature nor acidification showed a significant effect on food absorption efficiency. Our findings indicate that energy is allocated away from reproduction under reduced seawater pH, potentially resulting in an impaired or suppressed reproductive function. This interpretation is based on the fact that spawning was induced in only 56% of the clams grown at pH 7.4. Seawater acidification can therefore potentially impair the physiological energetics and spawning capacity of R. philippinarum. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of Ichthyophonus on blood plasma chemistry of spawning Chinook salmon and their resulting offspring in a Yukon River tributary.

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Floyd-Rump, T P; Horstmann-Dehn, L A; Atkinson, S; Skaugstad, C

2017-01-24

Ichthyophonus is a protozoan parasite of Alaska Chinook salmon Oncorhynchus tshawytscha. In this study, we determined whether spawning Chinook salmon in the Yukon River drainage exhibited a measurable stress response (i.e. elevated plasma cortisol concentrations) and detectable changes in selected blood plasma chemistry parameters when infected with Ichthyophonus. The resulting alevin were also analyzed for any differences in blood plasma chemistry caused by parental infection with Ichthyophonus. In 2010, 2011, and 2012, spawning adult Chinook salmon were collected from the Salcha River, Alaska, USA, and the prevalence of Ichthyophonus in these fish was 7.8, 6.3, and 8.3%, respectively. Fish with no clinical signs of Ichthyophonus and Ichthyophonus-positive parents were cross-fertilized to investigate potential second-generation effects as a result of Ichthyophonus infection. We found no significant difference in cortisol concentrations in blood plasma between Ichthyophonus-positive and -negative adults or between alevin from Ichthyophonus-positive and -negative parents. There were no significant differences in blood plasma parameters (e.g. alanine aminotransferase, creatine kinase, glucose) of Ichthyophonus-negative and -positive adults, with the exception of aspartate aminotransferase, which was significantly higher in plasma of Ichthyophonus-negative adults. All clinical chemistry parameters for alevin resulting from both Ichthyophonus-negative and -positive parents were not significantly different. Based on this study, which has a limited sample size and low prevalence of Ichthyophonus, offspring of Chinook salmon appear to suffer no disadvantage as a result of Ichthyophonus infection in their parents on the Salcha River.

Sibship reconstruction for inferring mating systems, dispersal and effective population size in headwater brook trout (Salvelinus fontinalis) populations

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Kanno, Yoichiro; Vokoun, Jason C.; Letcher, Benjamin H.

2011-01-01

Brook trout Salvelinus fontinalis populations have declined in much of the native range in eastern North America and populations are typically relegated to small headwater streams in Connecticut, USA. We used sibship reconstruction to infer mating systems, dispersal and effective population size of resident (non-anadromous) brook trout in two headwater stream channel networks in Connecticut. Brook trout were captured via backpack electrofishing using spatially continuous sampling in the two headwaters (channel network lengths of 4.4 and 7.7 km). Eight microsatellite loci were genotyped in a total of 740 individuals (80–140 mm) subsampled in a stratified random design from all 50 m-reaches in which trout were captured. Sibship reconstruction indicated that males and females were both mostly polygamous although single pair matings were also inferred. Breeder sex ratio was inferred to be nearly 1:1. Few large-sized fullsib families (>3 individuals) were inferred and the majority of individuals were inferred to have no fullsibs among those fish genotyped (family size = 1). The median stream channel distance between pairs of individuals belonging to the same large-sized fullsib families (>3 individuals) was 100 m (range: 0–1,850 m) and 250 m (range: 0–2,350 m) in the two study sites, indicating limited dispersal at least for the size class of individuals analyzed. Using a sibship assignment method, the effective population size for the two streams was estimated at 91 (95%CI: 67–123) and 210 (95%CI: 172–259), corresponding to the ratio of effective-to-census population size of 0.06 and 0.12, respectively. Both-sex polygamy, low variation in reproductive success, and a balanced sex ratio may help maintain genetic diversity of brook trout populations with small breeder sizes persisting in headwater channel networks.

Characteristics of the Norwegian Coastal Current during Years with High Recruitment of Norwegian Spring Spawning Herring (Clupea harengus L..

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Øystein Skagseth

Full Text Available Norwegian Spring Spawning herring (NSSH Clupea harengus L. spawn on coastal banks along the west coast of Norway. The larvae are generally transported northward in the Norwegian Coastal Current (NCC with many individuals utilizing nursery grounds in the Barents Sea. The recruitment to this stock is highly variable with a few years having exceptionally good recruitment. The principal causes of recruitment variability of this herring population have been elusive. Here we undertake an event analysis using data between 1948 and 2010 to gain insight into the physical conditions in the NCC that coincide with years of high recruitment. In contrast to a typical year when northerly upwelling winds are prominent during spring, the years with high recruitment coincide with predominantly southwesterly winds and weak upwelling in spring and summer, which lead to an enhanced northward coastal current during the larval drift period. Also in most peak recruitment years, low-salinity anomalies are observed to propagate northward during the spring and summer. It is suggested that consistent southwesterly (downwelling winds and propagating low-salinity anomalies, both leading to an enhanced northward transport of larvae, are important factors for elevated recruitment. At the same time, these conditions stabilize the coastal waters, possibly leading to enhanced production and improved feeding potential along the drift route to Barents Sea. Further studies on the drivers of early life history mortality can now be undertaken with a better understanding of the physical conditions that prevail during years when elevated recruitment occurs in this herring stock.

Flume Experiments on the Influence of Salmon Spawning Density on Grain Stability and Bedload Transport in Gravel-bed Streams

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Buxton, T. H.

2015-12-01

Salmon spawning in streams involves the female salmon digging a pit in the bed where she deposits eggs for fertilization before covering them with gravel excavated from the next pit upstream. Sequences of pit excavation and filling winnow fines, loosen sediment, and move bed material into a tailspill mound resembling the shape of a dune. Research suggests salmonid nests (redds) destabilize streambeds by reducing friction between loosened grains and converging flow that elevates shear stress on redd topography. However, bed stability may be enhanced by form drag from redds in clusters that lower shear stress on the granular bed, but this effect will vary with the proportion of the bed surface that is occupied by redds (P). I used simulated redds and water-worked ("unspawned") beds in a laboratory flume to evaluate these competing influences on grain stability and bedload transport rates with P=0.12, 0.34, and 0.41. Results indicate that competence (largest-grain) and reference transport rate estimates of critical conditions for particle entrainment inversely relate to P. Bedload transport increased as exponential functions of P and excess boundary shear stress. Therefore, redd form drag did not overcome the destabilizing effects of spawning. Instead, grain mobility and bedload transport increased with P because larger areas of the bed were composed of relatively loose, unstable grains and redd topography that experienced elevated shear stress. Consequently, the presence of redds in fish-bearing streams likely reduces the effects of sedimentation from landscape disturbance on stream habitats that salmon use for reproduction.

Swimming depth of migrating silver eels Anguilla japonica released at seamounts of the West Mariana Ridge, their estimated spawning sites

OpenAIRE

Aoyama, J.; Hissmann, Karen; Yoshinaga, T.; Sasai, S.; Uto, T.; Ueda, H.

1999-01-01

Five hormone-treated female Japanese silver eels Anguilla japonica were tagged with ultrasonic transmitters and released by submersible in the West Pacific at seamounts of the West Mariana Ridge, their supposed spawning grounds. Four eels were tracked for 60 to 423 min in the vicinity of the seamounts. They did not settle at the seamounts but swam at a mean speed of 0.37 m s-1 into open water above deep ground. Their mean swimming depth ranged from 81 to 172 m. Experiments suggest that pre-ma...

Estimating thermal regimes of bull trout and assessing the potential effects of climate warming on critical habitats

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Jones, Leslie A.; Muhlfeld, Clint C.; Marshall, Lucy A.; McGlynn, Brian L.; Kershner, Jeffrey L.

2013-01-01

Understanding the vulnerability of aquatic species and habitats under climate change is critical for conservation and management of freshwater systems. Climate warming is predicted to increase water temperatures in freshwater ecosystems worldwide, yet few studies have developed spatially explicit modelling tools for understanding the potential impacts. We parameterized a nonspatial model, a spatial flow-routed model, and a spatial hierarchical model to predict August stream temperatures (22-m resolution) throughout the Flathead River Basin, USA and Canada. Model comparisons showed that the spatial models performed significantly better than the nonspatial model, explaining the spatial autocorrelation found between sites. The spatial hierarchical model explained 82% of the variation in summer mean (August) stream temperatures and was used to estimate thermal regimes for threatened bull trout (Salvelinus confluentus) habitats, one of the most thermally sensitive coldwater species in western North America. The model estimated summer thermal regimes of spawning and rearing habitats at <13 C° and foraging, migrating, and overwintering habitats at <14 C°. To illustrate the useful application of such a model, we simulated climate warming scenarios to quantify potential loss of critical habitats under forecasted climatic conditions. As air and water temperatures continue to increase, our model simulations show that lower portions of the Flathead River Basin drainage (foraging, migrating, and overwintering habitat) may become thermally unsuitable and headwater streams (spawning and rearing) may become isolated because of increasing thermal fragmentation during summer. Model results can be used to focus conservation and management efforts on populations of concern, by identifying critical habitats and assessing thermal changes at a local scale.

Comparative gonadogenesis and hormonal induction of spawning of cultured and wild mediterranean amberjack (Seriola dumerili, Risso 1810

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V. Kozul

2001-09-01

Full Text Available The histological characteristics of wild and cultured Mediterranean amberjack gonads were studied during the first four years of their life cycle. No differences were found in the gonad development of both wild and captive males and females during the first and second year. In the third year, wild females showed more advanced oocyte development than captive females. In the fourth year, vitellogenic oocytes were noted for captive females. Fertilised eggs were obtained after a HCG hormone treatment of four- to nine-year old wild specimens. A smaller quantity of mature and fertilised eggs was also obtained through the spawning of hormone-treated four-year old captive broodstock specimens. Eggs in the stage of gastrulation died within eight hours following fertilisation.

Sardinella brasiliensis: tipo de desova, fecundidade e potencial reprodutivo relativo. I. Área entre 23º40's e 24º20's, Brasil Sardinella brasiliensis: spawning, fecundity and relative spawning power. I. Area between 23º40's and 24º20's, Brazil

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A. E. A. de M Vazzoler

1976-01-01

Full Text Available 1 Sardinella brasilieneis apresenta desova individual do tipo total; entretanto as fêmeas desovantes nao maturam todas ao mesmo tempo, ocorrendo maturação e desovas sucessivas de grupos de indivíduos (cardumes, o que determina um período de desova prolongado; 2 Durante o período de desova de 1964-65 foram constatados valores para os índices de maturidade e gonadal, e para o fator de condição, mais eleva dos que durante 1963-64, o que sugere melhores condições alimentares durante tal período; 3 Os pesos médios por classe de comprimento, para as fêmeas, também foram mais elevados durante 1964-65, bem como o comprimento médio, a fecundidade média por fêmea e o potencial reprodutivo relativo; 4 Os valores dos índices.considerados foram distintos dentro de um mes mo período, entre as varias fases, mas também variaram significativamente para uma mesma fase, entre os dois períodos, indicando não poderem ser utilizados como fator isolado para a caracterização do grau de desenvolvimento dos ovarios; 5 As relações entre fecundidade e comprimento total, peso total, peso das gonadas e peso do corpo mostraram-se significativamente diferentes entre os dois períodos; 6 O tamanho dos óvulos, para uma mesma fase, variou de um período para o outro, sendo mais elevado durante 1964-65; 7 Os resultados mostram que, apesar dos índices e relações terem um significado biológico, referem-se a organismos vivos submetidos à ação do meio ambiente variável, e não podem ser encarados como fixos; sua utilização deve ser associada a observações puramente biológicas, servindo apenas como "auxiliares" na determinação ou avaliação de um processo biológico qualquer.This paper is a contribution to the knowledgment of some aspects of the reproduction of Sardinella brasiliensis (Steindachner, 1879 from the area between 23º40'S and 24º20'S, Brazil. The individual spawning, fecundity, maturation and gonadal indexes, condition factor

Evaluating relationships between wild Skeena river sockeye salmon productivity and the abundance of spawning channel enhanced sockeye smolts.

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Price, Michael H H; Connors, Brendan M

2014-01-01

The enhancement of salmon populations has long been used to increase the abundance of salmon returning to spawn and/or to be captured in fisheries. However, in some instances enhancement can have adverse impacts on adjacent non-enhanced populations. In Canada's Skeena watershed, smolt-to-adult survival of Babine Lake sockeye from 1962-2002 was inversely related to the abundance of sockeye smolts leaving Babine Lake. This relationship has led to the concern that Babine Lake smolt production, which is primarily enhanced by spawning channels, may depress wild Skeena (Babine and non-Babine) sockeye populations as a result of increased competition between wild and enhanced sockeye smolts as they leave their natal lakes and co-migrate to sea. To test this hypothesis we used data on Skeena sockeye populations and oceanographic conditions to statistically examine the relationship between Skeena sockeye productivity (adult salmon produced per spawner) and an index of Babine Lake enhanced smolt abundance while accounting for the potential influence of early marine conditions. While we had relatively high power to detect large effects, we did not find support for the hypothesis that the productivity of wild Skeena sockeye is inversely related to the abundance of enhanced sockeye smolts leaving Babine Lake in a given year. Importantly, life-time productivity of Skeena sockeye is only partially explained by marine survival, and likely is an unreliable measure of the influence of smolt abundance. Limitations to our analyses, which include: (1) the reliance upon adult salmon produced per spawner (rather than per smolt) as an index of marine survival, and (2) incomplete age structure for most of the populations considered, highlight uncertainties that should be addressed if understanding relationships between wild and enhanced sockeye is a priority in the Skeena.

Evaluating relationships between wild Skeena river sockeye salmon productivity and the abundance of spawning channel enhanced sockeye smolts.

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Michael H H Price

Full Text Available The enhancement of salmon populations has long been used to increase the abundance of salmon returning to spawn and/or to be captured in fisheries. However, in some instances enhancement can have adverse impacts on adjacent non-enhanced populations. In Canada's Skeena watershed, smolt-to-adult survival of Babine Lake sockeye from 1962-2002 was inversely related to the abundance of sockeye smolts leaving Babine Lake. This relationship has led to the concern that Babine Lake smolt production, which is primarily enhanced by spawning channels, may depress wild Skeena (Babine and non-Babine sockeye populations as a result of increased competition between wild and enhanced sockeye smolts as they leave their natal lakes and co-migrate to sea. To test this hypothesis we used data on Skeena sockeye populations and oceanographic conditions to statistically examine the relationship between Skeena sockeye productivity (adult salmon produced per spawner and an index of Babine Lake enhanced smolt abundance while accounting for the potential influence of early marine conditions. While we had relatively high power to detect large effects, we did not find support for the hypothesis that the productivity of wild Skeena sockeye is inversely related to the abundance of enhanced sockeye smolts leaving Babine Lake in a given year. Importantly, life-time productivity of Skeena sockeye is only partially explained by marine survival, and likely is an unreliable measure of the influence of smolt abundance. Limitations to our analyses, which include: (1 the reliance upon adult salmon produced per spawner (rather than per smolt as an index of marine survival, and (2 incomplete age structure for most of the populations considered, highlight uncertainties that should be addressed if understanding relationships between wild and enhanced sockeye is a priority in the Skeena.

Riders on the storm: selective tidal movements facilitate the spawning migration of threatened delta smelt in the San Francisco Estuary

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Bennett, W.A.; Burau, Jon R.

2015-01-01

Migration strategies in estuarine fishes typically include behavioral adaptations for reducing energetic costs and mortality during travel to optimize reproductive success. The influence of tidal currents and water turbidity on individual movement behavior were investigated during the spawning migration of the threatened delta smelt, Hypomesus transpacificus, in the northern San Francisco Estuary, California, USA. Water current velocities and turbidity levels were measured concurrently with delta smelt occurrence at sites in the lower Sacramento River and San Joaquin River as turbidity increased due to first-flush winter rainstorms in January and December 2010. The presence/absence of fish at the shoal-channel interface and near the shoreline was quantified hourly over complete tidal cycles. Delta smelt were caught consistently at the shoal-channel interface during flood tides and near the shoreline during ebb tides in the turbid Sacramento River, but were rare in the clearer San Joaquin River. The apparent selective tidal movements by delta smelt would facilitate either maintaining position or moving upriver on flood tides, and minimizing advection down-estuary on ebb tides. These movements also may reflect responses to lateral gradients in water turbidity created by temporal lags in tidal velocities between the near-shore and mid-channel habitats. This migration strategy can minimize the energy spent swimming against strong river and tidal currents, as well as predation risks by remaining in turbid water. Selection pressure on individuals to remain in turbid water may underlie population-level observations suggesting that turbidity is a key habitat feature and cue initiating the delta smelt spawning migration.

Mercury levels in herring gulls and fish: 42 years of spatio-temporal trends in the Great Lakes.

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Blukacz-Richards, E Agnes; Visha, Ariola; Graham, Matthew L; McGoldrick, Daryl L; de Solla, Shane R; Moore, David J; Arhonditsis, George B

2017-04-01

Total mercury levels in aquatic birds and fish communities have been monitored across the Canadian Great Lakes by Environment and Climate Change Canada (ECCC) for the past 42 years (1974-2015). These data (22 sites) were used to examine spatio-temporal variability of mercury levels in herring gull (Larus argentatus) eggs, lake trout (Salvelinus namaycush), walleye (Sander vitreus), and rainbow smelt (Osmerus mordax). Trends were quantified with dynamic linear models, which provided time-variant rates of change of mercury concentrations. Lipid content (in both fish and eggs) and length in fish were used as covariates in all models. For the first three decades, mercury levels in gull eggs and fish declined at all stations. In the 2000s, trends for herring gull eggs reversed at two sites in Lake Erie and two sites in Lake Ontario. Similar trend reversals in the 2000s were observed for lake trout in Lake Superior and at a single station in Lake Ontario. Mercury levels in lake trout continued to slowly decline at all of the remaining stations, except for Lake Huron, where the levels remained stable. A post-hoc Bayesian regression analysis suggests strong trophic interactions between herring gulls and rainbow smelt in Lake Superior and Lake Ontario, but also pinpoints the likelihood of a trophic decoupling in Lake Huron and Lake Erie. Continued monitoring of mercury levels in herring gulls and fish is required to consolidate these trophic shifts and further evaluate their broader implications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Evaluating stocking efficacy in an ecosystem undergoing oligotrophication

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Kao, Yu-Chun; Rogers, Mark W.; Bunnell, David B.

2017-01-01

Oligotrophication has negatively affected fisheries production in many freshwater ecosystems and could conceivably reduce the efficacy of stockings used to enhance fisheries. In Lake Michigan, offshore oligotrophication has occurred since the 1970s, owing to reductions in total phosphorus (TP) inputs and nearshore sequestration of TP by nonindigenous dreissenid mussels. We evaluated simultaneous effects of stock enhancement and oligotrophication on salmonine species (Chinook salmon Oncorhynchus tshawytscha, lake trout Salvelinus namaycush, and steelhead O. mykiss) that support valuable recreational fisheries. We employed a novel application of an Ecopath with Ecosim model by conducting a full factorial simulation experiment. Our design included multiple levels of salmonine stocking, consumption by invasive quagga mussels (Dreissena bugensis), and TP that were informed by manager interests. Under all levels of TP and quagga mussel consumption, our results showed that stock enhancement could still increase salmonine biomass, but positive responses were stronger for lake trout and steelhead than Chinook salmon. Simulations showed that quagga mussel consumption has deleterious effects on pelagic-oriented prey fishes and Chinook salmon, which feed almost exclusively on the pelagic-oriented alewife (Alosa pseudoharengus). In summary, results from our simulation experiment suggested that lake trout and steelhead are better suited to the current ecosystem than Chinook salmon, and therefore, stock enhancement provides the highest gains for these two species. Furthermore, simulated biomass of all recreational salmonine species increased with increasing TP, indicating the need for managers to consider how potential future oligotrophication will limit the carrying capacity of salmonine biomass in Lake Michigan

Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron

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He, Ji X.; Bence, James R.; Madenjian, Charles P.; Pothoven, Steven A.; Dobiesz, Norine E.; Fielder, David G.; Johnson, James E.; Ebener, Mark P.; Cottrill, Adam R.; Mohr, Lloyd C.; Koproski, Scott R.

2015-01-01

We quantified piscivory patterns in the main basin of Lake Huron during 1984–2010 and found that the biomass transfer from prey fish to piscivores remained consistently high despite the rapid major trophic shift in the food webs. We coupled age-structured stock assessment models and fish bioenergetics models for lake trout (Salvelinus namaycush), Chinook salmon (Oncorhynchus tshawytscha), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis). The model system also included time-varying parameters or variables of growth, length–mass relations, maturity schedules, energy density, and diets. These time-varying models reflected the dynamic connections that a fish cohort responded to year-to-year ecosystem changes at different ages and body sizes. We found that the ratio of annual predation by lake trout, Chinook salmon, and walleye combined with the biomass indices of age-1 and older alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) increased more than tenfold during 1987–2010, and such increases in predation pressure were structured by relatively stable biomass of the three piscivores and stepwise declines in the biomass of alewives and rainbow smelt. The piscivore stability was supported by the use of alternative energy pathways and changes in relative composition of the three piscivores. In addition, lake whitefish became a new piscivore by feeding on round goby (Neogobius melanostomus). Their total fish consumption rivaled that of the other piscivores combined, although fish were still a modest proportion of their diet. Overall, the use of alternative energy pathways by piscivores allowed the increases in predation pressure on dominant diet species.

Quantification of 15 bile acids in lake charr feces by ultra-high performance liquid chromatography–tandem mass spectrometry

Science.gov (United States)

Li, Ke; Buchinger, Tyler J.; Bussy, Ugo; Fissette, Skye D.; Johnson, Nicholas; Li, Weiming

2015-01-01

Many fishes are hypothesized to use bile acids (BAs) as chemical cues, yet quantification of BAs in biological samples and the required methods remain limited. Here, we present an UHPLC–MS/MS method for simultaneous, sensitive, and rapid quantification of 15 BAs, including free, taurine, and glycine conjugated BAs, and application of the method to fecal samples from lake charr (Salvelinus namaycush). The analytes were separated on a C18 column with acetonitrile–water (containing 7.5 mM ammonium acetate and 0.1% formic acid) as mobile phase at a flow rate of 0.25 mL/min for 12 min. BAs were monitored with a negative electrospray triple quadrupole mass spectrometer (Xevo TQ-S™). Calibration curves of 15 BAs were linear over the concentration range of 1.00–5,000 ng/mL. Validation revealed that the method was specific, accurate, and precise. The method was applied to quantitative analysis of feces extract of fry lake charr and the food they were eating. The concentrations of analytes CA, TCDCA, TCA, and CDCA were 242.3, 81.2, 60.7, and 36.2 ng/mg, respectively. However, other taurine conjugated BAs, TUDCA, TDCA, and THDCA, were not detected in feces of lake charr. Interestingly, TCA and TCDCA were detected at high concentrations in food pellets, at 71.9 and 38.2 ng/mg, respectively. Application of the method to feces samples from lake charr supported a role of BAs as chemical cues, and will enhance further investigation of BAs as chemical cues in other fish species.

Factors influencing the distribution of native bull trout and westslope cutthroat trout in western Glacier National Park, Montana

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D'Angelo, Vincent S.; Muhlfeld, Clint C.

2013-01-01

The widespread declines of native bull trout (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) populations prompted researchers to investigate factors influencing their distribution and status in western Glacier National Park, Montana. We evaluated the association of a suite of abiotic factors (stream width, elevation, gradient, large woody debris density, pool density, August mean stream temperature, reach surface area) with the occurrence (presence or absence) of bull trout and westslope cutthroat trout in 79 stream reaches in five sub-drainages containing glacial lakes. We modeled the occurrence of each species using logistic regression and evaluated competing models using an information theoretic approach. Westslope cutthroat trout were widely distributed (47 of 79 reaches), and there appeared to be no restrictions on their distribution other than physical barriers. Westslope cutthroat trout were most commonly found in relatively warm reaches downstream of lakes and in headwater reaches with large amounts of large woody debris and abundant pools. By contrast, bull trout were infrequently detected (10 of 79 reaches), with 7 of the 10 (70%) detections in sub-drainages that have not been compromised by non-native lake trout (S. namaycush). Bull trout were most often found in cold, low-gradient reaches upstream of glacial lakes. Our results indicate that complex stream habitats in sub-drainages free of non-native species are important to the persistence of native salmonids in western Glacier National Park. Results from this study may help managers monitor and protect important habitats and populations, inform conservation and recovery programs, and guide non-native species suppression efforts in Glacier National Park and elsewhere.

Egg fatty acid composition from lake trout fed two Lake Michigan prey fish species.

Science.gov (United States)

Honeyfield, D.C.; Fitzsimons, J.D.; Tillitt, D.E.; Brown, S.B.

2009-01-01

We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife-bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos.

Fish populations in a large group of acid-stressed lakes

Energy Technology Data Exchange (ETDEWEB)

Harvey, H H

1975-01-01

The purpose of this study was to determine the effects of environmental stress on the number and diversity of fish species in a group of acid-stressed lakes. The study area was the La Cloche Mountains, a series of quartzite ridges covering 1,300 km/sup 2/ along the north shore of Georgian Bay and north channel of Lake Huron. Within these ridges are 173 lakes; 68 of the largest of these made up the study sample. The lakes of the La Cloche Mountains are undergoing rapid acidification. Coincident with this there has been the loss of sport fishes from several lakes. Lakes such as Nellie, Lumsden, O.S.A., Acid and Killarney supported good sport fisheries for the lake trout, (Salvelinus namaycush) for many years, but have ceased to do so in the last 5 to 15 years. Other sport fishes, notably the walleye (Stizostedion vitreum) and smallmouth bass (micropterus dolomieu) have disappeared from some of the La Cloche Lakes. Thus recreational fishing alone could not have been the cause of the change. Beamish (1974) recorded the extreme sparcity of the three remaining fish species in O.S.A. Lake. Many of the lakes of the La Cloche mountains are accessible only with difficulty and little or no information exists for these lakes prior to this study. This precluded simple comparison of these lakes before and during acidification. This lack of historic data determined in part the approach taken in this study; a comparison of the fish communities of a group of lakes differing in degree of acid stress.

Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

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Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

2016-01-01

Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

Is motivation important to brook trout passage through culverts?

Science.gov (United States)

Goerig, Elsa; Castro-Santos, Theodore R.

2017-01-01

Culverts can restrict movement of stream-dwelling fish. Motivation to enter and ascend these structures is an essential precursor for successful passage. However, motivation is challenging to quantify. Here, we use attempt rate to assess motivation of 447 brook trout (Salvelinus fontinalis) entering three culverts under a range of hydraulic, environmental, and biological conditions. A passive integrated transponder system allowed for the identification of passage attempts and success of individual fish. Attempt rate was quantified using time-to-event analysis allowing for time-varying covariates and recurrent events. Attempt rate was greatest during the spawning period, at elevated discharge, at dusk, and for longer fish. It decreased during the day and with increasing number of conspecifics downstream of the culvert. Results also show a positive correlation between elevated motivation and successful passage. This study enhances understanding of factors influencing brook trout motivation to ascend culverts and shows that attempt rate is a dynamic phenomenon, variable over time and among individuals. It also presents methods that could be used to investigate other species’ motivation to pass natural or anthropogenic barriers.

Assessment of Hydraulic Conditions Supporting the Recruitment of Asian Carp in the Illinois Waterway - A Case Study Using Known Spawning Events of 2015

Science.gov (United States)

Soong, D. T.; Garcia, T.; Duncker, J.; Zhu, Z.; Butler, S.; Diana, M.; Wahl, D.

2016-12-01

The upstream movement of Asian carp in the Illinois Waterway poses a potential threat to the Great Lakes. If established within the Great Lakes, Asian carp may disrupt the food web and harm the ecosystems of the Great Lakes. Understanding the Asian carp reproduction, including the timing and locations of adult spawning and the transport and dispersal of eggs and larvae, is essential information for managing the Asian carp population in the Illinois Waterway. The Fluvial Egg Drift Simulator (FluEgg) model, a Lagrangian particle tracking model, has been used to study the transport and dispersal of eggs and larvae. The FluEgg model inputs are water temperature and hydraulic properties. At present, field measured or modeled hydraulics from steady-state simulations have been used in FluEgg modeling and the applications have shown useful results for evaluating Asian carp reproduction in the Illinois Waterway. However, there is a need to use data based on more representative time-variable hydraulic conditions from spawning to the time larvae reach the Gas Bladder Inflation Stage (GBI). The GBI stage is critical because that is the stage when the young fish seek nursery habitat. In June 2015, Asian carp spawning was observed at two locations along the Illinois Waterway, one below Starved Rock Lock and Dam near Utica, and the one in the La Grange Pool near Havana, Illinois. This study analyzes how hydraulic modeling can improve the predictability of the FluEgg model. An unsteady HEC-RAS hydraulic model of the Illinois Waterway from Brandon Road Lock and Dam to Grafton, Illinois was used to reproduce the June 2015 flood event. Hydraulic data from HEC-RAS modeling, including predicted spatial and temporal discharge, water depth, and shear velocity; and measured water temperature data were used as input to the FluEgg model. FluEgg simulation results illustrate the downstream drifting of eggs and larvae until reaching the GBI stage. These simulation results can be analyzed

The developmental transcriptome of contrasting Arctic charr (Salvelinus alpinus morphs [version 2; referees: 1 approved, 2 approved with reservations

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Johannes Gudbrandsson

2016-04-01

Full Text Available Species and populations with parallel evolution of specific traits can help illuminate how predictable adaptations and divergence are at the molecular and developmental level. Following the last glacial period, dwarfism and specialized bottom feeding morphology evolved rapidly in several landlocked Arctic charr Salvelinus alpinus populations in Iceland.   To study the genetic divergence between small benthic morphs and limnetic morphs, we conducted RNA-sequencing charr embryos at four stages in early development. We studied two stocks with contrasting morphologies: the small benthic (SB charr from Lake Thingvallavatn and Holar aquaculture (AC charr. The data reveal significant differences in expression of several biological pathways during charr development. There was also an expression difference between SB- and AC-charr in genes involved in energy metabolism and blood coagulation genes. We confirmed differing expression of five genes in whole embryos with qPCR, including lysozyme and natterin-like which was previously identified as a fish-toxin of a lectin family that may be a putative immunopeptide. We also verified differential expression of 7 genes in the developing head that associated consistently with benthic v.s.limnetic morphology (studied in 4 morphs. Comparison of single nucleotide polymorphism (SNP frequencies reveals extensive genetic differentiation between the SB and AC-charr (~1300 with more than 50% frequency difference. Curiously, three derived alleles in the otherwise conserved 12s and 16s mitochondrial ribosomal RNA genes are found in benthic charr. The data implicate multiple genes and molecular pathways in divergence of small benthic charr and/or the response of aquaculture charr to domestication. Functional, genetic and population genetic studies on more freshwater and anadromous populations are needed to confirm the specific loci and mutations relating to specific ecological traits in Arctic charr.

The developmental transcriptome of contrasting Arctic charr (Salvelinus alpinus morphs [version 3; referees: 1 approved, 2 approved with reservations

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Johannes Gudbrandsson

2016-12-01

Full Text Available Species and populations with parallel evolution of specific traits can help illuminate how predictable adaptations and divergence are at the molecular and developmental level. Following the last glacial period, dwarfism and specialized bottom feeding morphology evolved rapidly in several landlocked Arctic charr Salvelinus alpinus populations in Iceland.   To study the genetic divergence between small benthic morphs and limnetic morphs, we conducted RNA-sequencing charr embryos at four stages in early development. We studied two stocks with contrasting morphologies: the small benthic (SB charr from Lake Thingvallavatn and Holar aquaculture (AC charr. The data reveal significant differences in expression of several biological pathways during charr development. There was also an expression difference between SB- and AC-charr in genes involved in energy metabolism and blood coagulation genes. We confirmed differing expression of five genes in whole embryos with qPCR, including lysozyme and natterin-like which was previously identified as a fish-toxin of a lectin family that may be a putative immunopeptide. We also verified differential expression of 7 genes in the developing head that associated consistently with benthic v.s.limnetic morphology (studied in 4 morphs. Comparison of single nucleotide polymorphism (SNP frequencies reveals extensive genetic differentiation between the SB and AC-charr (~1300 with more than 50% frequency difference. Curiously, three derived alleles in the otherwise conserved 12s and 16s mitochondrial ribosomal RNA genes are found in benthic charr. The data implicate multiple genes and molecular pathways in divergence of small benthic charr and/or the response of aquaculture charr to domestication. Functional, genetic and population genetic studies on more freshwater and anadromous populations are needed to confirm the specific loci and mutations relating to specific ecological traits in Arctic charr.

Adaptive Management of Bull Trout Populations in the Lemhi Basin

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Peterson, James T.; Tyre, Andrew J.; Converse, Sarah J.; Bogich, Tiffany L.; Miller, Damien; Post van der Burg, Max; Thomas, Carmen; Thompson, Ralph J.; Wood, Jeri; Brewer, Donna; Runge, Michael C.

2011-01-01

The bull trout Salvelinus confluentus, a stream-living salmonid distributed in drainages of the northwestern United States, is listed as threatened under the Endangered Species Act because of rangewide declines. One proposed recovery action is the reconnection of tributaries in the Lemhi Basin. Past water use policies in this core area disconnected headwater spawning sites from downstream habitat and have led to the loss of migratory life history forms. We developed an adaptive management framework to analyze which types of streams should be prioritized for reconnection under a proposed Habitat Conservation Plan. We developed a Stochastic Dynamic Program that identified optimal policies over time under four different assumptions about the nature of the migratory behavior and the effects of brook trout Salvelinus fontinalis on subpopulations of bull trout. In general, given the current state of the system and the uncertainties about the dynamics, the optimal policy would be to connect streams that are currently occupied by bull trout. We also estimated the value of information as the difference between absolute certainty about which of our four assumptions were correct, and a model averaged optimization assuming no knowledge. Overall there is little to be gained by learning about the dynamics of the system in its current state, although in other parts of the state space reducing uncertainties about the system would be very valuable. We also conducted a sensitivity analysis; the optimal decision at the current state does not change even when parameter values are changed up to 75% of the baseline values. Overall, the exercise demonstrates that it is possible to apply adaptive management principles to threatened and endangered species, but logistical and data availability constraints make detailed analyses difficult.

Nucleotide variation in the mitochondrial genome provides evidence for dual routes of postglacial recolonization and genetic recombination in the northeastern brook trout (Salvelinus fontinalis).

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Pilgrim, B L; Perry, R C; Barron, J L; Marshall, H D

2012-09-26

Levels and patterns of mitochondrial DNA (mtDNA) variation were examined to investigate the population structure and possible routes of postglacial recolonization of the world's northernmost native populations of brook trout (Salvelinus fontinalis), which are found in Labrador, Canada. We analyzed the sequence diversity of a 1960-bp portion of the mitochondrial genome (NADH dehydrogenase 1 gene and part of cytochrome oxidase 1) of 126 fish from 32 lakes distributed throughout seven regions of northeastern Canada. These populations were found to have low levels of mtDNA diversity, a characteristic trait of populations at northern extremes, with significant structuring at the level of the watershed. Upon comparison of northeastern brook trout sequences to the publicly available brook trout whole mitochondrial genome (GenBank AF154850), we infer that the GenBank sequence is from a fish whose mtDNA has recombined with that of Arctic charr (S. alpinus). The haplotype distribution provides evidence of two different postglacial founding groups contributing to present-day brook trout populations in the northernmost part of their range; the evolution of the majority of the haplotypes coincides with the timing of glacier retreat from Labrador. Our results exemplify the strong influence that historical processes such as glaciations have had on shaping the current genetic structure of northern species such as the brook trout.

EFFICIENCY EVALUATION OF USING DIFFERENT SPAWNING INDUCERS IN THE CONDITIONS OF ARTIFICIAL REPRODUCTION OF STЕRLET (ACIPENSER RUTHENUS L.

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V. Kovalenko

2015-09-01

Full Text Available Purpose. To study the efficiency of replacing the preparation of sturgeon hypophyses, which is traditional for sturgeon culture but scarce and expensive, with its carp analogue as well as with preparations, which induce own gonadotrophic function of brood sterlet hypophysis when producing offspring in aquaculture conditions. Methodology. The research was performed in the framework of the NULES research theme for 2013–2015, in the conditions of the Fishery Academic, Research and Production Laboratory of the Aquaculture Department (hatching room and fish culture facility with closed water supply in Nemishaev, Borodianka district, Kyiv region. The control in the experiment on a comparative evaluation of the efficiency of different spawning inducers for artificially reproduced sterlet was Reproginol (powder of acetoned sturgeon hypophysis in 50 mg capsules. The experimental variant 1 included acetoned hypophyses of Prussian carp and common carp (no older than a year and half since their collection. The experimental variant 2 is experimental synthetic fish spawning inducer Vadilen-2 (the developer of the preparation is Kovalenko V. O., assistant professor of the Aquaculture Department of the NULES of Ukraine. Collection and processing of experiment data were performed using conventional aquaculture research methods. Findings. It was found that Vadilen-2 produced inducing effect on the gonadotrophic function of sterlet hypophysis and transition from the 4th to the 5th stage of maturation. The effective doses of Vadilen-2 with water temperature of 13–15°C for sterlet females and males were 0.8–1.0 and 0.5–0.6 mg per 1 kg of brood fish, respectively. We observed that sterlet females, which were kept in basins of the recirculated water facility, showed worse results during incubation period when they missed winter period compared to fish, which were kept in the water with natural temperature in the winter. The possibility of replacing the

Use of an oiled gravel column dosing system to characterize exposure and toxicity of fish to sunken heavy oil on spawning substrates

International Nuclear Information System (INIS)

Martin, J.; Hodson, P.

2010-01-01

In August 2005, a freight train derailment near the shore of Lake Wabamun near Edmonton, Alberta resulted in the release of nearly 150,000 litres of Bunker C oil on the lakeshore. The purpose of this study was to define the toxic load of oil in sediments to better describe the exposure and toxicity of fish to sunken heavy oil on spawning substrates. Heavy Bunker C fuel contains a complex mixture of polycyclic aromatic hydrocarbons (PAH), particularly the 3-4 ringed alkylated forms that cause sublethal toxic responses in early life stages of rainbow trout (Oncorhynchus mykiss). Oil patches still persist in near-shore sediments where fish spawn. This study evaluated how the behaviour of heavy oil in water interacts with exposure and toxicity to trout embryo. Flow-through oiled gravel columns were used to determine whether the toxic constituents of heavy oil are transferred to water quickly enough to cause toxicity. Embryonic trout exposed to the outflow of these columns showed signs of sublethal toxicity and dose-dependent mortality. In addition, column output of hydrocarbons and CYP1A induction in fish were flow-dependent. The desorption kinetics of the gravel column dosing was characterized in order to evaluate the toxicity of oil on these substrates and relate it back to toxicity of oil in sediments. The time to steady-state desorption of oil constituents in water was first determined, and then the rate at which different classes of oil constituents partition into water were identified.

Influence of spawning procedure on gametes fertilization success in Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae: Implications for the conservation of this species

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Renato M. Honji

Full Text Available Artificial reproduction and gamete fertilization were evaluated in Salminus hilarii wild and domesticated broodstocks. Wild and domesticated broodstocks were artificially induced to reproduction using a carp pituitary treatment. Four groups were considered: Group 1 (G1, fish caught in the wild maintained for three years in the same conditions as the domesticated broodstocks and spawned naturally; Group 2 (G2, broodstock born and raised in captivity and spawned naturally; Group 3 (G3, wild broodstocks, which were manually stripped for gamete collection and dry fertilization; and Group 4 (G4, domesticated males and females, also manually stripped. Oocytes, eggs, and larvae were sampled at different time intervals throughout embryonic development. Yolk sac absorption occurred approximately 24-29 h after hatching. Twenty-six h after hatching, the larvae mouths opened. Cannibalism was identified just 28-30 h after hatching. There was no morphological difference in embryonic development among all groups. The number of released eggs per gram of female was: G1: 83.3 ± 24.5 and G2: 103.8 ± 37.4; however, the fertilization success was lower in G2 (42.0 ± 6.37 % compared with G1 (54.7 ± 3.02% (P = 0.011. Hand-stripping of oocytes was not successful and the fertilization rate was zero. The reproduction of this species in captivity is viable, but it is necessary to improve broodstock management to enhance fertilization rates and obtain better fingerling production for restocking programs.

A SNP Based Linkage Map of the Arctic Charr (Salvelinus alpinus Genome Provides Insights into the Diploidization Process After Whole Genome Duplication

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Cameron M. Nugent

2017-02-01

Full Text Available Diploidization, which follows whole genome duplication events, does not occur evenly across the genome. In salmonid fishes, certain pairs of homeologous chromosomes preserve tetraploid loci in higher frequencies toward the telomeres due to residual tetrasomic inheritance. Research suggests this occurs only in homeologous pairs where one chromosome arm has undergone a fusion event. We present a linkage map for Arctic charr (Salvelinus alpinus, a salmonid species with relatively fewer chromosome fusions. Genotype by sequencing identified 19,418 SNPs, and a linkage map consisting of 4508 markers was constructed from a subset of high quality SNPs and microsatellite markers that were used to anchor the new map to previous versions. Both male- and female-specific linkage maps contained the expected number of 39 linkage groups. The chromosome type associated with each linkage group was determined, and 10 stable metacentric chromosomes were identified, along with a chromosome polymorphism involving the sex chromosome AC04. Two instances of a weak form of pseudolinkage were detected in the telomeric regions of homeologous chromosome arms in both female and male linkage maps. Chromosome arm homologies within the Atlantic salmon (Salmo salar and rainbow trout (Oncorhynchus mykiss genomes were determined. Paralogous sequence variants (PSVs were identified, and their comparative BLASTn hit locations showed that duplicate markers exist in higher numbers on seven pairs of homeologous arms, previously identified as preserving tetrasomy in salmonid species. Homeologous arm pairs where neither arm has been part of a fusion event in Arctic charr had fewer PSVs, suggesting faster diploidization rates in these regions.

Identification of the Spawning, Rearing and Migratory Requirements of Fall Chinook Salmon in the Columbia River Basin, Annual Report 1992.

Energy Technology Data Exchange (ETDEWEB)

Rondorf, Dennis W.; Miller, William H.

1994-03-01

This document is the 1992 annual progress report for selected studies of fall chinook Salmon Oncorhynchus tshawytscha conducted by the National Biological Survey (NBS) and the US Fish and Wildlife Service. The decline in abundance of fall chinook salmon in the Snake River basin has become a growing concern. Effective recovery efforts for fall chinook salmon cannot be developed until we increase our knowledge of the factors that are limiting the various life history stages. This study attempts to identify those physical and biological factors which influence spawning of fall chinook salmon in the free-flowing Snake River and their rearing and seaward migration through Columbia River basin reservoirs.

Early spawning of Antarctic krill in the Scotia Sea is fuelled by “superfluous” feeding on non-ice associated phytoplankton blooms

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Schmidt, Katrin; Atkinson, Angus; Venables, Hugh J.; Pond, David W.

2012-01-01

The spawning success of Antarctic krill ( Euphausia superba) is generally assumed to depend on substantial winter sea ice extent, as ice biota can serve as a food source during winter/spring and the seasonal ice melt conditions the upper water column for extensive phytoplankton blooms. However, direct observations during spring are rare. Here we studied krill body condition and maturity stage in relation to feeding (i.e. stomach fullness, diet, absorption of individual fatty acids and defecation rate) across the Scotia Sea in November 2006. The phytoplankton concentrations were low at the marginal ice zone (MIZ) in the southern Scotia Sea (Stn. 1, 2, and 3), high in open waters of the Southern Antarctic Circumpolar Current Front (SACCF) in the central Scotia Sea (Stn. 5), and moderate further north (Stn. 6 and 7). Krill had low lipid reserves (˜6.5% of dry mass, DM), low mass:length ratios (˜1.7 mg DM mm -1), and small digestive glands (˜7% of total DM) near the ice edge. The stomachs contained lithogenic particles, diatom debris, and bacterial fatty acids, but low proportions of diatom-indicating fatty acids, which suggest that these krill were feeding on detritus rather than on fresh ice algae. In the SACCF, krill had higher lipid reserves (˜10% of DM), high mass:length ratios (˜2.2 mg DM mm -1), and large digestive glands (˜16% of total DM). Stomach content and tissue composition indicate feeding on diatoms. In the north, moderate food concentrations co-occurred with low lipid reserves in krill, and moderate mass:length ratios and digestive gland sizes. Only in the phytoplankton bloom in the SACCF had the mating season already started and some females were about to spawn. Based on the way krill processed their food at the different stations, we indicate two mechanisms that can lead to fast regeneration of body reserves and oocyte maturation in E. superba. One is "superfluous" feeding at high food concentrations, which maximises the overall nutrient gain

The effect of different feed on the spawning performance of mud crab Scylla serrata broodstock

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Bethsy J. Pattiasina

2013-11-01

Full Text Available Mud crab is one of the 12 aquaculture commodities of Ministry of Maritime Affairs and Fisheries. Control of reproduction to increase seed production through feed improvement, is one of the challenges and strategies in the mud crab aquaculture. Due to lack of knowledge about broodstock nutrition lead to producing rate of seeds still relatively low. This study aimed to obtain information on the kind of feed that has specific nutrient and plays a role in increasing the success of spawning and zoea survival. Mud crab of Scylla serrata with initial weight of 500.7±103.4 g, preferably under developed gonads were maintained in a fiber tank measuring length of 2.48 m, width 1.26 m, and a height of 60 cm which is partition sealed into 30×40×60 cm3 to put one crab. Tank was equipped with sand as a substrate as high as 15 cm and seawater system with flow rate of 1 L per six minutes and 25 cm high water. Treatments were consisted of: 1. PI (fresh meat fish of Decapterus sp. with dose of 5%, 2. PSC (fresh meat mixture of Decapterus sp. 1.8%, 3% of squid, and shrimp 1.2%, 3. PB (artificial feed dose of 10% of BW, each treatment was repeated three times. Parameters measured were the duration of ovarian to mature, egg diameter, hatching rate, fecundity, and zoea production. Data were analyzed using ANOVA. The quality of larval measured by survival and larval fat and protein content. The results showed that crabs treated by PI and PSC showed faster to get mature compared to PB treatment (p<0.05. Hatching rate of larvae in PSC treatment was higher compared to PI and PB treatments (p<0.05. Furthermore, all treatments did not affect egg diameter, fecundity, and the number of zoea (p>0.05. In conclusion, crab which fed fresh meat (PI and PSC could get mature earlier, and have high percentage of the larval hatching than those of fed by PB. In fact that larvae from broodstock feed of PI has survival as well as protein and fat content were higher than those of fed

Congener Patterns of Persistent Organic Pollutants Establish the Extent of Contaminant Biotransport by Pacific Salmon in the Great Lakes.

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Gerig, Brandon S; Chaloner, Dominic T; Janetski, David J; Rediske, Richard R; O'Keefe, James P; Moerke, Ashley H; Lamberti, Gary A

2016-01-19

In the Great Lakes, introduced Pacific salmon (Oncorhynchus spp.) can transport persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), to new environments during their spawning migrations. To explore the nature and extent of POP biotransport by salmon, we compared 58 PCB and 6 PBDE congeners found in spawning salmon directly to those in resident stream fish. We hypothesized that stream fish exposed to salmon spawners would have congener patterns similar to those of salmon, the presumed contaminant source. Using permutational multivariate analysis of variance (PERMANOVA) and nonmetric multidimensional scaling (NMDS), we found that POP congener patterns of Pacific salmon varied among regions in the Great Lakes basin (i.e., Lake Huron, Lake Michigan, or Lake Superior), tissue type (whole fish or eggs), and contaminant type (PCB or PBDE). For stream-resident fish, POP congener pattern was influenced by the presence of salmon, location (i.e., Great Lakes Basin), and species identity (i.e., brook trout [Salvelinus fontinalis] or mottled sculpin [Cottus bairdii]). Similarity in congener patterns indicated that salmon are a source of POPs to brook trout in stream reaches receiving salmon spawners from Lake Michigan and Lake Huron but not from Lake Superior. Congener patterns of mottled sculpin differed from those of brook trout and salmon, suggesting that brook trout and mottled sculpin either use salmon tissue to differing degrees, acquire POPs from different dietary sources, or bioaccumulate or metabolize POPs differently. Overall, our analyses identified the important role of salmon in contaminant biotransport but also demonstrated that the extent of salmon-mediated POP transfer and uptake in Great Lakes tributaries is location- and species-specific.

Kootenai River fisheries investigations: rainbow and bull trout recruitment: annual progress report 1999; ANNUAL

International Nuclear Information System (INIS)

Walters, Jody P.; Downs, Christopher Charles

2001-01-01

Our 1999 objectives were to determine sources of rainbow trout Oncorhynchus mykiss and bull trout Salvelinus confluentus spawning and recruitment in the Idaho reach of the Kootenai River. We used a rotary-screw trap to capture juvenile trout to determine age at out-migration and to estimate total out-migration from the Boundary Creek drainage to the Kootenai River. The out-migrant estimate for March through August 1999 was 1,574 (95% C. I.= 825-3,283) juvenile rainbow trout. Most juveniles out-migrated at age-2 and age-3. No out-migrating bull trout were caught. Five of 17 rainbow trout radio-tagged in Idaho migrated upstream into Montana waters during the spawning season. Five bull trout originally radio-tagged in O'Brien Creek, Montana in early October moved downstream into Idaho and British Columbia by mid-October. Annual angler exploitation for the rainbow trout population upstream of Bonners Ferry, Idaho was estimated to be 58%. Multi-pass depletion estimates for index reaches of Caboose, Curley, and Debt creeks showed 0.20, 0.01, and 0.13 rainbow trout juveniles/m(sup 2), respectively. We estimated rainbow trout (180-415 mm TL) standing stock of 1.6 kg/ha for the Hemlock Bar reach (29.4 ha) of the Kootenai River, similar to the 1998 estimate. Recruitment of juvenile rainbow and bull trout from Idaho tributaries is not sufficient to be the sole source of subsequent older fish in the mainstem Kootenai River. These populations are at least partly dependent on recruitment from Montana waters. The low recruitment and high exploitation rate may be indicators of a rainbow trout population in danger of further decline

Summary of the Skookumchuck Creek bull trout enumeration project 2001.; TOPICAL

International Nuclear Information System (INIS)

Baxter, James S.; Baxter, Jeremy

2002-01-01

This report summarizes the second year of a bull trout (Salvelinus confluentus) enumeration project on Skookumchuck Creek in southeastern British Columbia. An enumeration fence and traps were installed on the creek from September 6th to October 12th 2001 to enable the capture of post-spawning bull trout emigrating out of the watershed. During the study period, a total of 273 bull trout were sampled through the enumeration fence. Length and weight were determined for all bull trout captured. In total, 39 fish of undetermined sex, 61 males and 173 females were processed through the fence. An additional 19 bull trout were observed on a snorkel survey prior to the fence being removed on October 12th. Coupled with the fence count, the total bull trout enumerated during this project was 292 fish. Several other species of fish were captured at the enumeration fence including westslope cutthroat trout (Oncorhynchus clarki lewisi), Rocky Mountain whitefish (Prosopium williamsoni), and kokanee (O. nerka). A total of 143 bull trout redds were enumerated on the ground in two different locations (river km 27.5-30.5, and km 24.0-25.5) on October 3rd. The majority of redds (n=132) were observed in the 3.0 km index section (river km 27.5-30.5) that has been surveyed over the past five years. The additional 11 redds were observed in a 1.5 km section (river km 24.0-25.5). Summary plots of water temperature for Bradford Creek, Sandown Creek, Buhl Creek, and Skookumchuck Creek at three locations suggested that water temperatures were within the temperature range preferred by bull trout for spawning, egg incubation, and rearing

Monitor and Protect Wigwam River Bull Trout for Koocanusa Reservoir : Summary of the Skookumchuck Creek Bull Trout Enumeration Project, Annual Report 2001.

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Baxter, James S.; Baxter, Jeremy

2002-03-01

This report summarizes the second year of a bull trout (Salvelinus confluentus) enumeration project on Skookumchuck Creek in southeastern British Columbia. An enumeration fence and traps were installed on the creek from September 6th to October 12th 2001 to enable the capture of post-spawning bull trout emigrating out of the watershed. During the study period, a total of 273 bull trout were sampled through the enumeration fence. Length and weight were determined for all bull trout captured. In total, 39 fish of undetermined sex, 61 males and 173 females were processed through the fence. An additional 19 bull trout were observed on a snorkel survey prior to the fence being removed on October 12th. Coupled with the fence count, the total bull trout enumerated during this project was 292 fish. Several other species of fish were captured at the enumeration fence including westslope cutthroat trout (Oncorhynchus clarki lewisi), Rocky Mountain whitefish (Prosopium williamsoni), and kokanee (O. nerka). A total of 143 bull trout redds were enumerated on the ground in two different locations (river km 27.5-30.5, and km 24.0-25.5) on October 3rd. The majority of redds (n=132) were observed in the 3.0 km index section (river km 27.5-30.5) that has been surveyed over the past five years. The additional 11 redds were observed in a 1.5 km section (river km 24.0-25.5). Summary plots of water temperature for Bradford Creek, Sandown Creek, Buhl Creek, and Skookumchuck Creek at three locations suggested that water temperatures were within the temperature range preferred by bull trout for spawning, egg incubation, and rearing.