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Sample records for atlantic cod populations

  1. Transferrin gene polymorphisms and population genetic studies of Atlantic cod (Gadus morhua

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    Berhan Asmamaw

    2016-01-01

    Full Text Available Objective: To detect single nucleotide polymorphisms (SNPs in the cod transferrin gene by comparing the sequences from Norwegian (North East Atlantic Ocean and Canadian (North West Atlantic Ocean specimen, and to quantify the genetic variation and differentiation in East and West Atlantic cod populations. Methods: cDNA sequences between individuals of Canadian (North West Atlantic Ocean and Norwegian (North East Atlantic Ocean origin were aligned. Allele frequencies of the SNPs were used to discriminate the different Atlantic cod populations in West/East Atlantic Ocean, and the Baltic Sea. Results: The sequence alignment detected 19 SNPs, of which 18 of them resulted in amino acid changes in the transferrin protein. Nonsynonymous to synonymous site substitution ratio (dn/ ds was by far greater than 1 providing an evidence for the existence of positive selection. The West Atlantic cod populations showed high values of heterozygosity and the Baltic populations were found to be inbred. Conclusions: This study identified and indicated transferrin gene polymorphisms that can be used for population differentiations.

  2. Differences in salinity tolerance and gene expression between two populations of Atlantic cod (Gadus morhua) in response to salinity stress

    DEFF Research Database (Denmark)

    Larsen, Peter Foged; Eg Nielsen, Einar; Meier, Kristian

    2012-01-01

    in salinity tolerance and gene expression among Atlantic cod (Gadus morhua) from two populations distributed across a steep salinity gradient, we observed high mortality (45% North Sea cod and 80% Baltic Sea cod) in a reciprocal common garden setup. Quantitative RT-PCR assays for expression of hsp70 and Na....... The findings strongly suggest that Atlantic cod are adapted to local saline conditions, despite relatively low levels of neutral genetic divergence between populations...

  3. Hierarchical modelling of temperature and habitat size effects on population dynamics of North Atlantic cod

    DEFF Research Database (Denmark)

    Mantzouni, Irene; Sørensen, Helle; O'Hara, Robert B.

    2010-01-01

    Understanding how temperature affects cod (Gadus morhua) ecology is important for forecasting how populations will develop as climate changes in future. The effects of spawning-season temperature and habitat size on cod recruitment dynamics have been investigated across the North Atlantic. Ricker...... and Beverton and Holt stock–recruitment (SR) models were extended by applying hierarchical methods, mixed-effects models, and Bayesian inference to incorporate the influence of these ecosystem factors on model parameters representing cod maximum reproductive rate and carrying capacity. We identified...

  4. Environmental, population and life-stage plasticity in the visual system of Atlantic cod.

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    Valen, Ragnhild; Karlsen, Rita; Helvik, Jon Vidar

    2018-01-11

    The visual system is for many fishes essential in guiding behaviors, such as foraging, predator avoidance and mate choice. The marine environment is characterized by large spatio-temporal fluctuations in light intensity and spectral composition. However, visual capabilities are restricted by both space limitations set by eye size and by the genomic content of light-absorbing opsin genes. The rich array of visual opsins in teleosts may be used differentially to tune vision towards specific needs during ontogeny and to changing light. Yet, to what extent visual plasticity is a pre-programmed developmental event, or is triggered by photic environment, is unclear. Our previous studies on Atlantic cod revealed an evolutionary genomic loss of UV-sensitive sws1 and red-sensitive lws opsin families, while blue-sensitive sws2 and green-sensitive rh2 opsins had duplicated. The current study has taken an opsin expression approach to characterize visual plasticity in cod towards different spectral light during the larval stage, to maturation and extreme seasonal changes in the Barents Sea. Our data suggest that opsin plasticity in cod larvae is controlled by developmental programme rather than immediate light environment. The lack of expressional changes during maturation suggests a less important role for visual modulation related to mate choice. Although no seasonal effects on visual opsins were detected in migratory Northeast Arctic cod, the expressed opsin subset differed from the more stationary Norwegian coastal cod described in previous studies. Interestingly, these data provide the first indications of a population difference in actively used visual opsins associated with cod ecotypes. © 2018. Published by The Company of Biologists Ltd.

  5. Inter-population ovarian fluid variation differentially modulates sperm motility in Atlantic cod Gadus morhua.

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    Beirão, J; Purchase, C F; Wringe, B F; Fleming, I A

    2015-07-01

    This study tested the hypothesis that the effects of Atlantic cod Gadus morhua ovarian fluid on sperm motility variables are population specific. Sperm from a northern G. morhua population were activated in the presence of ovarian fluid from either northern or southern G. morhua at different concentrations. Ovarian fluid acted as a filter, in some cases reducing sperm swimming performance compared with seawater. Fluid from females foreign in population (southern) to the males (northern) had a greater inhibiting effect than those from the native population. Follow-up analysis indicated that the ovarian fluids had lower Ca(2+) concentration in northern than southern G. morhua, which could be the causative mechanism. If widespread, such cryptic female choice could reduce the incidence of intraspecific hybridization among diverged populations and contribute to reproductive isolation. © 2015 The Fisheries Society of the British Isles.

  6. Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population.

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    Stiasny, Martina H; Mittermayer, Felix H; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B H; Clemmesen, Catriona

    2016-01-01

    How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae's sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks.

  7. Bay-scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Wroblewski, J.S.; Taggart, C.T.

    2000-01-01

    of population structure suggest that important barriers to gene flow exist among five components that include two inshore (Gilbert and Trinity Bay) and three offshore cod aggregations on the north-east Newfoundland Shelf and the Grand Bank. D-A and D-SW estimates of genetic distance that involve Gilbert Bay cod...

  8. Population structure in Atlantic cod in the eastern North Sea-Skagerrak-Kattegat: early life stage dispersal and adult migration.

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    André, Carl; Svedäng, Henrik; Knutsen, Halvor; Dahle, Geir; Jonsson, Patrik; Ring, Anna-Karin; Sköld, Mattias; Jorde, Per Erik

    2016-02-03

    In marine fish species, where pelagic egg and larvae drift with ocean currents, population structure has been suggested to be maintained by larval retention due to hydrographic structuring and by homing of adult fish to natal areas. Whilst natal homing of adults has been demonstrated for anadromous and coral reef fishes, there are few documented examples of philopatric migration in temperate marine fish species. Here, we demonstrate temporally stable genetic differentiation among spawning populations of Atlantic cod (Gadus morhua L.), and present genetic and behavioural evidence for larval drift and philopatric migration in the eastern North Sea-Skagerrak-Kattegat area. We show that juvenile cod collected in the eastern Skagerrak and central Kattegat are genetically similar to cod from offshore spawning areas in the eastern North Sea. Genetic assignment of individual 2-5 year old fish indicates that cod residing at, or migrating towards, spawning areas in Kattegat and the North Sea display philopatric behaviours. Together these findings suggest a loop between spawning, larval drift and adult return-migrations to spawning areas and underlines that both oceanographic processes and migratory behaviour in the adult phase may be important for stock separation and integrity in marine temperate fishes such as Atlantic cod.

  9. Selection of reference genes for qRT-PCR examination of wild populations of Atlantic cod Gadus morhua

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    Lie Kai K

    2008-07-01

    Full Text Available Abstract Background Extensive sequencing efforts have been taking place for the Atlantic cod (Gadus morhua in recent years, the number of ESTs in the Genbank has reached more than 140.000. Despite its importance in North Atlantic fisheries and potential use in aquaculture, relatively few gene expression examination exists for this species, and systematic evaluations of reference gene stability in quantitative real-time RT-PCR (qRT-PCR studies are lacking. Results The stability of 10 potential reference genes was examined in six tissues of Atlantic cod obtained from four populations, to determine the most suitable genes to be used in qRT-PCR analyses. Relative transcription levels of genes encoding β-actin (ACTB, elongation factor 1A (EF1A, actin-related protein-2 (ARP-2, glyceraldehyde-3P-dehydrogenase (GAPDH, ubiquitin (Ubi, acidic ribosomal protein (ARP, ribosomal protein S9 (S9, ribosomal protein L4 (RPL4, RPL22 and RPL37 were quantified in gills, brain, liver, head kidney, muscle and middle intestine in six juvenile fish from three wild populations and from farmed Atlantic cod. Reference gene stability was investigated using the geNorm and NormFinder tools. Based on calculations performed with the geNorm, which determines the most stable genes from a set of tested genes in a given cDNA sample, ARP, Ubi, S9 and RPL37 were among the most stable genes in all tissues. When the same calculations were done with NormFinder, the same genes plus RPL4 and EF1A were ranked as the preferable genes. Conclusion Overall, this work suggests that the Ubi and ARP can be useful as reference genes in qRT-PCR examination of gene expression studying wild populations of Atlantic cod.

  10. Selection of reference genes for qRT-PCR examination of wild populations of Atlantic cod Gadus morhua.

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    Olsvik, Pål A; Søfteland, Liv; Lie, Kai K

    2008-07-16

    Extensive sequencing efforts have been taking place for the Atlantic cod (Gadus morhua) in recent years, the number of ESTs in the Genbank has reached more than 140.000. Despite its importance in North Atlantic fisheries and potential use in aquaculture, relatively few gene expression examination exists for this species, and systematic evaluations of reference gene stability in quantitative real-time RT-PCR (qRT-PCR) studies are lacking. The stability of 10 potential reference genes was examined in six tissues of Atlantic cod obtained from four populations, to determine the most suitable genes to be used in qRT-PCR analyses. Relative transcription levels of genes encoding beta-actin (ACTB), elongation factor 1A (EF1A), actin-related protein-2 (ARP-2), glyceraldehyde-3P-dehydrogenase (GAPDH), ubiquitin (Ubi), acidic ribosomal protein (ARP), ribosomal protein S9 (S9), ribosomal protein L4 (RPL4), RPL22 and RPL37 were quantified in gills, brain, liver, head kidney, muscle and middle intestine in six juvenile fish from three wild populations and from farmed Atlantic cod. Reference gene stability was investigated using the geNorm and NormFinder tools. Based on calculations performed with the geNorm, which determines the most stable genes from a set of tested genes in a given cDNA sample, ARP, Ubi, S9 and RPL37 were among the most stable genes in all tissues. When the same calculations were done with NormFinder, the same genes plus RPL4 and EF1A were ranked as the preferable genes. Overall, this work suggests that the Ubi and ARP can be useful as reference genes in qRT-PCR examination of gene expression studying wild populations of Atlantic cod.

  11. Large effective population size and temporal genetic stability in Atlantic cod (Gadus morhua) in the southern Gulf of St. Lawrence

    DEFF Research Database (Denmark)

    Therkildsen, Nina Overgaard; Eg Nielsen, Einar; Swain, Douglas P.

    2010-01-01

    compares the genetic variability at nine microsatellite loci in a Canadian population of Atlantic cod (Gadus morhua) over 80 years, spanning from before the fishery intensified to now when the population is at historically low abundance. Extensively validated genetic data from the temporally spaced samples......Worldwide, many commercial fish stocks have experienced dramatic declines due to overfishing. Such fisheries-induced population reductions could potentially erode the genetic diversity of marine fish populations. Based on analyses of DNA extracted from archived and contemporary samples, this paper...

  12. A review of the evidence for genetic structure of cod ( Gadus morhua ) populations in the NW Atlantic and population affinities of larval cod off Newfoundland and the Gulf of St. Lawrence

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Taggart, C.T.; Cook, D.

    1999-01-01

    We review our recent studies on the genetic structure of Atlantic cod (Gadus morhua) populations in the NW Atlantic. Our conclusions are based on knowledge of polymorphism at microsatellite DNA loci combined with known aspects of cod biology and ecology and with known oceanographic features...... in the NW Atlantic. Three case studies illustrate genetic heterogeneity between cod populations at the meso- and large- scales of coastal embayments and offshore banks and at the small-scale of oceanographic features. Our results generally highlight the importance of combining genetic with physiological......, ecological, and oceanographic information, when assessing the genetic structure of highly abundant, widely distributed, and high gene-flow marine fish species. We highlight the role that oceanographic features (e.g., gyre-like systems) and known spatio-temporal differences in spawning time may play...

  13. Life-history evolution and elevated natural mortality in a population of Atlantic cod (Gadus morhua).

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    Swain, Douglas P

    2011-01-01

    Fisheries-induced evolution has been hypothesized to delay the recovery of collapsed fish stocks through effects on their productivity. The cod stock in the southern Gulf of St. Lawrence (SGSL) collapsed in the early 1990s and has shown no recovery since then, due mainly to high natural mortality of adult cod. Age and size at maturation of SGSL cod decreased sharply over time in cohorts produced in the 1950s and 1960s, likely reflecting an evolutionary response to intensified fishing, and have remained low since then, despite severe reductions in fishing mortality over the past 15 years. A predicted consequence of early maturation is increased natural mortality due to higher costs to reproduction. Early maturation may be a cause of increases in natural mortality of SGSL cod in the 1970s but does not appear to be related to the much larger increases since then. Instead, the current high natural mortality of SGSL cod appears to be primarily a cause, rather than a consequence, of the continued early maturation in this population, now replacing fishing mortality as the agent of selection favouring early maturity. This striking example of the failure to reverse fisheries-induced evolution by relaxing fishing pressure emphasizes the need for management strategies that minimize the chances of harvest-induced genetic change.

  14. Evolutionary history and adaptive significance of the polymorphic Pan I in migratory and stationary populations of Atlantic cod (Gadus morhua).

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    Andersen, Øivind; Johnsen, Hanne; De Rosa, Maria Cristina; Præbel, Kim; Stjelja, Suzana; Kirubakaran, Tina Graceline; Pirolli, Davide; Jentoft, Sissel; Fevolden, Svein-Erik

    2015-08-01

    The synaptophysin (SYP) family comprises integral membrane proteins involved in vesicle-trafficking events, but the physiological function of several members has been enigmatic for decades. The presynaptic SYP protein controls neurotransmitter release, while SYP-like 2 (SYPL2) contributes to maintain normal Ca(2+)-signaling in the skeletal muscles. The polymorphic pantophysin (Pan I) of Atlantic cod shows strong genetic divergence between stationary and migratory populations, which seem to be adapted to local environmental conditions. We have investigated the functional involvement of Pan I in the different ecotypes by analyzing the 1) phylogeny, 2) spatio-temporal gene expression, 3) structure-function relationship of the Pan I(A) and I(B) protein variants, and 4) linkage to rhodopsin (rho) recently proposed to be associated with different light sensitivities in Icelandic populations of Atlantic cod. We searched for SYP family genes in phylogenetic key species and identified a single syp-related gene in three invertebrate chordates, while four members, Syp, Sypl1, Sypl2 and synaptoporin (Synpr), were found in tetrapods, Comoran coelacanth and spotted gar. Teleost fish were shown to possess duplicated syp, sypl2 and synpr genes of which the sypl2b paralog is identical to Pan I. The ubiquitously expressed cod Pan I codes for a tetra-spanning membrane protein possessing five amino acid substitutions in the first intravesicular loop, but only minor structural differences were shown between the allelic variants. Despite sizable genomic distance (>2.5 Mb) between Pan I and rho, highly significant linkage disequilibrium was found by genotyping shallow and deep water juvenile settlers predominated by the Pan I(A)-rho(A) and Pan I(B)-rho(B) haplotypes, respectively. However, the predicted rhodopsin protein showed no amino acid changes, while multiple polymorphic sites in the upstream region might affect the gene expression and pigment levels in stationary and migratory cod

  15. EVOLUTION OF ATLANTIC AND PACIFIC COD: LOSS OF GENETIC VARIATION AND GENE EXPRESSION IN PACIFIC COD.

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    Grant, W Stewart; Ståhl, Gunnar

    1988-01-01

    An allozyme investigation of 41 protein-coding loci in two morphologically similar fishes, Atlantic and Pacific cod, indicates that Pacific cod experienced a severe population bottleneck that led to the loss of gene diversity and gene expression. Pacific cod possesses a significantly lesser amount of gene diversity (H = 0.032) than Atlantic cod (H = 0.125) and lacks gene expression for Me-3. Allele-frequency distributions differ between species as predicted by neutral theory: Atlantic cod has a U-shaped distribution, which is expected for populations in drift-mutation equilibrium, whereas Pacific cod has a J-shaped distribution with an excess of low-frequency alleles. This excess may be explained by the appearance of new alleles through mutation which have not yet reached intermediate frequencies through drift. The population bottleneck in Pacific cod was most likely associated with founder populations that dispersed into the Pacific Ocean after the Bering Strait opened. Under the molecular-clock hypothesis a Nei genetic distance of 0.415 (based on 41 loci) suggests that Pacific cod dispersed into the Pacific Ocean soon after the Bering Strait opened in the mid-Pliocene, 3.0 to 3.5 million years ago. © 1988 The Society for the Study of Evolution.

  16. Cod Collapse and the Climate in the North Atlantic

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    Meng, K. C.; Oremus, K. L.; Gaines, S.

    2014-12-01

    Effective fisheries management requires forecasting population changes. We find a negative relationship between the North Atlantic Oscillation (NAO) index and subsequently surveyed biomass and catch of Atlantic cod, Gadus morhua, off the New England coast. A 1-unit NAO increase is associated with a 17% decrease in surveyed biomass of age-1 cod the following year. This relationship persists as the cod mature, such that observed NAO can be used to forecast future adult biomass. We also document that an NAO event lowers catch for up to 15 years afterward. In contrast to forecasts by existing stock assessment models, our NAO-driven statistical model successfully hindcasts the recent collapse of New England cod fisheries following strong NAO events in 2007 and 2008 (see figure). This finding can serve as a template for forecasting other fisheries affected by climatic conditions.

  17. Behavioral responses of Atlantic cod to sea temperature changes.

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    Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

    2015-05-01

    Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30-80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species.

  18. A nuclear DNA basis for shelf- and bank scale population structure in northwest Atlantic cod ( Gadus morhua ) : Labrador to Georges Bank

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Taggart, C.T.; Cook, D.

    1998-01-01

    Variation at five microsatellite DNA loci scored in approximate to 1300 individuals provided evidence of genetic structure among 14 cod (Gadus morhua) populations spanning the range of the species in the northwest (NW) Atlantic. Using DA and Ds, measures of genetic distance, as well as F-ST and R...... structure at spawning-bank scales consistent with variation in oceanographic features and in the spatiotemporal distribution of spawning, each of which may represent barriers to gene flow among geographically contiguous populations inhabiting a highly advective environment. The differences described...... by the associated oceanographic features and processes that conceivably form the template for the evolution of the structure. We suggest that bathymetric and hydrodynamic structure represents a rational starting point for developing hypotheses to examine the processes that lead to the genetic structuring of marine...

  19. Harvesting Atlantic Cod under Climate Variability

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    Oremus, K. L.

    2016-12-01

    Previous literature links the growth of a fishery to climate variability. This study uses an age-structured bioeconomic model to compare optimal harvest in the Gulf of Maine Atlantic cod fishery under a variable climate versus a static climate. The optimal harvest path depends on the relationship between fishery growth and the interest rate, with higher interest rates dictating greater harvests now at the cost of long-term stock sustainability. Given the time horizon of a single generation of fishermen under assumptions of a static climate, the model finds that the economically optimal management strategy is to harvest the entire stock in the short term and allow the fishery to collapse. However, if the biological growth of the fishery is assumed to vary with climate conditions, such as the North Atlantic Oscillation, there will always be pulses of high growth in the stock. During some of these high-growth years, the growth of the stock and its economic yield can exceed the growth rate of the economy even under high interest rates. This implies that it is not economically optimal to exhaust the New England cod fishery if NAO is included in the biological growth function. This finding may have theoretical implications for the management of other renewable yet exhaustible resources whose growth rates are subject to climate variability.

  20. Cod Collapse and Climate in the North Atlantic

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    Oremus, K. L.; Meng, K. C.; Gaines, S.

    2016-02-01

    Understanding the determinants of fish population dynamics is crucial to the recovery of many fisheries. Current research emphasizes the role of environmental conditions in driving fish populations, but the magnitude of and mechanisms behind these effects on crucial populations are not well established. Despite aggressive management efforts, New England cod fisheries have been in decline for several decades and have now reached unprecedented lows. We find a strong negative relationship between the North Atlantic Oscillation (NAO) and subsequent adult cod biomass and catch. In the Gulf of Maine fishery, a 1-unit NAO increase is associated with a 13% decrease in the biomass of age-1 cod the following year, a decrease that persists as the affected cohort matures. We further detect that a 1-unit NAO increase can lower commercial catch for up to 19 subsequent years, suggesting that fishing practices may be inadvertently exacerbating NAO's direct biological effects. These results imply that 18% and 32% of the overall decline in adult biomass and catch, respectively, since 1980 can be attributed to the NAO's recent multi-decadal positive phase. The Georges Bank cod fishery displays similar patterns. Because there is a delay between an NAO event and subsequent declines in adult biomass, our finding implies that already observed NAO events can be used in stock forecasts, providing lead time for adaptive policy. More broadly, our approach can inform forecasting efforts for other fisheries strongly affected by natural and anthropogenic climatic variation.

  1. Gillnet selectivity for North Sea Atlantic cod ( Gadus morhua )

    DEFF Research Database (Denmark)

    Hovgård, Holger; Lassen, H.; Madsen, Niels

    1999-01-01

    Gillnet selectivity curves for North Sea Atlantic cod (Gadus morhua) were fitted to catch data obtained with six different mesh sizes. The selectivity curves investigated included frequently used selectivity models following the normal, lognormal, and gamma distributions. Another group...

  2. Interactions between small pelagic fish and young cod across the north Atlantic.

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    Minto, Cóilín; Worm, Boris

    2012-10-01

    Species interactions that play out over large spatial scales are difficult to observe, particularly in the oceans. The current lack of empirical evidence for biologically meaningful interaction parameters likely delays the application of holistic management procedures. Here we estimate interactions during the early life history of fish across regions. We present separate and hierarchical Bayesian models that estimate the direction and strength of interactions between Atlantic cod and dominant pelagic fishes across much of their range in the North Atlantic. We test the hypothesis that small pelagic fish may reduce survival of cod at early life stages, and thereby contribute to the delayed recovery of depleted cod populations. Significant regional variation exists between cod recruitment and Atlantic herring abundance with eight of 14 regions displaying a negative relationship, four regions displaying no relationship, and a positive relationship observed in two regions. In contrast, most regions where Atlantic mackerel co-occurs showed no relationship with cod recruitment, with the possible exception of Gulf of St. Lawrence and Celtic Sea regions. Regions with sprat or capelin as dominant pelagics also displayed weak or no relationship, although the probability of a negative interaction with sprat increased when time series autocorrelation was accounted for. Overall, the interaction between herring and young cod was found to be negative with 94% probability, while the probability of negative interactions with mackerel was only 68%. Our findings suggest that the strength of predation or competition effects on young cod varies among small pelagic species but appears consistently for Atlantic herring; this effect may need to be considered in recovery trajectories for depleted cod populations. The methods introduced here are applicable in the investigation of species interactions from time series data collected across different study systems.

  3. Atlantic cod (Gadus morhua) hemoglobin genes: multiplicity and polymorphism

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    Borza, Tudor; Stone, Cynthia; Gamperl, A Kurt; Bowman, Sharen

    2009-01-01

    Background Hemoglobin (Hb) polymorphism, assessed by protein gel electrophoresis, has been used almost exclusively to characterize the genetic structure of Atlantic cod (Gadus morhua) populations and to establish correlations with phenotypic traits such as Hb oxygen binding capacity, temperature tolerance and growth characteristics. The genetic system used to explain the results of gel electrophoresis entails the presence of one polymorphic locus with two major alleles (HbI-1; HbI-2). However, vertebrates have more than one gene encoding Hbs and recent studies have reported that more than one Hb gene is present in Atlantic cod. These observations prompted us to re-evaluate the number of Hb genes expressed in Atlantic cod, and to perform an in depth search for polymorphisms that might produce relevant phenotypes for breeding programs. Results Analysis of Expressed Sequence Tags (ESTs) led to the identification of nine distinct Hb transcripts; four corresponding to the α Hb gene family and five to the β Hb gene family. To gain insights about the Hb genes encoding these transcripts, genomic sequence data was generated from heterozygous (HbI-1/2) parents and fifteen progeny; five of each HbI type, i.e., HbI-1/1, HbI-1/2 and HbI-2/2. β Hb genes displayed more polymorphism than α Hb genes. Two major allele types (β1A and β1B) that differ by two linked non-synonymous substitutions (Met55Val and Lys62Ala) were found in the β1 Hb gene, and the distribution of these β1A and β1B alleles among individuals was congruent with that of the HbI-1 and HbI-2 alleles determined by protein gel electrophoresis. RT-PCR and Q-PCR analysis of the nine Hb genes indicates that all genes are expressed in adult fish, but their level of expression varies greatly; higher expression of almost all Hb genes was found in individuals displaying the HbI-2/2 electrophoretic type. Conclusion This study indicates that more Hb genes are present and expressed in adult Atlantic cod than previously

  4. Atlantic cod (Gadus morhua hemoglobin genes: multiplicity and polymorphism

    Directory of Open Access Journals (Sweden)

    Gamperl A Kurt

    2009-09-01

    Full Text Available Abstract Background Hemoglobin (Hb polymorphism, assessed by protein gel electrophoresis, has been used almost exclusively to characterize the genetic structure of Atlantic cod (Gadus morhua populations and to establish correlations with phenotypic traits such as Hb oxygen binding capacity, temperature tolerance and growth characteristics. The genetic system used to explain the results of gel electrophoresis entails the presence of one polymorphic locus with two major alleles (HbI-1; HbI-2. However, vertebrates have more than one gene encoding Hbs and recent studies have reported that more than one Hb gene is present in Atlantic cod. These observations prompted us to re-evaluate the number of Hb genes expressed in Atlantic cod, and to perform an in depth search for polymorphisms that might produce relevant phenotypes for breeding programs. Results Analysis of Expressed Sequence Tags (ESTs led to the identification of nine distinct Hb transcripts; four corresponding to the α Hb gene family and five to the β Hb gene family. To gain insights about the Hb genes encoding these transcripts, genomic sequence data was generated from heterozygous (HbI-1/2 parents and fifteen progeny; five of each HbI type, i.e., HbI-1/1, HbI-1/2 and HbI-2/2. β Hb genes displayed more polymorphism than α Hb genes. Two major allele types (β1A and β1B that differ by two linked non-synonymous substitutions (Met55Val and Lys62Ala were found in the β1 Hb gene, and the distribution of these β1A and β1B alleles among individuals was congruent with that of the HbI-1 and HbI-2 alleles determined by protein gel electrophoresis. RT-PCR and Q-PCR analysis of the nine Hb genes indicates that all genes are expressed in adult fish, but their level of expression varies greatly; higher expression of almost all Hb genes was found in individuals displaying the HbI-2/2 electrophoretic type. Conclusion This study indicates that more Hb genes are present and expressed in adult

  5. Microgeographical population structure and adaptation in Atlantic cod Gadus morhua: spatio-temporal insights from gene-associated DNA markers

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Hemmer-Hansen, Jakob; Loeschcke, V.

    2011-01-01

    populations, indicating long-term temporal adaptive stability driven by strong local selection. In an environmentally dynamic area, on the other hand, patterns of genetic structuring were more variable. Overall, our results not only suggest separation of populations under both evolutionary and ecological...... paradigms, but also illustrate the usefulness of the spatio-temporal approach for making inferences about the dynamics and geographical distribution of adaptive genetic variation in natural populations.......Recent technical advances have stimulated studies on spatial scales of adaptive genetic variation in marine fishes. However, very few studies have combined spatial and temporal sampling to investigate adaptive genetic structuring at local and microgeographical scales, i.e. scales at which neutral...

  6. Large-scale sequence analyses of Atlantic cod.

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    Johansen, Steinar D; Coucheron, Dag H; Andreassen, Morten; Karlsen, Bård Ove; Furmanek, Tomasz; Jørgensen, Tor Erik; Emblem, Ase; Breines, Ragna; Nordeide, Jarle T; Moum, Truls; Nederbragt, Alexander J; Stenseth, Nils C; Jakobsen, Kjetill S

    2009-06-01

    The Atlantic cod (Gadus morhua) is a key species in the North Atlantic ecosystem and commercial fisheries, with increasing aquacultural production in several countries. A Norwegian effort to sequence the complete 0.9Gbp genome by the 454 pyrosequencing technology has been initiated and is in progress. Here we review recent progress in large-scale sequence analyses of the nuclear genome, the mitochondrial genome and genome-wide microRNA identification in the Atlantic cod. The nuclear genome will be de novo sequenced with 25 times oversampling. A total of 120 mitochondrial genomes, sampled from several locations in the North Atlantic, are being completely sequenced by Sanger technology in a high-throughput pipeline. These sequences will be included in a new database for maternal marker reference of Atlantic cod diversity. High-throughput 454 sequencing, as well as Evolutionary Image Array (EvoArray) informatics, is used to investigate the complete set of expressed microRNAs and corresponding mRNA targets in various developmental stages and tissues. Information about microRNA profiles will be essential in the understanding of transcriptome complexity and regulation. Finally, developments and perspectives of Atlantic cod aquaculture are discussed in the light of next-generation high-throughput sequence technologies.

  7. What is the carrying capacity for fish in the ocean? A meta analysis of population dynamics of North Atlantic cod

    DEFF Research Database (Denmark)

    Myers, R.A.; MacKenzie, Brian; Bowen, K.G.

    2001-01-01

    Population and community data in one study are usually analyzed in isolation from other data. Here, we introduce statistical methods that allow many data sets to be analyzed simultaneously such that different studies may "borrow strength" from each other. In the simplest case, we simultaneously m...

  8. Identification and characterisation of novel SNP markers in Atlantic cod: Evidence for directional selection

    Directory of Open Access Journals (Sweden)

    Fjalestad Kjersti T

    2008-02-01

    Full Text Available Abstract Background The Atlantic cod (Gadus morhua is a groundfish of great economic value in fisheries and an emerging species in aquaculture. Genetic markers are needed to identify wild stocks in order to ensure sustainable management, and for marker-assisted selection and pedigree determination in aquaculture. Here, we report on the development and evaluation of a large number of Single Nucleotide Polymorphism (SNP markers from the alignment of Expressed Sequence Tag (EST sequences in Atlantic cod. We also present basic population parameters of the SNPs in samples of North-East Arctic cod and Norwegian coastal cod obtained from three different localities, and test for SNPs that may have been targeted by natural selection. Results A total of 17,056 EST sequences were used to find 724 putative SNPs, from which 318 segregating SNPs were isolated. The SNPs were tested on Atlantic cod from four different sites, comprising both North-East Arctic cod (NEAC and Norwegian coastal cod (NCC. The average heterozygosity of the SNPs was 0.25 and the average minor allele frequency was 0.18. FST values were highly variable, with the majority of SNPs displaying very little differentiation while others had FST values as high as 0.83. The FST values of 29 SNPs were found to be larger than expected under a strictly neutral model, suggesting that these loci are, or have been, influenced by natural selection. For the majority of these outlier SNPs, allele frequencies in a northern sample of NCC were intermediate between allele frequencies in a southern sample of NCC and a sample of NEAC, indicating a cline in allele frequencies similar to that found at the Pantophysin I locus. Conclusion The SNP markers presented here are powerful tools for future genetics work related to management and aquaculture. In particular, some SNPs exhibiting high levels of population divergence have potential to significantly enhance studies on the population structure of Atlantic cod.

  9. Identification and characterisation of novel SNP markers in Atlantic cod: evidence for directional selection.

    Science.gov (United States)

    Moen, Thomas; Hayes, Ben; Nilsen, Frank; Delghandi, Madjid; Fjalestad, Kjersti T; Fevolden, Svein-Erik; Berg, Paul R; Lien, Sigbjørn

    2008-02-26

    The Atlantic cod (Gadus morhua) is a groundfish of great economic value in fisheries and an emerging species in aquaculture. Genetic markers are needed to identify wild stocks in order to ensure sustainable management, and for marker-assisted selection and pedigree determination in aquaculture. Here, we report on the development and evaluation of a large number of Single Nucleotide Polymorphism (SNP) markers from the alignment of Expressed Sequence Tag (EST) sequences in Atlantic cod. We also present basic population parameters of the SNPs in samples of North-East Arctic cod and Norwegian coastal cod obtained from three different localities, and test for SNPs that may have been targeted by natural selection. A total of 17,056 EST sequences were used to find 724 putative SNPs, from which 318 segregating SNPs were isolated. The SNPs were tested on Atlantic cod from four different sites, comprising both North-East Arctic cod (NEAC) and Norwegian coastal cod (NCC). The average heterozygosity of the SNPs was 0.25 and the average minor allele frequency was 0.18. FST values were highly variable, with the majority of SNPs displaying very little differentiation while others had FST values as high as 0.83. The FST values of 29 SNPs were found to be larger than expected under a strictly neutral model, suggesting that these loci are, or have been, influenced by natural selection. For the majority of these outlier SNPs, allele frequencies in a northern sample of NCC were intermediate between allele frequencies in a southern sample of NCC and a sample of NEAC, indicating a cline in allele frequencies similar to that found at the Pantophysin I locus. The SNP markers presented here are powerful tools for future genetics work related to management and aquaculture. In particular, some SNPs exhibiting high levels of population divergence have potential to significantly enhance studies on the population structure of Atlantic cod.

  10. Spatial and Temporal Patterns in the Cod Fisheries of the North Atlantic

    Directory of Open Access Journals (Sweden)

    Anne Hayden

    2015-01-01

    Full Text Available Atlantic Cod Gadus morhua has been subject to commercial exploitation since the thirteenth century. An analysis of cod fisheries over space and time reveals a pattern of serial depletion that reflects the cross-scale interaction of fish population structure, economic incentives, developments in fishing technology, and government efforts to limit access to fishing areas. Three case studies from Newfoundland and Labrador, the larger Northwest Atlantic, and the Gulf of Maine illustrate a pattern of fish population depletion followed by expansion of fishing activity that repeats at a range of scales. The meta-population structure of cod populations allows overharvesting, even when strict but broadscale controls are in place. The results argue for the reform of fisheries management to incorporate governance that more closely reflects the scale of the local components of metapopulations.

  11. Genome architecture enables local adaptation of Atlantic cod despite high connectivity

    DEFF Research Database (Denmark)

    Barth, Julia M I; Berg, Paul R; Jonsson, Per R.

    2017-01-01

    characterized by strong levels of gene flow. As one example, populations of the marine fish Atlantic cod (Gadus morhua) are highly connected due to immense dispersal capabilities but nevertheless show local adaptation in several key traits. By combining population genomic analyses based on 12K single......-nucleotide polymorphisms with larval dispersal patterns inferred using a biophysical ocean model, we show that Atlantic cod individuals residing in sheltered estuarine habitats of Scandinavian fjords mainly belong to offshore oceanic populations with considerable connectivity between these diverse ecosystems. Nevertheless...... Mb chromosomal rearrangement in fjord cod, previously proposed to comprise genes critical for the survival at low salinities. This suggests that despite considerable connectivity with offshore populations, local adaptation to fjord environments may be enabled by suppression of recombination...

  12. Transport of North Sea cod larvae into the Skagerrak coastal populations.

    OpenAIRE

    Knutsen, Halvor; André, Carl; Jorde, Per Erik; Skogen, Morten D.; Thuróczy, Emma; Stenseth, Nils Chr.

    2004-01-01

    The Atlantic cod (Gadus morhua) is economically one of the world's most important marine species--a species presently suffering from heavy overexploitation throughout its range of distribution. Although not fully understood, the Atlantic cod is believed to be structured into populations in a rather complex manner, whereby both highly migratory and more confined ocean-spawning stocks coexist with stationary coastal populations. Owing to the complex population structure, little is presently kno...

  13. Yersiniosis in Atlantic cod, Gadus morhua (L.), characterization of the infective strain and host reactions.

    Science.gov (United States)

    Gudmundsdottir, B K; Gudmundsdottir, S; Gudmundsdottir, S; Magnadottir, B

    2014-06-01

    A disease outbreak in farmed Atlantic cod caused by Yersinia ruckeri is reported. Mortality started following vaccination of cod reared in two tanks (A and B). The accumulated mortality reached 1.9% in A and 4.8% in B in the following 30 days when treatment with oxytetracycline was applied. Biochemical and molecular analysis of Y. ruckeri isolates from the cod and other fish species from fresh and marine waters in Iceland revealed a high salinity-tolerant subgroup of Y. ruckeri serotype O1. Infected fish showed clinical signs comparable with those of Y. ruckeri -infected salmonids, with the exception of granuloma formations in infected cod tissues, which is a known response of cod to bacterial infections. Immunohistological examination showed Y. ruckeri antigens in the core of granulomas and the involvement of immune parameters that indicates a strong association between complement and lysozyme killing of bacteria. Experimental infection of cod with a cod isolate induced disease, and the calculated LD50 was 1.7 × 10(4) CFU per fish. The results suggest that yersiniosis can be spread between populations of freshwater and marine fish. Treatment of infected cod with antibiotic did not eliminate the infection, which can be explained by the immune response of cod producing prolonged granulomatous infection. © 2013 John Wiley & Sons Ltd.

  14. Genomic divergence between the migratory and stationary ecotypes of Atlantic cod.

    Science.gov (United States)

    Karlsen, Bård O; Klingan, Kevin; Emblem, Åse; Jørgensen, Tor E; Jueterbock, Alexander; Furmanek, Tomasz; Hoarau, Galice; Johansen, Steinar D; Nordeide, Jarle T; Moum, Truls

    2013-10-01

    Atlantic cod displays a range of phenotypic and genotypic variations, which includes the differentiation into coastal stationary and offshore migratory types of cod that co-occur in several parts of its distribution range and are often sympatric on the spawning grounds. Differentiation of these ecotypes may involve both historical separation and adaptation to ecologically distinct environments, the genetic basis of which is now beginning to be unravelled. Genomic analyses based on recent sequencing advances are able to document genomic divergence in more detail and may facilitate the exploration of causes and consequences of genome-wide patterns. We examined genomic divergence between the stationary and migratory types of cod in the Northeast Atlantic, using next-generation sequencing of pooled DNA from each of two population samples. Sequence data was mapped to the published cod genome sequence, arranged in more than 6000 scaffolds (611 Mb). We identified 25 divergent scaffolds (26 Mb) with a higher than average gene density, against a backdrop of overall moderate genomic differentiation. Previous findings of localized genomic divergence in three linkage groups were confirmed, including a large (15 Mb) genomic region, which seems to be uniquely involved in the divergence of migratory and stationary cod. The results of the pooled sequencing approach support and extend recent findings based on single-nucleotide polymorphism markers and suggest a high degree of reproductive isolation between stationary and migratory cod in the North-east Atlantic. © 2013 John Wiley & Sons Ltd.

  15. Molecular responce of Atlantic cod's ( Gadus morhua L.) cypia ...

    African Journals Online (AJOL)

    A molecular response study was conducted to determine whether Polychlorinated Biphenyl or PCB (Clophen A40) had an effect on the induction of the zona radiata, prolactin and cytochrome P4501A (CYP1A) mRNAs in matured Atlantic cod (Gadus morhua). A total of 127 fishes were maintained under natural photoperiod ...

  16. Excess post hypoxic oxygen consumption in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Plambech, Marie; Deurs, Mikael van; Steffensen, J.F.

    2013-01-01

    Atlantic cod Gadus morhua experienced oxygen deficit (DO2 ) when exposed to oxygen levels below their critical level (c. 73% of pcrit) and subsequent excess post-hypoxic oxygen consumption (CEPHO) upon return to normoxic conditions, indicative of an oxygen debt. The mean±s.e. CEPHO:DO2 was 6...

  17. Anesthesia induces stress in Atlantic salmon (Salmo salar), Atlantic cod (Gadus morhua) and Atlantic halibut (Hippoglossus hippoglossus).

    Science.gov (United States)

    Zahl, Inger Hilde; Kiessling, Anders; Samuelsen, Ole Bent; Olsen, Rolf Erik

    2010-09-01

    Stress in response to anesthesia with benzocaine, MS-222, metomidate and isoeugenol was studied in Atlantic salmon (Salmo salar), Atlantic halibut (Hippoglossus hippoglossus), and Atlantic cod (Gadus morhua) with no concomitant stress from handling or confinement in association with anesthesia or sampling. All of the anesthetics tested induced a stress response in all species, displayed by a release of cortisol to the water. MS-222 anesthesia elicited the highest cortisol release rates, reaching maximum levels 0.5 h post-exposure and returning to basal levels after 3-4 h. Benzocaine anesthesia caused a bimodal response where the initial peak in cortisol release rate was followed by a second increase lasting towards the end of the trial (6 h). This bimodality was more profound in Atlantic salmon than in Atlantic halibut and Atlantic cod. Metomidate anesthesia induced the lowest release of cortisol of the agents tested in both Atlantic halibut and Atlantic cod, but resulted in a bimodal response in Atlantic salmon where the initial increase in cortisol release was followed by a larger increase peaking at 2-2.5 h post exposure before returning to basal levels after 5 h. The stress induced in Atlantic salmon by isoeugenol anesthesia resembled that of MS-222, but did not reach the same elevated level. Overall, the cortisol release was most profound in Atlantic salmon followed by Atlantic halibut and Atlantic cod.

  18. Potential Use of Atlantic Cod Trypsin in Biomedicine

    Science.gov (United States)

    Gudmundsdóttir, Ágústa; Hilmarsson, Hilmar; Stefansson, Bjarki

    2013-01-01

    Surface proteins of viruses and bacteria used for cell attachment and invasion are candidates for degradation by proteases. Trypsin from Atlantic cod (Gadus morhua) was previously demonstrated to have efficacy against influenza viruses in vitro and on skin. In this paper, cod trypsin is shown to be 3–12 times more effective in degrading large native proteins than its mesophilic analogue, bovine trypsin. This is in agreement with previous findings where cod trypsin was found to be the most active among twelve different proteases in cleaving various cytokines and pathological proteins. Furthermore, our results show that cod trypsin has high efficacy against herpes simplex virus type 1 (HSV-1) and the respiratory syncytial virus (RSV) in vitro. The results on the antipathogenic properties of cod trypsin are important because rhinovirus, RSV, and influenza are the most predominant pathogenic viruses in upper respiratory tract infections. Results from a clinical study presented in this paper show that a specific formulation containing cod trypsin was preferred for wound healing over other methods used in the study. Apparently, the high digestive ability of the cold-adapted cod trypsin towards large native proteins plays a role in its efficacy against pathogens and its positive effects on wounds. PMID:23555095

  19. Potential Use of Atlantic Cod Trypsin in Biomedicine

    Directory of Open Access Journals (Sweden)

    Ágústa Gudmundsdóttir

    2013-01-01

    Full Text Available Surface proteins of viruses and bacteria used for cell attachment and invasion are candidates for degradation by proteases. Trypsin from Atlantic cod (Gadus morhua was previously demonstrated to have efficacy against influenza viruses in vitro and on skin. In this paper, cod trypsin is shown to be 3–12 times more effective in degrading large native proteins than its mesophilic analogue, bovine trypsin. This is in agreement with previous findings where cod trypsin was found to be the most active among twelve different proteases in cleaving various cytokines and pathological proteins. Furthermore, our results show that cod trypsin has high efficacy against herpes simplex virus type 1 (HSV-1 and the respiratory syncytial virus (RSV in vitro. The results on the antipathogenic properties of cod trypsin are important because rhinovirus, RSV, and influenza are the most predominant pathogenic viruses in upper respiratory tract infections. Results from a clinical study presented in this paper show that a specific formulation containing cod trypsin was preferred for wound healing over other methods used in the study. Apparently, the high digestive ability of the cold-adapted cod trypsin towards large native proteins plays a role in its efficacy against pathogens and its positive effects on wounds.

  20. Protein genes in repetitive sequence—antifreeze glycoproteins in Atlantic cod genome

    Directory of Open Access Journals (Sweden)

    Zhuang Xuan

    2012-07-01

    Full Text Available Abstract Background Highly repetitive sequences are the bane of genome sequence assembly, and the short read lengths produced by current next generation sequencing technologies further exacerbates this obstacle. An adopted practice is to exclude repetitive sequences in genome data assembly, as the majority of repeats lack protein-coding genes. However, this could result in the exclusion of important genotypes in newly sequenced non-model species. The absence of the antifreeze glycoproteins (AFGP gene family in the recently sequenced Atlantic cod genome serves as an example. Results The Atlantic cod (Gadus morhua genome was assembled entirely from Roche 454 short reads, demonstrating the feasibility of this approach. However, a well-known major adaptive trait, the AFGP, essential for survival in frigid Arctic marine habitats was absent in the annotated genome. To assess whether this resulted from population difference, we performed Southern blot analysis of genomic DNA from multiple individuals from the North East Arctic cod population that the sequenced cod belonged, and verified that the AFGP genotype is indeed present. We searched the raw assemblies of the Atlantic cod using our G. morhua AFGP gene, and located partial AFGP coding sequences in two sequence scaffolds. We found these two scaffolds constitute a partial genomic AFGP locus through comparative sequence analyses with our newly assembled genomic AFGP locus of the related polar cod, Boreogadus saida. By examining the sequence assembly and annotation methodologies used for the Atlantic cod genome, we deduced the primary cause of the absence of the AFGP gene family from the annotated genome was the removal of all repetitive Roche 454 short reads before sequence assembly, which would exclude most of the highly repetitive AFGP coding sequences. Secondarily, the model teleost genomes used in projection annotation of the Atlantic cod genome have no antifreeze trait, perpetuating the

  1. Protein genes in repetitive sequence-antifreeze glycoproteins in Atlantic cod genome.

    Science.gov (United States)

    Zhuang, Xuan; Yang, Chun; Fevolden, Svein-Erik; Cheng, C-H Christina

    2012-07-02

    Highly repetitive sequences are the bane of genome sequence assembly, and the short read lengths produced by current next generation sequencing technologies further exacerbates this obstacle. An adopted practice is to exclude repetitive sequences in genome data assembly, as the majority of repeats lack protein-coding genes. However, this could result in the exclusion of important genotypes in newly sequenced non-model species. The absence of the antifreeze glycoproteins (AFGP) gene family in the recently sequenced Atlantic cod genome serves as an example. The Atlantic cod (Gadus morhua) genome was assembled entirely from Roche 454 short reads, demonstrating the feasibility of this approach. However, a well-known major adaptive trait, the AFGP, essential for survival in frigid Arctic marine habitats was absent in the annotated genome. To assess whether this resulted from population difference, we performed Southern blot analysis of genomic DNA from multiple individuals from the North East Arctic cod population that the sequenced cod belonged, and verified that the AFGP genotype is indeed present. We searched the raw assemblies of the Atlantic cod using our G. morhua AFGP gene, and located partial AFGP coding sequences in two sequence scaffolds. We found these two scaffolds constitute a partial genomic AFGP locus through comparative sequence analyses with our newly assembled genomic AFGP locus of the related polar cod, Boreogadus saida. By examining the sequence assembly and annotation methodologies used for the Atlantic cod genome, we deduced the primary cause of the absence of the AFGP gene family from the annotated genome was the removal of all repetitive Roche 454 short reads before sequence assembly, which would exclude most of the highly repetitive AFGP coding sequences. Secondarily, the model teleost genomes used in projection annotation of the Atlantic cod genome have no antifreeze trait, perpetuating the unawareness that the AFGP gene family is missing. We

  2. Protein genes in repetitive sequence—antifreeze glycoproteins in Atlantic cod genome

    Science.gov (United States)

    2012-01-01

    Background Highly repetitive sequences are the bane of genome sequence assembly, and the short read lengths produced by current next generation sequencing technologies further exacerbates this obstacle. An adopted practice is to exclude repetitive sequences in genome data assembly, as the majority of repeats lack protein-coding genes. However, this could result in the exclusion of important genotypes in newly sequenced non-model species. The absence of the antifreeze glycoproteins (AFGP) gene family in the recently sequenced Atlantic cod genome serves as an example. Results The Atlantic cod (Gadus morhua) genome was assembled entirely from Roche 454 short reads, demonstrating the feasibility of this approach. However, a well-known major adaptive trait, the AFGP, essential for survival in frigid Arctic marine habitats was absent in the annotated genome. To assess whether this resulted from population difference, we performed Southern blot analysis of genomic DNA from multiple individuals from the North East Arctic cod population that the sequenced cod belonged, and verified that the AFGP genotype is indeed present. We searched the raw assemblies of the Atlantic cod using our G. morhua AFGP gene, and located partial AFGP coding sequences in two sequence scaffolds. We found these two scaffolds constitute a partial genomic AFGP locus through comparative sequence analyses with our newly assembled genomic AFGP locus of the related polar cod, Boreogadus saida. By examining the sequence assembly and annotation methodologies used for the Atlantic cod genome, we deduced the primary cause of the absence of the AFGP gene family from the annotated genome was the removal of all repetitive Roche 454 short reads before sequence assembly, which would exclude most of the highly repetitive AFGP coding sequences. Secondarily, the model teleost genomes used in projection annotation of the Atlantic cod genome have no antifreeze trait, perpetuating the unawareness that the AFGP gene

  3. Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod.

    Science.gov (United States)

    Berg, Paul R; Star, Bastiaan; Pampoulie, Christophe; Sodeland, Marte; Barth, Julia M I; Knutsen, Halvor; Jakobsen, Kjetill S; Jentoft, Sissel

    2016-03-17

    Identification of genome-wide patterns of divergence provides insight on how genomes are influenced by selection and can reveal the potential for local adaptation in spatially structured populations. In Atlantic cod - historically a major marine resource - Northeast-Arctic- and Norwegian coastal cod are recognized by fundamental differences in migratory and non-migratory behavior, respectively. However, the genomic architecture underlying such behavioral ecotypes is unclear. Here, we have analyzed more than 8.000 polymorphic SNPs distributed throughout all 23 linkage groups and show that loci putatively under selection are localized within three distinct genomic regions, each of several megabases long, covering approximately 4% of the Atlantic cod genome. These regions likely represent genomic inversions. The frequency of these distinct regions differ markedly between the ecotypes, spawning in the vicinity of each other, which contrasts with the low level of divergence in the rest of the genome. The observed patterns strongly suggest that these chromosomal rearrangements are instrumental in local adaptation and separation of Atlantic cod populations, leaving footprints of large genomic regions under selection. Our findings demonstrate the power of using genomic information in further understanding the population dynamics and defining management units in one of the world's most economically important marine resources.

  4. Experimental mycobacteriosis in Atlantic cod, Gadus morhua L.

    Science.gov (United States)

    Zerihun, M A; Colquhoun, D J; Poppe, T T

    2012-05-01

    Piscine mycobacteriosis causes losses in a number of fish species both in the wild and in aquaculture worldwide. Mycobacterium salmoniphilum infections have on several occasions been reported in farmed Atlantic salmon, Salmo salar L. The present study tested and confirmed the susceptibility of Atlantic cod, Gadus morhua L., an important yet relatively novel aquaculture species, to infection with M. salmoniphilum. Atlantic cod injected intraperitoneally with a suspension of this bacterium were maintained together with cohabitant (COH) fish in a flow-through marine water system at 10-11 °C. The fish were supervised daily and samples taken at 2, 7, 14, 23, 34 and 53 weeks post-infection and examined pathologically, bacteriologically and using molecular biology. Injected mycobacteria were re-isolated in high concentrations from both injected and COH fish groups. Death attributable to mycobacterial infection was observed in both injected (47%) and COH (28%) fish groups. Extensive development of granuloma in visceral organs, mainly the mesenteries, spleen, kidney and liver (lesser extent) and at later stages of the infection in heart tissues and gills, was observed in both injected and COH fish. Granulomas underwent a temporal progression of distinct morphological stages, culminating in well-circumscribed lesions surrounded by normal or healing tissue. Acid-fast bacilli were detected in both granulomas and non-granulomatous tissues. This study confirms that Atlantic cod is highly susceptible to M. salmoniphilum infection and that this bacterial species may be a threat to cod both in the wild and in the aquaculture. © 2012 Blackwell Publishing Ltd.

  5. Genomic characterization of the Atlantic cod sex-locus.

    Science.gov (United States)

    Star, Bastiaan; Tørresen, Ole K; Nederbragt, Alexander J; Jakobsen, Kjetill S; Pampoulie, Christophe; Jentoft, Sissel

    2016-08-08

    A variety of sex determination mechanisms can be observed in evolutionary divergent teleosts. Sex determination is genetic in Atlantic cod (Gadus morhua), however the genomic location or size of its sex-locus is unknown. Here, we characterize the sex-locus of Atlantic cod using whole genome sequence (WGS) data of 227 wild-caught specimens. Analyzing more than 55 million polymorphic loci, we identify 166 loci that are associated with sex. These loci are located in six distinct regions on five different linkage groups (LG) in the genome. The largest of these regions, an approximately 55 Kb region on LG11, contains the majority of genotypes that segregate closely according to a XX-XY system. Genotypes in this region can be used genetically determine sex, whereas those in the other regions are inconsistently sex-linked. The identified region on LG11 and its surrounding genes have no clear sequence homology with genes or regulatory elements associated with sex-determination or differentiation in other species. The functionality of this sex-locus therefore remains unknown. The WGS strategy used here proved adequate for detecting the small regions associated with sex in this species. Our results highlight the evolutionary flexibility in genomic architecture underlying teleost sex-determination and allow practical applications to genetically sex Atlantic cod.

  6. Learning from ‘apparent consensus’ in TAC disputes: Exploring knowledge overlaps in LEK and genetic categorization of Atlantic cod

    DEFF Research Database (Denmark)

    Hedeholm, R. B.; Jacobsen, R. B.; Eg Nielsen, Einar

    2016-01-01

    Atlantic have often held a local knowledge about local cod populations, this study examines the extent to which genetic analysis corroborates this local knowledge and vice versa. In Nuuk, capital of Greenland situated by the Nuuk fiord system, local fishers say that they and generations before them have...... been observing both inshore and offshore cod in the Nuuk fiord system. Fisher interviews were conducted in order to understand the construction as well as the content of this specific local ecological knowledge. Furthermore, fishers were invited to assign cod from their catches into categories based...... on their knowledge of inshore and offshore cod. These cod were subsequently analyzed and assigned to population using genetic methodologies. The comparison between visual and genetic assignment was not able to confirm any convincing consensus between fishers' understanding of offshore and inshore cod...

  7. Spatial and temporal trends of BFRs in Atlantic cod and polar cod in the North-East Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Bytingsvik, J.; Gaustad, H.; Pettersvik Salmer, M.; Soermo, E.G.; Munro Jenssen, B. [Norwegian Univ. of Science and Technology, Dept. of Biology, Trondheim (Norway); Baek, K.; Foereid, S. [Norwegian School of Veterinary Science, Oslo (Norway); Ruus, A. [Norwegian Insitute for Water Research, Oslo (Norway); Utne Skaare, J. [National Veterinary Institute, Oslo (Norway)

    2004-09-15

    Brominated Flame Retardants (BFRs) such as polybrominated diphenylethers (PBDEs) and hexabromocyclododecane (HBCD) are added to materials (e.g., textiles and electronic materials) to reduce flammability. BFRs are lipophilic and resistant against degradation causing them to biomagnify in the marine food chain. Thus, due to industrial activities and surface run-off from applications and dumping sites, sediments and aquatic organism in rivers, estuaries and coastal waters close to rural areas may be particularly contaminated by these chemicals. Furthermore, because of their semi-volatile properties BFRs may also bioaccumulate in humans and wildlife at more remote locations such as the Arctic2. Their different degrees of bromination determine their actual environmental behaviour and fate. The higher brominated compounds tend to accumulate near the source whereas the lower brominated, which are more volatile, tend to end up in more remote areas such as the Arctic region. The aim of the present study was to measure BFR concentrations in cod (i.e., Atlantic cod [Gadus morhua] and polar cod [Boreogadus saida]) at different locations in Norwegian waters, ranging from the estuary of the largest river in Norway, Glomma, to the pristine Artic waters of Svalbard. Glomma has its outlet near Hvaler, outer Oslofjord, and is draining water from some of the largest rivers and lakes of the more industrialised areas of Norway. An example is its connection to Mjoesa, the largest lake in Norway, where very high levels of BFRs have been reported. Concentrations of BFRs in Atlantic cod sampled at Hvaler (58 circle 59'N, 10 circle 47'E) were therefore compared to concentrations in Atlantic cod sampled at Froan, (64 circle 10'N, 09 circle 20'E) situated in the more open waters of the Norwegian Sea off coast of Mid-Norway and polar cod from Bear Island, Svalbard (73 circle 4' N, 18 circle 3'E). A second aim was to study temporal changes in concentrations of BFRs

  8. A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths.

    Directory of Open Access Journals (Sweden)

    Guðbjörg Ásta Ólafsdóttir

    Full Text Available Archaeological excavations of historical fishing sites across the North Atlantic have recovered high quantities of Atlantic cod (Gadus morhua bones. In the current study we use Atlantic cod otoliths from archaeological excavations of a historical fishing sites in north-west Iceland, dated to AD 970 -AD 1910 to examine historical growth trajectories of cod. No large scale growth variations or shifts in growth patterns were observed in the current chronologies, supporting the stability of historical Atlantic cod growth trajectories. The most significant variation in growth patterns was consistent with those that have been observed in recent times, for example, reduced early juvenile growth during periods of colder ocean temperature. The current results represent a high resolution chronological record of north-east Atlantic cod growth, greatly increasing the prior temporal range of such data, thereby providing a valuable baseline for a broad range of studies on Atlantic cod growth.

  9. A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths.

    Science.gov (United States)

    Ólafsdóttir, Guðbjörg Ásta; Pétursdóttir, Gróa; Bárðarson, Hlynur; Edvardsson, Ragnar

    2017-01-01

    Archaeological excavations of historical fishing sites across the North Atlantic have recovered high quantities of Atlantic cod (Gadus morhua) bones. In the current study we use Atlantic cod otoliths from archaeological excavations of a historical fishing sites in north-west Iceland, dated to AD 970 -AD 1910 to examine historical growth trajectories of cod. No large scale growth variations or shifts in growth patterns were observed in the current chronologies, supporting the stability of historical Atlantic cod growth trajectories. The most significant variation in growth patterns was consistent with those that have been observed in recent times, for example, reduced early juvenile growth during periods of colder ocean temperature. The current results represent a high resolution chronological record of north-east Atlantic cod growth, greatly increasing the prior temporal range of such data, thereby providing a valuable baseline for a broad range of studies on Atlantic cod growth.

  10. Development and experimental validation of a 20K Atlantic cod (Gadus morhua) oligonucleotide microarray based on a collection of over 150,000 ESTs.

    Science.gov (United States)

    Booman, Marije; Borza, Tudor; Feng, Charles Y; Hori, Tiago S; Higgins, Brent; Culf, Adrian; Léger, Daniel; Chute, Ian C; Belkaid, Anissa; Rise, Marlies; Gamperl, A Kurt; Hubert, Sophie; Kimball, Jennifer; Ouellette, Rodney J; Johnson, Stewart C; Bowman, Sharen; Rise, Matthew L

    2011-08-01

    The collapse of Atlantic cod (Gadus morhua) wild populations strongly impacted the Atlantic cod fishery and led to the development of cod aquaculture. In order to improve aquaculture and broodstock quality, we need to gain knowledge of genes and pathways involved in Atlantic cod responses to pathogens and other stressors. The Atlantic Cod Genomics and Broodstock Development Project has generated over 150,000 expressed sequence tags from 42 cDNA libraries representing various tissues, developmental stages, and stimuli. We used this resource to develop an Atlantic cod oligonucleotide microarray containing 20,000 unique probes. Selection of sequences from the full range of cDNA libraries enables application of the microarray for a broad spectrum of Atlantic cod functional genomics studies. We included sequences that were highly abundant in suppression subtractive hybridization (SSH) libraries, which were enriched for transcripts responsive to pathogens or other stressors. These sequences represent genes that potentially play an important role in stress and/or immune responses, making the microarray particularly useful for studies of Atlantic cod gene expression responses to immune stimuli and other stressors. To demonstrate its value, we used the microarray to analyze the Atlantic cod spleen response to stimulation with formalin-killed, atypical Aeromonas salmonicida, resulting in a gene expression profile that indicates a strong innate immune response. These results were further validated by quantitative PCR analysis and comparison to results from previous analysis of an SSH library. This study shows that the Atlantic cod 20K oligonucleotide microarray is a valuable new tool for Atlantic cod functional genomics research.

  11. Mitogenome sequence variation in migratory and stationary ecotypes of North-east Atlantic cod.

    Science.gov (United States)

    Karlsen, Bård O; Emblem, Åse; Jørgensen, Tor E; Klingan, Kevin A; Nordeide, Jarle T; Moum, Truls; Johansen, Steinar D

    2014-06-01

    Sequencing of mitochondrial gene fragments from specimens representing a wide range of geographical locations has indicated limited population structuring in Atlantic cod (Gadus morhua). We recently performed whole genome analysis based on next-generation sequencing of two pooled ecotype samples representing offshore migratory and inshore stationary cod from the North-east Atlantic Ocean. Here we report molecular features and variability of the 16.7kb mitogenome component that was collected from the datasets. These sequences represented more than 25 times coverage of each individual and more than 1100 times coverage of each ecotype sample. We estimated the mitogenome to have evolved 14 times more rapidly than the nuclear genome. Among the 365 single nucleotide polymorphism (SNP) sites identified, 121 were shared between ecotypes, and 151 and 93 were private within the migratory and stationary cod, respectively. We found 323 SNPs to be located in protein coding genes, of which 29 were non-synonymous. One synonymous site in ND2 was likely to be under positive selection. FST measurements indicated weak differentiation in ND1 and ND2 between ecotypes. We conclude that the Atlantic cod mitogenome and the nuclear genome apparently evolved by distinct evolutionary constraints, and that the reproductive isolation observed from whole genome analysis was not visible in the mtDNA sequences. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua) larvae

    Science.gov (United States)

    Penglase, S; Harboe, T; Sæle, Ø; Helland, S; Nordgreen, A

    2013-01-01

    Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I), at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua) were fed rotifers enriched to intermediate (26 mg I kg-1 dry weight; MI group) or copepod (129 mg I kg-1 DW; HI group) I levels and compared to cod larvae fed control rotifers (0.6 mg I kg-1 DW). Larval I concentrations were increased by 3 (MI) and 7 (HI) fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg-1 DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg-1 DW. PMID:23638355

  13. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua larvae

    Directory of Open Access Journals (Sweden)

    S Penglase

    2013-02-01

    Full Text Available Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I, at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua were fed rotifers enriched to intermediate (26 mg I kg-1 dry weight; MI group or copepod (129 mg I kg-1 DW; HI group I levels and compared to cod larvae fed control rotifers (0.6 mg I kg-1 DW. Larval I concentrations were increased by 3 (MI and 7 (HI fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg-1 DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg-1 DW.

  14. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua) larvae.

    Science.gov (United States)

    Penglase, S; Harboe, T; Sæle, O; Helland, S; Nordgreen, A; Hamre, K

    2013-01-01

    Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I), at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua) were fed rotifers enriched to intermediate (26 mg I kg(-1) dry weight; MI group) or copepod (129 mg I kg(-1) DW; HI group) I levels and compared to cod larvae fed control rotifers (0.6 mg I kg(-1) DW). Larval I concentrations were increased by 3 (MI) and 7 (HI) fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg(-1) DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg(-1) DW.

  15. Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.)

    Science.gov (United States)

    Berg, Paul R.; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer H.; Knutsen, Halvor; Lien, Sigbjørn; Jakobsen, Kjetill S.; André, Carl

    2015-01-01

    How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation. PMID:25994933

  16. Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.).

    Science.gov (United States)

    Berg, Paul R; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer H; Knutsen, Halvor; Lien, Sigbjørn; Jakobsen, Kjetill S; André, Carl

    2015-05-20

    How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  17. Transcriptome analysis of gill tissue of Atlantic cod Gadus morhua L. from the Baltic Sea.

    Science.gov (United States)

    Małachowicz, Magdalena; Kijewska, Agnieszka; Wenne, Roman

    2015-10-01

    The Atlantic cod (Gadus morhua L.) is one of the most ecologically and economically important marine fish species in the North Atlantic Ocean. Using Roche GS-FLX 454 pyrosequencing technique 962,516 reads, representing 379Mbp of the Baltic cod transcriptome, were obtained. Data was assembled into 14,029 contigs of which 100% displayed homology to the Atlantic cod transcriptome. Despite a high similarity between transcripts, evidence for significant differences between Baltic and Atlantic cod was found. Copyright © 2015. Published by Elsevier B.V.

  18. Mitochondrial acclimation potential to ocean acidification and warming of Polar cod (Boreogadus saida) and Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Leo, Elettra; Kunz, Kristina L; Schmidt, Matthias; Storch, Daniela; Pörtner, Hans-O; Mark, Felix C

    2017-01-01

    Ocean acidification and warming are happening fast in the Arctic but little is known about the effects of ocean acidification and warming on the physiological performance and survival of Arctic fish. In this study we investigated the metabolic background of performance through analyses of cardiac mitochondrial function in response to control and elevated water temperatures and PCO2 of two gadoid fish species, Polar cod (Boreogadus saida), an endemic Arctic species, and Atlantic cod (Gadus morhua), which is a temperate to cold eurytherm and currently expanding into Arctic waters in the wake of ocean warming. We studied their responses to the above-mentioned drivers and their acclimation potential through analysing the cardiac mitochondrial function in permeabilised cardiac muscle fibres after 4 months of incubation at different temperatures (Polar cod: 0, 3, 6, 8 °C and Atlantic cod: 3, 8, 12, 16 °C), combined with exposure to present (400μatm) and year 2100 (1170μatm) levels of CO2. OXPHOS, proton leak and ATP production efficiency in Polar cod were similar in the groups acclimated at 400μatm and 1170μatm of CO2, while incubation at 8 °C evoked increased proton leak resulting in decreased ATP production efficiency and decreased Complex IV capacity. In contrast, OXPHOS of Atlantic cod increased with temperature without compromising the ATP production efficiency, whereas the combination of high temperature and high PCO2 depressed OXPHOS and ATP production efficiency. Polar cod mitochondrial efficiency decreased at 8 °C while Atlantic cod mitochondria were more resilient to elevated temperature; however, this resilience was constrained by high PCO2. In line with its lower habitat temperature and higher degree of stenothermy, Polar cod has a lower acclimation potential to warming than Atlantic cod.

  19. Structure of chymotrypsin variant B from Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Leth-Larsen, Rikke; Asgeirsson, B; Thórólfsson, M

    1996-01-01

    The amino-acid sequence of chymotrypsin variant B isolated from the pyloric caeca of Atlantic cod has been elucidated. The characterization of the primary structure is based on N-terminal Edman degradation and mass spectrometry of the native protein and enzymatically derived peptides. Chymotrypsin...... variant B showed 72% sequence identity with the A-variant and 64% and 62%, respectively, with the bovine counterparts A and B, all consisting of 245 amino acids. This new sequence contains a higher proportion of charged residues compared with bovine chymotrypsin but fewer polar hydrogen-bond forming...... side-chains may contribute to the maintenance of flexibility at low temperatures. Several amino-acid sequence differences adjacent to the catalytic site are observed in the two cod chymotrypsin variants which also differ in kinetic properties. Unlike the mammalian chymotrypsins, which contain several...

  20. Highly localized divergence within supergenes in Atlantic cod (Gadus morhua) within the Gulf of Maine.

    Science.gov (United States)

    Barney, Bryan T; Munkholm, Christiane; Walt, David R; Palumbi, Stephen R

    2017-03-31

    Atlantic cod (Gadus morhua), is known to vary genetically across the North Atlantic, Greenland, and Newfoundland. This genetic variation occurs both spatially and temporally through decades of heavy fishing, and is concentrated in three linkage disequilibrium blocks, previously defined by pedigreed linkage mapping analysis. Variation within these genomic regions is correlated with both seawater temperature and behavioral ecotype. The full extent and nature of these linkage groups is important information for interpreting cod genetic structure as a tool for future fisheries management. We conducted whole genome sequencing for 31 individual cod from three sub-populations in the Gulf of Maine. Across the genome, we found 3,390,654 intermediate to high frequency Single Nucleotide Polymorphisms (SNPs). We show that pairwise linkage analysis among these SNPs is a powerful tool to detect linkage disequilibrium clusters by recovering the three previously detected linkage groups and identifying the 1031 genes contained therein. Across these genes, we found significant population differentiation among spawning groups in the Gulf of Maine and between Georges Bank and Gulf of Maine. Coordinated divergence among these genes and their differentiation at both short and long spatial scales suggests that they are acting as linked supergenes in local adaptation of cod populations. Differentiation between SNPs in linkage disequilibrium blocks is the major signal of genetic differentiation between all groups tested within the Gulf of Maine. Our data provide a map of genes contained in these blocks, allowing an enhanced search for neutral genetic structure for demographic inference and fisheries modeling. Patterns of selection and the history of populations may be possible to identify in cod using this description of linkage disequilibrium blocks and future data sets to robustly separate neutral and selected genetic markers.

  1. Effects of Loma morhua (Microsporidia) infection on the cardiorespiratory performance of Atlantic cod Gadus morhua (L).

    Science.gov (United States)

    Powell, M D; Gamperl, A K

    2016-02-01

    The microsporidian Loma morhua infects Atlantic cod (Gadus morhua) in the wild and in culture and results in the formation of xenomas within the gill filaments, heart and spleen. Given the importance of the two former organs to metabolic capacity and thermal tolerance, the cardiorespiratory performance of cod with a naturally acquired infection of Loma was measured during an acute temperature increase (2 °C h(-1)) from 10 °C to the fish's critical thermal maximum (CT(Max)). In addition, oxygen consumption and swimming performance were measured during two successive critical swimming speed (U(crit)) tests at 10 °C. While Loma infection had a negative impact on cod cardiac function at warm temperatures, and on metabolic capacity in both the CT(Max) and U(crit) tests (i.e. a reduction of 30-40%), it appears that the Atlantic cod can largely compensate for these Loma-induced cardiorespiratory limitations. For example, (i) CT(Max) (21.0 ± 0.3 °C) and U(crit) (~1.75 BL s(-1)) were very comparable to those reported in previous studies using uninfected fish from the same founder population; and (ii) our data suggest that tissue oxygen extraction, and potentially the capacity for anaerobic metabolism, is enhanced in fish infected with this microsporidian. © 2015 The Authors Journal of Fish Diseases Published by John Wiley & Sons Ltd.

  2. The Effects of Temperature, Hypoxia and Hypercapnia on the Metabolism of Atlantic Cod Gadus morhua

    DEFF Research Database (Denmark)

    Tirsgård, Bjørn

    showed that RMRlow and RMRhigh increased with age, by scaling exponents ranging between 0.58 and 0.87 at the three temperature tested. In periods with low prey availability a low water temperature and body size increase the survival rate whereas high water temperatures enhance growth rate when prey......The Atlantic cod (Gadus morhua L. 1758) is an important species both as a major top predator in the ecosystem and economical marine resource in the fishing industry of Northern Europe (Andersen, 2012). As an ectothermic water breather the Atlantic cod is continuously exposed to annual changes...... in the water conditions affecting their performance, growth and reproduction. Variations in the water conditions between years and due to climatic changes, affects the survival rate, population dynamic and bio-energetic distribution of the Atlantic cod (Hansson et al., 1996; Essington et al., 2001...

  3. An improved genome assembly uncovers prolific tandem repeats in Atlantic cod.

    Science.gov (United States)

    Tørresen, Ole K; Star, Bastiaan; Jentoft, Sissel; Reinar, William B; Grove, Harald; Miller, Jason R; Walenz, Brian P; Knight, James; Ekholm, Jenny M; Peluso, Paul; Edvardsen, Rolf B; Tooming-Klunderud, Ave; Skage, Morten; Lien, Sigbjørn; Jakobsen, Kjetill S; Nederbragt, Alexander J

    2017-01-18

    The first Atlantic cod (Gadus morhua) genome assembly published in 2011 was one of the early genome assemblies exclusively based on high-throughput 454 pyrosequencing. Since then, rapid advances in sequencing technologies have led to a multitude of assemblies generated for complex genomes, although many of these are of a fragmented nature with a significant fraction of bases in gaps. The development of long-read sequencing and improved software now enable the generation of more contiguous genome assemblies. By combining data from Illumina, 454 and the longer PacBio sequencing technologies, as well as integrating the results of multiple assembly programs, we have created a substantially improved version of the Atlantic cod genome assembly. The sequence contiguity of this assembly is increased fifty-fold and the proportion of gap-bases has been reduced fifteen-fold. Compared to other vertebrates, the assembly contains an unusual high density of tandem repeats (TRs). Indeed, retrospective analyses reveal that gaps in the first genome assembly were largely associated with these TRs. We show that 21% of the TRs across the assembly, 19% in the promoter regions and 12% in the coding sequences are heterozygous in the sequenced individual. The inclusion of PacBio reads combined with the use of multiple assembly programs drastically improved the Atlantic cod genome assembly by successfully resolving long TRs. The high frequency of heterozygous TRs within or in the vicinity of genes in the genome indicate a considerable standing genomic variation in Atlantic cod populations, which is likely of evolutionary importance.

  4. Rhodopsin gene polymorphism associated with divergent light environments in Atlantic cod.

    Science.gov (United States)

    Pampoulie, Christophe; Skirnisdottir, Sigurlaug; Star, Bastiaan; Jentoft, Sissel; Jónsdóttir, Ingibjörg G; Hjörleifsson, Einar; Thorsteinsson, Vilhjálmur; Pálsson, Ólafur K; Berg, Paul R; Andersen, Øivind; Magnusdottir, Steinunn; Helyar, Sarah J; Daníelsdóttir, Anna K

    2015-03-01

    The spectral sensitivity of visual pigments in vertebrate eyes is optimized for specific light conditions. One of such pigments, rhodopsin (RH1), mediates dim-light vision. Amino acid replacements at tuning sites may alter spectral sensitivity, providing a mechanism to adapt to ambient light conditions and depth of habitat in fish. Here we present a first investigation of RH1 gene polymorphism among two ecotypes of Atlantic cod in Icelandic waters, which experience divergent light environments throughout the year due to alternative foraging behaviour. We identified one synonymous single nucleotide polymorphism (SNP) in the RH1 protein coding region and one in the 3' untranslated region (3'-UTR) that are strongly divergent between these two ecotypes. Moreover, these polymorphisms coincided with the well-known panthophysin (Pan I) polymorphism that differentiates coastal and frontal (migratory) populations of Atlantic cod. While the RH1 SNPs do not provide direct inference for a specific molecular mechanism, their association with this dim-sensitive pigment indicates the involvement of the visual system in local adaptation of Atlantic cod.

  5. Induction of meiotic gynogenesis in Atlantic cod (Gadus morhua L.) through pressure shock.

    Science.gov (United States)

    Ghigliotti, Laura; Bolla, Sylvie L; Duc, Michal; Ottesen, Oddvar H; Babiak, Igor

    2011-08-01

    The Atlantic cod, Gadus morhua, is one of the most important species for commercial fisheries and a promising candidate for aquaculture. Precocious sexual maturation of males is one of the major issues compromising large scale production. The potential approaches to this problem include production of all female populations. Consequently, the objective of this study was to develop an effective protocol to induce meiotic gynogenesis in the Atlantic cod by using hydrostatic pressure shock. Our first experiment tested the relevance of gamete quality on achievement of chromosome manipulation and identified the best time interval between fertilization and pressure shock. Our second experiment was designed to determine the optimal pressure value and duration of the pressure shock. Eight combinations of pressure values and durations were tested. Among them, the 34.47 MPa/6 min combination gave the best survival rate (23.6 ± 3.9%), the highest percentage of normal larvae (15.7 ± 3.6%), and the highest percentage of meiotic diploids (88.89%). In both experiments, haploid controls served as an indirect reference for paternal DNA inactivation. Chromosome counting confirmed the restoration of diploidy in gynogenetic fish. The present study optimizes a procedure for the induction of meiotic gynogenesis in the Atlantic cod, thus laying the basis for further applications towards producing monosex and defining the sex determination system. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Conserving marine biodiversity: insights from life-history trait candidate genes in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Hansen, Jakob Hemmer; Therkildsen, Nina Overgaard; Meldrup, Dorte

    2014-01-01

    Recent technological developments have facilitated an increased focus on identifying genomic regions underlying adaptive trait variation in natural populations, and it has been advocated that this information should be important for designating population units for conservation. In marine fishes......, phenotypic studies have suggested adaptation through divergence of life-history traits among natural populations, but the distribution of adaptive genetic variation in these species is still relatively poorly known. In this study, we extract information about the geographical distribution of genetic...... variation for 33 single nucleotide polymorphisms (SNPs) associated with life-history trait candidate genes, and compare this to variation in 70 putatively neutral SNPs in Atlantic cod (Gadus morhua). We analyse samples covering the major population complexes in the eastern Atlantic and find strong evidence...

  7. Atlantic Cod (Gadus morhua benefits from the availability of seagrass (Zostera marina nursery habitat

    Directory of Open Access Journals (Sweden)

    Richard J. Lilley

    2014-12-01

    Full Text Available The Atlantic cod (Gadus morhua is a species of significant economic and historic importance but infamous for its decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved. Indeed, the degree to which specific habitats are important for this species remains unquantified at the scale of North Atlantic. Here, the literature on the role of eelgrass meadows (Zostera marina as valuable nursery habitat for the Atlantic cod is reviewed and synthesized. Evidence is presented on relative densities of Atlantic cod in shallow water environments and in eelgrass meadows in comparison to alternative habitats. In addition, evidence pertaining to the ’viability gains’ attributed to the use of eelgrass meadows as nursery habitat (growth and survival by juvenile Atlantic cod is analyzed. Although juvenile Atlantic cod use of Z. marina is found to be facultative, when possible, available literatures indicates that they may select Z. marina as a nursery habitat where they are found in high density (average of at least 246 ha−1. From their use of Z. marina habitat the juvenile Atlantic cod receives viability benefits from it, improving their chances of reaching maturation. This paper provides strong evidence that eelgrass meadows are of significant importance to contributing to Atlantic cod stocks.

  8. Spatiotemporal SNP analysis reveals pronounced biocomplexity at the northern range margin of Atlantic cod Gadus morhua

    DEFF Research Database (Denmark)

    Therkildsen, Nina Overgaard; Hansen, Jakob Hemmer; Hedeholm, R.B.

    2013-01-01

    Accurate prediction of species distribution shifts in the face of climate change requires a sound understanding of population diversity and local adaptations. Previous modeling has suggested that global warming will lead to increased abundance of Atlantic cod (Gadus morhua) in the ocean around...... increased temporal changes at a subset of loci also suggest that adaptation may be ongoing. These findings illustrate the power of spatiotemporal population genomics for revealing biocomplexity in both space and time and for informing future fisheries management and conservation efforts...

  9. Authentication of Atlantic cod (Gadus morhua) using real time PCR.

    Science.gov (United States)

    Herrero, Beatriz; Madriñán, María; Vieites, Juan M; Espiñeira, Montserrat

    2010-04-28

    This work describes the development of a real-time polymerase chain reaction (RT-PCR) system for the detection and identification of Atlantic cod (Gadus morhua). Among the advantages of this technique, it is worth highlighting that this is reliable in terms of specificity and sensitivity. The TaqMan real-time PCR is the simplest, fastest testing process and has the highest potential for automation, therefore representing the currently most suitable method for screening, allowing the detection of fraudulent or unintentional mislabeling of this species. The method can be applied to all kinds of products, fresh, frozen, and processed products, including those undergoing intensive processes of transformation. The developed methodology using specific primer-probe set was validated and further applied to 40 commercial samples labeled as cod in order to determinate if the species used for their manufacturing corresponded to G. morhua, detecting 20% that were incorrectly labeled. A C(t) value of about 19 was obtained when G. morhua was present. In samples with a species mixture, all samples that had a fluorescence signal were positive (C(t) fisheries control.

  10. An integrated approach to gene discovery and marker development in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Bowman, Sharen; Hubert, Sophie; Higgins, Brent; Stone, Cynthia; Kimball, Jennifer; Borza, Tudor; Bussey, Jillian Tarrant; Simpson, Gary; Kozera, Catherine; Curtis, Bruce A; Hall, Jennifer R; Hori, Tiago S; Feng, Charles Y; Rise, Marlies; Booman, Marije; Gamperl, A Kurt; Trippel, Edward; Symonds, Jane; Johnson, Stewart C; Rise, Matthew L

    2011-04-01

    Atlantic cod is a species that has been overexploited by the capture fishery. Programs to domesticate this species are underway in several countries, including Canada, to provide an alternative route for production. Selective breeding programs have been successfully applied in the domestication of other species, with genomics-based approaches used to augment conventional methods of animal production in recent years. Genomics tools, such as gene sequences and sets of variable markers, also have the potential to enhance and accelerate selective breeding programs in aquaculture, and to provide better monitoring tools to ensure that wild cod populations are well managed. We describe the generation of significant genomics resources for Atlantic cod through an integrated genomics/selective breeding approach. These include 158,877 expressed sequence tags (ESTs), a set of annotated putative transcripts and several thousand single nucleotide polymorphism markers that were developed from, and have been shown to be highly variable in, fish enrolled in two selective breeding programs. Our EST collection was generated from various tissues and life cycle stages. In some cases, tissues from which libraries were generated were isolated from fish exposed to stressors, including elevated temperature, or antigen stimulation (bacterial and viral) to enrich for transcripts that are involved in these response pathways. The genomics resources described here support the developing aquaculture industry, enabling the application of molecular markers within selective breeding programs. Marker sets should also find widespread application in fisheries management.

  11. Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada.

    Science.gov (United States)

    Khan, R A; Chandra, C V

    2006-06-01

    A study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotyle reflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

  12. Genome architecture enables local adaptation of Atlantic cod despite high connectivity.

    Science.gov (United States)

    Barth, Julia M I; Berg, Paul R; Jonsson, Per R; Bonanomi, Sara; Corell, Hanna; Hemmer-Hansen, Jakob; Jakobsen, Kjetill S; Johannesson, Kerstin; Jorde, Per Erik; Knutsen, Halvor; Moksnes, Per-Olav; Star, Bastiaan; Stenseth, Nils Chr; Svedäng, Henrik; Jentoft, Sissel; André, Carl

    2017-09-01

    Adaptation to local conditions is a fundamental process in evolution; however, mechanisms maintaining local adaptation despite high gene flow are still poorly understood. Marine ecosystems provide a wide array of diverse habitats that frequently promote ecological adaptation even in species characterized by strong levels of gene flow. As one example, populations of the marine fish Atlantic cod (Gadus morhua) are highly connected due to immense dispersal capabilities but nevertheless show local adaptation in several key traits. By combining population genomic analyses based on 12K single nucleotide polymorphisms with larval dispersal patterns inferred using a biophysical ocean model, we show that Atlantic cod individuals residing in sheltered estuarine habitats of Scandinavian fjords mainly belong to offshore oceanic populations with considerable connectivity between these diverse ecosystems. Nevertheless, we also find evidence for discrete fjord populations that are genetically differentiated from offshore populations, indicative of local adaptation, the degree of which appears to be influenced by connectivity. Analyses of the genomic architecture reveal a significant overrepresentation of a large ~5 Mb chromosomal rearrangement in fjord cod, previously proposed to comprise genes critical for the survival at low salinities. This suggests that despite considerable connectivity with offshore populations, local adaptation to fjord environments may be enabled by suppression of recombination in the rearranged region. Our study provides new insights into the potential of local adaptation in high gene flow species within fine geographical scales and highlights the importance of genome architecture in analyses of ecological adaptation. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  13. Genomic signatures of local directional selection in a high gene flow marine organism, the Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Hansen, Jakob Hemmer; Poulsen, Nina Aagaard

    2009-01-01

    -associated single nucleotide polymorphisms (SNPs) for evidence of selection in local populations of Atlantic cod (Gadus morhua L.) across the species distribution. Results: Our global genome scan analysis identified eight outlier gene loci with very high statistical support, likely to be subject to directional...... selection in local demes, or closely linked to loci under selection. Likewise, on a regional south/north transect of central and eastern Atlantic populations, seven loci displayed strongly elevated levels of genetic differentiation. Selection patterns among populations appeared to be relatively widespread...

  14. Thermal niche of Atlantic cod Gadus morhua: limits, tolerance and optima

    DEFF Research Database (Denmark)

    Righton, David A.; Andersen, Ken Haste; Neat, Francis

    2010-01-01

    Recent studies in the marine environment have suggested that the limited phenotypic plasticity of cold-adapted species such as Atlantic cod Gadus morhua L. will cause distributions to shift toward the poles in response to rising sea temperatures. Some cod stocks are predicted to collapse, but thi...

  15. Evaluation of Electrical Stunning of Atlantic Cod (Gadus morhua) and Turbot (Psetta maxima) in Seawater

    NARCIS (Netherlands)

    Lambooij, E.; Digre, H.; Erikson, U.; Reimert, H.G.M.; Burggraaf, D.; Vis, van de J.W.

    2013-01-01

    The aim of this study was to assess electrical stunning of Atlantic cod and turbot in seawater to develop a protocol for the process of stunning and killing. An induced general epileptiform insult (unconscious) had a duration of 40 ± 27 s (n =14) in cod (2.6 ± 0.5 kg) and 34 ± 18 s (n = 19) in

  16. Proteome reference map of the skin mucus of Atlantic cod (Gadus morhua) revealing immune competent molecules

    NARCIS (Netherlands)

    Rajan, B.; Fernandes, J.M.O.; Caipang, C.M.A.; Kiron, V.; Rombout, J.H.W.M.; Brinchmann, M.

    2011-01-01

    The skin mucosal proteome of Atlantic cod (Gadus morhua) was mapped using a 2D PAGE, LC–MS/MS coupled approach. Mucosal proteins from naive fish were identified primarily by similarity searches across various cod EST databases. The identified proteins were clustered into 8 groups based on gene

  17. Two adjacent inversions maintain genomic differentiation between migratory and stationary ecotypes of Atlantic cod.

    Science.gov (United States)

    Kirubakaran, Tina Graceline; Grove, Harald; Kent, Matthew P; Sandve, Simen R; Baranski, Matthew; Nome, Torfinn; De Rosa, Maria Cristina; Righino, Benedetta; Johansen, Torild; Otterå, Håkon; Sonesson, Anna; Lien, Sigbjørn; Andersen, Øivind

    2016-05-01

    Atlantic cod is composed of multiple migratory and stationary populations widely distributed in the North Atlantic Ocean. The Northeast Arctic cod (NEAC) population in the Barents Sea undertakes annual spawning migrations to the northern Norwegian coast. Although spawning occurs sympatrically with the stationary Norwegian coastal cod (NCC), phenotypic and genetic differences between NEAC and NCC are maintained. In this study, we resolve the enigma by revealing the mechanisms underlying these differences. Extended linkage disequilibrium (LD) and population divergence were demonstrated in a 17.4-Mb region on linkage group 1 (LG1) based on genotypes of 494 SNPs from 192 parents of farmed families of NEAC, NCC or NEACxNCC crosses. Linkage analyses revealed two adjacent inversions within this region that repress meiotic recombination in NEACxNCC crosses. We identified a NEAC-specific haplotype consisting of 186 SNPs that was fixed in NEAC sampled from the Barents Sea, but segregating under Hardy-Weinberg equilibrium in eight NCC stocks. Comparative genomic analyses determine the NEAC configuration of the inversions to be the derived state and date it to ~1.6-2.0 Mya. The haplotype block harbours 763 genes, including candidates regulating swim bladder pressure, haem synthesis and skeletal muscle organization conferring adaptation to long-distance migrations and vertical movements down to large depths. Our results suggest that the migratory ecotype experiences strong directional selection for the two adjacent inversions on LG1. Despite interbreeding between NEAC and NCC, the inversions are maintaining genetic differentiation, and we hypothesize the co-occurrence of multiple adaptive alleles forming a 'supergene' in the NEAC population. © 2016 John Wiley & Sons Ltd.

  18. Bacterial composition and succession during storage of North-Atlantic cod (Gadus morhua at superchilled temperatures

    Directory of Open Access Journals (Sweden)

    Marteinsson Viggó

    2009-12-01

    Full Text Available Abstract Background The bacteriology during storage of the North-Atlantic cod has been investigated for the past decades using conventional cultivation strategies which have generated large amount of information. This paper presents a study where both conventional cultivation and cultivation independent approaches were used to investigate the bacterial succession during storage of cod loins at chilled and superchilled temperatures. Results Unbrined (0.4% NaCl and brined (2.5% NaCl cod loins were stored at chilled (0°C and superchilled (-2 and -3.6°C temperatures in air or modified atmosphere (MA, % CO2/O2/N2: 49.0 ± 0.6/7.4 ± 0.2/43.7 ± 0.4. Discrepancy was observed between cultivation enumeration and culture independent methods where the former showed a general dominance of Pseudomonas spp. (up to 59% while the latter showed a dominance of Photobacterium phosphoreum (up to 100%. Gas chromatography-mass spectrophotometry (GC-MC showed that trimethylamine was the most abundant volatile in mid- and late storage periods. Terminal restriction polymorphism (t-RFLP analysis showed that the relative abundance of P. phosphoreum increased with storage time. Conclusion The present study shows the bacteriological developments on lightly salted or non-salted cod loins during storage at superchilled temperatures. It furthermore confirms the importance of P. phosphoreum as a spoilage organism during storage of cod loins at low temperatures using molecular techniques. The methods used compensate each other, giving more detailed data on bacterial population developments during spoilage.

  19. Bacterial composition and succession during storage of North-Atlantic cod (Gadus morhua) at superchilled temperatures

    Science.gov (United States)

    2009-01-01

    Background The bacteriology during storage of the North-Atlantic cod has been investigated for the past decades using conventional cultivation strategies which have generated large amount of information. This paper presents a study where both conventional cultivation and cultivation independent approaches were used to investigate the bacterial succession during storage of cod loins at chilled and superchilled temperatures. Results Unbrined (0.4% NaCl) and brined (2.5% NaCl) cod loins were stored at chilled (0°C) and superchilled (-2 and -3.6°C) temperatures in air or modified atmosphere (MA, % CO2/O2/N2: 49.0 ± 0.6/7.4 ± 0.2/43.7 ± 0.4). Discrepancy was observed between cultivation enumeration and culture independent methods where the former showed a general dominance of Pseudomonas spp. (up to 59%) while the latter showed a dominance of Photobacterium phosphoreum (up to 100%). Gas chromatography-mass spectrophotometry (GC-MC) showed that trimethylamine was the most abundant volatile in mid- and late storage periods. Terminal restriction polymorphism (t-RFLP) analysis showed that the relative abundance of P. phosphoreum increased with storage time. Conclusion The present study shows the bacteriological developments on lightly salted or non-salted cod loins during storage at superchilled temperatures. It furthermore confirms the importance of P. phosphoreum as a spoilage organism during storage of cod loins at low temperatures using molecular techniques. The methods used compensate each other, giving more detailed data on bacterial population developments during spoilage. PMID:19961579

  20. Trans-species polymorphism at antimicrobial innate immunity cathelicidin genes of Atlantic cod and related species.

    Science.gov (United States)

    Halldórsdóttir, Katrín; Árnason, Einar

    2015-01-01

    Natural selection, the most important force in evolution, comes in three forms. Negative purifying selection removes deleterious variation and maintains adaptations. Positive directional selection fixes beneficial variants, producing new adaptations. Balancing selection maintains variation in a population. Important mechanisms of balancing selection include heterozygote advantage, frequency-dependent advantage of rarity, and local and fluctuating episodic selection. A rare pathogen gains an advantage because host defenses are predominantly effective against prevalent types. Similarly, a rare immune variant gives its host an advantage because the prevalent pathogens cannot escape the host's apostatic defense. Due to the stochastic nature of evolution, neutral variation may accumulate on genealogical branches, but trans-species polymorphisms are rare under neutrality and are strong evidence for balancing selection. Balanced polymorphism maintains diversity at the major histocompatibility complex (MHC) in vertebrates. The Atlantic cod is missing genes for both MHC-II and CD4, vital parts of the adaptive immune system. Nevertheless, cod are healthy in their ecological niche, maintaining large populations that support major commercial fisheries. Innate immunity is of interest from an evolutionary perspective, particularly in taxa lacking adaptive immunity. Here, we analyze extensive amino acid and nucleotide polymorphisms of the cathelicidin gene family in Atlantic cod and closely related taxa. There are three major clusters, Cath1, Cath2, and Cath3, that we consider to be paralogous genes. There is extensive nucleotide and amino acid allelic variation between and within clusters. The major feature of the results is that the variation clusters by alleles and not by species in phylogenetic trees and discriminant analysis of principal components. Variation within the three groups shows trans-species polymorphism that is older than speciation and that is suggestive of

  1. Long distance linkage disequilibrium and limited hybridization suggest cryptic speciation in atlantic cod.

    Science.gov (United States)

    Bradbury, Ian R; Bowman, Sharen; Borza, Tudor; Snelgrove, Paul V R; Hutchings, Jeffrey A; Berg, Paul R; Rodríguez-Ezpeleta, Naiara; Lighten, Jackie; Ruzzante, Daniel E; Taggart, Christopher; Bentzen, Paul

    2014-01-01

    Hybrid zones provide unprecedented opportunity for the study of the evolution of reproductive isolation, and the extent of hybridization across individuals and genomes can illuminate the degree of isolation. We examine patterns of interchromosomal linkage disequilibrium (ILD) and the presence of hybridization in Atlantic cod, Gadus morhua, in previously identified hybrid zones in the North Atlantic. Here, previously identified clinal loci were mapped to the cod genome with most (∼70%) occurring in or associated with (cod either through strong selection against hybrid individuals, or genetic incompatibility and intrinsic barriers to hybridization. In either case, the presence of strong clinal trends, and little gene flow despite extensive hybridization supports a hypothesis of reproductive isolation and cryptic speciation in Atlantic cod. Further work is required to test the degree and nature of reproductive isolation in this species.

  2. Gene expression profiling of Atlantic cod (Gadus morhua) embryogenesis using microarray.

    Science.gov (United States)

    Drivenes, Øyvind; Taranger, Geir Lasse; Edvardsen, Rolf B

    2012-04-01

    Atlantic cod (Gadus morhua) is a fish species of high importance, as a key species in a range of Northern ecosystems, in fisheries, and as an emerging species in aquaculture. So far, little is known about the transcriptional activity during early developmental stages of Atlantic cod. Hence, we decided to use a cDNA microarray covering 7,000 genes to analyze the temporal activity of the transcriptome during cod embryogenesis. Twelve different embryonic time points were selected, covering major developmental stages and processes such as maternally derived mRNA, blastula, gastrula, segmentation, hatching, and first-feeding larval stage. The microarray analysis revealed a highly dynamic transcriptional profile, showing for the first time the differential expression of thousands of known and unknown genes during Atlantic cod embryogenesis. These initial findings will serve as an important baseline for future in-depth studies of candidate genes involved in development, reproductive control, disease resistance, growth, nutrient digestion, and metabolism.

  3. Ocean Acidification Portends Acute Habitat Compression for Atlantic Cod (Gadus morhua) in a Physiologically-informed Metabolic Rate Model

    Science.gov (United States)

    Del Raye, G.; Weng, K.

    2011-12-01

    Ocean acidification affects organisms on a biochemical scale, yet its societal impacts manifest from changes that propagate through entire populations. Successful forecasting of the effects of ocean acidification therefore depends on at least two steps: (1) deducing systemic physiology based on subcellular stresses and (2) scaling individual physiology up to ecosystem processes. Predictions that are based on known biological processes (process-based models) may fare better than purely statistical models in both these steps because the latter are less robust to novel environmental conditions. Here we present a process-based model that uses temperature, pO2, and pCO2 to predict maximal aerobic scope in Atlantic cod. Using this model, we show that (i) experimentally-derived physiological parameters are sufficient to capture the response of cod aerobic scope to temperature and oxygen, and (ii) subcellular pH effects can be used to predict the systemic physiological response of cod to an acidified ocean. We predict that acute pH stress (on a scale of hours) could limit the mobility of Atlantic cod during diel vertical migration across a pCO2 gradient, promoting habitat compression. Finally, we use a global sensitivity analysis to identify opportunities for the improvement of model uncertainty as well as some physiological adaptations that could mitigate climate stresses on cod in the future.

  4. Feasibility of Ocean Acoustic Waveguide Remote Sensing (OAWRS of Atlantic Cod with Seafloor Scattering Limitations

    Directory of Open Access Journals (Sweden)

    Ankita D. Jain

    2013-12-01

    Full Text Available Recently reported declines in the population of Atlantic cod have led to calls for additional survey methods for stock assessments. In combination with conventional line-transect methods that may have ambiguities in sampling fish populations, Ocean Acoustic Waveguide Remote Sensing (OAWRS has been shown to have a potential for providing accurate stock assessments (Makris N.C., et al. Science 2009, 323, 1,734–1,737; 54th Northeast Regional Stock Assessment Workshop (54th SAW US Department of Commerce, Northeast Fisheries Science Center, 2012. The use of OAWRS technology enables instantaneous wide-area sensing of fish aggregations over thousands of square kilometers. The ratio of the intensity of scattered returns from fish versus the seafloor in any resolution cell typically determines the maximum fish detection range of OAWRS, which then is a function of fish population density, scattering amplitude and depth distribution, as well as the level of seafloor scattering. With the knowledge of oceanographic parameters, such as bathymetry, sound speed structure and attenuation, we find that a Rayleigh–Born volume scattering approach can be used to efficiently and accurately estimate seafloor scattering over wide areas. From hundreds of OAWRS measurements of seafloor scattering, we determine the Rayleigh–Born scattering amplitude of the seafloor, which we find has a ƒ2,4 frequency dependence below roughly 2 kHz in typical continental shelf environments along the US northeast coast. We then find that it is possible to robustly detect cod aggregations across frequencies at and near swim bladder resonance for observed spawningconfigurations along the U.S. northeast coast, roughly the two octave range 150–600 Hzfor water depths up to roughly 100 m. This frequency range is also optimal for long-rangeocean acoustic waveguide propagation, because it enables multimodal acoustic waveguidepropagation with minimal acoustic absorption and forward

  5. Spatiotemporal SNP analysis reveals pronounced biocomplexity at the northern range margin of Atlantic cod Gadus morhua

    Science.gov (United States)

    Therkildsen, Nina Overgaard; Hemmer-Hansen, Jakob; Hedeholm, Rasmus Berg; Wisz, Mary S; Pampoulie, Christophe; Meldrup, Dorte; Bonanomi, Sara; Retzel, Anja; Olsen, Steffen Malskær; Nielsen, Einar Eg

    2013-01-01

    Accurate prediction of species distribution shifts in the face of climate change requires a sound understanding of population diversity and local adaptations. Previous modeling has suggested that global warming will lead to increased abundance of Atlantic cod (Gadus morhua) in the ocean around Greenland, but the dynamics of earlier abundance fluctuations are not well understood. We applied a retrospective spatiotemporal population genomics approach to examine the temporal stability of cod population structure in this region and to search for signatures of divergent selection over a 78-year period spanning major demographic changes. Analyzing >900 gene-associated single nucleotide polymorphisms in 847 individuals, we identified four genetically distinct groups that exhibited varying spatial distributions with considerable overlap and mixture. The genetic composition had remained stable over decades at some spawning grounds, whereas complete population replacement was evident at others. Observations of elevated differentiation in certain genomic regions are consistent with adaptive divergence between the groups, indicating that they may respond differently to environmental variation. Significantly increased temporal changes at a subset of loci also suggest that adaptation may be ongoing. These findings illustrate the power of spatiotemporal population genomics for revealing biocomplexity in both space and time and for informing future fisheries management and conservation efforts. PMID:23789034

  6. Spatiotemporal SNP analysis reveals pronounced biocomplexity at the northern range margin of Atlantic cod Gadus morhua.

    Science.gov (United States)

    Therkildsen, Nina Overgaard; Hemmer-Hansen, Jakob; Hedeholm, Rasmus Berg; Wisz, Mary S; Pampoulie, Christophe; Meldrup, Dorte; Bonanomi, Sara; Retzel, Anja; Olsen, Steffen Malskær; Nielsen, Einar Eg

    2013-06-01

    Accurate prediction of species distribution shifts in the face of climate change requires a sound understanding of population diversity and local adaptations. Previous modeling has suggested that global warming will lead to increased abundance of Atlantic cod (Gadus morhua) in the ocean around Greenland, but the dynamics of earlier abundance fluctuations are not well understood. We applied a retrospective spatiotemporal population genomics approach to examine the temporal stability of cod population structure in this region and to search for signatures of divergent selection over a 78-year period spanning major demographic changes. Analyzing >900 gene-associated single nucleotide polymorphisms in 847 individuals, we identified four genetically distinct groups that exhibited varying spatial distributions with considerable overlap and mixture. The genetic composition had remained stable over decades at some spawning grounds, whereas complete population replacement was evident at others. Observations of elevated differentiation in certain genomic regions are consistent with adaptive divergence between the groups, indicating that they may respond differently to environmental variation. Significantly increased temporal changes at a subset of loci also suggest that adaptation may be ongoing. These findings illustrate the power of spatiotemporal population genomics for revealing biocomplexity in both space and time and for informing future fisheries management and conservation efforts.

  7. Diel variation in feeding and movement patterns of juvenile Atlantic cod at offshore wind farms

    Science.gov (United States)

    Reubens, Jan T.; De Rijcke, Maarten; Degraer, Steven; Vincx, Magda

    2014-01-01

    Atlantic cod (Gadus morhua) is a commercially important fish species suffering from overexploitation in the North-East Atlantic. In recent years, their natural environment is being intensively altered by the construction of offshore wind farms in many coastal areas. These constructions form artificial reefs influencing local biodiversity and ecosystem functioning. It has been demonstrated that Atlantic cod is present in the vicinity of these constructions. However, empirical data concerning the diel activity and feeding behaviour of Atlantic cod in the vicinity of these artificial reefs is lacking. Atlantic cod has a flexible diel activity cycle linked to spatio-temporal variations in food availability and predation risk. In this study we integrated acoustic telemetry with stomach content analysis to quantify diel activity and evaluate diel feeding patterns at a windmill artificial reef (WAR) in the Belgian part of the North Sea. Atlantic cod exhibited crepuscular movements related to feeding activity; a 12 h cycle was found and the highest catch rates and stomach fullness were recorded close to sunset and sunrise. It is suggested that the observed diel movement pattern is related to the prey species community and to predation pressure. Foraging at low ambient light levels (i.e. at dusk and dawn) probably causes a trade-off between foraging success and reducing predation pressure. Fish did not leave the area in-between feeding periods. Hence other benefits (i.e. shelter against currents and predators) besides food availability stimulate the aggregation behaviour at the WARs.

  8. Polymorphism, selection and tandem duplication of transferrin genes in Atlantic cod (Gadus morhua - Conserved synteny between fish monolobal and tetrapod bilobal transferrin loci

    Directory of Open Access Journals (Sweden)

    Tooming-Klunderud Ave

    2011-05-01

    Full Text Available Abstract Background The two homologous iron-binding lobes of transferrins are thought to have evolved by gene duplication of an ancestral monolobal form, but any conserved synteny between bilobal and monolobal transferrin loci remains unexplored. The important role played by transferrin in the resistance to invading pathogens makes this polymorphic gene a highly valuable candidate for studying adaptive divergence among local populations. Results The Atlantic cod genome was shown to harbour two tandem duplicated serum transferrin genes (Tf1, Tf2, a melanotransferrin gene (MTf, and a monolobal transferrin gene (Omp. Whereas Tf1 and Tf2 were differentially expressed in liver and brain, the Omp transcript was restricted to the otoliths. Fish, chicken and mammals showed highly conserved syntenic regions in which monolobal and bilobal transferrins reside, but contrasting with tetrapods, the fish transferrin genes are positioned on three different linkage groups. Sequence alignment of cod Tf1 cDNAs from Northeast (NE and Northwest (NW Atlantic populations revealed 22 single nucleotide polymorphisms (SNP causing the replacement of 16 amino acids, including eight surface residues revealed by the modelled 3D-structures, that might influence the binding of pathogens for removal of iron. SNP analysis of a total of 375 individuals from 14 trans-Atlantic populations showed that the Tf1-NE variant was almost fixed in the Baltic cod and predominated in the other NE Atlantic populations, whereas the NW Atlantic populations were more heterozygous and showed high frequencies of the Tf-NW SNP alleles. Conclusions The highly conserved synteny between fish and tetrapod transferrin loci infers that the fusion of tandem duplicated Omp-like genes gave rise to the modern transferrins. The multiple nonsynonymous substitutions in cod Tf1 with putative structural effects, together with highly divergent allele frequencies among different cod populations, strongly suggest

  9. Polymorphism, selection and tandem duplication of transferrin genes in Atlantic cod (Gadus morhua)--conserved synteny between fish monolobal and tetrapod bilobal transferrin loci.

    Science.gov (United States)

    Andersen, Øivind; De Rosa, Maria Cristina; Pirolli, Davide; Tooming-Klunderud, Ave; Petersen, Petra E; André, Carl

    2011-05-25

    The two homologous iron-binding lobes of transferrins are thought to have evolved by gene duplication of an ancestral monolobal form, but any conserved synteny between bilobal and monolobal transferrin loci remains unexplored. The important role played by transferrin in the resistance to invading pathogens makes this polymorphic gene a highly valuable candidate for studying adaptive divergence among local populations. The Atlantic cod genome was shown to harbour two tandem duplicated serum transferrin genes (Tf1, Tf2), a melanotransferrin gene (MTf), and a monolobal transferrin gene (Omp). Whereas Tf1 and Tf2 were differentially expressed in liver and brain, the Omp transcript was restricted to the otoliths. Fish, chicken and mammals showed highly conserved syntenic regions in which monolobal and bilobal transferrins reside, but contrasting with tetrapods, the fish transferrin genes are positioned on three different linkage groups. Sequence alignment of cod Tf1 cDNAs from Northeast (NE) and Northwest (NW) Atlantic populations revealed 22 single nucleotide polymorphisms (SNP) causing the replacement of 16 amino acids, including eight surface residues revealed by the modelled 3D-structures, that might influence the binding of pathogens for removal of iron. SNP analysis of a total of 375 individuals from 14 trans-Atlantic populations showed that the Tf1-NE variant was almost fixed in the Baltic cod and predominated in the other NE Atlantic populations, whereas the NW Atlantic populations were more heterozygous and showed high frequencies of the Tf-NW SNP alleles. The highly conserved synteny between fish and tetrapod transferrin loci infers that the fusion of tandem duplicated Omp-like genes gave rise to the modern transferrins. The multiple nonsynonymous substitutions in cod Tf1 with putative structural effects, together with highly divergent allele frequencies among different cod populations, strongly suggest evidence for positive selection and local adaptation in

  10. Polymorphism, selection and tandem duplication of transferrin genes in Atlantic cod (Gadus morhua) - Conserved synteny between fish monolobal and tetrapod bilobal transferrin loci

    Science.gov (United States)

    2011-01-01

    Background The two homologous iron-binding lobes of transferrins are thought to have evolved by gene duplication of an ancestral monolobal form, but any conserved synteny between bilobal and monolobal transferrin loci remains unexplored. The important role played by transferrin in the resistance to invading pathogens makes this polymorphic gene a highly valuable candidate for studying adaptive divergence among local populations. Results The Atlantic cod genome was shown to harbour two tandem duplicated serum transferrin genes (Tf1, Tf2), a melanotransferrin gene (MTf), and a monolobal transferrin gene (Omp). Whereas Tf1 and Tf2 were differentially expressed in liver and brain, the Omp transcript was restricted to the otoliths. Fish, chicken and mammals showed highly conserved syntenic regions in which monolobal and bilobal transferrins reside, but contrasting with tetrapods, the fish transferrin genes are positioned on three different linkage groups. Sequence alignment of cod Tf1 cDNAs from Northeast (NE) and Northwest (NW) Atlantic populations revealed 22 single nucleotide polymorphisms (SNP) causing the replacement of 16 amino acids, including eight surface residues revealed by the modelled 3D-structures, that might influence the binding of pathogens for removal of iron. SNP analysis of a total of 375 individuals from 14 trans-Atlantic populations showed that the Tf1-NE variant was almost fixed in the Baltic cod and predominated in the other NE Atlantic populations, whereas the NW Atlantic populations were more heterozygous and showed high frequencies of the Tf-NW SNP alleles. Conclusions The highly conserved synteny between fish and tetrapod transferrin loci infers that the fusion of tandem duplicated Omp-like genes gave rise to the modern transferrins. The multiple nonsynonymous substitutions in cod Tf1 with putative structural effects, together with highly divergent allele frequencies among different cod populations, strongly suggest evidence for positive

  11. Constant proportion harvest policies: dynamic implications in the Pacific halibut and Atlantic cod fisheries.

    Science.gov (United States)

    Yakubu, Abdul-Aziz; Li, Nianpeng; Conrad, Jon M; Zeeman, Mary-Lou

    2011-07-01

    Overfishing, pollution and other environmental factors have greatly reduced commercially valuable stocks of fish. In a 2006 Science article, a group of ecologists and economists warned that the world may run out of seafood from natural stocks if overfishing continues at current rates. In this paper, we explore the interaction between a constant proportion harvest policy and recruitment dynamics. We examine the discrete-time constant proportion harvest policy discussed in Ang et al. (2009) and then expand the framework to include stock-recruitment functions that are compensatory and overcompensatory, both with and without the Allee effect. We focus on constant proportion policies (CPPs). CPPs have the potential to stabilize complex overcompensatory stock dynamics, with or without the Allee effect, provided the rates of harvest stay below a threshold. If that threshold is exceeded, CPPs are known to result in the sudden collapse of a fish stock when stock recruitment exhibits the Allee effect. In case studies, we analyze CPPs as they might be applied to Gulf of Alaska Pacific halibut fishery and the Georges Bank Atlantic cod fishery based on harvest rates from 1975 to 2007. The best fit models suggest that, under high fishing mortalities, the halibut fishery is vulnerable to sudden population collapse while the cod fishery is vulnerable to steady decline to zero. The models also suggest that CPP with mean harvesting levels from the last 30 years can be effective at preventing collapse in the halibut fishery, but these same policies would lead to steady decline to zero in the Atlantic cod fishery. We observe that the likelihood of collapse in both fisheries increases with increased stochasticity (for example, weather variability) as predicted by models of global climate change. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Multidimensionality of behavioural phenotypes in Atlantic cod, Gadus morhua.

    Science.gov (United States)

    Meager, Justin J; Fernö, Anders; Skjæraasen, Jon Egil; Järvi, Torbjörn; Rodewald, Petra; Sverdrup, Gisle; Winberg, Svante; Mayer, Ian

    2012-06-25

    Much of the inter-individual variation observed in animal behaviour is now attributed to the existence of behavioural phenotypes or animal personalities. Such phenotypes may be fundamental to fisheries and aquaculture, yet there have been few detailed studies of this phenomenon in exploited marine animals. We investigated the behavioural and neuroendocrine responses of Atlantic cod (Gadus morhua L.), to situations reflecting critical ecological challenges: predator attacks and territorial challenges. Both hatchery-reared and wild fish were tested and behavioural profiles were compared with baseline conditions. We then used an objective, multivariate approach, rather than assigning individuals along one-dimensional behavioural axes, to examine whether distinct behavioural phenotypes were present. Our results indicate that two distinct behavioural phenotypes were evident in fish from each background. In hatchery-reared fish, phenotypes displayed divergent locomotor activity, sheltering, brain monoamine concentrations and responses to competitive challenges. In wild fish, phenotypes were distinguished primarily by locomotor activity, sheltering and responsiveness to predator stimuli. Hatcheries presumably represent a more stressful social environment, and social behaviour and neuroendocrine responses were important in discerning behavioural phenotypes in hatchery fish, whereas antipredator responses were important in discerning phenotypes in wild fish that have previously encountered predators. In both fish types, behavioural and physiological traits that classified individuals into phenotypes were not the same as those that were correlated across situations. These results highlight the multidimensionality of animal personalities, and that the processes that regulate one suite of behavioural traits may be very different to the processes that regulate other behaviours. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Mercury concentration trend as a possible result of changes in cod population demography.

    Science.gov (United States)

    Ruus, Anders; Hjermann, Dag Ø; Beylich, Bjørnar; Schøyen, Merete; Øxnevad, Sigurd; Green, Norman W

    2017-09-01

    Mercury (Hg) in Atlantic cod (Gadus morhua) is one of many parameters that are monitored through OSPAR's Joint Assessment and Monitoring Programme. Time series for cod in the Inner Oslofjord (Norway) go back to 1984. Until 2014, annual median Hg-concentrations in cod from the Inner Oslofjord showed both significant upward long-term (whole time series) and short-term (recent 10 years) trends (when 2015 was included, the short-term trend was not significant). However, the median length of the cod sampled also showed upward trends. This may have been caused by low cod recruitment in the area since the start of the 2000s, as indicated by beach seine surveys. To investigate how length would impact the trend analysis, the Hg-concentrations in the cod were normalised to 50 cm. No significant short-term trend in Hg-concentrations could be detected for length-normalised concentrations. The results indicated that most of the upward trend in Hg-concentrations could be attributed to the sampling of larger fish. The reasons for the apparent change in the cod population demography are not conclusive, however, sampling bias must also be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Forecasting future recruitment success for Atlantic cod in the warming and acidifying Barents Sea.

    Science.gov (United States)

    Koenigstein, Stefan; Dahlke, Flemming T; Stiasny, Martina H; Storch, Daniela; Clemmesen, Catriona; Pörtner, Hans-Otto

    2018-01-01

    Productivity of marine fish stocks is known to be affected by environmental and ecological drivers, and global climate change is anticipated to alter recruitment success of many stocks. While the direct effects of environmental drivers on fish early life stage survival can be quantified experimentally, indirect effects in marine ecosystems and the role of adaptation are still highly uncertain. We developed an integrative model for the effects of ocean warming and acidification on the early life stages of Atlantic cod in the Barents Sea, termed SCREI (Simulator of Cod Recruitment under Environmental Influences). Experimental results on temperature and CO 2 effects on egg fertilization, egg and larval survival and development times are incorporated. Calibration using empirical time series of egg production, temperature, food and predator abundance reproduces age-0 recruitment over three decades. We project trajectories of recruitment success under different scenarios and quantify confidence limits based on variation in experiments. A publicly accessible web version of the SCREI model can be run under www.oceanchange.uni-bremen.de/;SCREI. Severe reductions in average age-0 recruitment success of Barents Sea cod are projected under uncompensated warming and acidification toward the middle to end of this century. Although high population stochasticity was found, considerable rates of evolutionary adaptation to acidification and shifts in organismal thermal windows would be needed to buffer impacts on recruitment. While increases in food availability may mitigate short-term impacts, an increase in egg production achieved by stock management could provide more long-term safety for cod recruitment success. The SCREI model provides a novel integration of multiple driver effects in different life stages and enables an estimation of uncertainty associated with interindividual and ecological variation. The model thus helps to advance toward an improved empirical foundation for

  15. Development of a SNP resource and a genetic linkage map for Atlantic cod (Gadus morhua)

    Science.gov (United States)

    2010-01-01

    Background Atlantic cod (Gadus morhua) is a species with increasing economic significance for the aquaculture industry. The genetic improvement of cod will play a critical role in achieving successful large-scale aquaculture. While many microsatellite markers have been developed in cod, the number of single nucleotide polymorphisms (SNPs) is currently limited. Here we report the identification of SNPs from sequence data generated by a large-scale expressed sequence tag (EST) program, focusing on fish originating from Canadian waters. Results A total of 97976 ESTs were assembled to generate 13448 contigs. We detected 4753 SNPs that met our selection criteria (depth of coverage ≥ 4 reads; minor allele frequency > 25%). 3072 SNPs were selected for testing. The percentage of successful assays was 75%, with 2291 SNPs amplifying correctly. Of these, 607 (26%) SNPs were monomorphic for all populations tested. In total, 64 (4%) of SNPs are likely to represent duplicated genes or highly similar members of gene families, rather than alternative alleles of the same gene, since they showed a high frequency of heterozygosity. The remaining polymorphic SNPs (1620) were categorised as validated SNPs. The mean minor allele frequency of the validated loci was 0.258 (± 0.141). Of the 1514 contigs from which validated SNPs were selected, 31% have a significant blast hit. For the SNPs predicted to occur in coding regions (141), we determined that 36% (51) are non-synonymous. Many loci (1033 SNPs; 64%) are polymorphic in all populations tested. However a small number of SNPs (184) that are polymorphic in the Western Atlantic were monomorphic in fish tested from three European populations. A preliminary linkage map has been constructed with 23 major linkage groups and 924 mapped SNPs. Conclusions These SNPs represent powerful tools to accelerate the genetic improvement of cod aquaculture. They have been used to build a genetic linkage map that can be applied to quantitative trait

  16. Development of a SNP resource and a genetic linkage map for Atlantic cod (Gadus morhua

    Directory of Open Access Journals (Sweden)

    Higgins Brent

    2010-03-01

    Full Text Available Abstract Background Atlantic cod (Gadus morhua is a species with increasing economic significance for the aquaculture industry. The genetic improvement of cod will play a critical role in achieving successful large-scale aquaculture. While many microsatellite markers have been developed in cod, the number of single nucleotide polymorphisms (SNPs is currently limited. Here we report the identification of SNPs from sequence data generated by a large-scale expressed sequence tag (EST program, focusing on fish originating from Canadian waters. Results A total of 97976 ESTs were assembled to generate 13448 contigs. We detected 4753 SNPs that met our selection criteria (depth of coverage ≥ 4 reads; minor allele frequency > 25%. 3072 SNPs were selected for testing. The percentage of successful assays was 75%, with 2291 SNPs amplifying correctly. Of these, 607 (26% SNPs were monomorphic for all populations tested. In total, 64 (4% of SNPs are likely to represent duplicated genes or highly similar members of gene families, rather than alternative alleles of the same gene, since they showed a high frequency of heterozygosity. The remaining polymorphic SNPs (1620 were categorised as validated SNPs. The mean minor allele frequency of the validated loci was 0.258 (± 0.141. Of the 1514 contigs from which validated SNPs were selected, 31% have a significant blast hit. For the SNPs predicted to occur in coding regions (141, we determined that 36% (51 are non-synonymous. Many loci (1033 SNPs; 64% are polymorphic in all populations tested. However a small number of SNPs (184 that are polymorphic in the Western Atlantic were monomorphic in fish tested from three European populations. A preliminary linkage map has been constructed with 23 major linkage groups and 924 mapped SNPs. Conclusions These SNPs represent powerful tools to accelerate the genetic improvement of cod aquaculture. They have been used to build a genetic linkage map that can be applied to

  17. The genome sequence of Atlantic cod reveals a unique immune system.

    Science.gov (United States)

    Star, Bastiaan; Nederbragt, Alexander J; Jentoft, Sissel; Grimholt, Unni; Malmstrøm, Martin; Gregers, Tone F; Rounge, Trine B; Paulsen, Jonas; Solbakken, Monica H; Sharma, Animesh; Wetten, Ola F; Lanzén, Anders; Winer, Roger; Knight, James; Vogel, Jan-Hinnerk; Aken, Bronwen; Andersen, Oivind; Lagesen, Karin; Tooming-Klunderud, Ave; Edvardsen, Rolf B; Tina, Kirubakaran G; Espelund, Mari; Nepal, Chirag; Previti, Christopher; Karlsen, Bård Ove; Moum, Truls; Skage, Morten; Berg, Paul R; Gjøen, Tor; Kuhl, Heiner; Thorsen, Jim; Malde, Ketil; Reinhardt, Richard; Du, Lei; Johansen, Steinar D; Searle, Steve; Lien, Sigbjørn; Nilsen, Frank; Jonassen, Inge; Omholt, Stig W; Stenseth, Nils Chr; Jakobsen, Kjetill S

    2011-08-10

    Atlantic cod (Gadus morhua) is a large, cold-adapted teleost that sustains long-standing commercial fisheries and incipient aquaculture. Here we present the genome sequence of Atlantic cod, showing evidence for complex thermal adaptations in its haemoglobin gene cluster and an unusual immune architecture compared to other sequenced vertebrates. The genome assembly was obtained exclusively by 454 sequencing of shotgun and paired-end libraries, and automated annotation identified 22,154 genes. The major histocompatibility complex (MHC) II is a conserved feature of the adaptive immune system of jawed vertebrates, but we show that Atlantic cod has lost the genes for MHC II, CD4 and invariant chain (Ii) that are essential for the function of this pathway. Nevertheless, Atlantic cod is not exceptionally susceptible to disease under natural conditions. We find a highly expanded number of MHC I genes and a unique composition of its Toll-like receptor (TLR) families. This indicates how the Atlantic cod immune system has evolved compensatory mechanisms in both adaptive and innate immunity in the absence of MHC II. These observations affect fundamental assumptions about the evolution of the adaptive immune system and its components in vertebrates.

  18. Trans-oceanic genomic divergence of Atlantic cod ecotypes is associated with large inversions.

    Science.gov (United States)

    Berg, P R; Star, B; Pampoulie, C; Bradbury, I R; Bentzen, P; Hutchings, J A; Jentoft, S; Jakobsen, K S

    2017-12-01

    Chromosomal rearrangements such as inversions can play a crucial role in maintaining polymorphism underlying complex traits and contribute to the process of speciation. In Atlantic cod (Gadus morhua), inversions of several megabases have been identified that dominate genomic differentiation between migratory and nonmigratory ecotypes in the Northeast Atlantic. Here, we show that the same genomic regions display elevated divergence and contribute to ecotype divergence in the Northwest Atlantic as well. The occurrence of these inversions on both sides of the Atlantic Ocean reveals a common evolutionary origin, predating the >100 000-year-old trans-Atlantic separation of Atlantic cod. The long-term persistence of these inversions indicates that they are maintained by selection, possibly facilitated by coevolution of genes underlying complex traits. Our data suggest that migratory behaviour is derived from more stationary, ancestral ecotypes. Overall, we identify several large genomic regions-each containing hundreds of genes-likely involved in the maintenance of genomic divergence in Atlantic cod on both sides of the Atlantic Ocean.

  19. First record of brown colouration of Atlantic cod (Gadus morhua, L. from the North Sea

    Directory of Open Access Journals (Sweden)

    Agnieszka Rybczyk

    2014-01-01

    Full Text Available This paper reports the biological characterisation of a specimen of Atlantic cod (Gadus morhua L. with a unique brown colour, which is the first fish of this species with such a colouration recorded from European waters. It was caught in the coastal zone of the North Sea in June 2011. This ‘brown’ cod fish weighed 1074.3 g and had an overall length of 422 mm.

  20. Automatic feeding and Harvesting of Juvenile Atlantic Cod (Gadus Morhua L. in a Pond

    Directory of Open Access Journals (Sweden)

    V. Øiestad

    1987-01-01

    Full Text Available Large scale production of juvenile Atlantic cod has been carried out since 1980 in a saltwater pond. A break-through was obtained in 1983 with high survival rates of cod larvae to metamorphosis. In 1985 we made progress in two fiels, reduced cannibalism and automatic harvesting. Juvenile cod formed large schools while fed dry pellets in the currents set up by five propellers. An underwater loudspeaker was programmed to give sound pulses just before feeding. During harvesting dry pellets were released inside a fish trap while giving the sound signals the cod juveniles were conditioned to. The cod readily entered the trap and a computer-controlled fish pump transported the fish from the fish trap into a storing tank and grading grids. The trap gradually emptied the pond of fish and more than 80

  1. Karyotyping and cytogenetic mapping of Atlantic cod (Gadus morhua Linnaeus, 1758).

    Science.gov (United States)

    Ghigliotti, L; Fevolden, S-E; Cheng, C-H C; Babiak, I; Dettai, A; Pisano, E

    2012-12-01

    The Atlantic cod (Gadus morhua) is an important natural resource for northern societies and is now also considered to be a promising candidate for aquaculture. In recent years, much effort has been directed towards the development of genomic tools, and genome initiatives for Atlantic cod have been established. Despite the growing attention devoted to the Atlantic cod genomics, basic aspects of its genome structure and organization remain unknown. Thus, the present work aims to study cytogenetic features of the Atlantic cod as a contribution to the knowledge of this species' genome. The Atlantic cod displays a diploid number of 46 chromosomes, with a karyotypic formula 16 m/sm + 30 st/t. Conventional karyotyping was improved by chromosomal mapping of two classes of repetitive sequences. 18S rDNA clusters were assigned to pairs 2 and 4; small amounts of 18S rDNA clusters were occasionally detected on pair 5. These findings could not be related to the geographical origin of the specimens, but were consistent with the variability of these repeated genes in fish in general. 5S ribosomal gene clusters, apparently corresponding to a single 5S rDNA class, were detected on twelve chromosomes (pairs 11, 12, 14, 17, 20 and 21). The present update of the existing but meagre information on the karyotype of Atlantic cod, plus the first physical mapping of repetitive genes in this species herein, opens the way for an integrated approach that combines genetic and physical mapping with the assembly of the genome of this commercially important species. © 2012 The Authors, Animal Genetics © 2012 Stichting International Foundation for Animal Genetics.

  2. Historical DNA reveals the demographic history of Atlantic cod (Gadus morhua) in medieval and early modern Iceland.

    Science.gov (United States)

    Ólafsdóttir, Guðbjörg Ásta; Westfall, Kristen M; Edvardsson, Ragnar; Pálsson, Snæbjörn

    2014-02-22

    Atlantic cod (Gadus morhua) vertebrae from archaeological sites were used to study the history of the Icelandic Atlantic cod population in the time period of 1500-1990. Specifically, we used coalescence modelling to estimate population size and fluctuations from the sequence diversity at the cytochrome b (cytb) and Pantophysin I (PanI) loci. The models are consistent with an expanding population during the warm medieval period, large historical effective population size (NE), a marked bottleneck event at 1400-1500 and a decrease in NE in early modern times. The model results are corroborated by the reduction of haplotype and nucleotide variation over time and pairwise population distance as a significant portion of nucleotide variation partitioned across the 1550 time mark. The mean age of the historical fished stock is high in medieval times with a truncation in age in early modern times. The population size crash coincides with a period of known cooling in the North Atlantic, and we conclude that the collapse may be related to climate or climate-induced ecosystem change.

  3. Genome architecture enables local adaptation of Atlantic cod despite high connectivity

    DEFF Research Database (Denmark)

    Barth, Julia M I; Berg, Paul R; Jonsson, Per R.

    2017-01-01

    Adaptation to local conditions is a fundamental process in evolution; however, mechanisms maintaining local adaptation despite high gene flow are still poorly understood. Marine ecosystems provide a wide array of diverse habitats that frequently promote ecological adaptation even in species......-nucleotide polymorphisms with larval dispersal patterns inferred using a biophysical ocean model, we show that Atlantic cod individuals residing in sheltered estuarine habitats of Scandinavian fjords mainly belong to offshore oceanic populations with considerable connectivity between these diverse ecosystems. Nevertheless...... in the rearranged region. Our study provides new insights into the potential of local adaptation in high gene flow species within fine geographical scales and highlights the importance of genome architecture in analyses of ecological adaptation. This article is protected by copyright. All rights reserved....

  4. Elucidation of different cold-adapted Atlantic cod (Gadus morhua) trypsin X isoenzymes.

    Science.gov (United States)

    Stefansson, Bjarki; Sandholt, Gunnar B; Gudmundsdottir, Ágústa

    2017-01-01

    Trypsins from Atlantic cod (Gadus morhua), consisting of several isoenzymes, are highly active cold-adapted serine proteases. These trypsins are isolated for biomedical use in an eco-friendly manner from underutilized seafood by-products. Our group has explored the biochemical properties of trypsins and their high potential in biomedicine. For broader utilization of cod trypsins, further characterization of biochemical properties of the individual cod trypsin isoenzymes is of importance. For that purpose, a benzamidine purified trypsin isolate from Atlantic cod was analyzed. Anion exchange chromatography revealed eight peaks containing proteins around 24kDa with tryptic activity. Based on mass spectrometric analysis, one isoenzyme gave the best match to cod trypsin I and six isoenzymes gave the best match to cod trypsin X. Amino terminal sequencing of two of these six trypsin isoenzymes showed identity to cod trypsin X. Three sequence variants of trypsin X were identified by cDNA analysis demonstrating that various forms of this enzyme exist. One trypsin X isoenzyme was selected for further characterization based on abundance and stability. Stepwise increase in catalytic efficiency (kcat/Km) of this trypsin X isoenzyme was obtained with substrates containing one to three amino acid residues. The study demonstrates that the catalytic efficiency of this trypsin X isoenzyme is comparable to that of cod trypsin I, the most abundant and highly active isoenzyme in the benzamidine cod trypsin isolate. Differences in pH stability and sensitivity to inhibitors of the trypsin X isoenzyme compared to cod trypsin I were detected that may be important for practical use. Copyright © 2016. Published by Elsevier B.V.

  5. Egg distribution, bottom topography and small-scale cod population structure in a coastal marine system

    OpenAIRE

    Knutsen, Halvor; Olsen, Espen Moland; Ciannelli, Lorenzo; Espeland, Sigurd Heiberg; Knutsen, Jan Atle; Simonsen, Jan Henrik; Skreslet, Stig; Stenseth, Nils Christian

    2007-01-01

    Coastal marine species with pelagic egg and larval stages, such as the Atlantic cod Gadus morhua, can be structured into genetically distinct local populations on a surprisingly small geographic scale considering their dispersal potential. Mechanisms responsible for such small-scale genetic structure may involve homing of adults to their natal spawning grounds, but also local retention of pelagic eggs and larvae. For example, spawning within sheltered fjord habitats is expected to favour loca...

  6. A statistical discrimination method using sagittal otolith dimensions between sibling species of juvenile cod Gadus morhua and Gadus ogac from the North-West Atlantic

    DEFF Research Database (Denmark)

    Nielsen, J. Rasmus; Methven, D. A.; Kristensen, Kasper

    2010-01-01

    Greenland cod (Gadus ogac) and Atlantic cod (Gadus morhua) co-exist and are caught in the same fisheries in coastal waters off western Greenland and eastern Canada. Juveniles (......Greenland cod (Gadus ogac) and Atlantic cod (Gadus morhua) co-exist and are caught in the same fisheries in coastal waters off western Greenland and eastern Canada. Juveniles (...

  7. The effects of production water, WAF or CEWAF on the fertilization success of Atlantic cod eggs

    Energy Technology Data Exchange (ETDEWEB)

    Burridge, L; Wong, D.; Trippel, E. [Fisheries and Oceans Canada, Ottawa, ON (Canada)

    2010-07-01

    Production water (PW), dispersed oil, and oil released from offshore oil and gas platforms can adversely affect fish populations. In this study, eggs from Atlantic cod were fertilized in the presence of PW collected from the Terra Nova and Hibernia offshore platforms in 2008. Cod eggs were also fertilized in the presence of the water accommodated fraction (WAF) and chemically enhanced water accommodated fraction (CEWAF) of Alaskan North Slope oil (ANS). Results of the study showed that exposure to the Terra Nova PW at 12 per cent (V/V) or higher resulted in significantly lower fertilization rates than those observed in controls. Exposure to Hibernia PW at 0.5 per cent (V/V) also resulted in significantly lower fertilization rates. The WAF of ANS up to 25 per cent (V/V) had no effect on fertilization rates. At 50 per cent (V/V), the fertilization rate for WAF ANS was much lower than rates observed in controls. The CEWAF significantly reduced fertilization at all tested concentrations.

  8. Effect of produced water on feeding and metabolism of Atlantic cod (Gadus morhua)

    Energy Technology Data Exchange (ETDEWEB)

    Volkoff, H.; Parrish, C. [Memorial Univ. of Newfoundland, St. John' s, NL (Canada); Hamoutene, D.; Mabrouk, G.; Samuelson, S.; Mansour, A.; Lee, K. [Fisheries and Oceans Canada, Dartmouth, NS (Canada). Maritimes Region, Ocean Sciences Division

    2007-07-01

    This paper addressed concerns regarding potentially detrimental cumulative effects of waste products from oil industry activities on marine organisms around production sites. The metabolic capacities, feeding and digestive physiology of fish have been shown to change with environmental parameters, which could impact the growth and health status of fish populations. In this study, the effects of produced water (PW) on feeding and metabolism of Atlantic cod was investigated by exposing fish to 0.100 ppm (x 10,000 PW dilution) or 200 ppm (x 500 dilution) of PW for 76 days. Throughout the experiment, food intake and mean weight were monitored. In addition, serum lipids, metabolites and gene expression of a brain appetite regulating factor were measured at the end of the experiment. No significant differences were observed in weight gain or food intake between the 3 groups of fish. Serum metabolites and neuropeptide Y expression remained unchanged between groups. The study is ongoing to complete comparative measurements of whole blood fatty acid profiles in plasma. The preliminary results indicate that feeding and metabolism in cod is not affected by produced water.

  9. Harvest selection on Atlantic cod behavioral traits: implications for spatial management.

    Science.gov (United States)

    Olsen, Esben Moland; Heupel, Michelle R; Simpfendorfer, Colin A; Moland, Even

    2012-07-01

    Harvesting wild populations may contrast or reinforce natural agents of selection and potentially cause evolutionary changes in life-history traits such as growth and maturation. Harvest selection may also act on behavioral traits, although this field of research has so far received less attention. We used acoustic tags and a network of receivers to monitor the behavior and fate of individual Atlantic cod (Gadus morhua, N = 60) in their natural habitat on the Norwegian Skagerrak coast. Fish with a strong diel vertical migration, alternating between shallow- and deep-water habitats, had a higher risk of being captured in the fishery (traps, gillnet, hand line) as compared to fish that stayed in deeper water. There was also a significant negative correlation between fish size (30-66 cm) and the magnitude of diel vertical migration. Natural selection on behavior was less clear, but tended to favor fish with a large activity space. On a monthly time scale we found significant repeatabilities for cod behavior, meaning that individual characteristics tended to persist and therefore may be termed personality traits. We argue that an evolutionary approach to fisheries management should consider fish behavior. This would be of particular relevance for spatial management actions such as marine reserve design.

  10. Recruitment variability in North Atlantic cod and match-mismatch dynamics.

    Science.gov (United States)

    Kristiansen, Trond; Drinkwater, Kenneth F; Lough, R Gregory; Sundby, Svein

    2011-03-07

    Fisheries exploitation, habitat destruction, and climate are important drivers of variability in recruitment success. Understanding variability in recruitment can reveal mechanisms behind widespread decline in the abundance of key species in marine and terrestrial ecosystems. For fish populations, the match-mismatch theory hypothesizes that successful recruitment is a function of the timing and duration of larval fish abundance and prey availability. However, the underlying mechanisms of match-mismatch dynamics and the factors driving spatial differences between high and low recruitment remain poorly understood. We used empirical observations of larval fish abundance, a mechanistic individual-based model, and a reanalysis of ocean temperature data from 1960 to 2002 to estimate the survival of larval cod (Gadus morhua). From the model, we quantified how survival rates changed during the warmest and coldest years at four important cod spawning sites in the North Atlantic. The modeled difference in survival probability was not large for any given month between cold or warm years. However, the cumulative effect of higher growth rates and survival through the entire spawning season in warm years was substantial with 308%, 385%, 154%, and 175% increases in survival for Georges Bank, Iceland, North Sea, and Lofoten cod stocks, respectively. We also found that the importance of match-mismatch dynamics generally increased with latitude. Our analyses indicate that a key factor for enhancing survival is the duration of the overlap between larval and prey abundance and not the actual timing of the peak abundance. During warm years, the duration of the overlap between larval fish and their prey is prolonged due to an early onset of the spring bloom. This prolonged season enhances cumulative growth and survival, leading to a greater number of large individuals with enhanced potential for survival to recruitment.

  11. Recruitment variability in North Atlantic cod and match-mismatch dynamics.

    Directory of Open Access Journals (Sweden)

    Trond Kristiansen

    Full Text Available BACKGROUND: Fisheries exploitation, habitat destruction, and climate are important drivers of variability in recruitment success. Understanding variability in recruitment can reveal mechanisms behind widespread decline in the abundance of key species in marine and terrestrial ecosystems. For fish populations, the match-mismatch theory hypothesizes that successful recruitment is a function of the timing and duration of larval fish abundance and prey availability. However, the underlying mechanisms of match-mismatch dynamics and the factors driving spatial differences between high and low recruitment remain poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: We used empirical observations of larval fish abundance, a mechanistic individual-based model, and a reanalysis of ocean temperature data from 1960 to 2002 to estimate the survival of larval cod (Gadus morhua. From the model, we quantified how survival rates changed during the warmest and coldest years at four important cod spawning sites in the North Atlantic. The modeled difference in survival probability was not large for any given month between cold or warm years. However, the cumulative effect of higher growth rates and survival through the entire spawning season in warm years was substantial with 308%, 385%, 154%, and 175% increases in survival for Georges Bank, Iceland, North Sea, and Lofoten cod stocks, respectively. We also found that the importance of match-mismatch dynamics generally increased with latitude. CONCLUSIONS/SIGNIFICANCE: Our analyses indicate that a key factor for enhancing survival is the duration of the overlap between larval and prey abundance and not the actual timing of the peak abundance. During warm years, the duration of the overlap between larval fish and their prey is prolonged due to an early onset of the spring bloom. This prolonged season enhances cumulative growth and survival, leading to a greater number of large individuals with enhanced potential for

  12. Trans-species polymorphism at antimicrobial innate immunity cathelicidin genes of Atlantic cod and related species

    Directory of Open Access Journals (Sweden)

    Katrín Halldórsdóttir

    2015-05-01

    Full Text Available Natural selection, the most important force in evolution, comes in three forms. Negative purifying selection removes deleterious variation and maintains adaptations. Positive directional selection fixes beneficial variants, producing new adaptations. Balancing selection maintains variation in a population. Important mechanisms of balancing selection include heterozygote advantage, frequency-dependent advantage of rarity, and local and fluctuating episodic selection. A rare pathogen gains an advantage because host defenses are predominantly effective against prevalent types. Similarly, a rare immune variant gives its host an advantage because the prevalent pathogens cannot escape the host’s apostatic defense. Due to the stochastic nature of evolution, neutral variation may accumulate on genealogical branches, but trans-species polymorphisms are rare under neutrality and are strong evidence for balancing selection. Balanced polymorphism maintains diversity at the major histocompatibility complex (MHC in vertebrates. The Atlantic cod is missing genes for both MHC-II and CD4, vital parts of the adaptive immune system. Nevertheless, cod are healthy in their ecological niche, maintaining large populations that support major commercial fisheries. Innate immunity is of interest from an evolutionary perspective, particularly in taxa lacking adaptive immunity. Here, we analyze extensive amino acid and nucleotide polymorphisms of the cathelicidin gene family in Atlantic cod and closely related taxa. There are three major clusters, Cath1, Cath2, and Cath3, that we consider to be paralogous genes. There is extensive nucleotide and amino acid allelic variation between and within clusters. The major feature of the results is that the variation clusters by alleles and not by species in phylogenetic trees and discriminant analysis of principal components. Variation within the three groups shows trans-species polymorphism that is older than speciation and that

  13. [Crystallization of aqueous solutions of cryoprotectors from Atlantic cod and lake Gammarus].

    Science.gov (United States)

    Andreev, A A; Petropavlov, N N

    1996-01-01

    A comparative analysis of two types of cryoprotectants, antifreeze glycoproteins from Atlantic cod (Gadus morhua) and carbohydrates from hemolymph of amphypoid crustacean (Gammarus lacustris) has been performed. Both glycoprotein and carbohydrate antifreezes effectively decreased the freezing point of water solutions and diminished the size of ice crystals formed. Noncolligative and colligative mechanisms of action are characteristic correspondingly for glycoproteins and carbohydrates.

  14. Genomic Sequencing of Ranaviruses Isolated from Turbot (Scophthalmus maximus) and Atlantic Cod (Gadus morhua).

    Science.gov (United States)

    Ariel, Ellen; Steckler, Natalie K; Subramaniam, Kuttichantran; Olesen, Niels J; Waltzek, Thomas B

    2016-12-15

    Ranaviruses have been isolated from Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) in Denmark. Phylogenomic analyses revealed that these two ranaviruses are nearly identical and form a distinct clade at the base of the ranavirus tree branching off near other fish ranaviruses. Copyright © 2016 Ariel et al.

  15. Correlations between hemoglobin type and temperature preference of juvenile Atlantic cod Gadus morhua

    DEFF Research Database (Denmark)

    Behrens, Jane W.; Gräns, Albin; Therkildsen, Nina Overgaard

    2012-01-01

    Atlantic cod (Gadus morhua L.) exhibits polymorphic hemoglobin variants with the HbI locus showing a strong North-South geographic cline in frequency distribution of three main types (1/1, 1/2 and 2/2). This may indicate selective advantages of the different HbI types under various temperature...

  16. Distribution and drift of Atlantic cod ( Gadus morhua ) eggs and larvae in Greenland offshore waters

    DEFF Research Database (Denmark)

    Wieland, Kai; Hovgård, Holger

    2002-01-01

    Catches of Atlantic cod (Gadus morhua) eggs and larvae from 45 national and international ichthyoplankton surveys conducted in Greenland offshore waters during the period 1950 to 1984 have been compiled and re-analysed. Southeast and Southwest Greenland were identified as im- portant spawning are...

  17. The effect of external dummy transmitters on oxygen consumption and performance of swimming Atlantic cod

    DEFF Research Database (Denmark)

    Steinhausen, M.F.; Andersen, Niels Gerner; Steffensen, J.F.

    2006-01-01

    Decreased critical swimming speed and increased oxygen consumption (Mo-2) was found for externally tagged Atlantic cod Gadus morhua swimming at a high speed of 0 center dot 9 body length (total length, L-Gamma) s(-1). No difference was found in the standard metabolic rate, indicating...

  18. Genomic Sequencing of Ranaviruses Isolated from Turbot (Scophthalmus maximus) and Atlantic Cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Ariel, Ellen; Steckler, Natalie K.; Subramaniam, Kuttichantran

    2016-01-01

    Ranaviruses have been isolated from Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) in Denmark. Phylogenomic analyses revealed that these two ranaviruses are nearly identical and form a distinct clade at the base of the ranavirus tree branching off near other fish ranaviruses....

  19. Immunological differences in intestine and rectum of Atlantic cod (Gadus morhua L.)

    NARCIS (Netherlands)

    Inami, M.; Taverne-Thiele, J.J.; Schroder, M.B.; Kiron, V.; Rombout, J.H.W.M.

    2009-01-01

    The defence system of the distal gut (hindgut and rectum) of Atlantic cod, (Gadus morhua L.) was studied using (immuno)histochemical, electron microscopical and real-time quantitative PCR techniques. The uptake and transport of macromolecules in the intestinal epithelium was also investigated. In

  20. Differential expression of immune and stress genes in the skin of Atlantic cod (Gadus morhua)

    NARCIS (Netherlands)

    Caipang, C.M.A.; Lazado, C.C.; Brinchmann, M.; Rombout, J.H.W.M.; Kiron, V.

    2011-01-01

    The present study describes the transcriptional profiles of selected immune and stress genes with putative important roles in the cutaneous immune defense of Atlantic cod (Gadus morhua). In addition it shows differential expression of many genes at the dorsal and ventral sides of fish, in general

  1. Atlantic Cod Show a Highly Variable Sensitivity to Electric-Induced Spinal Injuries

    NARCIS (Netherlands)

    Soetaert, M.; Haan, de D.; Verschueren, B.; Decostere, A.; Puvanendran, V.; Saunders, J.; Polet, H.; Chiers, K.

    2016-01-01

    Pulse trawling is the most promising alternative to conventional beam trawls targeting Sole Solea solea (also known as Solea vulgaris), but due to the electric fields created by electrotrawls spinal injuries are reported in gadoid round fishes such as Atlantic Cod Gadus morhua. This study aimed

  2. Genomic analysis of the host response to nervous necrosis virus in Atlantic cod (Gadus morhua) brain.

    Science.gov (United States)

    Krasnov, Aleksei; Kileng, Øyvind; Skugor, Stanko; Jørgensen, Sven Martin; Afanasyev, Sergey; Timmerhaus, Gerrit; Sommer, Ann-Inger; Jensen, Ingvill

    2013-07-01

    Genome sequencing combined with transcriptome profiling promotes exploration of defence against pathogens and discovery of immune genes. Based on sequences from the recently released genome of Atlantic cod, a genome-wide oligonucleotide microarray (ACIQ-1) was designed and used for analyses of gene expression in the brain during infection with nervous necrosis virus (NNV). A challenge experiment with NNV was performed with Atlantic cod juveniles and brain samples from virus infected and uninfected fish were used for microarray analysis. Expression of virus induced genes increased at 5 days post challenge and persisted at stable level to the last sampling at 25 days post challenge. A large fraction of the up-regulated genes (546 features) were known or expected to have immune functions and most of these have not previously been characterized in Atlantic cod. Transcriptomic changes induced by the virus involved strong activation of genes associated with interferon and tumour necrosis factor related responses and acute inflammation. Up-regulation of genes involved in adaptive immunity suggested a rapid recruitment of B and T lymphocytes to the NNV infected brain. QPCR analyses of 15 candidate genes of innate immunity showed rapid induction by poly(I:C) in Atlantic cod larvae cells suggesting an antiviral role. Earliest and greatest expression changes after poly I:C stimulation was observed for interferon regulatory factors IRF4 and IRF7. Comparative studies between teleost species provided new knowledge about the evolution of innate antiviral immunity in fish. A number of genes is present or responds to viruses only in fish. Innate immunity of Atlantic cod is characterized by selective expansion of several medium-sized multigene families with ribose binding domains. An interesting finding was the high representation of three large gene families among the early antiviral genes, including tripartite motif proteins (TRIM) and proteins with PRY-SPRY and NACHT domains. The

  3. Influence of photoperiod on expression of DNA (cytosine-5) methyltransferases in Atlantic cod.

    Science.gov (United States)

    Giannetto, Alessia; Nagasawa, Kazue; Fasulo, Salvatore; Fernandes, Jorge M O

    2013-05-01

    Photoperiod manipulation during early juvenile stages can influence growth in Atlantic cod. In the present study, one group of cod juveniles were reared under natural photoperiod conditions for Bodø (67° N, 14° E), whereas their counterparts were kept under continuous illumination. The mean weight of juvenile cod reared under continuous illumination was found to be 13% greater than those kept under natural photoperiod after 120days of light treatment. The molecular basis of this phenotypic plasticity is currently unknown but it is likely that DNA (cytosine-5)-methyltransferases (dnmts) are involved, since these genes play a crucial role in epigenetic regulation of gene expression. Phylogenetic analysis of Atlantic cod dnmt1, dnmt2 and dnmt3a revealed that within each group, the phylogeny follows the taxonomic relationship between the various species and comparative mapping of dnmt paralogues showed that these genes lie within regions of conserved synteny amongst teleosts. Of the three dnmt paralogues, dnmt3a had the highest expression in fast muscle of adult cod. In addition, dnmt1 and dnmt2 were differentially expressed between tissues but with prominent expression in gonads. Dnmt1 and dnmt3a transcript levels showed a significant increase in fast muscle of juvenile cod from the continuous light group at several time points. Remarkably, dnmt1 and dnmt3a transcript levels were 2-fold higher at 120days, by which point photoperiod conditions between the two light groups had become identical. Our data revealed that photoperiod can have an extended effect on expression of dnmt genes, which may be involved in the epigenetic regulation of muscle growth by photoperiod in Atlantic cod. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. 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.

  5. 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, Guđrún

    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.

  6. Daily rhythmicity of clock gene transcripts in atlantic cod fast skeletal muscle.

    Science.gov (United States)

    Lazado, Carlo C; Kumaratunga, Hiruni P S; Nagasawa, Kazue; Babiak, Igor; Giannetto, Alessia; Fernandes, Jorge M O

    2014-01-01

    The classical notion of a centralized clock that governs circadian rhythmicity has been challenged with the discovery of peripheral oscillators that enable organisms to cope with daily changes in their environment. The present study aimed to identify the molecular clock components in Atlantic cod (Gadus morhua) and to investigate their daily gene expression in fast skeletal muscle. Atlantic cod clock genes were closely related to their orthologs in teleosts and tetrapods. Synteny was conserved to varying degrees in the majority of the 18 clock genes examined. In particular, aryl hydrocarbon receptor nuclear translocator-like 2 (arntl2), RAR-related orphan receptor A (rora) and timeless (tim) displayed high degrees of conservation. Expression profiling during the early ontogenesis revealed that some transcripts were maternally transferred, namely arntl2, cryptochrome 1b and 2 (cry1b and cry2), and period 2a and 2b (per2a and per2b). Most clock genes were ubiquitously expressed in various tissues, suggesting the possible existence of multiple peripheral clock systems in Atlantic cod. In particular, they were all detected in fast skeletal muscle, with the exception of neuronal PAS (Per-Arnt-Single-minded) domain-containing protein (npas1) and rora. Rhythmicity analysis revealed 8 clock genes with daily rhythmic expression, namely arntl2, circadian locomotor output cycles kaput (clock), npas2, cry2, cry3 per2a, nuclear receptor subfamily 1, group D, member 1 (nr1d1), and nr1d2a. Transcript levels of the myogenic genes myogenic factor 5 (myf5) and muscleblind-like 1 (mbnl1) strongly correlated with clock gene expression. This is the first study to unravel the molecular components of peripheral clocks in Atlantic cod. Taken together, our data suggest that the putative clock system in fast skeletal muscle of Atlantic cod has regulatory implications on muscle physiology, particularly in the expression of genes related to myogenesis.

  7. Daily rhythmicity of clock gene transcripts in atlantic cod fast skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Carlo C Lazado

    Full Text Available The classical notion of a centralized clock that governs circadian rhythmicity has been challenged with the discovery of peripheral oscillators that enable organisms to cope with daily changes in their environment. The present study aimed to identify the molecular clock components in Atlantic cod (Gadus morhua and to investigate their daily gene expression in fast skeletal muscle. Atlantic cod clock genes were closely related to their orthologs in teleosts and tetrapods. Synteny was conserved to varying degrees in the majority of the 18 clock genes examined. In particular, aryl hydrocarbon receptor nuclear translocator-like 2 (arntl2, RAR-related orphan receptor A (rora and timeless (tim displayed high degrees of conservation. Expression profiling during the early ontogenesis revealed that some transcripts were maternally transferred, namely arntl2, cryptochrome 1b and 2 (cry1b and cry2, and period 2a and 2b (per2a and per2b. Most clock genes were ubiquitously expressed in various tissues, suggesting the possible existence of multiple peripheral clock systems in Atlantic cod. In particular, they were all detected in fast skeletal muscle, with the exception of neuronal PAS (Per-Arnt-Single-minded domain-containing protein (npas1 and rora. Rhythmicity analysis revealed 8 clock genes with daily rhythmic expression, namely arntl2, circadian locomotor output cycles kaput (clock, npas2, cry2, cry3 per2a, nuclear receptor subfamily 1, group D, member 1 (nr1d1, and nr1d2a. Transcript levels of the myogenic genes myogenic factor 5 (myf5 and muscleblind-like 1 (mbnl1 strongly correlated with clock gene expression. This is the first study to unravel the molecular components of peripheral clocks in Atlantic cod. Taken together, our data suggest that the putative clock system in fast skeletal muscle of Atlantic cod has regulatory implications on muscle physiology, particularly in the expression of genes related to myogenesis.

  8. Molecular genetic analysis of stomach contents reveals wild Atlantic cod feeding on piscine reovirus (PRV infected Atlantic salmon originating from a commercial fish farm.

    Directory of Open Access Journals (Sweden)

    Kevin Alan Glover

    Full Text Available In March 2012, fishermen operating in a fjord in Northern Norway reported catching Atlantic cod, a native fish forming an economically important marine fishery in this region, with unusual prey in their stomachs. It was speculated that these could be Atlantic salmon, which is not typical prey for cod at this time of the year in the coastal zone. These observations were therefore reported to the Norwegian Directorate of Fisheries as a suspected interaction between a local fish farm and this commercial fishery. Statistical analyses of genetic data from 17 microsatellite markers genotyped on 36 partially-degraded prey, samples of salmon from a local fish farm, and samples from the nearest wild population permitted the following conclusions: 1. The prey were Atlantic salmon, 2. These salmon did not originate from the local wild population, and 3. The local farm was the most probable source of these prey. Additional tests demonstrated that 21 of the 36 prey were infected with piscine reovirus. While the potential link between piscine reovirus and the disease heart and skeletal muscle inflammation is still under scientific debate, this disease had caused mortality of large numbers of salmon in the farm in the month prior to the fishermen's observations. These analyses provide new insights into interactions between domesticated and wild fish.

  9. Molecular genetic analysis of stomach contents reveals wild Atlantic cod feeding on piscine reovirus (PRV) infected Atlantic salmon originating from a commercial fish farm.

    Science.gov (United States)

    Glover, Kevin Alan; Sørvik, Anne Grete Eide; Karlsbakk, Egil; Zhang, Zhiwei; Skaala, Øystein

    2013-01-01

    In March 2012, fishermen operating in a fjord in Northern Norway reported catching Atlantic cod, a native fish forming an economically important marine fishery in this region, with unusual prey in their stomachs. It was speculated that these could be Atlantic salmon, which is not typical prey for cod at this time of the year in the coastal zone. These observations were therefore reported to the Norwegian Directorate of Fisheries as a suspected interaction between a local fish farm and this commercial fishery. Statistical analyses of genetic data from 17 microsatellite markers genotyped on 36 partially-degraded prey, samples of salmon from a local fish farm, and samples from the nearest wild population permitted the following conclusions: 1. The prey were Atlantic salmon, 2. These salmon did not originate from the local wild population, and 3. The local farm was the most probable source of these prey. Additional tests demonstrated that 21 of the 36 prey were infected with piscine reovirus. While the potential link between piscine reovirus and the disease heart and skeletal muscle inflammation is still under scientific debate, this disease had caused mortality of large numbers of salmon in the farm in the month prior to the fishermen's observations. These analyses provide new insights into interactions between domesticated and wild fish.

  10. Molecular Genetic Analysis of Stomach Contents Reveals Wild Atlantic Cod Feeding on Piscine Reovirus (PRV) Infected Atlantic Salmon Originating from a Commercial Fish Farm

    Science.gov (United States)

    Glover, Kevin Alan; Sørvik, Anne Grete Eide; Karlsbakk, Egil; Zhang, Zhiwei; Skaala, Øystein

    2013-01-01

    In March 2012, fishermen operating in a fjord in Northern Norway reported catching Atlantic cod, a native fish forming an economically important marine fishery in this region, with unusual prey in their stomachs. It was speculated that these could be Atlantic salmon, which is not typical prey for cod at this time of the year in the coastal zone. These observations were therefore reported to the Norwegian Directorate of Fisheries as a suspected interaction between a local fish farm and this commercial fishery. Statistical analyses of genetic data from 17 microsatellite markers genotyped on 36 partially-degraded prey, samples of salmon from a local fish farm, and samples from the nearest wild population permitted the following conclusions: 1. The prey were Atlantic salmon, 2. These salmon did not originate from the local wild population, and 3. The local farm was the most probable source of these prey. Additional tests demonstrated that 21 of the 36 prey were infected with piscine reovirus. While the potential link between piscine reovirus and the disease heart and skeletal muscle inflammation is still under scientific debate, this disease had caused mortality of large numbers of salmon in the farm in the month prior to the fishermen's observations. These analyses provide new insights into interactions between domesticated and wild fish. PMID:23620726

  11. Ontogeny of redox regulation in Atlantic cod (Gadus morhua) larvae.

    Science.gov (United States)

    Hamre, Kristin; Penglase, Samuel J; Rasinger, Josef D; Skjærven, Kaja H; Olsvik, Pål A

    2014-08-01

    The reduction potential of a cell is related to its fate. Proliferating cells are more reduced than those that are differentiating, whereas apoptotic cells are generally the most oxidized. Glutathione is considered the most important cellular redox buffer and the average reduction potential (Eh) of a cell or organism can be calculated from the concentrations of glutathione (GSH) and glutathione disulfide (GSSG). In this study, triplicate groups of cod larvae at various stages of development (3 to 63 days post-hatch; dph) were sampled for analyses of GSSG/2GSH concentrations, together with activities of antioxidant enzymes and expression of genes encoding proteins involved in redox metabolism. The concentration of total GSH (GSH+GSSG) increased from 610 ± 100 to 1260 ± 150 μmol/kg between 7 and 14 dph and was then constant until 49 dph, after which it decreased to 810 ± 100 μmol/kg by 63 dph. The 14- to 49-dph period, when total GSH concentrations were stable, coincides with the proposed period of metamorphosis in cod larvae. The concentration of GSSG comprised approximately 1% of the total GSH concentration and was stable throughout the sampling series. This resulted in a decreasing Eh from -239 ± 1 to -262 ± 7 mV between 7 and 14 dph, after which it remained constant until 63 dph. The changes in GSH and Eh were accompanied by changes in the expression of several genes involved in redox balance and signaling, as well as changes in activities of antioxidant enzymes, with the most dynamic responses occurring in the early phase of cod larval development. It is hypothesized that metamorphosis in cod larvae starts with the onset of mosaic hyperplasia in the skeletal muscle at approximately 20 dph (6.8mm standard length (SL)) and ends with differentiation of the stomach and disappearance of the larval finfold at 40 to 50 dph (10-15 mm SL). Thus, metamorphosis in cod larvae seems to coincide with high and stable total concentrations of GSH. Copyright © 2014 The

  12. Small-scale biocomplexity in coastal Atlantic cod supporting a Darwinian perspective on fisheries management.

    Science.gov (United States)

    Olsen, Esben Moland; Knutsen, Halvor; Gjøsæter, Jakob; Jorde, Per Erik; Knutsen, Jan Atle; Stenseth, Nils Chr

    2008-08-01

    Harvesting of marine resources raises concerns about how to identify and preserve biocomplexity, including the diversity of life histories found within and among wild populations of a species. In order to fully accomplish this, there is a need to elucidate the underlying causes of phenotypic variation, and how this variation responds to environmental changes. In general, both evolutionary (genetic) and nonevolutionary (plastic) responses may occur. Plastic responses to environmental change are expected to shift the phenotype along a reaction norm, while an evolutionary response is expected to shift the reaction norm itself. Here, we assess the maturation patterns of coastal Atlantic cod (Gadus morhua) in Skagerrak, where studies using neutral markers have revealed genetically differentiated populations of this harvested fish within tens of kilometres of coastline. Our results suggest that physiological state prior to the spawning season, as well as juvenile growth, both influence the probability of completing sexual maturation at a given age. Furthermore, our results point towards a spatial structuring of this plasticity (i.e. the maturation reaction norms) comparable with population connectivity inferred from neutral markers. We argue that such fine-scale biocomplexity calls for a Darwinian approach to fisheries management.

  13. Characterization of an Atlantic cod (Gadus morhua embryonic stem cell cDNA library

    Directory of Open Access Journals (Sweden)

    Holen Elisabeth

    2009-05-01

    Full Text Available Abstract Background The Atlantic cod is an ecologically and economically important North Atlantic fish species and also an emerging aquaculture species. To study gene expression in Atlantic cod embryonic stem (ES cells, our goal was to generate and analyze expressed sequence tags (ESTs from an ES cell cDNA library of mRNA consisting of approximately 3,900 ESTs. Results We sequenced 3,935 EST clones using a directional cDNA library made from pooled ES cells harvested at the blastula stage. Quality filtering of these ESTs allowed identification of 2,719 high-quality sequences with an average length of 442 bp containing 368 contigs and 1,276 singletons (1,644 unique sequences. BLASTX searches produced 889 significant (E-value -3 hits, of which 698 (42.5% were annotated with Gene Ontology terms (E-value -6. The number of unknown unique sequences was 946 (57.5%. All the high-quality EST sequences have been deposited in GenBank (GenBank: 2,719 sequences in UniGene library dbEST id: 22,021. Gene discovery and annotations are presented and discussed. Conclusion This set of ESTs represents one of the first attempts to describe mRNA in ES cells from a marine cold-water fish species, and provides a basis for gene expression studies of Atlantic cod ES cells.

  14. Spatiotemporal distribution and composition of mixed stock fishery of Atlantic cod (Gadus morhua) in West Greenlandic waters based on retrospective genetic analysis

    DEFF Research Database (Denmark)

    Bonanomi, Sara; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg

    Historical samples of fish are a unique source of DNA to investigate the temporal dynamics of fish population structure and distribution over time. During the last century Atlantic cod (Gadus morhua) stocks have declined dramatically in Greenlandic Waters. Recent genetic investigations have...... in the contribution from the different spawning groups in population mixtures of cod in West Greenland Waters in response to climate variability and fisheries. Performing genetic assignment test, we found stable genetic composition of feeding aggregations over decades in some areas, whereas shifts in composition were...

  15. Novel mannose binding natterin-like protein in the skin mucus of Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Rajan, Binoy; Patel, Deepti M; Kitani, Yoichiro; Viswanath, Kiron; Brinchmann, Monica F

    2017-09-01

    This study presents the first report of purification of natterin-like protein (Nlp) in a non-venomous fish. The peptide identities of purified cod Nlp were confirmed through LC-MSMS and matched to a cod expressed sequence tag (EST). A partial cod nlp nucleotide sequence was amplified and sequenced based on this EST. Multiple sequence alignment of cod Nlp showed considerable homology with other teleost Nlps and the presence of an N-terminal jacalin-like lectin domain coupled with a C-terminal toxin domain. nlp expression was higher in skin, head kidney, liver and spleen than in other tissues studied. Hemaggluttination of horse red blood cells by Nlp was calcium dependent and inhibited by mannose. A Vibrio anguillarum bath challenge however, did not alter the expression of cod nlp transcripts in the skin and gills. Further functional characterization is required to establish the significance of this unique protein in Atlantic cod and other teleosts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Slow Adaptation in the Face of Rapid Warming Leads to the Collapse of Atlantic Cod in the Gulf of Maine

    Science.gov (United States)

    Pershing, A. J.; Alexander, M. A.; Hernandez, C.; Kerr, L. A.; Le Bris, A.; Mills, K.; Nye, J. A.; Record, N.; Scannell, H. A.; Scott, J. D.; Sherwood, G. D.; Thomas, A. C.

    2016-02-01

    Climate change is altering conditions in all marine ecosystems, but the pace of change is not uniform. Rapid changes in environmental conditions pose a challenge for resource management, especially when available tools or policies assume the environment is stationary. Between 2004 and 2013, the Gulf of Maine and northwest Atlantic Shelf warmed at a rate that few large marine ecosystems have ever experienced. This warming was associated with a northward shift in the Gulf Stream and with Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation. The unprecedented warming led to reduced recruitment and enhanced mortality of Atlantic cod. Fisheries management has built-in feedbacks designed to reduce quotas as populations decline, but the management process could not keep pace with the rapid temperature-related changes in the Gulf of Maine cod stock. Future recovery of this fishery now depends on both sound management and favorable temperatures. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management and to build resiliency in coupled social-ecological systems. It also highlights a need for scientific and policy guidance for managing species threatened by future warming.

  17. Thermal habitat constraints on zooplankton species associated with Atlantic cod (Gadus morhua) on the US Northeast Continental Shelf

    Science.gov (United States)

    Friedland, Kevin D.; Kane, Joe; Hare, Jonathan A.; Lough, R. Gregory; Fratantoni, Paula S.; Fogarty, Michael J.; Nye, Janet A.

    2013-09-01

    The US Northeast Continental Shelf is experiencing a period of increasing temperature levels and range, which impacts the quantity of thermal habitats within the ecosystem. With increasing temperatures, the amount of warmer, surface water thermal habitats (16-27 °C) has increased while there has been a reciprocal decline in cooler water habitats (5-15 °C). These cooler water habitats are the most abundant and comprise the core habitats of the ecosystem. The coldest thermal habitats (1-4 °C), however, have increased slightly in amount or have remained constant, reflecting a discontinuity in the progression of warming along a latitudinal gradient. This discontinuity may be the result of recent changes in the circulation of water masses in the northern Gulf of Maine, potentially associated with the Labrador Current. The contraction of core thermal habitats appears to have had biological consequences on multiple trophic levels. In particular, two zooplankton species associated with the larval feeding of Atlantic cod, Gadus morhua, have declined in abundance in the same areas where cod populations have exhibited continually poor recruitment. The zooplankton species group Pseudocalanus spp., which is associated with winter-spawning cod, has declined on Georges Bank and in the Eastern Gulf of Maine. The zooplankton Centropages typicus has declined in the Gulf of Maine during late summer into fall, potentially affecting spring-spawning cod in that area. These observations are consistent with the hypothesis that portions of the population complex of cod have lower reproductive output due to changes in zooplankton abundance, which we associate with the distribution of temperatures within the ecosystem.

  18. Underwater sound from vessel traffic reduces the effective communication range in Atlantic cod and haddock.

    Science.gov (United States)

    Stanley, Jenni A; Van Parijs, Sofie M; Hatch, Leila T

    2017-11-07

    Stellwagen Bank National Marine Sanctuary is located in Massachusetts Bay off the densely populated northeast coast of the United States; subsequently, the marine inhabitants of the area are exposed to elevated levels of anthropogenic underwater sound, particularly due to commercial shipping. The current study investigated the alteration of estimated effective communication spaces at three spawning locations for populations of the commercially and ecologically important fishes, Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Both the ambient sound pressure levels and the estimated effective vocalization radii, estimated through spherical spreading models, fluctuated dramatically during the three-month recording periods. Increases in sound pressure level appeared to be largely driven by large vessel activity, and accordingly exhibited a significant positive correlation with the number of Automatic Identification System tracked vessels at the two of the three sites. The near constant high levels of low frequency sound and consequential reduction in the communication space observed at these recording sites during times of high vocalization activity raises significant concerns that communication between conspecifics may be compromised during critical biological periods. This study takes the first steps in evaluating these animals' communication spaces and alteration of these spaces due to anthropogenic underwater sound.

  19. Time matters: post-surgical recovery of gastric evacuation rate in Atlantic cod

    DEFF Research Database (Denmark)

    Behrens, Jane; Gräns, Albin; Andersen, Niels Gerner

    GER was affected after surgically introducing dummies of a blood-flow biotelemetry system into the abdominal cavity of Atlantic cod. Two days post surgery the cod with implants were, together with a control group, force-fed a standardized meal and the stomach contents recovered 24h later...... into the fish, which may affect the animal, and studies dealing with the affect of surgery and implants are still scarce. A variable known to be sensitive to postsurgical and other stressors is the gastric evacuation rate (GER). GER is tightly linked to gut blood flow and in the present study we analysed how...... of postsurgical recovery will stabilize GER in cod. The results indicate that the presence of the implant per se did not affect GER but that the effects observed came from surgery and/or postsurgical stress. 10 days should consequently be a starting point for future studies even if longer recovery periods...

  20. Amino acid sequence of the cold-active alkaline phosphatase from Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Asgeirsson, Bjarni; Nielsen, Berit Noesgaard; Højrup, Peter

    2003-01-01

    Atlantic cod is a marine fish that lives at low temperatures of 0-10 degrees C and contains a cold-adapted alkaline phosphatase (AP). Preparations of AP from either the lower part of the intestines or the pyloric caeca area were subjected to proteolytic digestion, mass spectrometry and amino acid...... has the same variable residues as mammalian APs (His153 and His328 by E. coli AP numbering). General comparison of the amino acid composition with mammalian APs showed that cod AP contains fewer Cys, Leu, Met and Ser, but proportionally more Asn, Asp, Ile, Lys, Trp and Tyr residues. Three N......-linked glycosylation sites were found. The glycan structure was determined as complex biantennary in type with fucose and sialic acid attached, although a trace of complex tri-antennary structure was also observed. A three-dimensional model was obtained by homology modelling using the human placental AP scaffold. Cod...

  1. Effect of petroleum aromatic hydrocarbons on monogeneids parasitizing Atlantic cod, Gadus morhua L

    Energy Technology Data Exchange (ETDEWEB)

    Khan, R.A.; Kiceniuk, J.W.

    1988-07-01

    Fish gills appear to be more susceptible than other tissues to toxicants. The latter include petroleum aromatic hydrocarbons, which can induce lesions characterized by excessive mucus secretion, hyperplasia, fusion of secondary gill lamellae and capillary dilation. Fish are also natural hosts to several species of ectoparasites, especially monogeneans which live among the gill filaments. A previous study on the interrelation of water quality, gill parasites and gill pathology provided evidence that fish living in habitats degraded by pollutants such as Biscayne Bay, Florida, were heavily infested with monogeneids especially when gill lesions were severe. Atlantic cod, Gadus morhua, are hosts to monogeneans. The authors reported previously that crude oil fractions induced gill lesions in cod and also affected some gastrointestinal parasites. In the light of these reports, a study was undertaken to ascertain whether any relationship existed between gill lesions and gill parasites in cod following chronic exposure to petroleum hydrocarbons.

  2. Expression of vasa and nanos3 during primordial germ cell formation and migration in Atlantic cod (Gadus morhua L.).

    Science.gov (United States)

    Presslauer, C; Nagasawa, K; Fernandes, J M O; Babiak, I

    2012-10-01

    Primordial germ cells (PGCs), progenitors of gametes, are specified very early in embryonic development and undergo an active migration to the site where the future gonads will form. While the developmental pattern of PGCs during embryogenesis has been documented in few model teleost fishes, there is currently no information available for any representative of Superorder Paracanthopterygii. This includes Atlantic cod (Gadus morhua), which is a historically important food fish in both fisheries and aquaculture industries. In the present study, we cloned and characterized vasa and nanos3 and used them as germ cell markers in Atlantic cod. Sequencing results showed prospective vasa and nanos3 mRNA contained the domains used to describe their respective protein family. Furthermore, phylogenetic analysis using the amino acid sequence placed Atlantic cod Vasa distinct from representatives of three other taxonomic Superorders. Atlantic cod Nanos3 was placed with other homologues from the Nanos3 subfamily. Expression of both genes was detected from the first cleavage division; both were specifically expressed in Atlantic cod PGCs from the 32-cell stage. While nanos3 expression ceased during early somitogenesis, vasa was strongly expressed throughout embryonic development. Using vasa as a marker, we described the Atlantic cod PGC migration pattern. We demonstrated that Atlantic cod PGCs migrate ventral to the trunk mesoderm. With the exception of Pacific herring (Clupea pallasii), PGCs in other described teleost fishes migrate lateral to the trunk. The results from this study are the first step toward understanding germ line formation in Atlantic cod. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Photoperiod influences growth and mll (mixed-lineage leukaemia expression in Atlantic cod.

    Directory of Open Access Journals (Sweden)

    Kazue Nagasawa

    Full Text Available Photoperiod is associated to phenotypic plasticity of somatic growth in several teleost species. However, the molecular mechanisms underlying this phenomenon are currently unknown but it is likely that epigenetic regulation by methyltransferases is involved. The MLL (mixed-lineage leukaemia family comprises histone methyltransferases that play a critical role in regulating gene expression during early development in mammals. So far, these genes have received scant attention in teleost fish. In the present study, the mean weight of Atlantic cod juveniles reared under continuous illumination was found to be 13% greater than those kept under natural photoperiod conditions for 120 days. We newly determined cDNA sequences of five mll (mll1, mll2, mll3a, mll4b and mll5 and two setd1 (setd1a and setd1ba paralogues from Atlantic cod. Phylogenetic analysis revealed that the cod genes clustered within the appropriate mll clade and comparative mapping of mll paralogues showed that these genes lie within a region of conserved synteny among teleosts. All mll and setd1 genes were highly expressed in gonads and fast muscle of adult cod, albeit at different levels, and they were differentially regulated with photoperiod in muscle of juvenile fish. Following only one day of exposure to constant light, mll1, mll4b and setd1a were up to 57% lower in these fish compared to the natural photoperiod group. In addition, mRNA expression of myogenic regulatory factors (myog and myf-5 and pax7 in fast muscle was also affected by different photoperiod conditions. Notably, myog was significantly elevated in the continuous illumination group throughout the time course of the experiment. The absence of a day/night cycle is associated with a generalised decrease in mll expression concomitant with an increase in myog transcript levels in fast muscle of Atlantic cod, which may be involved in the observed epigenetic regulation of growth by photoperiod in this species.

  4. Photoperiod Influences Growth and mll (Mixed-Lineage Leukaemia) Expression in Atlantic Cod

    Science.gov (United States)

    Nagasawa, Kazue; Giannetto, Alessia; Fernandes, Jorge M. O.

    2012-01-01

    Photoperiod is associated to phenotypic plasticity of somatic growth in several teleost species. However, the molecular mechanisms underlying this phenomenon are currently unknown but it is likely that epigenetic regulation by methyltransferases is involved. The MLL (mixed-lineage leukaemia) family comprises histone methyltransferases that play a critical role in regulating gene expression during early development in mammals. So far, these genes have received scant attention in teleost fish. In the present study, the mean weight of Atlantic cod juveniles reared under continuous illumination was found to be 13% greater than those kept under natural photoperiod conditions for 120 days. We newly determined cDNA sequences of five mll (mll1, mll2, mll3a, mll4b and mll5) and two setd1 (setd1a and setd1ba) paralogues from Atlantic cod. Phylogenetic analysis revealed that the cod genes clustered within the appropriate mll clade and comparative mapping of mll paralogues showed that these genes lie within a region of conserved synteny among teleosts. All mll and setd1 genes were highly expressed in gonads and fast muscle of adult cod, albeit at different levels, and they were differentially regulated with photoperiod in muscle of juvenile fish. Following only one day of exposure to constant light, mll1, mll4b and setd1a were up to 57% lower in these fish compared to the natural photoperiod group. In addition, mRNA expression of myogenic regulatory factors (myog and myf-5) and pax7 in fast muscle was also affected by different photoperiod conditions. Notably, myog was significantly elevated in the continuous illumination group throughout the time course of the experiment. The absence of a day/night cycle is associated with a generalised decrease in mll expression concomitant with an increase in myog transcript levels in fast muscle of Atlantic cod, which may be involved in the observed epigenetic regulation of growth by photoperiod in this species. PMID:22590633

  5. Identification of the Atlantic cod L-amino acid oxidase and its alterations following bacterial exposure.

    Science.gov (United States)

    Kitani, Yoichiro; Fernandes, Jorge M O; Kiron, Viswanath

    2015-06-01

    Antibacterial factors that are present in epidermal mucus of fish have a potential role in the first line of host defence to bacterial pathogens. This study reports the identification of L-amino acid oxidase (LAO) in Atlantic cod (GmLao) and the changes in the molecule following bacterial exposure. The gmlao transcripts and LAO activity were present on both the body surface and in the internal organs of the fish. Relative mRNA level of gmlao increased significantly in the gills, the spleen and the head kidney (up to 8-fold) of fish that were challenged with the pathogen Vibrio anguillarum. The gmlao expression in skin was 4-fold higher in challenged fish. Our data indicate that LAO may be an important effector of antibacterial defence in Atlantic cod. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Integrating the markers Pan I and haemoglobin with the genetic linkage map of Atlantic cod (Gadus morhua

    Directory of Open Access Journals (Sweden)

    Simpson Gary

    2010-10-01

    Full Text Available Abstract Background Haemoglobin (Hb and pantophysin (Pan I markers have been used intensively in population studies of Atlantic cod (Gadus morhua and in the analysis of traits such as temperature tolerance, growth characteristics and sexual maturation. We used an Illumina GoldenGate panel and the KASPar SNP genotyping system to analyse SNPs in three Atlantic cod families, one of which was polymorphic at the Hb β1 locus, and to generate a genetic linkage map integrating Pan I and multiple Hb loci. Findings Data generated allowed the mapping of nine Hb loci, the Pan I locus, and other 122 SNPs onto an existing linkage genetic map for Atlantic cod. Four Hb genes (i.e. α1, α4, β1 and β5 have been mapped on linkage group (LG 2 while the other five (i.e. α2, α3, β2, β3 and β4 were placed on LG18. Pan I was mapped on LG 1 using a newly developed KASPar assay for a SNP variable only in Pan IA allelic variants. The new linkage genetic map presented here comprises 1046 SNPs distributed between 23 linkage groups, with a length of 1145.6 cM. A map produced by forcing additional loci, resulting in a reduced goodness-of-fit for mapped markers, allowed the mapping of a total of 1300 SNPs. Finally, we compared our genetic linkage map data with the genetic linkage map data produced by a different group and identified 29 shared SNPs distributed on 10 different linkage groups. Conclusions The genetic linkage map presented here incorporates the marker Pan I, together with multiple Hb loci, and integrates genetic linkage data produced by two different research groups. This represents a useful resource to further explore if Pan I and Hbs or other genes underlie quantitative trait loci (QTL for temperature sensitivity/tolerance or other phenotypes.

  7. The effects of WAF and CEWAF on EROD activity in juvenile Atlantic cod

    Energy Technology Data Exchange (ETDEWEB)

    Burridge, L.; Lyons, M.; Wong, D.; Li, Z.; Lee, K. [Fisheries and Oceans Canada, Ottawa, ON (Canada)

    2010-07-01

    The affects of dispersed oil and hydrocarbons on Atlantic cod were examined in this study in which water accommodated fractions (WAF) of two types of oil were generated in a wave tank or in a baffled flask. Oil droplet sizes of the two systems were comparable. Chemically enhanced water accommodated fractions (CEWAF) of combinations of two oils and two dispersants were prepared in a similar manner. Juvenile Atlantic cod (Gadus morhua) were exposed to a broad range of concentrations of either WAF or CEWAF before being transferred to clean seawater. Periodic sampling of 5 fish confirmed the liver ethoxyresorufin-O-deethylas (EROD) activity. At the end of a 4 hour exposure, EROD activity was no different from the controls, but it was much higher after 20 hours at CEWAF concentrations above 2 percent v/v regardless of oil or dispersant type. Over the next 48 hours, EROD activity declined and did not return to control or pre-treatment levels even after 72 hours. EROD in livers from cod exposed to WAF was much higher after 24 hours at concentrations of 12 percent v/v or higher, reaching a maximum of 8 picomoles/mg protein/min. After 72 hours, EROD activity in WAF-exposed livers decreased to pre-treatment levels. The study showed that a brief 4 hour exposure to WAF and CEWAF can induce EROD activity in livers of juvenile cod and that the surge in enzyme activity can continue for 24-48 hours.

  8. 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...... reproductive skew with decreasing size variation among males under natural conditions. (c) 2006 The Author Journal compilation (c) 2006 The Fisheries Society of the British Isles...

  9. Evolutionary redesign of the Atlantic cod (Gadus morhua L.) Toll-like receptor repertoire by gene losses and expansions.

    Science.gov (United States)

    Solbakken, Monica H; Tørresen, Ole K; Nederbragt, Alexander J; Seppola, Marit; Gregers, Tone F; Jakobsen, Kjetill S; Jentoft, Sissel

    2016-04-29

    Genome sequencing of the teleost Atlantic cod demonstrated loss of the Major Histocompatibility Complex (MHC) class II, an extreme gene expansion of MHC class I and gene expansions and losses in the innate pattern recognition receptor (PRR) family of Toll-like receptors (TLR). In a comparative genomic setting, using an improved version of the genome, we characterize PRRs in Atlantic cod with emphasis on TLRs demonstrating the loss of TLR1/6, TLR2 and TLR5 and expansion of TLR7, TLR8, TLR9, TLR22 and TLR25. We find that Atlantic cod TLR expansions are strongly influenced by diversifying selection likely to increase the detectable ligand repertoire through neo- and subfunctionalization. Using RNAseq we find that Atlantic cod TLRs display likely tissue or developmental stage-specific expression patterns. In a broader perspective, a comprehensive vertebrate TLR phylogeny reveals that the Atlantic cod TLR repertoire is extreme with regards to losses and expansions compared to other teleosts. In addition we identify a substantial shift in TLR repertoires following the evolutionary transition from an aquatic vertebrate (fish) to a terrestrial (tetrapod) life style. Collectively, our findings provide new insight into the function and evolution of TLRs in Atlantic cod as well as the evolutionary history of vertebrate innate immunity.

  10. The Impact of Egg Ozonation on Hatching Success, Larval Growth, and Survival of Atlantic Cod, Atlantic Salmon, and Rainbow Trout.

    Science.gov (United States)

    Fry, Jessica; Casanova, Pérez Juan; Hamoutene, Dounia; Lush, Lynn; Walsh, Andy; Couturier, Cyr

    2015-03-01

    The direct exposure of fish eggs to ozonated water has generated interest as a means of ensuring pathogen-free eggs without the use of harsh chemicals. However, there are numerous knowledge gaps, including safe contact times, exposure levels, and potential long-term effects on aquaculture species in both freshwater and seawater. The effect of different ozone (O3) doses (0.5-1.0, 1.5-2.0, and 2.5-3.0 mg of O3/L for 90 s) on recently fertilized eggs of Atlantic Cod Gadus morhua and eyed eggs of Atlantic Salmon Salmo salar and Rainbow Trout Oncorhynchus mykiss was evaluated in comparison with the effects of two commercial disinfectants: Perosan (0.004 mg/L) and Ovadine (100 mg/L). The impact of ozone application was evaluated based on hatching success, larval nucleic acid concentration, larval growth, and survival. Overall, results indicated that ozonation of Atlantic Cod eggs at a dose less than 3.0 mg/L for 90 s produced no negative effect on the larvae up to 30 d posthatch. Furthermore, ozonation of Atlantic Salmon and Rainbow Trout eggs generated no negative effect on the larvae, based on monitoring until 85% yolk sac re-absorption (16 d posthatch).

  11. Isolation and characterisation of two cDNAs encoding transglutaminase from Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Furnes, Clemens; Kileng, Øyvind; Jensen, Ingvill; Karki, Pralav; Eichacker, Lutz; Robertsen, Børre

    2014-01-01

    Two cDNAs encoding transglutaminase (TG) were identified in a subtractive cDNA library prepared from the head kidney of poly I:C stimulated Atlantic cod (Gadus morhua). Full-length TG-1 and TG-2 cDNA were cloned from the head kidney by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The deduced amino acid (aa) sequence for TG-1 was 695 aa with an estimated molecular mass of 78.3 kDa, while TG-2 was a 698 aa protein with an estimated molecular mass of 78.8 kDa. The two proteins were named TG-1 and TG-2 and both possess transglutaminase/protease-like homologous domains (TGc) and full conservation of amino acids cysteine, histidine, and aspartate residues that form the catalytic triad. Sequence analysis showed high similarity (93.1%) with Alaska pollock TG, and the TGs were grouped together with TGs from chum salmon, Japanese flounder, Nile tilapia, and red sea bream in addition to Alaska pollock in phylogenetic analysis. Interestingly, they showed different tissue distribution with highest constitutive expression in reproductive and immunological organs, indicating important roles in these organs. Furthermore, the up-regulation of TG-1 and TG-2 in head kidney after stimulating Atlantic cod with poly I:C suggested a role of TGs in immune response in Atlantic cod. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Spatial ecology of coastal Atlantic cod Gadus morhua associated with parasite load.

    Science.gov (United States)

    Aalvik, I M; Moland, E; Olsen, E M; Stenseth, N C

    2015-08-01

    Acoustic tags and receivers were used to investigate the spatial ecology of coastal Atlantic cod Gadus morhua (n = 32, mean fork length: 50 cm, range: 33-80 cm) on the Norwegian Skagerrak coast in 2012. Monthly home ranges (HR), swimming activity and depth use varied considerably among individuals and through the months of June, July and August. HR sizes for the period ranged from 0.25 to 5.20 km2 (mean = 2.30 km2. Two thirds of the tagged G. morhua were infected with black spot disease Cryptocotyle lingua parasites; these fish had larger HRs and occupied deeper water compared with non-infected fish. The infected fish also tended to be more active in terms of horizontal swimming. From an ecological and evolutionary perspective, any environmental change that modifies G. morhua behaviour may therefore also alter the parasite load of the population, and its conservation and fishery status. © 2015 The Fisheries Society of the British Isles.

  13. Ultrapure LPS induces inflammatory and antibacterial responses attenuated in vitro by exogenous sera in Atlantic cod and Atlantic salmon.

    Science.gov (United States)

    Seppola, Marit; Mikkelsen, Helene; Johansen, Audny; Steiro, Kari; Myrnes, Bjørnar; Nilsen, Inge W

    2015-05-01

    Phagocyte recognition of lipopolysaccharide (LPS) is an early key event for triggering the host innate immune response necessary for clearance of invading bacteria. The ability of fishes to recognise LPS has been questioned as contradictory results have been presented. We show here that monocyte/macrophage cultures from Atlantic cod (Gadus morhua) and Atlantic salmon (Salmo salar) respond with an increased expression of inflammatory and antibacterial genes to both crude and ultrapure Escherichia coli LPS. Crude LPS produces higher induction than the ultrapure LPS type in both species in vitro as well as in vivo in cod injected with LPS. Crude LPS gave, in contrast to ultrapure LPS, an additional weak up-regulation of antiviral genes in salmon macrophages, most likely because of contaminants in the LPS preparation. Increased levels of chicken (c)-type lysozyme transcripts and enzyme activity were measured in salmon macrophages following ultrapure LPS stimulation demonstrating not only increased transcription but also translation. Simultaneous use and even pre-treatment with bovine sera suppressed the LPS-induced expression thereby reflecting the presence of transcription inhibitory components in sera. Together, these findings show that both cod and salmon recognise LPS per se and that the observed induction is highly dependent on the absence of sera. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Pre-anaesthetic metomidate sedation delays the stress response after caudal artery cannulation in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Karlsson, Anders; Rosseland, Bjørn Olav; Massabuau, Jean-Charles; Kiessling, Anders

    2012-04-01

    Recovery from caudal artery cannulation with and without pre-anaesthesia metomidate sedation was assessed in Atlantic cod (Gadus morhua). The levels of plasma cortisol, glucose, electrolytes and acid-base parameters were compared between sedated and unsedated cod and to those in uncannulated individuals, where the samples were obtained by sacrificial sampling (reference level). Metomidate sedation delayed the stress response, causing sedated cod plasma cortisol to return to the reference level more slowly [day 4 post surgery (PS)] than in unsedated cod (day 2 PS). Plasma glucose was elevated in both sedated and unsedated cod up to and including day 5 PS. Plasma K(+) was lower and pH was higher in cannulated cod than in the reference from 24 h PS until the end of experimentation, indicating a stress effect of sacrificial sampling on plasma K(+) and pH that was likely caused by an acute stress response. Metomidate sedation delayed the stress response following CA cannulation and should therefore not be used as a pre-anaesthetic sedation in Atlantic cod. The caudal artery cannulation can be a useful tool in obtaining repeated blood samples from Atlantic cod given an adequate recovery time, which was determined to be 6 days irrespective of pre-anaesthesia sedation status.

  15. A novel beta-defensin antimicrobial peptide in Atlantic cod with stimulatory effect on phagocytic activity.

    Directory of Open Access Journals (Sweden)

    Jareeporn Ruangsri

    Full Text Available A novel defensin antimicrobial peptide gene was identified in Atlantic cod, Gadus morhua. This three exon/two intron defensin gene codes for a peptide precursor consisting of two domains: a signal peptide of 26 amino acids and a mature peptide of 40 residues. The mature cod defensin has six conserved cysteine residues that form 1-5, 2-4 and 3-6 disulphide bridges. This pattern is typical of beta-defensins and this gene was therefore named cod beta-defensin (defb. The tertiary structure of Defb exhibits an α/β fold with one α helix and β1β2β3 sheets. RT-PCR analysis indicated that defb transcripts were present mainly in the swim bladder and peritoneum wall but could also be detected at moderate to low levels in skin, head- and excretory kidneys. In situ hybridisation revealed that defb was specifically expressed by cells located in the swim bladder submucosa and the oocytes. During embryonic development, defb gene transcripts were detectable from the golden eye stage onwards and their expression was restricted to the swim bladder and retina. Defb was differentially expressed in several tissues following antigenic challenge with Vibrio anguillarum, being up-regulated up to 25-fold in head kidney. Recombinant Defb displayed antibacterial activity, with a minimal inhibitory concentration of 0.4-0.8 µM and 25-50 µM against the Gram-(+ bacteria Planococcus citreus and Micrococcus luteus, respectively. In addition, Defb stimulated phagocytic activity of cod head kidney leucocytes in vitro. These findings imply that beta-defensins may play an important role in the innate immune response of Atlantic cod.

  16. A Novel Beta-Defensin Antimicrobial Peptide in Atlantic Cod with Stimulatory Effect on Phagocytic Activity

    Science.gov (United States)

    Ruangsri, Jareeporn; Kitani, Yoichiro; Kiron, Viswanath; Lokesh, Jep; Brinchmann, Monica F.; Karlsen, Bård Ove; Fernandes, Jorge M. O.

    2013-01-01

    A novel defensin antimicrobial peptide gene was identified in Atlantic cod, Gadus morhua. This three exon/two intron defensin gene codes for a peptide precursor consisting of two domains: a signal peptide of 26 amino acids and a mature peptide of 40 residues. The mature cod defensin has six conserved cysteine residues that form 1–5, 2–4 and 3–6 disulphide bridges. This pattern is typical of beta-defensins and this gene was therefore named cod beta-defensin (defb). The tertiary structure of Defb exhibits an α/β fold with one α helix and β1β2β3 sheets. RT-PCR analysis indicated that defb transcripts were present mainly in the swim bladder and peritoneum wall but could also be detected at moderate to low levels in skin, head- and excretory kidneys. In situ hybridisation revealed that defb was specifically expressed by cells located in the swim bladder submucosa and the oocytes. During embryonic development, defb gene transcripts were detectable from the golden eye stage onwards and their expression was restricted to the swim bladder and retina. Defb was differentially expressed in several tissues following antigenic challenge with Vibrio anguillarum, being up-regulated up to 25-fold in head kidney. Recombinant Defb displayed antibacterial activity, with a minimal inhibitory concentration of 0.4–0.8 µM and 25–50 µM against the Gram-(+) bacteria Planococcus citreus and Micrococcus luteus, respectively. In addition, Defb stimulated phagocytic activity of cod head kidney leucocytes in vitro. These findings imply that beta-defensins may play an important role in the innate immune response of Atlantic cod. PMID:23638029

  17. Long distance linkage disequilibrium and limited hybridization suggest cryptic speciation in atlantic cod.

    Directory of Open Access Journals (Sweden)

    Ian R Bradbury

    Full Text Available Hybrid zones provide unprecedented opportunity for the study of the evolution of reproductive isolation, and the extent of hybridization across individuals and genomes can illuminate the degree of isolation. We examine patterns of interchromosomal linkage disequilibrium (ILD and the presence of hybridization in Atlantic cod, Gadus morhua, in previously identified hybrid zones in the North Atlantic. Here, previously identified clinal loci were mapped to the cod genome with most (∼70% occurring in or associated with (<5 kb coding regions representing a diverse array of possible functions and pathways. Despite the observation that clinal loci were distributed across three linkage groups, elevated ILD was observed among all groups of clinal loci and strongest in comparisons involving a region of low recombination along linkage group 7. Evidence of ILD supports a hypothesis of divergence hitchhiking transitioning to genome hitchhiking consistent with reproductive isolation. This hypothesis is supported by Bayesian characterization of hybrid classes present and we find evidence of common F1 hybrids in several regions consistent with frequent interbreeding, yet little evidence of F2 or backcrossed individuals. This work suggests that significant barriers to hybridization and introgression exist among these co-occurring groups of cod either through strong selection against hybrid individuals, or genetic incompatibility and intrinsic barriers to hybridization. In either case, the presence of strong clinal trends, and little gene flow despite extensive hybridization supports a hypothesis of reproductive isolation and cryptic speciation in Atlantic cod. Further work is required to test the degree and nature of reproductive isolation in this species.

  18. Nucleotide variation and balancing selection at the Ckma gene in Atlantic cod: analysis with multiple merger coalescent models.

    Science.gov (United States)

    Árnason, Einar; Halldórsdóttir, Katrín

    2015-01-01

    High-fecundity organisms, such as Atlantic cod, can withstand substantial natural selection and the entailing genetic load of replacing alleles at a number of loci due to their excess reproductive capacity. High-fecundity organisms may reproduce by sweepstakes leading to highly skewed heavy-tailed offspring distribution. Under such reproduction the Kingman coalescent of binary mergers breaks down and models of multiple merger coalescent are more appropriate. Here we study nucleotide variation at the Ckma (Creatine Kinase Muscle type A) gene in Atlantic cod. The gene shows extreme differentiation between the North (Canada, Greenland, Iceland, Norway, Barents Sea) and the South (Faroe Islands, North-, Baltic-, Celtic-, and Irish Seas) with FST > 0.8 between regions whereas neutral loci show no differentiation. This is evidence of natural selection. The protein sequence is conserved by purifying selection whereas silent and non-coding sites show extreme differentiation. The unfolded site-frequency spectrum has three modes, a mode at singleton sites and two high frequency modes at opposite frequencies representing divergent branches of the gene genealogy that is evidence for balancing selection. Analysis with multiple-merger coalescent models can account for the high frequency of singleton sites and indicate reproductive sweepstakes. Coalescent time scales vary with population size and with the inverse of variance in offspring number. Parameter estimates using multiple-merger coalescent models show that times scales are faster than under the Kingman coalescent.

  19. An estrogen-responsive plasma protein expression signature in Atlantic cod (Gadus morhua) revealed by SELDI-TOF MS

    DEFF Research Database (Denmark)

    Nielsen, Mari Mæland; Meyer, Sonnich; Larsen, Bodil Katrine

    2011-01-01

    an estrogen-responsive PES in plasma of Atlantic cod (Gadus morhua) using the SELDI-TOF MS technique. Protein expression analysis of male cod exposed to 17 b-estradiol (E2) showed that 27 plasma peaks were differentially expressed following exposure.There producibility of this result was evaluated...... by reanalyzing the samples six months later,and a significant change in expression was confirmed for 13 of the 27 peaks detected in the first analysis. The performance of the reproducible E2-responsive PES, constituting these 13 peaks, was then tested on samples from juvenile cod exposed to 4-nonylphenol, North...... Sea oil, or North Sea oil spiked with alkylphenols. Principal component analysis revealed that nonylphenol-exposed cod could be separated from unexposed cod based on the E2-responsive PES, indicating that the PES can be used to assess estrogenic exposure of both juvenile and adult specimens of cod...

  20. Effects of ocean acidification on the calcification of otoliths of larval Atlantic cod, Gadus morhua L.

    Science.gov (United States)

    Maneja, R. H.; Frommel, A. Y.; Geffen, A. J.; Folkvord, A.; Piatkowski, U.; Chang, M. Y.; Clemmesen, C.

    2012-04-01

    The aragonitic calcium carbonate composition of the otoliths of teleost fishes could bring the organism in direct risk to ocean acidification. The potential effects of increase in atmospheric CO2 on the calcification of the otoliths were investigated by rearing Atlantic cod larvae (Gadus morhua L.) in three pCO2 concentrations, control-370, medium-1800, and high-4200 ppm from March to May 2010. Hypercalcification of otoliths were observed from 7 to 46-dph cod larvae cultured at elevated pCO2 concentrations. The sagittae and lapilli were largest at the high pCO2 treatment followed by medium and control with the biggest difference (83.8%) in mean otolith (sagitta) surface area at 32-dph between the high and control groups. The shift in the growth rates of the sagittae and lapilli also occurred much earlier in the high treatment with the growth of the sagitta surpassing that of the lapillus already at 32-dph. On the other hand, Atlantic cod larvae showed no trends in fluctuating asymmetry of the otoliths vis-a-vis the increase in otolith growth from elevated pCO2.

  1. Francisella noatunensis subsp. noatunensis invades, survives and replicates in Atlantic cod cells.

    Science.gov (United States)

    Bakkemo, Kathrine R; Mikkelsen, Helene; Johansen, Audny; Robertsen, Børre; Seppola, Marit

    2016-09-26

    Systemic infection caused by the facultative intracellular bacterium Francisella noatunensis subsp. noatunensis remains a disease threat to Atlantic cod Gadus morhua L. Future prophylactics could benefit from better knowledge on how the bacterium invades, survives and establishes infection in its host cells. Here, facilitated by the use of a gentamicin protection assay, this was studied in primary monocyte/macrophage cultures and an epithelial-like cell line derived from Atlantic cod larvae (ACL cells). The results showed that F. noatunensis subsp. noatunensis is able to invade primary monocyte/macrophages, and that the actin-polymerisation inhibitor cytochalasin D blocked internalisation, demonstrating that the invasion is mediated through phagocytosis. Interferon gamma (IFNγ) treatment of cod macrophages prior to infection enhanced bacterial invasion, potentially by stimulating macrophage activation in an early step in host defence against F. noatunensis subsp. noatunensis infections. We measured a rapid drop of the initial high levels of internalised bacteria in macrophages, indicating the presence and action of a cellular immune defence mechanism before intracellular bacterial replication took place. Low levels of bacterial internalisation and replication were detected in the epithelial-like ACL cells. The capacity of F. noatunensis subsp. noatunensis to enter, survive and even replicate within an epithelial cell line may play an important role in its ability to infect live fish and transverse epithelial barriers to reach the bacterium's main target cells-the macrophage.

  2. Effect of petroleum hydrocarbons on Atlantic cod, Gadusmorhua, following chronic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kiceniuk, J.W. (Dept. of Fisheries and Oceans, St. John' s, NF (Canada)); Khan, R.A. (Memorial Univ. of Newfoundland, St. John' s, NF (Canada))

    1987-01-01

    Experiments were conducted to ascertain the effects of crude oils at low concentrations on Atlantic cod (Gadus morhua) following long-term exposure (3-21 weeks) in a flow-through seawater system. Control and oil-treated fish were fed to satiation. Effects were assessed by comparing condition factor, organ indices, and hematological values with those of corresponding control animals. No mortality occurred but food consumption was significantly reduced in oil-treated cod, especially during summer-autumn. Condition factor and somatic indices of some organs were lower in oil-treated fish. Gall bladders were enlarged in oil-treated fish. Effects of oil exposure were less pronounced during winter, as food intake in both groups of fish was reduced considerably. The rate of gametogenesis was slower in male cod exposed to oil fractions in summer-autumn whereas spermeation was delayed in fish treated in winter-spring. These studies provide evidence that feeding, growth, and reproduction in male cod are biologically important variables that are affected following chronic exposure to petroleum. 22 refs., 4 tabs.

  3. Gene regulation of lipid and phospholipid metabolism in Atlantic cod (Gadus morhua) larvae.

    Science.gov (United States)

    Li, Keshuai; Østensen, Mari-Ann; Attramadal, Kari; Winge, Per; Sparstad, Torfinn; Bones, Atle M; Vadstein, Olav; Kjørsvik, Elin; Olsen, Yngvar

    2015-12-01

    The mechanism of essentiality of dietary phospholipid (PL) for larval fish is not clear. The main objective of the present study was to determine if the PL requirement of Atlantic cod larvae was due to any genetic impairment caused by functional immaturity. Cod larvae were sampled at 1, 3, 8, 13, 17, 18, 30, 42 and 60 days post hatch (dph) for transcriptome analysis using a recently developed microarray. The fatty acid profile and gene expression levels of cod larvae at 17 dph were compared after feeding differently enriched rotifers, which contained different DHA levels in PL. No significant differences (pcod larvae, their growth and survival, and their DHA levels in total lipid and PL fraction. The fatty acid data suggested that dietary EPA was elongated to DPA by cod larvae, and a threshold DHA level in PL to maintain membrane fluidity and other functions may exist. There appeared to be no major effect of development on the expression of key genes of PL biosynthesis suggesting no genetic constrain in early developmental stages. Our overall data suggested that besides the possible limited de novo PC synthesis ability in the intestine, other metabolic constraints should also be considered, especially the possible low input of bile PC as a result of immature liver. Further studies are needed to elucidate the gene expression level and enzyme activity in the PL biosynthesis pathways for specific tissue or cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Plastic ingestion by Atlantic cod (Gadus morhua) from the Norwegian coast.

    Science.gov (United States)

    Bråte, Inger Lise N; Eidsvoll, David P; Steindal, Calin Constantin; Thomas, Kevin V

    2016-11-15

    This study documents the occurrence of microplastic (20mm) in Atlantic cod (Gadus morhua), a common and economically important species of marine fish in Norway. Fish stomachs (n=302) were examined from six different locations along the coast of Norway. Three percent of the individual stomachs contained items identified by Fourier transform infrared spectroscopy (FTIR) as synthetic polymers. Bergen City Harbour was a hotspot with 27% of the cod examined found to contain plastic. Polyester was the most frequently detected polymer. All bar one of the stomachs that contained plastic were full of organic stomach content, suggesting a plastic gut clearance rate similar to the ingested food. It is proposed that stomach fullness is an important metric in order to avoid underestimations when assessing the levels of microplastic ingested by fish. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Factors regulating early life history dispersal of Atlantic cod (Gadus morhua from coastal Newfoundland.

    Directory of Open Access Journals (Sweden)

    Ryan R E Stanley

    Full Text Available To understand coastal dispersal dynamics of Atlantic cod (Gadus morhua, we examined spatiotemporal egg and larval abundance patterns in coastal Newfoundland. In recent decades, Smith Sound, Trinity Bay has supported the largest known overwintering spawning aggregation of Atlantic cod in the region. We estimated spawning and dispersal characteristics for the Smith Sound-Trinity Bay system by fitting ichthyoplankton abundance data to environmentally-driven, simplified box models. Results show protracted spawning, with sharply increased egg production in early July, and limited dispersal from the Sound. The model for the entire spawning season indicates egg export from Smith Sound is 13%•day(-1 with a net mortality of 27%•day(-1. Eggs and larvae are consistently found in western Trinity Bay with little advection from the system. These patterns mirror particle tracking models that suggest residence times of 10-20 days, and circulation models indicating local gyres in Trinity Bay that act in concert with upwelling dynamics to retain eggs and larvae. Our results are among the first quantitative dispersal estimates from Smith Sound, linking this spawning stock to the adjacent coastal waters. These results illustrate the biophysical interplay regulating dispersal and connectivity originating from inshore spawning of coastal northwest Atlantic.

  6. Factors Regulating Early Life History Dispersal of Atlantic Cod (Gadus morhua) from Coastal Newfoundland

    Science.gov (United States)

    Stanley, Ryan R. E.; deYoung, Brad; Snelgrove, Paul V. R.; Gregory, Robert S.

    2013-01-01

    To understand coastal dispersal dynamics of Atlantic cod (Gadus morhua), we examined spatiotemporal egg and larval abundance patterns in coastal Newfoundland. In recent decades, Smith Sound, Trinity Bay has supported the largest known overwintering spawning aggregation of Atlantic cod in the region. We estimated spawning and dispersal characteristics for the Smith Sound-Trinity Bay system by fitting ichthyoplankton abundance data to environmentally-driven, simplified box models. Results show protracted spawning, with sharply increased egg production in early July, and limited dispersal from the Sound. The model for the entire spawning season indicates egg export from Smith Sound is 13%•day−1 with a net mortality of 27%•day–1. Eggs and larvae are consistently found in western Trinity Bay with little advection from the system. These patterns mirror particle tracking models that suggest residence times of 10–20 days, and circulation models indicating local gyres in Trinity Bay that act in concert with upwelling dynamics to retain eggs and larvae. Our results are among the first quantitative dispersal estimates from Smith Sound, linking this spawning stock to the adjacent coastal waters. These results illustrate the biophysical interplay regulating dispersal and connectivity originating from inshore spawning of coastal northwest Atlantic. PMID:24058707

  7. Physiological and behavioural responses to noxious stimuli in the Atlantic cod (Gadus morhua.

    Directory of Open Access Journals (Sweden)

    Jared R Eckroth

    Full Text Available In the present study, our aim was to compare physiological and behavioural responses to different noxious stimuli to those of a standardized innocuous stimulus, to possibly identify aversive responses indicative of injury detection in a commercially important marine teleost fish, the Atlantic cod. Individual fish were administered with a noxious stimulus to the lip under short-term general anaesthesia (MS-222. The noxious treatments included injection of 0.1% or 2% acetic acid, 0.005% or 0.1% capsaicin, or piercing the lip with a commercial fishing hook. Counts of opercular beat rate (OBR at 10, 30, 60, 90 and 120 min and observations of behaviour at 30 and 90 min post-treatment were compared with pre-treatment values and with control fish injected with physiological saline, an innocuous stimulus. Circulatory levels of physiological stress indicators were determined in all fish at 120 minutes post-treatment. All treatments evoked temporarily increased OBR that returned to pre-treatment levels at 60 minutes (saline, 0.005% capsaicin, hook, 90 minutes (0.1% acetic acid, 0.1% capsaicin, or 120 minutes (2% acetic acid, but with no significant differences from the control group at any time point. Fish treated with 0.1% and 2% acetic acid and 0.1% capsaicin displayed increased hovering close to the bottom of the aquaria and fish given 2% acetic acid and 0.1% capsaicin also displayed a reduced use of shelter. The only effect seen in hooked fish was brief episodes of lateral head shaking which were not seen pre-treatment or in the other groups, possibly reflecting a resiliency to tissue damage in the mouth area related to the tough nature of the Atlantic cod diet. There were no differences between groups in circulatory stress indicators two hours after treatment. This study provides novel data on behavioural indicators that could be used to assess potentially aversive events in Atlantic cod.

  8. Effects of dietary arachidonic acid on the reproductive physiology of female Atlantic cod (Gadus morhua L.).

    Science.gov (United States)

    Norberg, Birgitta; Kleppe, Lene; Andersson, Eva; Thorsen, Anders; Rosenlund, Grethe; Hamre, Kristin

    2017-09-01

    The present study was designed to investigate potential effects of arachidonic acid (ARA) on the reproductive physiology of female Atlantic cod (Gadus morhua L.). Two-year old Atlantic cod of both sexes were equally distributed into eight sea cages after completion of their first spawning in May 2005. Four experimental groups were established and fed diets with different levels of ARA corresponding to 0.5, 1, 2 and 4% of total fatty acid. Ovarian growth and development was documented every month. Fatty acid composition was analysed in ovaries, liver and plasma at the beginning of the experiment, one month prior to spawning, and in spent fish, one month after spawning was completed. Plasma concentrations of estradiol-17β, testosterone and vitellogenin, and ovarian gene transcript levels of steroidogenic acute regulatory protein (star), P450aromatase (cyp19a1a) and 20β-hydroxy steroid dehydrogenase (20bhsd/cbr1) were monitored every month in fish fed the experimental diets and related to oocyte stage. Potential fecundity was calculated based on ovarian samples taken one month before onset of spawning. Ovarian and plasma ARA levels were highly correlated to dietary ARA levels. There was a net accumulation of ARA compared to other essential fatty acids in ovarian tissue that was reflected in a decrease in EPA:ARA ratio. Plasma concentrations of vitellogenin, estradiol-17β and testosterone and key gene transcript levels were affected by dietary ARA and stage of maturation. The results show that ARA has a significant influence on the reproductive physiology of female Atlantic cod. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Physiological and Behavioural Responses to Noxious Stimuli in the Atlantic Cod (Gadus morhua)

    Science.gov (United States)

    Eckroth, Jared R.; Aas-Hansen, Øyvind; Sneddon, Lynne U.; Bichão, Helena; Døving, Kjell B.

    2014-01-01

    In the present study, our aim was to compare physiological and behavioural responses to different noxious stimuli to those of a standardized innocuous stimulus, to possibly identify aversive responses indicative of injury detection in a commercially important marine teleost fish, the Atlantic cod. Individual fish were administered with a noxious stimulus to the lip under short-term general anaesthesia (MS-222). The noxious treatments included injection of 0.1% or 2% acetic acid, 0.005% or 0.1% capsaicin, or piercing the lip with a commercial fishing hook. Counts of opercular beat rate (OBR) at 10, 30, 60, 90 and 120 min and observations of behaviour at 30 and 90 min post-treatment were compared with pre-treatment values and with control fish injected with physiological saline, an innocuous stimulus. Circulatory levels of physiological stress indicators were determined in all fish at 120 minutes post-treatment. All treatments evoked temporarily increased OBR that returned to pre-treatment levels at 60 minutes (saline, 0.005% capsaicin, hook), 90 minutes (0.1% acetic acid, 0.1% capsaicin), or 120 minutes (2% acetic acid), but with no significant differences from the control group at any time point. Fish treated with 0.1% and 2% acetic acid and 0.1% capsaicin displayed increased hovering close to the bottom of the aquaria and fish given 2% acetic acid and 0.1% capsaicin also displayed a reduced use of shelter. The only effect seen in hooked fish was brief episodes of lateral head shaking which were not seen pre-treatment or in the other groups, possibly reflecting a resiliency to tissue damage in the mouth area related to the tough nature of the Atlantic cod diet. There were no differences between groups in circulatory stress indicators two hours after treatment. This study provides novel data on behavioural indicators that could be used to assess potentially aversive events in Atlantic cod. PMID:24936652

  10. Transcriptome profiling of the antiviral immune response in Atlantic cod macrophages.

    Science.gov (United States)

    Eslamloo, Khalil; Xue, Xi; Booman, Marije; Smith, Nicole C; Rise, Matthew L

    2016-10-01

    A study was conducted to determine the transcriptome response of Atlantic cod (Gadus morhua) macrophages to the viral mimic, polyriboinosinic polyribocytidylic acid (pIC), using a 20K Atlantic cod microarray platform and qPCR. We identified 285 significantly up-regulated and 161 significantly down-regulated probes in cod macrophages 24 h after pIC stimulation. A subset of 26 microarray-identified transcripts was subjected to qPCR validation using samples treated with pIC or phosphate-buffered saline (control) over time (3, 6, 12, 24, 48 h), and 77% of them showed a significant response to pIC. The microarray and qPCR analyses in this study showed that pIC induced the expression of cod macrophage transcripts involved in RLR- and TLR-dependent pathogen recognition (e.g. tlr3, tlr7, mda5 and lgp2), as well as signal transducers (e.g. stat1 and nfkbia) and transcription activators (e.g. irf7 and irf10) in the MyD88-independent and dependent signalling pathways. Several immune effectors (e.g. isg15s, viperin, herc4, mip2 and ccl13) were significantly up-regulated in pIC-stimulated cod macrophages. The expression of some transcripts (e.g. irf7, irf10, viperin) was significantly up-regulated by pIC as early as 12 h. All pIC-induced transcripts had peak expression at either 24 h (e.g. tlr7, irf7, mip2) or 48 h (e.g. tlr3, lgp2, stat1). This study suggests possible roles of both vertebrate-conserved (e.g. tlr3 as an up-regulated gene) and fish-specific (tlr22g as a down-regulated gene) receptors in dsRNA recognition, and the importance of conserved and potentially fish-specific interferon stimulated genes in cod macrophages. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effect of moderate hypoxia at three acclimation temperatures on stress responses in Atlantic cod with different haemoglobin types

    DEFF Research Database (Denmark)

    Methling, Caroline; Aluru, Neelakanteswar; Vijayan, Mathilakath M

    2010-01-01

    This study examines stress responses in Atlantic cod (Gadus morhua) when exposed to a moderate and transient reduction (35% O(2) sat.) in dissolved oxygen at a range of temperatures (5 degrees C, 10 degrees C and 15 degrees C), conditions occurring in some areas they inhabit. Given...... in a difference in stress response to hypoxia exposure. Two hsp70-isoforms (labelled a and b) were detected and they differed in expression in the gills but not in the liver of Atlantic cod. Acclimation temperature significantly affected the expression of hsp70 in the liver, and in an isoform-specific manner...... hypoxic exposure influence the organismal and cellular stress responses in Atlantic cod. We hypothesise that HbI-2 fish are more tolerant to short-term hypoxic episodes than HbI-1 fish, and this adaptation may be independent of tissue hsp70 expression....

  12. Low plastic ingestion rate in Atlantic cod (Gadus morhua) from Newfoundland destined for human consumption collected through citizen science methods.

    Science.gov (United States)

    Liboiron, Max; Liboiron, France; Wells, Emily; Richárd, Natalie; Zahara, Alexander; Mather, Charles; Bradshaw, Hillary; Murichi, Judyannet

    2016-12-15

    Marine microplastics are a contaminant of concern because their small size allows ingestion by a wide range of marine life. Using citizen science during the Newfoundland recreational cod fishery, we sampled 205 Atlantic cod (Gadus morhua) destined for human consumption and found that 5 had eaten plastic, an ingestion prevalence rate of 2.4%. This ingestion rate for Atlantic cod is the second lowest recorded rate in the reviewed published literature (the lowest is 1.4%), and the lowest for any fish in the North Atlantic. This is the first report for plastic ingestion in fish in Newfoundland, Canada, a province dependent on fish for sustenance and livelihoods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Distinction among North Atlantic cod Gadus morhua stocks by tissue fatty acid profiles.

    Science.gov (United States)

    Joensen, H; Grahl-Nielsen, O

    2014-06-01

    The fatty acid (FA) profiles of the white muscle and heart tissues of cod Gadus morhua from five locations, Faroe Bank, Faroe Plateau, North-West Iceland, Norway-Barents Sea and Denmark-Skagerrak, were population dependent. The interregional differences of FAs were significantly dissimilar (P Fisheries Society of the British Isles.

  14. Diet affects the redox system in developing Atlantic cod (Gadus morhua) larvae.

    Science.gov (United States)

    Penglase, Samuel; Edvardsen, Rolf B; Furmanek, Tomasz; Rønnestad, Ivar; Karlsen, Ørjan; van der Meeren, Terje; Hamre, Kristin

    2015-08-01

    The growth and development of marine fish larvae fed copepods is superior to those fed rotifers, but the underlying molecular reasons for this are unclear. In the following study we compared the effects of such diets on redox regulation pathways during development of Atlantic cod (Gadus morhua) larvae. Cod larvae were fed a control diet of copepods or the typical rotifer/Artemia diet commonly used in commercial marine fish hatcheries, from first feeding until after metamorphosis. The oxidised and reduced glutathione levels, the redox potential, and the mRNA expression of 100 genes in redox system pathways were then compared between treatments during larval development. We found that rotifer/Artemia-fed cod larvae had lower levels of oxidised glutathione, a more reduced redox potential, and altered expression of approximately half of the redox system genes when compared to copepod-fed larvae. This rotifer/Artemia diet-induced differential regulation of the redox system was greatest during periods of suboptimal growth. Upregulation of the oxidative stress response transcription factor, nrf2, and NRF2 target genes in rotifer/Artemia fed larvae suggest this diet induced an NRF2-mediated oxidative stress response. Overall, the data demonstrate that nutritional intake plays a role in regulating the redox system in developing fish larvae. This may be a factor in dietary-induced differences observed in larval growth. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Diet affects the redox system in developing Atlantic cod (Gadus morhua larvae

    Directory of Open Access Journals (Sweden)

    Samuel Penglase

    2015-08-01

    Full Text Available The growth and development of marine fish larvae fed copepods is superior to those fed rotifers, but the underlying molecular reasons for this are unclear. In the following study we compared the effects of such diets on redox regulation pathways during development of Atlantic cod (Gadus morhua larvae. Cod larvae were fed a control diet of copepods or the typical rotifer/Artemia diet commonly used in commercial marine fish hatcheries, from first feeding until after metamorphosis. The oxidised and reduced glutathione levels, the redox potential, and the mRNA expression of 100 genes in redox system pathways were then compared between treatments during larval development. We found that rotifer/Artemia-fed cod larvae had lower levels of oxidised glutathione, a more reduced redox potential, and altered expression of approximately half of the redox system genes when compared to copepod-fed larvae. This rotifer/Artemia diet-induced differential regulation of the redox system was greatest during periods of suboptimal growth. Upregulation of the oxidative stress response transcription factor, nrf2, and NRF2 target genes in rotifer/Artemia fed larvae suggest this diet induced an NRF2-mediated oxidative stress response. Overall, the data demonstrate that nutritional intake plays a role in regulating the redox system in developing fish larvae. This may be a factor in dietary-induced differences observed in larval growth.

  16. Characterizing ovarian gene expression during oocyte growth in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Breton, Timothy S; Berlinsky, David L

    2014-03-01

    Vertebrate oocytes undergo dramatic changes during development as they accumulate many RNA transcripts, glycoproteins, and yolk proteins, necessary to ensure proper fertilization and embryogenesis. Oogenesis in teleosts often requires several years for completion, but very little is known about the early developmental stages. Recently, two-stage gene expression comparisons were made during oocyte growth in coho salmon (Oncorhynchus kisutch) and Atlantic cod (Gadus morhua), but more broad-scale, comprehensive assessments have not been conducted. The objectives of the present study were to characterize the gene expression patterns throughout oocyte growth in cod and compare them to changes previously identified in coho salmon. A quantitative PCR survey was conducted using 50 genes at six ovarian stages, ranging from the onset of primary growth (oocyte differentiation) to late vitellogenesis. Most expression patterns could be grouped into three major clusters, consisting of oocyte-derived (cluster 1) and likely follicle cell (clusters 2 and 3) genes. Oocyte genes were elevated during primary growth, while many follicle cell transcripts were abundant during oocyte differentiation and vitellogenesis. Few expression changes identified in coho salmon were evident in cod, which is likely due to differences in reproductive strategies. These results demonstrate that dynamic changes in gene expression occur during oocyte growth in teleost fish. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Evolutionary redesign of the Atlantic cod (Gadus morhua L.) Toll-like receptor repertoire by gene losses and expansions

    OpenAIRE

    Solbakken, Monica H.; T?rresen, Ole K.; Nederbragt, Alexander J.; Seppola, Marit; Gregers, Tone F.; Jakobsen, Kjetill S.; Jentoft, Sissel

    2016-01-01

    Published version. Source at http://doi.org/10.1038/srep25211. License CC BY 4.0. Genome sequencing of the teleost Atlantic cod demonstrated loss of the Major Histocompatibility Complex (MHC) class II, an extreme gene expansion of MHC class I and gene expansions and losses in the innate pattern recognition receptor (PRR) family of Toll-like receptors (TLR). In a comparative genomic setting, using an improved version of the genome, we characterize PRRs in Atlantic cod with emphasis on TL...

  18. Ubiquitous presence of piscidin-1 in Atlantic cod as evidenced by immunolocalisation

    Directory of Open Access Journals (Sweden)

    Ruangsri Jareeporn

    2012-07-01

    Full Text Available Abstract Background Antimicrobial peptides (AMPs, the natural antibiotics bestowed upon all forms of life, consist of small molecular weight proteins with a broad spectrum antimicrobial activity against a variety of pathogenic microorganisms. Piscidins are one of the AMP families that are imperative for the innate defence mechanisms of teleosts. Atlantic cod, a basal fish belonging to the superorder Paracanthopterygii also possesses multiple piscidin peptides. Two piscidin paralogues (pis1 and pis2 and a novel alternative splice variant of pis2 of this fish were previously described by us. To shed light on other potent roles of these molecules, now we have mapped the distribution of piscidin 1 (Pis1, in different tissues and organs of cod through immunohistochemistry (IHC employing an affinity purified polyclonal antibody specific to Pis1. Results Various cell types and tissues of Atlantic cod including those from the immune organs of naïve fish are armed with Pis1 peptide. Different types of the blood leucocytes and phagocytic cells among the leucocytes examined gave a relatively strong indication of Pis1 immunopositivity. In addition, other cell types such as hematopoietic cells, epithelial cells and multi-granular cells located in the mucosal and hematopoietic tissues were also Pis1-immunoreactive. More interestingly, chondrocytes appear to produce Pis1 and this is the first report on the presence of an AMP in cartilage tissue of fish. Furthermore, Pis1 immunopositivity was detected in other tissues and organs of naïve fish including neural tissues, exocrine and endocrine glands, compound gland cells, excretory kidney, intestinal and respiratory epithelial cells, swim bladder, skin and hypodermis layer, myosepta, liver, heart, eye and oocytes. Conclusions Pis1 peptide is produced by various cell types located in different tissues and organs of Atlantic cod. It is present in all immune-related organs of naïve fish and the elevated peptide

  19. Thermal growth potential of Atlantic cod by the end of the 21st century.

    Science.gov (United States)

    Butzin, Martin; Pörtner, Hans-Otto

    2016-12-01

    Ocean warming may lead to smaller body sizes of marine ectotherms, because metabolic rates increase exponentially with temperature while the capacity of the cardiorespiratory system to match enhanced oxygen demands is limited. Here, we explore the impact of rising sea water temperatures on Atlantic cod (Gadus morhua), an economically important fish species. We focus on changes in the temperature-dependent growth potential by a transfer function model combining growth observations with climate model ensemble temperatures. Growth potential is expressed in terms of asymptotic body weight and depends on water temperature. We consider changes between the periods 1985-2004 and 2081-2100, assuming that future sea water temperatures will evolve according to climate projections for IPCC AR5 scenario RCP8.5. Our model projects a response of Atlantic cod to future warming, differentiated according to ocean regions, leading to increases of asymptotic weight in the Barents Sea, while weights are projected to decline at the southern margin of the biogeographic range. Southern spawning areas will disappear due to thermal limitation of spawning stages. These projections match the currently observed biogeographic shifts and the temperature- and oxygen-dependent decline in routine aerobic scope at southern distribution limits. © 2016 John Wiley & Sons Ltd.

  20. Substantial Downregulation of Myogenic Transcripts in Skeletal Muscle of Atlantic Cod during the Spawning Period

    Science.gov (United States)

    Edvardsen, Vigdis

    2016-01-01

    Gonadal maturation is an extremely energy consuming process for batch spawners and it is associated with a significant decrease in growth and seasonal deterioration in flesh quality. Our knowledge about the molecular mechanisms linking sexual maturation and muscle growth is still limited. In the present study, we performed RNA-Seq using 454 GS-FLX pyrosequencing in fast skeletal muscle sampled from two-year-old Atlantic cod (Gadus morhua) at representative time points throughout the reproductive cycle (August, March and May). In total, 126,937 good quality reads were obtained, with 546 nucleotide length and 52% GC content on average. RNA-Seq analysis using the CLC Genomics Workbench with the Atlantic cod reference UniGene cDNA data revealed 59,581 (46.9%) uniquely annotated reads. Pairwise comparison for expression levels identified 153 differentially expressed UniGenes between time points. Notably, we found a significant suppression of myh13 and myofibrillar gene isoforms in fast skeletal muscle during the spawning season. This study uncovered a large number of differentially expressed genes that may be influenced by gonadal maturation, thus representing a significant contribution to our limited understanding of the molecular mechanisms regulating muscle wasting and regeneration in batch spawners during their reproductive cycle. PMID:26844771

  1. The effect of carbon dioxide on growth of juvenile Atlantic cod Gadus morhua L

    DEFF Research Database (Denmark)

    Moran, Damian; Støttrup, Josianne

    2011-01-01

    A trial was undertaken to investigate how exposure to graded hypercapnia affected the growth performance of juvenile (15-80 g) Atlantic cod. Juveniles were grown at 20‰ salinity and 10 °C for 55 days under three hypercapnic regimes: low (2 ± 0.9 mg L−1 CO2, 0.6 mm Hg, 1000 μatm), medium (8 ± 0.5 mg...... L−1 CO2, 2.8 mm Hg, 3800 μatm) and high CO2 exposure (18 ± 0.2 mg L−1 CO2, 6.3 mm Hg, 8500 μatm). All water quality parameters were within the range of what might normally be considered acceptable for good growth, including the CO2 levels tested. Weight gain, growth rate and condition factor were...... experiments using marine fish species. The test concentrations were recalculated from the reported carbonate chemistry conditions, and indicated that the CO2 concentration effect threshold may have been overestimated in two of these studies. Our study suggests that juvenile Atlantic cod are more susceptible...

  2. Sex differentiation in Atlantic cod (Gadus morhua L.: morphological and gene expression studies

    Directory of Open Access Journals (Sweden)

    Haugen Trine

    2012-06-01

    Full Text Available Abstract Background In differentiated gonochoristic species, a bipotential gonad develops into an ovary or testis during sex differentiation. Knowledge about this process is necessary to improve methods for masculinizing genetically female Atlantic cod for the subsequent purpose of producing all-female populations. Methods Gonads were examined histologically in juveniles from 14 to 39 mm total body length (TL. Number and size of germ cells were determined in a subset of the samples. Relevant genes were cloned, and mRNA levels determined by qPCR of amh, cyp19a1a; dax1 (nr0b2; shp (nr0b2a and sox9b in a mixed-sex and an all-female population ranging from 12–49 mm TL. Results Individuals between 14–20 mm TL could be separated in two subgroups based on gonad size and germ cell number. Ovarian cavity formation was observed in some individuals from 18–20 mm TL. The mixed sex population displayed bimodal expression patterns as regards cyp19a1a (starting at 12 mm TL and amh (starting at 20 mm TL mRNA levels. After approximately 30 mm TL, cyp19a1a and amh displayed a gradual increase in both sexes. No apparent, sex-dependent expression patterns were found for dax1, shp or sox9b transcripts. However, shp levels were high until the larvae reached around 35 mm TL and then dropped to low levels, while dax1 remained low until 35 mm TL, and then increased sharply. Conclusions The morphological sex differentiation in females commenced between 14–20 mm TL, and ovarian cavities were evident by 18–20 mm TL. Testis development occurred later, and was morphologically evident after 30 mm TL. This pattern was corroborated with sexually dimorphic expression patterns of cyp19a1a from 12–13 mm TL, and a male-specific increase in amh from 20 mm TL.

  3. Genomic signatures of local directional selection in a high gene flow marine organism; the Atlantic cod (Gadus morhua

    Directory of Open Access Journals (Sweden)

    Mittelholzer Christian

    2009-12-01

    Full Text Available Abstract Background Marine fishes have been shown to display low levels of genetic structuring and associated high levels of gene flow, suggesting shallow evolutionary trajectories and, possibly, limited or lacking adaptive divergence among local populations. We investigated variation in 98 gene-associated single nucleotide polymorphisms (SNPs for evidence of selection in local populations of Atlantic cod (Gadus morhua L. across the species distribution. Results Our global genome scan analysis identified eight outlier gene loci with very high statistical support, likely to be subject to directional selection in local demes, or closely linked to loci under selection. Likewise, on a regional south/north transect of central and eastern Atlantic populations, seven loci displayed strongly elevated levels of genetic differentiation. Selection patterns among populations appeared to be relatively widespread and complex, i.e. outlier loci were generally not only associated with one of a few divergent local populations. Even on a limited geographical scale between the proximate North Sea and Baltic Sea populations four loci displayed evidence of adaptive evolution. Temporal genome scan analysis applied to DNA from archived otoliths from a Faeroese population demonstrated stability of the intra-population variation over 24 years. An exploratory landscape genetic analysis was used to elucidate potential effects of the most likely environmental factors responsible for the signatures of local adaptation. We found that genetic variation at several of the outlier loci was better correlated with temperature and/or salinity conditions at spawning grounds at spawning time than with geographic distance per se. Conclusion These findings illustrate that adaptive population divergence may indeed be prevalent despite seemingly high levels of gene flow, as found in most marine fishes. Thus, results have important implications for our understanding of the interplay of

  4. Genomic signatures of local directional selection in a high gene flow marine organism; the Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Nielsen, Einar E; Hemmer-Hansen, Jakob; Poulsen, Nina A; Loeschcke, Volker; Moen, Thomas; Johansen, Torild; Mittelholzer, Christian; Taranger, Geir-Lasse; Ogden, Rob; Carvalho, Gary R

    2009-12-01

    Marine fishes have been shown to display low levels of genetic structuring and associated high levels of gene flow, suggesting shallow evolutionary trajectories and, possibly, limited or lacking adaptive divergence among local populations. We investigated variation in 98 gene-associated single nucleotide polymorphisms (SNPs) for evidence of selection in local populations of Atlantic cod (Gadus morhua L.) across the species distribution. Our global genome scan analysis identified eight outlier gene loci with very high statistical support, likely to be subject to directional selection in local demes, or closely linked to loci under selection. Likewise, on a regional south/north transect of central and eastern Atlantic populations, seven loci displayed strongly elevated levels of genetic differentiation. Selection patterns among populations appeared to be relatively widespread and complex, i.e. outlier loci were generally not only associated with one of a few divergent local populations. Even on a limited geographical scale between the proximate North Sea and Baltic Sea populations four loci displayed evidence of adaptive evolution. Temporal genome scan analysis applied to DNA from archived otoliths from a Faeroese population demonstrated stability of the intra-population variation over 24 years. An exploratory landscape genetic analysis was used to elucidate potential effects of the most likely environmental factors responsible for the signatures of local adaptation. We found that genetic variation at several of the outlier loci was better correlated with temperature and/or salinity conditions at spawning grounds at spawning time than with geographic distance per se. These findings illustrate that adaptive population divergence may indeed be prevalent despite seemingly high levels of gene flow, as found in most marine fishes. Thus, results have important implications for our understanding of the interplay of evolutionary forces in general, and for the conservation of

  5. Accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.) following dietary exposure

    Energy Technology Data Exchange (ETDEWEB)

    Amlund, Heidi [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway)]. E-mail: heidi.amlund@nifes.no; Lundebye, Anne-Katrine [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway); Berntssen, Marc H.G. [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway)

    2007-08-01

    Methylmercury is known to bioaccumulate and biomagnify up the marine food chain. Fish from high levels of the marine food chain may contain relatively high concentrations of mercury, and most (>70%) of the mercury found in muscle is methylmercury. In aquaculture, marine protein (mainly fishmeal) is the dominant source of methylmercury, and this raises some concern with regards to fish welfare and consumer safety. A dietary exposure study, including a depuration period, was carried out in order to study the accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.), and to estimate the transfer of methylmercury from feed to fish. Fish were sampled throughout a three month exposure period and a three month depuration period. Muscle samples were fractionated into a protein and a lipid fraction by lipid extraction using methanol and chloroform. Mercury and methylmercury were determined by inductively coupled plasma mass spectrometry (ICPMS) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS), respectively. A continuous accumulation of methylmercury, after a lag period of 10 days, was observed in muscle tissue during the three months exposure to methylmercury (0.95+/-0.03{mu}g Hg/g feed, n=6). After three months, the final concentration in muscle was 0.38+/-0.04{mu}g Hg/gww (n=6), where methylmercury constituted 90-95% of the mercury present. The elimination of methylmercury from muscle was slow and incomplete (within the three months of depuration) with an estimated elimination half-life (t{sub 1/2}) of 377 days. The transfer of methylmercury from feed to Atlantic cod, described by the estimated absorption efficiency, was 38%. In muscle more than 99% of the mercury was found in the protein fraction. These results suggest that Atlantic cod readily takes up dietary methylmercury, which is efficiently accumulated into muscle, where it is incorporated into larger peptides or proteins. Comparable results were found for

  6. Synergies between climate and management for Atlantic cod fisheries at high latitudes.

    Science.gov (United States)

    Kjesbu, Olav Sigurd; Bogstad, Bjarte; Devine, Jennifer A; Gjøsæter, Harald; Howell, Daniel; Ingvaldsen, Randi B; Nash, Richard D M; Skjæraasen, Jon Egil

    2014-03-04

    The widespread depletion of commercially exploited marine living resources is often seen as a general failure of management and results in criticism of contemporary management procedures. When populations show dramatic and positive changes in population size, this invariably leads to questions about whether favorable climatic conditions or good management (or both) were responsible. The Barents Sea cod (Gadus morhua) stock has recently increased markedly and the spawning stock biomass is now at an unprecedented high. We identify the crucial social and environmental factors that made this unique growth possible. The relationship between vital rates of Barents Sea cod stock productivity (recruitment, growth, and mortality) and environment is investigated, followed by simulations of population size under different management scenarios. We show that the recent sustained reduction in fishing mortality, facilitated by the implementation of a "harvest control rule," was essential to the increase in population size. Simulations show that a drastic reduction in fishing mortality has resulted in a doubling of the total population biomass compared with that expected under the former management regime. However, management alone was not solely responsible. We document that prevailing climate, operating through several mechanistic links, positively reinforced management actions. Heightened temperature resulted in an increase in the extent of the suitable feeding area for Barents Sea cod, likely offering a release from density-dependent effects (for example, food competition and cannibalism) through prolonged overlap with prey and improved adult stock productivity. Management and climate may thus interact to give a positive outlook for exploited high-latitude marine resources.

  7. The influence of feeding behaviour on growth of Atlantic cod (Gadus morhua, Linnaeus, 1758) in the North Sea

    DEFF Research Database (Denmark)

    Hüssy, Karin; Andersen, Niels Gerner; Pedersen, Eva Maria

    2016-01-01

    The objective of this study was to resolve key mechanisms driving individual growth patterns of Atlantic cod (Gadus morhua). Growth dynamics were analysed by linking growth patterns with stomach content composition and environmental temperature. Samples were collected in August/September of the y......The objective of this study was to resolve key mechanisms driving individual growth patterns of Atlantic cod (Gadus morhua). Growth dynamics were analysed by linking growth patterns with stomach content composition and environmental temperature. Samples were collected in August......% by mass), of which six were used for growth analyses: “Sandeel”, “Clupeids”, “Norway pout”, “Flatfishes”, “Crustaceans” and “Brittle stars”. For each group, growth patterns were estimated based on measures of otolith growth increments. The stomach contents showed that cod as a species are opportunistic...... decreased with increasing cod size, whereas that of fish and predominantly herring increased. Prey type had a significant effect on growth, while temperature had no effect. Slowest growth was observed in the cod group preying on sandeel, while cod preying on Norway pout showed the fastest growth...

  8. An investigation of appetite-related peptide transcript expression in Atlantic cod (Gadus morhua) brain following a Camelina sativa meal-supplemented feeding trial.

    Science.gov (United States)

    Tuziak, Sarah M; Rise, Matthew L; Volkoff, Hélène

    2014-10-25

    Camelina sativa is a hardy oilseed crop with seeds that contain high levels of ω3 polyunsaturated fatty acids and protein, which are critical components of fish feed. Camelina might thus be used as a cheaper and more sustainable supplement to fish-based products in aquaculture. Atlantic cod, Gadus morhua, is a species of interest in the aquaculture industry due to a decrease in wild populations and subsequent collapse of some cod fisheries. As cod are carnivorous fish, it is necessary to determine how this species physiologically tolerates plant-based diets. In this study, juvenile Atlantic cod were subjected to 13 weeks of either 15 or 30% camelina meal (CM)-supplemented diets or a control fish meal feed. Growth and food intake were evaluated and the mRNA expression of appetite-related hormones [pro-melanin-concentrating hormone (pmch), hypocretin (synonym: orexin, hcrt), neuropeptide Y (npy) and cocaine- and amphetamine-regulated transcript (cart)] was assessed using quantitative real-time PCR in brain regions related to food intake regulation (telencephalon/preoptic area, optic tectum/thalamus and hypothalamus). CM inclusion diets caused decreases in both growth and food intake in Atlantic cod. Optic tectum pmch transcript expression was significantly higher in fish fed the 30% CM diet compared to fish fed the 15% CM diet. In the hypothalamus, compared to fish fed the control diet, hcrt expression was significantly higher in fish fed the 30% CM diet, while npy transcript expression was significantly higher in fish fed the 15% CM diet. cart mRNA expression was not affected by diet in any brain region. Further studies are needed to determine which factors (e.g. anti-nutritional factors, palatability and nutritional deficits) contribute to reduced feed intake and growth, as well as the maximum CM inclusion level that does not negatively influence feed intake, growth rate and the transcript expression of appetite-related factors in Atlantic cod. Copyright © 2014

  9. Electrical stunning of farmed Atlantic cod Gadus morhua L.: a comparison of an industrial and experimental method

    NARCIS (Netherlands)

    Digre, H.; Erikson, U.; Misimi, E.; Lambooij, E.; Vis, van de J.W.

    2010-01-01

    An industrial and experimental electrical method for stunning farmed Atlantic cod in air and seawater (SW), respectively, were compared. The impacts of sedation with AQUI-S™ and exercise to exhaustion before electrical stunning were also assessed to monitor the possible depletion of rested muscle

  10. Residency, site fidelity and habitat use of Atlantic cod (Gadus morhua) at an offshore wind farm using acoustic telemetry.

    Science.gov (United States)

    Reubens, Jan T; Pasotti, Francesca; Degraer, Steven; Vincx, Magda

    2013-09-01

    Because offshore wind energy development is fast growing in Europe it is important to investigate the changes in the marine environment and how these may influence local biodiversity and ecosystem functioning. One of the species affected by these ecosystem changes is Atlantic cod (Gadus morhua), a heavily exploited, commercially important fish species. In this research we investigated the residency, site fidelity and habitat use of Atlantic cod on a temporal scale at windmill artificial reefs in the Belgian part of the North Sea. Acoustic telemetry was used and the Vemco VR2W position system was deployed to quantify the movement behaviour. In total, 22 Atlantic cod were tagged and monitored for up to one year. Many fish were present near the artificial reefs during summer and autumn, and demonstrated strong residency and high individual detection rates. When present within the study area, Atlantic cod also showed distinct habitat selectivity. We identified aggregation near the artificial hard substrates of the wind turbines. In addition, a clear seasonal pattern in presence was observed. The high number of fish present in summer and autumn alternated with a period of very low densities during the winter period. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. The responses of Atlantic cod (Gadus morhua L.) to ultrasound-emitting predators: stress, behavioural changes or debilitation?

    DEFF Research Database (Denmark)

    Schack, H.B.; Malte, H.; Madsen, Peter Teglberg

    2008-01-01

    A previous study has reported that Atlantic cod can be conditioned to detect ultrasonic sound pulses of high intensity. This capability has been proposed as a mean for detection and avoidance of echolocating toothed whales that emit intense ultrasonic clicks. In this study, we use acoustic playba...

  12. Influences of potential predictor variables on gastric evacuation in Atlantic cod Gadus morhua L. feeding on fish prey

    DEFF Research Database (Denmark)

    Andersen, Niels Gerner

    2012-01-01

    The parameter values of a generic model of gastric evacuation were estimated from evacuation data on Atlantic cod Gadus morhua fed meals of four fish prey: herring Clupea harengus, sprat Sprattus sprattus, lesser sandeel Ammodytes tobianus and dab Limanda limanda. The effects on evacuation...

  13. The Effects of Temperature, Hypoxia and Hypercapnia on the Metabolism of Atlantic Cod Gadus morhua

    DEFF Research Database (Denmark)

    Tirsgård, Bjørn

    The Atlantic cod (Gadus morhua L. 1758) is an important species both as a major top predator in the ecosystem and economical marine resource in the fishing industry of Northern Europe (Andersen, 2012). As an ectothermic water breather the Atlantic cod is continuously exposed to annual changes...... into bio-energetic models used to predict survival, growth and reproduction rates and cod stock dynamics. Furthermore, due to the growing interest of the continuing global increase in atmospheric and oceanic CO2 levels (ICES, 2010), and the rapid expansion of fish farming in land-based recirculated...... species can survive in relatively high dissolved CO2 concentrations (hypercapnia) (Crocker and Cech, 1996; McKenzie et al., 2003), long-term exposure to sub-lethal environmental hypercapnia is known to affect growth, feed conversion efficiency and body condition index (Smart, 1981; Fivelstad et al., 1998...

  14. Impact of water-accommodated fractions of crude oil on Atlantic cod, Gadus morhua following chronic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Khan, R. [Memorial Univ. of Newfoundland, St. John' s, NL (Canada)

    2010-07-01

    This study examined the long-term effects of hydrocarbon exposure on the gonadal development of fish. Mature Atlantic cod (Gadus morhua) were exposed to low concentrations of water accommodated fractions (WAFs) of polycyclic aromatic hydrocarbons (PAHs) in an ambient flowthrough seawater system. Some PAH-exposed cod groups were depurated afterwards for 38 to 287 days. Mortality was rare, and external lesions occurred only in the PAH-exposed groups. The gonado-somatic index revealed that gonadal development was disrupted in both sexes and spawning and spermiation was delayed in the 33 depurated PAH-groups. The findings indicate that chronic exposure to WAFs in the water column may have an adverse effect on reproduction in Atlantic cod.

  15. Composition and structure of the parasite faunas of cod, Gadus morhua L. (Teleostei: Gadidae, in the North East Atlantic

    Directory of Open Access Journals (Sweden)

    Kostadinova Aneta

    2008-07-01

    Full Text Available Abstract Background Although numerous studies on parasites of the Atlantic cod, Gadus morhua L. have been conducted in the North Atlantic, comparative analyses on local cod parasite faunas are virtually lacking. The present study is based on examination of large samples of cod from six geographical areas of the North East Atlantic which yielded abundant baseline data on parasite distribution and abundance. Materials and Methods A total of 826 fish was sampled in the Baltic, Celtic, Irish and North seas, Icelandic waters and Trondheimsfjord (Norway in 2002 (spring and autumn and 2003 (spring. The gills and internal organs (oesophagus, stomach, intestine, pyloric caeca, liver, heart, spleen, gall bladder and gonads were examined for macroparasites following a standardised protocol. The taxonomic consistency of the identification was ensured thorough the entire study. Results We discuss some problems in parasite identification, outline the composition of the parasite faunas in cod in the six North East Atlantic regions, provide novel data on parasite prevalence and abundance and a comparative assessment of the structure of the regional parasite faunas with respect to the higher-level taxonomic groupings, host specificity and zoogeographical distribution of the parasites. Altogether 57 different parasite forms were found including seven new host records (Diclidophora merlangi, Rhipidocotyle sp., Fellodistomum sp., Steringotrema sp., Cucullanus sp., Spinitectus sp., and Chondracanthus ornatus. The predominant groups of cod parasites were trematodes (19 species and nematodes (13 species including larval anisakids which comprised 58.2% of the total number of individuals. Conclusion Our study reveals relatively rich regional parasite faunas in cod from the North East Atlantic which are dominated by generalist parasites with Arcto-Boreal distribution. Further, it provides more detailed data on the distribution in the North East Atlantic of the majority

  16. Parallel adaptive evolution of Atlantic cod on both sides of the Atlantic Ocean in response to temperature.

    Science.gov (United States)

    Bradbury, Ian R; Hubert, Sophie; Higgins, Brent; Borza, Tudor; Bowman, Sharen; Paterson, Ian G; Snelgrove, Paul V R; Morris, Corey J; Gregory, Robert S; Hardie, David C; Hutchings, Jeffrey A; Ruzzante, Daniel E; Taggart, Chris T; Bentzen, Paul

    2010-12-22

    Despite the enormous economic and ecological importance of marine organisms, the spatial scales of adaptation and biocomplexity remain largely unknown. Yet, the preservation of local stocks that possess adaptive diversity is critical to the long-term maintenance of productive stable fisheries and ecosystems. Here, we document genomic evidence of range-wide adaptive differentiation in a broadcast spawning marine fish, Atlantic cod (Gadus morhua), using a genome survey of single nucleotide polymorphisms. Of 1641 gene-associated polymorphisms examined, 70 (4.2%) tested positive for signatures of selection using a Bayesian approach. We identify a subset of these loci (n=40) for which allele frequencies show parallel temperature-associated clines (pAtlantic. Temperature associations were robust to the statistical removal of geographic distance or latitude effects, and contrasted 'neutral' loci, which displayed no temperature association. Allele frequencies at temperature-associated loci were significantly correlated, spanned three linkage groups and several were successfully annotated supporting the involvement of multiple independent genes. Our results are consistent with the evolution and/or selective sweep of multiple genes in response to ocean temperature, and support the possibility of a new conservation paradigm for non-model marine organisms based on genomic approaches to resolving functional and adaptive diversity.

  17. Prey exoskeletons influence the course of gastric evacuation in Atlantic cod Gadus morhua

    DEFF Research Database (Denmark)

    Couturier, C. S.; Andersen, N. G.; Audet, C.

    2013-01-01

    This study examined the effects of prey exoskeleton characteristics on gastric evacuation patterns in Atlantic cod Gadus morhua. Three distinct stages were highlighted in the gastric evacuation of crustacean prey characterized by a robust exoskeleton. The experiments confirmed that the three shrimp...... of the prey exoskeleton all affected gastric evacuation: duration of initial delay, overall evacuation rate and a decreased evacuation rate at the end of the process. The power exponential function (PEF), with its shape parameter, described the course of evacuation for these prey types well, especially...... the initial delay. The PEF does not, however, allow describing evacuation by the current stomach content mass independent of meal size, which limits its usefulness in estimating consumption rates of wild G. morhua. To predict and describe gastric evacuation of prey with a robust exoskeleton, it is therefore...

  18. Fathers modify thermal reaction norms for hatching success in Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Dahlke, Flemming T.; Politis, Sebastian Nikitas; Butts, Ian

    2016-01-01

    Climate-driven warming is altering marine ecosystems at an unprecedented rate and evolutionary adaptation may represent the last resort for many ectothermic organisms to avoid local extinction. The first step to elucidate the potential for adaptation to unfavorable thermal conditions is to assess...... therefore hold important implications for resilience. This study examined how males differ in their ability to sire viable offspring and whether the paternal contribution modified thermal reaction norms for hatching success in two replicated trials with cod Gadus morhua from the Northwest Atlantic (trial 1...... hatching success significantly decreased towards thermal extremes. However, half-sibling families varied in their response to different incubation temperatures as indicated by significant paternity × temperature interactions and crossing of reaction norms. The influence of paternity itself was highly...

  19. Paternal effects on early life history traits in Northwest Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Kroll, M.-M.; Peck, M.A.; Butts, Ian A.E.

    2013-01-01

    and survival. In marine fish, rates of natural mortality are highest during early life and are negatively correlated with rates of growth and body size. In these early life stages (eggs, larvae, young juveniles) subtle differences in mortality can cause large differences in recruitment and year-class success....... Therefore, it is particularly critical to understand factors that contribute to variability in mortality during early life. This study focuses on evaluating the potential influence of paternity on rates of mortality and development in eggs and larvae of Northwest Atlantic cod, Gadus morhua. To accomplish...... this 12 males and two females were crossed using a full-factorial breeding design. Paternity had a strong influence on fertilization success, hatching success, cumulative embryonic mortality, larval standard length, eye diameter, yolk-sac area, and cumulative larval mortality. Female 1 showed an overall...

  20. Correlations of age and growth rate with microbiota composition in Atlantic cod (Gadus morhua) larvae.

    Science.gov (United States)

    Trinh, Ly T T; Bakke, Ingrid; Vadstein, Olav

    2017-08-17

    Little information is available on the link between host development (growth rate and ontogeny) and the composition of the microbiota in fish larvae. This study was carried out to examine potential correlations of microbiota composition with age and growth rate of Atlantic cod larvae. Small and large cod larvae of the same age, representing slow and fast growing individuals, were sampled 10 times during a period of 42 days post hatching (dph), and the composition of the larval microbiota was investigated using a PCR/DGGE (Denaturing Gradient Gel Electrophoresis) strategy. We found significant differences in the intestinal microbiota of small and large larvae of the same age for 4 of the 10 age stages studied. We further found that the variation in the composition of the larval microbiota was more strongly correlated to age than to growth rate for larvae up to 28 dph, whereas for the older larvae growth rate and age was equally correlated to the composition of the microbiota. These results indicate that larval development may structure the microbiota through a change in selection pressure due to host-microbe and microbe-microbe interactions, and that the composition of the microbiota may influence larval development through improved energy gain.

  1. Gender differences in health and aging of Atlantic cod subject to size selective fishery.

    Science.gov (United States)

    Carney Almroth, Bethanie; Sköld, Mattias; Nilsson Sköld, Helen

    2012-09-15

    We have analyzed health and physiological aging parameters in male and female Atlantic cod, Gadus morhua, captured in Kattegat, Skagerrak and in Öresund. Gender differences were clearly evident in a number of variables. Males had longer liver telomeres and higher catalase activities than females, while females had higher superoxide dismutase activity, liver somatic index and condition factor. Effects of age were found for males where levels of the antioxidant glutathione and telomere length declined with age, indicating physiological aging. Liver somatic index increased and percentage oxidized glutathione decreased with age. Between-site comparisons of males show that percentage oxidized glutathione and catalase were lowest in Kattegat, whereas protein carbonyls and condition factor were higher in Skagerrak. Females, on the other hand, showed no differences between sites or indications of somatic aging or age-related effects in egg quality, indicating that older and larger female cod are healthy and show no changes in eggs with age. In contrast, males showed indications of physiological aging and lower condition than females. The results emphasize the importance of conserving old mature fish, in particular high egg-productive females, when managing fisheries.

  2. Gender differences in health and aging of Atlantic cod subject to size selective fishery

    Directory of Open Access Journals (Sweden)

    Bethanie Carney Almroth

    2012-07-01

    We have analyzed health and physiological aging parameters in male and female Atlantic cod, Gadus morhua, captured in Kattegat, Skagerrak and in Öresund. Gender differences were clearly evident in a number of variables. Males had longer liver telomeres and higher catalase activities than females, while females had higher superoxide dismutase activity, liver somatic index and condition factor. Effects of age were found for males where levels of the antioxidant glutathione and telomere length declined with age, indicating physiological aging. Liver somatic index increased and percentage oxidized glutathione decreased with age. Between-site comparisons of males show that percentage oxidized glutathione and catalase were lowest in Kattegat, whereas protein carbonyls and condition factor were higher in Skagerrak. Females, on the other hand, showed no differences between sites or indications of somatic aging or age-related effects in egg quality, indicating that older and larger female cod are healthy and show no changes in eggs with age. In contrast, males showed indications of physiological aging and lower condition than females. The results emphasize the importance of conserving old mature fish, in particular high egg-productive females, when managing fisheries.

  3. First feed affects the expressions of microRNA and their targets in Atlantic cod.

    Science.gov (United States)

    Bizuayehu, Teshome Tilahun; Furmanek, Tomasz; Karlsen, Ørjan; van der Meeren, Terje; Edvardsen, Rolf Brudvik; Rønnestad, Ivar; Hamre, Kristin; Johansen, Steinar D; Babiak, Igor

    2016-04-14

    To our knowledge, there is no report on microRNA (miRNA) expression and their target analysis in relation to the type of the first feed and its effect on the further growth of fish. Atlantic cod (Gadus morhua) larvae have better growth and development performance when fed natural zooplankton as a start-feed, as compared with those fed typical aquaculture start-feeds. In our experiment, two groups of Atlantic cod larvae were fed reference feed (zooplankton, mostly copepods, filtered from a seawater pond) v. aquaculture feeds: enriched rotifers (Brachionus sp.) and later brine shrimp (Artemia salina). We examined the miRNA expressions of six defined developmental stages as determined and standardised by body length from first feeding for both diet groups. We found eight miRNA (miR-9, miR-19a, miR-130b, miR-146, miR-181a, miR-192, miR-206 and miR-11240) differentially expressed between the two feeding groups in at least one developmental stage. We verified the next-generation sequencing data using real-time RT-PCR. We found 397 putative targets (mRNA) to the differentially expressed miRNA; eighteen of these mRNA showed differential expression in at least one stage. The patterns of differentially expressed miRNA and their putative target mRNA were mostly inverse, but sometimes also concurrent. The predicted miRNA targets were involved in different pathways, including metabolic, phototransduction and signalling pathways. The results of this study provide new nutrigenomic information on the potential role of miRNA in mediating nutritional effects on growth during the start-feeding period in fish larvae.

  4. Influence of environmental changes in the north-western Atlantic Ocean on a parasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod ( Gadus morhua) occurring off coastal Labrador, Canada.

    Science.gov (United States)

    Khan, R A

    2008-09-01

    A study was conducted to determine the influence of environmental change on an endoparasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod (Gadus morhua) over a 30-year period off the coast of Labrador in the north-western Atlantic, North Atlantic Fisheries Organization subareas 2J-3K. Cod, once an abundant fish species that had been commercially exploited for many decades, declined precipitously during the mid-1980s onwards. This decline was attributed to climatic changes that affected the entire food chain from zooplankton to fish, sea birds and marine mammals. A monitoring programme was introduced, sampling cod by otter trawling using research vessels. The fish, after capture, were frozen at - 20 degrees C, subsequently thawed and the digestive tract removed and examined for the parasite in 2006. Data from samples taken in 1976, 1980-81, 1986, 1990, 2000 and 2003 were compared statistically with those collected in 2006. The results indicate a decline in the prevalence and mean abundance of E. gadi in 1986 with a minimum in 2000 but increasing gradually in 2003 and 2006. These changes were coincident initially with a decline of oceanic temperature and the entire food web, including capelin (Mallotus villosus), a preferred prey of cod and primary source of E. gadi. The increase in prevalence and mean abundance of the parasite in 2006 were associated with an increase of oceanic temperature and the return of small schools of capelin to offshore areas. Cod older than 4 years harboured a greater abundance of E. gadi than younger fish, while no difference was observed between the sexes. The results suggest that the abundance of E. gadi can be useful as a bioindicator of environmental changes in the north-western Atlantic.

  5. Multiple specialised goose-type lysozymes potentially compensate for an exceptional lack of chicken-type lysozymes in Atlantic cod.

    Science.gov (United States)

    Seppola, Marit; Bakkemo, Kathrine Ryvold; Mikkelsen, Helene; Myrnes, Bjørnar; Helland, Ronny; Irwin, David M; Nilsen, Inge W

    2016-06-21

    Previous analyses of the Atlantic cod genome showed unique combinations of lacking and expanded number of genes for the immune system. The present study examined lysozyme activity, lysozyme gene distribution and expression in cod. Enzymatic assays employing specific bacterial lysozyme inhibitors provided evidence for presence of g-type, but unexpectedly not for c-type lysozyme activity. Database homology searches failed to identify any c-type lysozyme gene in the cod genome or in expressed sequence tags from cod. In contrast, we identified four g-type lysozyme genes (LygF1a-d) constitutively expressed, although differentially, in all cod organs examined. The active site glutamate residue is replaced by alanine in LygF1a, thus making it enzymatic inactive, while LygF1d was found in two active site variants carrying alanine or glutamate, respectively. In vitro and in vivo infection by the intracellular bacterium Francisella noatunensis gave a significantly reduced LygF1a and b expression but increased expression of the LygF1c and d genes as did also the interferon gamma (IFNγ) cytokine. These results demonstrate a lack of c-type lysozyme that is unprecedented among vertebrates. Our results further indicate that serial gene duplications have produced multiple differentially regulated cod g-type lysozymes with specialised functions potentially compensating for the lack of c-type lysozymes.

  6. Sex steroids differentially regulate fshb, lhb and gnrhr expression in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    von Krogh, Kristine; Bjørndal, Gunnveig Toft; Nourizadeh-Lillabadi, Rasoul; Hodne, Kjetil; Ropstad, Erik; Haug, Trude M; Weltzien, Finn-Arne

    2017-11-01

    Depending on the stage of gonad maturation, as well as other factors, gonadal steroids can exert either a positive or negative feedback at the brain and pituitary level. While this has been demonstrated in many teleost species, little is known about the nature of steroid feedback in Gadiform fish. Using an optimized in vitro model system of the Atlantic cod pituitary, the present study investigated the potential effects of two physiologically relevant doses of estradiol, testosterone (TS) or dihydrotestosterone (DHTS) on cell viability and gene expression of gonadotropin subunits (fshb/lhb) and two suggested reproduction-relevant gonadotropin-releasing hormone receptors (gnrhr1b/gnrhr2a) during three stages of sexual maturity. In general, all steroids stimulated cell viability in terms of metabolic activity and membrane integrity. Furthermore, all steroids affected fshb expression, with the effect depending on both the specific steroid, dose and maturity status. Conversely, only DHTS exposure affected lhb levels, and this occurred only during the spawning season. Using single-cell qPCR, co-transcription of gnrhr1b and gnrhr2a was confirmed to both fshb- and lhb- expressing gonadotropes, with gnrhr2a being the most prominently expressed isoform. While steroid exposure had no effect on gnrhr1b expression, all steroids affected gnrhr2a transcript levels in at least one maturity stage. These and previous results from our group point to Gnrhr2a as the main modulator of gonadotropin regulation in cod and that regulation of its gene expression level might function as a direct mechanism for steroid feedback at the pituitary level. © 2017 Society for Reproduction and Fertility.

  7. Molecular ontogenesis of digestive capability and associated endocrine control in Atlantic cod (Gadus morhua) larvae.

    Science.gov (United States)

    Kortner, Trond M; Overrein, Ingrid; Oie, Gunvor; Kjørsvik, Elin; Bardal, Tora; Wold, Per-Arvid; Arukwe, Augustine

    2011-10-01

    We have profiled the expression of twelve genes, in order to provide an overview on the molecular ontogeny of digestive capability with the associated endocrine control during Atlantic cod (Gadus morhua) larval development. Enzyme activity levels for the key digestive enzyme, trypsin, was also measured. Specifically, transcripts for trypsin, amylase, lipolytic enzymes: bile salt activated lipase (BAL), phospholipase A2 (PLA2) and Acyl CoA dehydrogenase (ACADM), regulatory peptides: neuropeptide Y (NPY), orexin (OX) cholecystokinin (CCK) and cocaine and amphetamine-related transcript (CART), the somatotropic factors: growth hormone (GH), preprosomatostatin 1 (PPSS1) and thyroid hormone receptors (TRα and TRβ) were analyzed using quatitative (real-time) polymerase chain reaction (qPCR). Trypsin and BAL mRNA levels peaked at approximately day 17 and 25 post-hatch, respectively, and thereafter displayed a decreasing pattern until metamorphosis. GH mRNA levels decreased moderately from 3 to 33dph, and thereafter, an increase was observed until 46dph. TRα mRNA levels showed a fluctuating pattern peaking at day 39 post-hatch. TRβ mRNA levels were too low to obtain quantitative measurements. Amylase mRNA slightly increased from day 3 to 17 post-hatch, and thereafter showed a steady decrease until day 60. Interestingly, PLA2 mRNA expression showed a consistent increase throughout the study period, indicating an increasingly important role during larval development. Overall, data from this study indicate that cod larvae show differential developmental mode of expression patterns for key genes and endocrine factors that regulate digestive capability, growth and development. These data are discussed in relation to larval trypsin enzyme activity and previous reports for other teleost species. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Effects of sex, stock, and environment on the shape of known-age Atlantic cod ( Gadus morhua ) otoliths

    DEFF Research Database (Denmark)

    Cardinale, M.; Doering-Arjes, P.; Kastowsky, M.

    2004-01-01

    The effects of sex, stock, and environment on the shape of known-age Atlantic cod (Gadus morhua) otoliths from the Faroe Islands were investigated. Moreover, the feasibility of otolith shape analysis for stock identification was evaluated. The shape was described by using several normalized Fourier...... descriptors and morphometric variables. There were no consistent differences between the left and right otoliths and between sexes within different age classes, stocks, and environments. With our experimental design, we could evaluate the relative importance of genetic and environmental conditions (water....... The significant differences in otolith shape between Faroe Bank and Faroe Plateau cod stocks provided a phenotypic basis for stock separation. Stock and environmental influences were substantial in determining the shape of cod otoliths....

  9. Variation in embryonic mortality and maternal transcript expression among Atlantic cod (Gadus morhua) broodstock: a functional genomics study.

    Science.gov (United States)

    Rise, Matthew L; Nash, Gordon W; Hall, Jennifer R; Booman, Marije; Hori, Tiago S; Trippel, Edward A; Gamperl, A Kurt

    2014-12-01

    Early life stage mortality is an important issue for Atlantic cod aquaculture, yet the impact of the cod maternal (egg) transcriptome on egg quality and mortality during embryonic development is poorly understood. In the present work, we studied embryonic mortality and maternal transcript expression using eggs from 15 females. Total mortality at 7days post-fertilization (7 dpf, segmentation stage) was used as an indice of egg quality. A 20,000 probe (20K) microarray experiment compared the 7hours post-fertilization (7 hpf, ~2-cell stage) egg transcriptome of the two lowest quality females (>90% mortality at 7 dpf) to that of the highest quality female (~16% mortality at 7 dpf). Forty-three microarray probes were consistently differentially expressed in both low versus high quality egg comparisons (25 higher expressed in low quality eggs, and 18 higher expressed in high quality eggs). The microarray experiment also identified many immune-relevant genes [e.g. interferon (IFN) pathway genes ifngr1 and ifrd1)] that were highly expressed in eggs of all 3 females regardless of quality. Twelve of the 43 candidate egg quality-associated genes, and ifngr1, ifrd1 and irf7, were included in a qPCR study with 7 hpf eggs from all 15 females. Then, the genes that were confirmed by qPCR to be greater than 2-fold differentially expressed between 7 hpf eggs from the lowest and highest quality females (dcbld1, ddc, and acy3 more highly expressed in the 2 lowest quality females; kpna7 and hacd1 more highly expressed in the highest quality female), and the 3 IFN pathway genes, were included in a second qPCR study with unfertilized eggs. While some maternal transcripts included in these qPCR studies were associated with extremes in egg quality, there was little correlation between egg quality and gene expression when all females were considered. Both dcbld1 and ddc showed greater than 100-fold differences in transcript expression between females and were potentially influenced by

  10. Effects of ocean acidification increase embryonic sensitivity to thermal extremes in Atlantic cod, Gadus morhua.

    Science.gov (United States)

    Dahlke, Flemming T; Leo, Elettra; Mark, Felix C; Pörtner, Hans-Otto; Bickmeyer, Ulf; Frickenhaus, Stephan; Storch, Daniela

    2017-04-01

    Thermal tolerance windows serve as a powerful tool for estimating the vulnerability of marine species and their life stages to increasing temperature means and extremes. However, it remains uncertain to which extent additional drivers, such as ocean acidification, modify organismal responses to temperature. This study investigated the effects of CO 2 -driven ocean acidification on embryonic thermal sensitivity and performance in Atlantic cod, Gadus morhua, from the Kattegat. Fertilized eggs were exposed to factorial combinations of two PCO 2 conditions (400 μatm vs. 1100 μatm) and five temperature treatments (0, 3, 6, 9 and 12 °C), which allow identifying both lower and upper thermal tolerance thresholds. We quantified hatching success, oxygen consumption (MO 2 ) and mitochondrial functioning of embryos as well as larval morphometrics at hatch and the abundance of acid-base-relevant ionocytes on the yolk sac epithelium of newly hatched larvae. Hatching success was high under ambient spawning conditions (3-6 °C), but decreased towards both cold and warm temperature extremes. Elevated PCO 2 caused a significant decrease in hatching success, particularly at cold (3 and 0 °C) and warm (12 °C) temperatures. Warming imposed limitations to MO 2 and mitochondrial capacities. Elevated PCO 2 stimulated MO 2 at cold and intermediate temperatures, but exacerbated warming-induced constraints on MO 2 , indicating a synergistic interaction with temperature. Mitochondrial functioning was not affected by PCO 2 . Increased MO 2 in response to elevated PCO 2 was paralleled by reduced larval size at hatch. Finally, ionocyte abundance decreased with increasing temperature, but did not differ between PCO 2 treatments. Our results demonstrate increased thermal sensitivity of cod embryos under future PCO 2 conditions and suggest that acclimation to elevated PCO 2 requires reallocation of limited resources at the expense of embryonic growth. We conclude that ocean acidification

  11. Study of the plasma proteome of Atlantic cod (Gadus morhua): Effect of exposure to two PAHs and their corresponding diols.

    Science.gov (United States)

    Skogland Enerstvedt, Karianne; Sydnes, Magne O; Pampanin, Daniela M

    2017-09-01

    Occurrence of polycyclic aromatic hydrocarbon (PAH) contamination in the marine environment represents a risk to marine life and humans. In this study, plasma samples from Atlantic cod (Gadus morhua) were analysed by shotgun mass spectrometry to investigate the plasma proteome in response to exposure to single PAHs (naphthalene or chrysene) and their corresponding metabolites (dihydrodiols). In total, 369 proteins were identified and ranked according to their relative abundance. The levels of 12 proteins were found significantly altered in PAH exposed fish and are proposed as new biomarker candidates. Eleven proteins were upregulated, primarily immunoglobulin components, and one protein was downregulated (antifreeze protein type IV.) The uniformity of the upregulated proteins suggests a triggered immune response in the exposed fish. Overall, the results provide valuable knowledge for future studies of the Atlantic cod plasma proteome and generate grounds for establishing new plasma protein biomarkers for environmental monitoring of PAH related exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Effects of chronic produced water exposure on the expression of some immune-related genes of juvenile Atlantic cod

    Energy Technology Data Exchange (ETDEWEB)

    Perez Casanova, J.; Hamoutene, D.; Samuelson, S.; Burt, K.; King, T. [Fisheries and Oceans Canada, St. John' s, NL (Canada); Lee, K. [Fisheries and Oceans Canada, Dartmouth, NS (Canada)

    2010-07-01

    This study assessed the impacts of exposure to processed water produced by offshore oil operators on immune-related genes of juvenile Atlantic cod exposed to processed water for a period of 22 weeks. The study investigated the influence of processed water concentrations on growth parameters; food consumption; plasma cortisol; respiratory burst activity (RB); and mRNA expression. The study showed that the RB of circulating leukocytes was significantly elevated. Significant up-regulation of the mRNA expression of microglobulin, immunoglobulin light chain, and interleukins was observed in some fish. The down-regulation of the interferon stimulated gene was also observed. The study indicated that chronic exposure to significant amounts of processed water causes modulations of the immune system of juvenile Atlantic cod.

  13. Direct and social genetic parameters for growth and fin damage traits in Atlantic cod (Gadus morhua)

    Science.gov (United States)

    2014-01-01

    Background The aim of the study was to estimate genetic parameters for direct and social genetic effects (SGE) for growth and welfare traits in farmed Atlantic cod (Gadus morhua). A SGE refers to the effect of an individual’s genes on trait performance of its social partners. In total, 2100 individually tagged juveniles from 100 families at an average age of 222 days post-hatching were used. Each family was separated into three groups of seven fish, and were randomly assigned to 100 experimental tanks, together with fish from two other families. Body weight and length of the first, second and third dorsal fin and the caudal fin measured by digital image analysis were measured at the start of the experiment, after two weeks, and after six weeks. Fin erosion was scored subjectively after six weeks. Variance components estimated using a conventional animal model were compared to those of an animal model including a SGE. Results Heritabilities from the conventional animal model ranged from 0.24 to 0.34 for body weight and 0.05 to 0.80 for fin length. Heritabilities for fin erosion were highest for the first dorsal fin (0.83 ± 0.08, mean ± standard error) and lowest for the third dorsal fin (0.01 ± 0.04). No significant SGE were found for body weight, whereas SGE for fin lengths were significant after two and six weeks. Contributions to the total heritable variance were equal to 21.5% (6.1 ± 2.1) for the direct effect, 33.1% (9.4 ± 3.2) for the direct-social covariance, and 45.4% (12.9 ± 4.1) for the social variance for length of the first dorsal fin. For fin erosion, SGE were only significant for the second and third dorsal fin. Conclusions Including SGE for fin length and fin erosion in the animal model increased the estimated heritable variation. However, estimates of total heritable variances were inaccurate and a larger experiment is needed to accurately quantify total heritable variance. Despite this, our results demonstrate that

  14. Temperature during early development has long-term effects on microRNA expression in Atlantic cod.

    Science.gov (United States)

    Bizuayehu, Teshome Tilahun; Johansen, Steinar D; Puvanendran, Velmurugu; Toften, Hilde; Babiak, Igor

    2015-04-17

    Environmental temperature has serious implications in life cycle of aquatic ectotherms. Understanding the molecular mechanisms of temperature acclimation and adaptation of marine organisms is of the uttermost importance for ecology, fisheries, and aquaculture, as it allows modeling the effects of global warming on population dynamics. Regulatory molecules are major modulators of acclimation and adaptation; among them, microRNAs (miRNAs) are versatile and substantial contributors to regulatory networks of development and adaptive plasticity. However, their role in thermal plasticity is poorly known. We have asked whether the temperature and its shift during the early ontogeny (embryonic and larval development) affect the miRNA repertoire of Atlantic cod (Gadus morhua), and if thermal experience has long-term consequences in the miRNA profile. We characterized miRNA during different developmental stages and in juvenile tissues using next generation sequencing. We identified 389 putative miRNA precursor loci, 120 novel precursor miRNAs, and 281 mature miRNAs. Some miRNAs showed stage- or tissue-enriched expression and miRNAs, such as the miR-17 ~ 92 cluster, myomiRs (miR-206), neuromiRs (miR-9, miR-124), miR-130b, and miR-430 showed differential expression in different temperature regimes. Long-term effect of embryonic incubation temperature was revealed on expression of some miRNAs in juvenile pituitary (miR-449), gonad (miR-27c, miR-30c, and miR-200a), and liver (let-7 h, miR-7a, miR-22, miR-34c, miR-132a, miR-192, miR-221, miR-451, miR-2188, and miR-7550), but not in brain. Some of differentially expressed miRNAs in the liver were confirmed using LNA-based rt-qPCR. The effect of temperature on methylation status of selected miRNA promoter regions was mostly inconclusive. Temperature elevation by several degrees during embryonic and larval developmental stages significantly alters the miRNA profile, both short-term and long-term. Our results suggest that a further

  15. Experimental Challenge of Atlantic Cod (Gadus morhua) with a Brucella pinnipedialis Strain from Hooded Seal (Cystophora cristata).

    Science.gov (United States)

    Nymo, Ingebjørg Helena; Seppola, Marit; Al Dahouk, Sascha; Bakkemo, Kathrine Ryvold; Jiménez de Bagüés, María Pilar; Godfroid, Jacques; Larsen, Anett Kristin

    2016-01-01

    Pathology has not been observed in true seals infected with Brucella pinnipedialis. A lack of intracellular survival and multiplication of B. pinnipedialis in hooded seal (Cystophora cristata) macrophages in vitro indicates a lack of chronic infection in hooded seals. Both epidemiology and bacteriological patterns in the hooded seal point to a transient infection of environmental origin, possibly through the food chain. To analyse the potential role of fish in the transmission of B. pinnipedialis, Atlantic cod (Gadus morhua) were injected intraperitoneally with 7.5 x 107 bacteria of a hooded seal field isolate. Samples of blood, liver, spleen, muscle, heart, head kidney, female gonads and feces were collected on days 1, 7, 14 and 28 post infection to assess the bacterial load, and to determine the expression of immune genes and the specific antibody response. Challenged fish showed an extended period of bacteremia through day 14 and viable bacteria were observed in all organs sampled, except muscle, until day 28. Neither gross lesions nor mortality were recorded. Anti-Brucella antibodies were detected from day 14 onwards and the expression of hepcidin, cathelicidin, interleukin (IL)-1β, IL-10, and interferon (IFN)-γ genes were significantly increased in spleen at day 1 and 28. Primary mononuclear cells isolated from head kidneys of Atlantic cod were exposed to B. pinnipedialis reference (NCTC 12890) and hooded seal (17a-1) strain. Both bacterial strains invaded mononuclear cells and survived intracellularly without any major reduction in bacterial counts for at least 48 hours. Our study shows that the B. pinnipedialis strain isolated from hooded seal survives in Atlantic cod, and suggests that Atlantic cod could play a role in the transmission of B. pinnipedialis to hooded seals in the wild.

  16. Experimental Challenge of Atlantic Cod (Gadus morhua with a Brucella pinnipedialis Strain from Hooded Seal (Cystophora cristata.

    Directory of Open Access Journals (Sweden)

    Ingebjørg Helena Nymo

    Full Text Available Pathology has not been observed in true seals infected with Brucella pinnipedialis. A lack of intracellular survival and multiplication of B. pinnipedialis in hooded seal (Cystophora cristata macrophages in vitro indicates a lack of chronic infection in hooded seals. Both epidemiology and bacteriological patterns in the hooded seal point to a transient infection of environmental origin, possibly through the food chain. To analyse the potential role of fish in the transmission of B. pinnipedialis, Atlantic cod (Gadus morhua were injected intraperitoneally with 7.5 x 107 bacteria of a hooded seal field isolate. Samples of blood, liver, spleen, muscle, heart, head kidney, female gonads and feces were collected on days 1, 7, 14 and 28 post infection to assess the bacterial load, and to determine the expression of immune genes and the specific antibody response. Challenged fish showed an extended period of bacteremia through day 14 and viable bacteria were observed in all organs sampled, except muscle, until day 28. Neither gross lesions nor mortality were recorded. Anti-Brucella antibodies were detected from day 14 onwards and the expression of hepcidin, cathelicidin, interleukin (IL-1β, IL-10, and interferon (IFN-γ genes were significantly increased in spleen at day 1 and 28. Primary mononuclear cells isolated from head kidneys of Atlantic cod were exposed to B. pinnipedialis reference (NCTC 12890 and hooded seal (17a-1 strain. Both bacterial strains invaded mononuclear cells and survived intracellularly without any major reduction in bacterial counts for at least 48 hours. Our study shows that the B. pinnipedialis strain isolated from hooded seal survives in Atlantic cod, and suggests that Atlantic cod could play a role in the transmission of B. pinnipedialis to hooded seals in the wild.

  17. Circadian rhythmicity and photic plasticity of myosin gene transcription in fast skeletal muscle of Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Lazado, Carlo C; Nagasawa, Kazue; Babiak, Igor; Kumaratunga, Hiruni P S; Fernandes, Jorge M O

    2014-12-01

    The circadian rhythm is a fundamental adaptive mechanism to the daily environmental changes experienced by many organisms, including fish. Myosins constitute a large family of contractile proteins that are essential functional components of skeletal muscle. They are known to display thermal plasticity but the influence of light on myosin expression remains to be investigated in fish. In the present study, we have examined the circadian rhythmicity and photoperiodic plasticity of myosin gene transcription in Atlantic cod (Gadus morhua) fast skeletal muscle. In silico mining of the Atlantic cod genome resulted in the identification of 76 myosins representing different classes, many of which were hitherto uncharacterized. Among the 23 fast skeletal muscle myosin genes, myh_tc, myh_n1, myh_n4, myo18a_2, and myo18b_2 displayed circadian rhythmic expression and contained several circadian-related transcription factor binding sites (Creb, Mef2 and E-box motifs) within their putative promoter regions. Also, the circadian expression of these 5 myosins strongly correlated with the transcription pattern of clock genes in fast skeletal muscle. Under ex vivo conditions, myosin transcript levels lost their circadian rhythmicity. Nonetheless, different photoperiod regimes influenced the mRNA levels of myh_n4, myo18a_2 and myo18b_2 in fast skeletal muscle explants. Photoperiod manipulation in Atlantic cod juveniles revealed that continuous light significantly elevated mRNA levels of several myosins in fast skeletal muscle when compared to natural photoperiod. The daily rhythmicity observed in some fast skeletal muscle myosin genes suggests that they may be under circadian clock regulation. In addition, the influence of photoperiod on their expression implies that myosins may be involved in the photic plasticity of muscle growth observed in Atlantic cod. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Thermal stress alters expression of genes involved in one carbon and DNA methylation pathways in Atlantic cod embryos.

    Science.gov (United States)

    Skjærven, Kaja H; Hamre, Kristin; Penglase, Samuel; Finn, Roderick Nigel; Olsvik, Pål A

    2014-03-16

    One-carbon (1-C) metabolism is essential for normal embryonic development through its regulation of DNA methylation and cell proliferation. With consideration to the potential future anthropogenic oceanic warming, we studied the effects of both acute thermal stress and continuous thermal stress (10°C) during Atlantic cod embryo development on the expression levels of genes associated with the 1-C metabolism, including DNA methyltransferases. We conducted a phylogenetic analysis of vertebrate DNA methyltransferases to determine the number and similarity of DNMT found in Atlantic cod. This analysis revealed that Atlantic cod have one maintenance dnmt (dnmt1) and five de novo DNMTs (dnmt4, dnmt3, dnmt3b, dnmt3aa, dnmt3ab). Stage specific changes in expression levels occurred for all genes analyzed. The effect of acute thermal stress was evaluated during early development. Compared to controls these experiments showed significant alterations in expression levels of several genes, that in some instances were reversed at later stages of development. A significant effect of continuous thermal stress was found in gastrula embryos where lower mRNA expression levels of 1-C metabolism, de novo DNMTs and cell proliferation genes were detected. One exception was the maintenance DNMT, which was only sensitive to acute and not continuous thermal stress. DNA methylation status indicated that blastula embryos were hypomethylated compared to spermatozoa and late gastrula stages. In post-gastrula stage, however, continuous thermal stress resulted in a higher degree of DNA methylation compared to controls. These data reveal that the regulation of epigenetically important transcripts in the 1-C metabolism of Atlantic cod embryos is sensitive to thermal stress. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Integrative Approach for the Reliable Detection and Specific Identification of the Microsporidium Loma morhua in Atlantic Cod (Gadus morhua).

    Science.gov (United States)

    Frenette, Aaron P; Eydal, Matthías; Hansen, Haakon; Burt, Michael D B; Duffy, Michael S

    2017-01-01

    Microsporidia are fungal parasites that infect diverse invertebrate and vertebrate hosts. Finfish aquaculture supports epizootics due to high host density and the high biotic potential of these parasites. Reliable methods for parasite detection and identification are a necessary precursor to empirical assessment of strategies to mitigate the effects of these pathogens during aquaculture. We developed an integrative approach to detect and identify Loma morhua infecting Atlantic cod. We show that the spleen is more reliable than the commonly presumed gills as best organ for parasite detection in spite of substantial morphological plasticity in xenoma complexes. We developed rDNA primers with 100% sensitivity in detecting L. morhua and with utility in distinguishing some congeneric Loma species. ITS sequencing is necessary to distinguish L. morhua from other congeneric microsporidia due to intraspecific nucleotide variation. 64% of L. morhua ITS variants from Atlantic cod have a 9-nucleotide motif that distinguishes it from Loma spp. infecting non-Gadus hosts. The remaining 36% of ITS variants from Atlantic cod are distinguished from currently represented Loma spp., particularly those infecting Gadus hosts, based on a 14-nucleotide motif. This research approach is amenable to developing templates in support of reliable detection and identification of other microsporidian parasites in fishes. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

  20. Microevolution in time and space: SNP analysis of historical DNA reveals dynamic signatures of selection in Atlantic cod.

    Science.gov (United States)

    Therkildsen, Nina O; Hemmer-Hansen, Jakob; Als, Thomas D; Swain, Douglas P; Morgan, M Joanne; Trippel, Edward A; Palumbi, Stephen R; Meldrup, Dorte; Nielsen, Einar E

    2013-05-01

    Little is known about how quickly natural populations adapt to changes in their environment and how temporal and spatial variation in selection pressures interact to shape patterns of genetic diversity. We here address these issues with a series of genome scans in four overfished populations of Atlantic cod (Gadus morhua) studied over an 80-year period. Screening of >1000 gene-associated single-nucleotide polymorphisms (SNPs) identified 77 loci that showed highly elevated levels of differentiation, likely as an effect of directional selection, in either time, space or both. Exploratory analysis suggested that temporal allele frequency shifts at certain loci may correlate with local temperature variation and with life history changes suggested to be fisheries induced. Interestingly, however, largely nonoverlapping sets of loci were temporal outliers in the different populations and outliers from the 1928 to 1960 period showed almost complete stability during later decades. The contrasting microevolutionary trajectories among populations resulted in sequential shifts in spatial outliers, with no locus maintaining elevated spatial differentiation throughout the study period. Simulations of migration coupled with observations of temporally stable spatial structure at neutral loci suggest that population replacement or gene flow alone could not explain all the observed allele frequency variation. Thus, the genetic changes are likely to at least partly be driven by highly dynamic temporally and spatially varying selection. These findings have important implications for our understanding of local adaptation and evolutionary potential in high gene flow organisms and underscore the need to carefully consider all dimensions of biocomplexity for evolutionarily sustainable management. © 2013 Blackwell Publishing Ltd.

  1. Preferred temperature of juvenile Atlantic cod Gadus morhua with different haemoglobin genotypes at normoxia and moderate hypoxia

    DEFF Research Database (Denmark)

    Petersen, Maria Faldborg; Steffensen, John Fleng

    2003-01-01

    .2+/-1.5 degrees C while HbI-1 cod preferred 15.4+/-1.1 degrees C, and this preference was significant. The effect of hypoxia (35% oxygen saturation) on the preferred temperature was also measured. Previous studies showed that the preferred temperature of fish decreases during hypoxia, and this was the case for Hb......I-1 cod, which preferred 9.8+/-1.8 degrees C during hypoxia, whereas HbI-2 cod did not show this effect. The results indicate that environmental temperature changes will lead to a distributional change in the different haemoglobin types of Atlantic cod, global warming providing an advantage for HbI-1...... in northern regions, and the HbI(1) allele dominant in warmer areas. To determine if temperature is a selective parameter in the distribution of the haemoglobin types, the preferred temperature of the homozygous genotypes HbI-1 and HbI-2 was measured. We found that HbI-2 cod preferred a temperature of 8...

  2. Unraveling the evolution of the Atlantic cod's (Gadus morhua L. alternative immune strategy.

    Directory of Open Access Journals (Sweden)

    Martin Malmstrøm

    Full Text Available Genes encoding the major histocompatibility complex (MHC have been thought to play a vital role in the adaptive immune system in all vertebrates. The discovery that Atlantic cod (Gadus morhua has lost important components of the MHC II pathway, accompanied by an unusually high number of MHC I genes, shed new light on the evolution and plasticity of the immune system of teleosts as well as in higher vertebrates. The overall aim of this study was to further investigate the highly expanded repertoire of MHC I genes using a cDNA approach to obtain sequence information of both the binding domains and the sorting signaling potential in the cytoplasmic tail. Here we report a novel combination of two endosomal sorting motifs, one tyrosine-based associated with exogenous peptide presentation by cross-presenting MHCI molecules, and one dileucine-based associated with normal MHC II functionality. The two signal motifs were identified in the cytoplasmic tail in a subset of the genes. This indicates that these genes have evolved MHC II-like functionality, allowing a more versatile use of MHC I through cross-presentation. Such an alternative immune strategy may have arisen through adaptive radiation and acquisition of new gene function as a response to changes in the habitat of its ancestral lineage.

  3. Long-term stability and effective population size in North Sea and Baltic Sea cod ( Gadus morhua )

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Eg Nielsen, Einar; Schierup, M.H.

    2006-01-01

    for the Moray Firth population, while subtle but significant genetic changes over time were detected for the Bornholm Basin population. Estimates of the effective population size (N-e) generally exceeded 500 for both populations when employing a number of varieties of the temporal genetic method. However......, confidence intervals were very wide and N-e's most likely range in the thousands. There was no apparent loss of genetic variability and no evidence of a genetic bottleneck for either of the populations. Calculations of the expected levels of genetic variability under different scenarios of N-e showed...... that the number of alleles commonly reported at microsatellite loci in Atlantic cod is best explained by N-e's exceeding thousand. Recent fishery-induced bottlenecks can, however, not be ruled out as an explanation for the apparent discrepancy between high levels of variability and recently reported estimates...

  4. [Formation of genetic diversity in populations of Pacific cod (Gadus macrocephalus Tilesius) (Gadidae)].

    Science.gov (United States)

    Stroganov, A N

    2013-11-01

    The variability of the Gmo3, Gmo34, Gmo35, Pgmo32, Gmo19 microsatellite DNA loci was examined in the population samples of Pacific cod from different parts of the North Pacific. The statistical tests showed that the differentiation of the population was the result of different levels of reproductive autonomy of the individual Pacific cod populations, formed in the Pleistocene-Holocene period with the specific features of transgressions and regressions of the World Ocean, and supported by the existing system of currents and the features of the migratory behavior of cod in the North Pacific.

  5. Diversification of the expanded teleost-specific toll-like receptor family in Atlantic cod, Gadus morhua

    Directory of Open Access Journals (Sweden)

    Sundaram Arvind YM

    2012-12-01

    Full Text Available Abstract Background Toll-like receptors (Tlrs are major molecular pattern recognition receptors of the innate immune system. Atlantic cod (Gadus morhua is the first vertebrate known to have lost most of the mammalian Tlr orthologues, particularly all bacterial recognising and other cell surface Tlrs. On the other hand, its genome encodes a unique repertoire of teleost-specific Tlrs. The aim of this study was to investigate if these duplicate Tlrs have been retained through adaptive evolution to compensate for the lack of other cell surface Tlrs in the cod genome. Results In this study, one tlr21, 12 tlr22 and two tlr23 genes representing the teleost-specific Tlr family have been cloned and characterised in cod. Phylogenetic analysis grouped all tlr22 genes under a single clade, indicating that the multiple cod paralogues have arisen through lineage-specific duplications. All tlrs examined were transcribed in immune-related tissues as well as in stomach, gut and gonads of adult cod and were differentially expressed during early development. These tlrs were also differentially regulated following immune challenge by immersion with Vibrio anguillarum, indicating their role in the immune response. An increase in water temperature from 4 to 12°C was associated with a 5.5-fold down-regulation of tlr22d transcript levels in spleen. Maximum likelihood analysis with different evolution models revealed that tlr22 genes are under positive selection. A total of 24 codons were found to be positively selected, of which 19 are in the ligand binding region of ectodomain. Conclusion Positive selection pressure coupled with experimental evidence of differential expression strongly support the hypothesis that teleost-specific tlr paralogues in cod are undergoing neofunctionalisation and can recognise bacterial pathogen-associated molecular patterns to compensate for the lack of other cell surface Tlrs.

  6. The effect of temperature and body size on metabolic scope of activity in juvenile Atlantic cod Gadus morhua L.

    Science.gov (United States)

    Tirsgaard, Bjørn; Behrens, Jane W; Steffensen, John F

    2015-01-01

    Changes in ambient temperature affect the physiology and metabolism and thus the distribution of fish. In this study we used intermittent flow respirometry to determine the effect of temperature (2, 5, 10, 15 and 20°C) and wet body mass (BM) (~30-460g) on standard metabolic rate (SMR, mgO2h(-1)), maximum metabolic rate (MMR, mgO2h(-1)) and metabolic scope (MS, mgO2h(-1)) of juvenile Atlantic cod. SMR increased with BM irrespectively of temperature, resulting in an average scaling exponent of 0.87 (0.82-0.92). Q10 values were 1.8-2.1 at temperatures between 5 and 15°C but higher (2.6-4.3) between 2 and 5°C and lower (1.6-1.4) between 15 and 20°C in 200 and 450g cod. MMR increased with temperature in the smallest cod (50g) but in the larger cod MMR plateaued between 10, 15 and 20°C. This resulted in a negative correlation between the optimal temperature for MS (Topt) and BM, Topt being respectively 14.5, 11.8 and 10.9°C in a 50, 200 and 450g cod. Irrespective of BM cold water temperatures resulted in a reduction (30-35%) of MS whereas the reduction of MS at warm temperatures was only evident for larger fish (200 and 450g), caused by plateauing of MMR at 10°C and above. Warm temperatures thus seem favourable for smaller (50g) juvenile cod, but not for larger conspecifics (200 and 450g). Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Diversification of the expanded teleost-specific toll-like receptor family in Atlantic cod, Gadus morhua

    Science.gov (United States)

    2012-01-01

    Background Toll-like receptors (Tlrs) are major molecular pattern recognition receptors of the innate immune system. Atlantic cod (Gadus morhua) is the first vertebrate known to have lost most of the mammalian Tlr orthologues, particularly all bacterial recognising and other cell surface Tlrs. On the other hand, its genome encodes a unique repertoire of teleost-specific Tlrs. The aim of this study was to investigate if these duplicate Tlrs have been retained through adaptive evolution to compensate for the lack of other cell surface Tlrs in the cod genome. Results In this study, one tlr21, 12 tlr22 and two tlr23 genes representing the teleost-specific Tlr family have been cloned and characterised in cod. Phylogenetic analysis grouped all tlr22 genes under a single clade, indicating that the multiple cod paralogues have arisen through lineage-specific duplications. All tlrs examined were transcribed in immune-related tissues as well as in stomach, gut and gonads of adult cod and were differentially expressed during early development. These tlrs were also differentially regulated following immune challenge by immersion with Vibrio anguillarum, indicating their role in the immune response. An increase in water temperature from 4 to 12°C was associated with a 5.5-fold down-regulation of tlr22d transcript levels in spleen. Maximum likelihood analysis with different evolution models revealed that tlr22 genes are under positive selection. A total of 24 codons were found to be positively selected, of which 19 are in the ligand binding region of ectodomain. Conclusion Positive selection pressure coupled with experimental evidence of differential expression strongly support the hypothesis that teleost-specific tlr paralogues in cod are undergoing neofunctionalisation and can recognise bacterial pathogen-associated molecular patterns to compensate for the lack of other cell surface Tlrs. PMID:23273344

  8. Changes in natural mortality of Atlantic cod ( Gadus morhua) on Eastern Georges Bank

    Science.gov (United States)

    Wang, Yanjun

    2016-10-01

    The assessment of Eastern Georges Bank cod with the assumption of a constant natural mortality of 0.2 has over-estimated stock productivity, resulting in a severe retrospective pattern since the late 2000s. Comparing relative exploitation rate (ratio of fishery catch at age to survey abundance indices at age) with total mortality calculated from the age distribution in surveys indicated a conflict when constant natural mortality was assumed. This inconsistency implies an increase in natural mortality since the mid-1990s. In this paper, natural mortality estimated by Virtual Population Analysis (VPA) indicated that natural mortality for this stock has increased to 0.8 since the mid-1990s for ages 6+. Potential factors contributing to this elevated natural mortality, including poor fish conditions and increased losses due to seal predation were discussed.

  9. Global transcriptome analysis identifies regulated transcripts and pathways activated during oogenesis and early embryogenesis in Atlantic cod.

    Science.gov (United States)

    Kleppe, Lene; Edvardsen, Rolf Brudvik; Furmanek, Tomasz; Taranger, Geir Lasse; Wargelius, Anna

    2014-07-01

    The molecular mechanisms underlying oogenesis and maternally controlled embryogenesis in fish are not fully understood, especially in marine species. Our aim was to study the egg and embryo transcriptome during oogenesis and early embryogenesis in Atlantic cod. Follicles from oogenesis stages (pre-, early-, and late-vitellogenic), ovulated eggs, and two embryonic stages (blastula, gastrula) were collected from broodstock fish and fertilized eggs. Gene expression profiles were measured in a 44 K oligo microarray consisting of 23,000 cod genes. Hundreds of differentially expressed genes (DEGs) were identified in the follicle stages investigated, implicating a continuous accumulation and degradation of polyadenylated transcripts throughout oogenesis. Very few DEGs were identified from ovulated egg to blastula, showing a more stable maternal RNA pool in early embryonic stages. The highest induction of expression was observed between blastula and gastrula, signifying the onset of zygotic transcription. During early vitellogenesis, several of the most upregulated genes are linked to nervous system signaling, suggesting increasing requirements for ovarian synaptic signaling to stimulate the rapid growth of oocytes. Highly upregulated genes during late vitellogenesis are linked to protein processing, fat metabolism, osmoregulation, and arrested meiosis. One of the genes with the highest upregulation in the ovulated egg is involved in oxidative phosphorylation, reflecting increased energy requirements during fertilization and the first rapid cell divisions of early embryogenesis. In conclusion, this study provides a large-scale presentation of the Atlantic cod's maternally controlled transcriptome in ovarian follicles through oogenesis, ovulated eggs, and early embryos. Published 2014 Wiley Periodicals, Inc.

  10. Differentially expressed proteins in the skin mucus of Atlantic cod (Gadus morhua) upon natural infection with Vibrio anguillarum

    Science.gov (United States)

    2013-01-01

    Background Vibriosis caused by V. anguillarum is a commonly encountered disease in Atlantic cod farms and several studies indicate that the initiation of infection occurs after the attachment of the pathogen to the mucosal surfaces (gut, skin and gills) of fish. Therefore it is necessary to investigate the role of different mucosal components in fish upon V. anguillarum infection. The present study has two parts; in the first part we analyzed the differential expression of skin mucus proteins from Atlantic cod naturally infected with V. anguillarum using two dimensional gel electrophoresis coupled with mass spectrometry. In the second part, a separate bath challenge experiment with V. anguillarum was conducted to assess the mRNA levels of the genes in skin tissue, corresponding to the selected proteins identified in the first part. Results Comparative proteome analysis of skin mucus of cod upon natural infection with V. anguillarum revealed key immune relevant proteins like calpain small subunit 1, glutathione-S-transferase omega 1, proteasome 26S subunit, 14-kDa apolipoprotein, beta 2-tubulin, cold inducible RNA binding protein, malate dehydrogenase 2 (mitochondrial) and type II keratin that exhibited significant differential expression. Additionally a number of protein spots which showed large variability amongst individual fish were also identified. Some of the proteins identified were mapped to the immunologically relevant JNK (c-Jun N-terminal kinases) signalling pathway that is connected to cellular events associated with pathogenesis. A bath challenge experiment with V. anguillarum showed differential expression of beta 2-tubulin, calpain small subunit 1, cold inducible RNA binding protein, flotillin1, and glutathione S-transferase omega 1 transcripts in the skin tissue of cod during early stages of infection. Conclusions Differentially expressed proteins identified in the cod skin mucus point towards their possible involvement in V. anguillarum pathogenesis

  11. Differentially expressed proteins in the skin mucus of Atlantic cod (Gadus morhua) upon natural infection with Vibrio anguillarum.

    Science.gov (United States)

    Rajan, Binoy; Lokesh, Jep; Kiron, Viswanath; Brinchmann, Monica F

    2013-05-14

    Vibriosis caused by V. anguillarum is a commonly encountered disease in Atlantic cod farms and several studies indicate that the initiation of infection occurs after the attachment of the pathogen to the mucosal surfaces (gut, skin and gills) of fish. Therefore it is necessary to investigate the role of different mucosal components in fish upon V. anguillarum infection. The present study has two parts; in the first part we analyzed the differential expression of skin mucus proteins from Atlantic cod naturally infected with V. anguillarum using two dimensional gel electrophoresis coupled with mass spectrometry. In the second part, a separate bath challenge experiment with V. anguillarum was conducted to assess the mRNA levels of the genes in skin tissue, corresponding to the selected proteins identified in the first part. Comparative proteome analysis of skin mucus of cod upon natural infection with V. anguillarum revealed key immune relevant proteins like calpain small subunit 1, glutathione-S-transferase omega 1, proteasome 26S subunit, 14-kDa apolipoprotein, beta 2-tubulin, cold inducible RNA binding protein, malate dehydrogenase 2 (mitochondrial) and type II keratin that exhibited significant differential expression. Additionally a number of protein spots which showed large variability amongst individual fish were also identified. Some of the proteins identified were mapped to the immunologically relevant JNK (c-Jun N-terminal kinases) signalling pathway that is connected to cellular events associated with pathogenesis. A bath challenge experiment with V. anguillarum showed differential expression of beta 2-tubulin, calpain small subunit 1, cold inducible RNA binding protein, flotillin1, and glutathione S-transferase omega 1 transcripts in the skin tissue of cod during early stages of infection. Differentially expressed proteins identified in the cod skin mucus point towards their possible involvement in V. anguillarum pathogenesis. The role of some of these

  12. The impact of a moderate chronic temperature increase on spleen immune-relevant gene transcription depends on whether Atlantic cod (Gadus morhua) are stimulated with bacterial versus viral antigens.

    Science.gov (United States)

    Hori, Tiago S; Gamperl, A Kurt; Nash, Gord; Booman, Marije; Barat, Ashoktaru; Rise, Matthew L

    2013-10-01

    Exposure to elevated temperature is an inherent feature of Atlantic cod (Gadus morhua) sea-cage culture in some regions (e.g., Newfoundland) and may also become an increasingly prevalent challenge for wild fish populations because of accelerated climate change. Therefore, understanding how elevated temperatures impacts the immune response of this commercially important species may help to reduce the potential negative impacts of such challenges. Previously, we investigated the impacts of moderately elevated temperature on the antiviral responses of Atlantic cod (Hori et al. 2012) and reported that elevated temperature modulated the spleen transcriptome response to polyriboinosinic polyribocytidylic acid (pIC, a viral mimic). Herein, we report a complementary microarray study that investigated the impact of the same elevated temperature regime on the Atlantic cod spleen transcriptome response to intraperitoneal (IP) injection of formalin-killed Aeromonas salmonicida (ASAL). Fish were held at two different temperatures (10 °C and 16 °C) prior to immune stimulation and sampled 6 and 24 h post-injection (HPI). In this experiment, we identified 711 and 666 nonredundant ASAL-responsive genes at 6HPI and 24HPI, respectively. These included several known antibacterial genes, including hepcidin, cathelicidin, ferritin heavy subunit, and interleukin 8. However, we only identified 15 differentially expressed genes at 6HPI and 2 at 24HPI (FDR 1%) when comparing ASAL-injected fish held at 10 °C versus 16 °C. In contrast, the same comparisons with pIC-injected fish yielded 290 and 339 differentially expressed genes (FDR 1%) at 6HPI and 24HPI, respectively. These results suggest that moderately elevated temperature has a lesser effect on the Atlantic cod spleen transcriptome response to ASAL (i.e., the antibacterial response) than to pIC (i.e., antiviral response). Thus, the impacts of high temperatures on the cod's immune response may be pathogen dependent.

  13. Monitoring contaminants from oil production at sea by measuring gill EROD activity in Atlantic cod (Gadus morhua)

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamson, Alexandra [Uppsala University, Department of Environmental Toxicology, Norbyvaegen 18A, SE-752 36 Uppsala (Sweden)], E-mail: alexandra.abrahamson@ebc.uu.se; Brandt, Ingvar [Uppsala University, Department of Environmental Toxicology, Norbyvaegen 18A, SE-752 36 Uppsala (Sweden)], E-mail: ingvar.brandt@ebc.uu.se; Brunstroem, Bjoern [Uppsala University, Department of Environmental Toxicology, Norbyvaegen 18A, SE-752 36 Uppsala (Sweden)], E-mail: bjorn.brunstrom@ebc.uu.se; Sundt, Rolf C. [International Research Institute of Stavanger (IRIS), Akvamiljo, P.O. Box 8046, N-4068 Stavanger (Norway)], E-mail: rolf.sundt@irisresearch.no; Jorgensen, Even H. [Norwegian College of Fishery Science, University of Tromso, N-9037 Tromso (Norway); Norwegian Institute for Nature Research, Polar Environmental Centre, N-9296 Tromso (Norway)], E-mail: even.jorgensen@nfh.uit.no

    2008-05-15

    An ex vivo gill EROD assay was applied in Atlantic cod (Gadus morhua) as a biomarker for waterborne CYP1A-inducing compounds derived from oil production at sea. Exposure to nominal concentrations of 1 ppm or 10 ppm North Sea crude oil in a static water system for 24 h caused a concentration-dependent gill EROD induction. Further, exposure of cod for 14 days to environmentally relevant concentrations of produced water (PW, diluted 1:200 or 1:1000) from a platform in the North Sea using a flow-through system resulted in a concentration-dependent induction of gill EROD. Crude oil (0.2 ppm) from the same oil field also proved to induce EROD. Finally, gill EROD activity in cod caged for 6 weeks at 500-10 000 m from two platforms outside Norway was measured. The activities in these fish were very low and did not differ from those in fish caged at reference sites. - Gill EROD activity is a sensitive biomarker for CYP1A-inducing pollutants in cod.

  14. Genotype by Environment Interaction for Growth in Atlantic Cod (Gadus morhua L. in Four Farms of Norway

    Directory of Open Access Journals (Sweden)

    Rama Bangera

    2015-06-01

    Full Text Available We studied genotype by environment interaction (G × E for body weight (BW of Atlantic cod (Gadus morhua L. from the National cod breeding program in Norway. Records of 13,811 fish in a nucleus farm (NUC and two test farms (PENorth, PESouth in year-class (YC 2007, and for 9149 fish in NUC and one test farm in YC 2010 were available. Heterogeneity of variances and heritabilities ( were estimated using a univariate animal model with environmental effects common to full-sibs (full-model. Genetic correlations ( between farms were estimated using a multivariate full-model and a reduced-model (without for each YC. Heterogeneity of  was observed in both YC 2007 (0.10 to 0.16 and YC 2010 (0.08 to 0.26. The estimates of  between NUC and test farms were relatively high for both models (0.81 ± 0.19 to 0.96 ± 0.17 and (0.81 ± 0.08 to 0.86 ± 0.04, suggesting low re-ranking of genotypes. Strong re-ranking of genotypes between PESouth and PENorth may be less important because most cod producers are situated close to the breeding nucleus. In conclusion, G × E between NUC and test farms were low and at present there is no need for separate breeding programs for BW in cod.

  15. Temperature Modulates the Effects of Ocean Acidification on Intestinal Ion Transport in Atlantic Cod, Gadus morhua.

    Science.gov (United States)

    Hu, Marian Y; Michael, Katharina; Kreiss, Cornelia M; Stumpp, Meike; Dupont, Sam; Tseng, Yung-Che; Lucassen, Magnus

    2016-01-01

    CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid-base regulatory machinery of Atlantic cod (Gadus morhua) and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for 4 weeks to three CO2 levels (550, 1200, and 2200 μatm) covering present and near-future natural variability, at optimum (10°C) and summer maximum temperature (18°C), respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na(+)/K(+)-ATPase (NKA), Na(+)/H(+)-exchanger 3 (NHE3), Na(+)/[Formula: see text] cotransporter (NBC1), pendrin-like Cl(-)/[Formula: see text] exchanger (SLC26a6), V-type H(+)-ATPase subunit a (VHA), and Cl(-) channel 3 (CLC3) in epithelial cells of the anterior intestine. At 10°C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal [Formula: see text] secretion rates in response to CO2 induced seawater acidification. At 18°C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood [Formula: see text] levels to stabilize pHe, but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans.

  16. Temperature modulates the effects of ocean acidification on intestinal ion transport in Atlantic cod, Gadus morhua

    Directory of Open Access Journals (Sweden)

    Marian Yong-An Hu

    2016-06-01

    Full Text Available CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid–base regulatory machinery of Atlantic cod (Gadus morhua and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for four weeks to three CO2 levels (550, 1,200 and 2,200 μatm covering present and near-future natural variability, at optimum (10°C and summer maximum temperature (18°C, respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na+/K+-ATPase (NKA, Na+/H+-exchanger 3 (NHE3, Na+/HCO3- cotransporter (NBC1, pendrin-like Cl-/HCO3- exchanger (SLC26a6, V-type H+-ATPase subunit a (VHA and Cl- channel 3 (CLC3 in epithelial cells of the anterior intestine. At 10°C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal HCO3- secretion rates in response to CO2 induced seawater acidification. At 18°C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood HCO3- levels to stabilize pHe, but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans.

  17. Temperature Modulates the Effects of Ocean Acidification on Intestinal Ion Transport in Atlantic Cod, Gadus morhua

    Science.gov (United States)

    Hu, Marian Y.; Michael, Katharina; Kreiss, Cornelia M.; Stumpp, Meike; Dupont, Sam; Tseng, Yung-Che; Lucassen, Magnus

    2016-01-01

    CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid–base regulatory machinery of Atlantic cod (Gadus morhua) and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for 4 weeks to three CO2 levels (550, 1200, and 2200 μatm) covering present and near-future natural variability, at optimum (10°C) and summer maximum temperature (18°C), respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na+/K+-ATPase (NKA), Na+/H+-exchanger 3 (NHE3), Na+/HCO3− cotransporter (NBC1), pendrin-like Cl−/HCO3− exchanger (SLC26a6), V-type H+-ATPase subunit a (VHA), and Cl− channel 3 (CLC3) in epithelial cells of the anterior intestine. At 10°C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal HCO3− secretion rates in response to CO2 induced seawater acidification. At 18°C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood HCO3− levels to stabilize pHe, but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans. PMID:27313538

  18. Proteome changes in Atlantic cod (Gadus morhua) exposed to oil and produced water: Discovery of biomarker candidates for environmental monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kjersem, Anneli B

    2007-07-15

    Proteomics were applied to identify changes in the proteome of Atlantic cod (Gadus morhua) exposed to crude North Sea oil and North Sea produced water at different life stages and during early development. Apparent protein changes were identified and linked to possible signalling pathways and mechanisms involved in the biological response of fish following exposure. Exposure to North Sea crude oil and produced water appeared to induce a large number of changes, also at low levels of exposure. More than 40 of the 137 protein changes detected in plasma of juvenile cod following exposed to crude oil and surrogate produced water appeared at the lowest level of exposure, 0.06 ppm crude oil. Almost all of the protein changes detected in whole fry and fry liver following produced water exposure occurred at the lowest levels of produced water, 0.01% and 0.1% produced water

  19. Population structure of Atlantic Mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis; Gislason, Henrik

    2013-01-01

    model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic...

  20. Skeletal muscle growth dynamics and the influence of first-feeding diet in Atlantic cod larvae (Gadus morhua L.).

    Science.gov (United States)

    Vo, Tu A; Galloway, Trina F; Bardal, Tora; Halseth, Christine K; Øie, Gunvor; Kjørsvik, Elin

    2016-11-15

    Dynamics between hypertrophy (increase in cell size) and hyperplasia (increase in cell numbers) of white and red muscle in relation to body size [standard length (SL)], and the influence of the first-feeding diets on muscle growth were investigated in Atlantic cod larvae (Gadus morhua). Cod larvae were fed copepod nauplii or rotifers of different nutritional qualities from 4 to 29 days post hatching (dph), Artemia nauplii from 20 to 40 dph and a formulated diet from 36 to 60 dph. The short period of feeding with cultivated copepod nauplii had a positive effect on both muscle hyperplasia and hypertrophy after the copepod/rotifer phase (19 dph), and a positive long term effect on muscle hypertrophy (60 dph). The different nutritional qualities of rotifers did not significantly affect muscle growth. We suggest here a model of the dynamics between hyperplasia and hypertrophy of red and white muscle fibre cells in relation to cod SL (4 to 30 mm), where the different red and white muscle growth phases clearly coincided with different metamorphosis stages in cod larvae. These shifts could be included as biomarkers for the different stages of development during metamorphosis. The main dietary muscle effect was that hypertrophic growth of red muscle fibres was stronger in cod larvae that were fed copepods than in larvae that were fed rotifers, both in relation to larval age and size. Red muscle fibres are directly involved in larval locomotory performance, but may also play an important role in the larval myogenesis. This can have a long term effect on growth potential and fish performance. © 2016. Published by The Company of Biologists Ltd.

  1. Skeletal muscle growth dynamics and the influence of first-feeding diet in Atlantic cod larvae (Gadus morhua L.

    Directory of Open Access Journals (Sweden)

    Tu A. Vo

    2016-11-01

    Full Text Available Dynamics between hypertrophy (increase in cell size and hyperplasia (increase in cell numbers of white and red muscle in relation to body size [standard length (SL], and the influence of the first-feeding diets on muscle growth were investigated in Atlantic cod larvae (Gadus morhua. Cod larvae were fed copepod nauplii or rotifers of different nutritional qualities from 4 to 29 days post hatching (dph, Artemia nauplii from 20 to 40 dph and a formulated diet from 36 to 60 dph. The short period of feeding with cultivated copepod nauplii had a positive effect on both muscle hyperplasia and hypertrophy after the copepod/rotifer phase (19 dph, and a positive long term effect on muscle hypertrophy (60 dph. The different nutritional qualities of rotifers did not significantly affect muscle growth. We suggest here a model of the dynamics between hyperplasia and hypertrophy of red and white muscle fibre cells in relation to cod SL (4 to 30 mm, where the different red and white muscle growth phases clearly coincided with different metamorphosis stages in cod larvae. These shifts could be included as biomarkers for the different stages of development during metamorphosis. The main dietary muscle effect was that hypertrophic growth of red muscle fibres was stronger in cod larvae that were fed copepods than in larvae that were fed rotifers, both in relation to larval age and size. Red muscle fibres are directly involved in larval locomotory performance, but may also play an important role in the larval myogenesis. This can have a long term effect on growth potential and fish performance.

  2. Plasma FITC-dextran exchange between the primary and secondary circulatory systems in the Atlantic cod, Gadus Morhua

    DEFF Research Database (Denmark)

    Fischer, Claes; Steffensen, John Fleng

    2008-01-01

    Fluorescein isothiocyanate dextran (FITC-dextran) exchange between the primary (PCS) and secondary (SCS) circulatory systems in the Atlantic cod, Gadus morhua (Linnaeus, 1752), were studied using 20-kDa (n = 4) and 500-kDa (n = 4) FITC-dextran. In order to give a qualitative perspective...... of the injected 500-kDa FITC-dextran was also examined, and it was observed that of the 500-kDa FITC-dextran lost from the primary and secondary vascular systems, 63.0 +/- 9.2% could be recovered from the liver....

  3. Maturation Trends Suggestive of Rapid Evolution Preceded the Collapse of Northern Cod

    OpenAIRE

    Olsen, E.M.; Heino, M.; Lilly, G.R.; Morgan, M J; Brattey, J.; Ernande, B.; Dieckmann, U.

    2004-01-01

    Northern cod, comprising populations of Atlantic cod (Gadus morhua) off southern Labrador and eastern Newfoundland, supported major fisheries for hundreds of years. But in the late 1980s and early 1990s, northern cod underwent one of the worst collapses in the history of fisheries. The Canadian government closed the directed fishing for northern cod in July 1992, but even after a decade-long offshore moratorium, population sizes remain historically low. Here we show that, up until the morator...

  4. Back-calculated fish lengths and Hg and Zn levels from recent and 100-yr-old cleithrum bones from Atlantic Cod (Gadus morhua)

    Energy Technology Data Exchange (ETDEWEB)

    Scott, J.S.

    1977-01-01

    Dimensions of cleithrum bones from recently caught Atlantic cod (Gadus morhua) were measured and plotted against observed fish lengths to back-calculate cod lengths from cleithra from a ship wrecked in 1865. Mercury levels in the historical bones were approximately the same as those in recent material and showed no increase with fish length, but zinc levels appear to have increased since 1865 and increased with fish length.

  5. Historical changes in genotypic frequencies at the Pantophysin locus in Atlantic cod (Gadus morhua) in Icelandic waters: evidence of fisheries-induced selection?

    OpenAIRE

    Jakobsdóttir, Klara B; Pardoe, Heidi; Magnússon, Árni; Björnsson, Höskuldur; Pampoulie, Christophe; Ruzzante, Daniel E.; Marteinsdóttir, Guðrún

    2011-01-01

    The intense fishing mortality imposed on Atlantic cod in Icelandic waters during recent decades has resulted in marked changes in stock abundance, as well as in age and size composition. Using a molecular marker known to be under selection (Pan I) along with a suite of six neutral microsatellite loci, we analysed an archived data set and revealed evidence of distinct temporal changes in the frequencies of genotypes at the Pan I locus among spawning Icelandic cod, collected between 1948 and 20...

  6. Identification of an albumin-like protein in plasma of Atlantic cod (Gadus morhua and its biomarker potential for PAH contamination

    Directory of Open Access Journals (Sweden)

    Karianne Skogland Enerstvedt

    2017-08-01

    Full Text Available Increased research efforts are currently focusing on Atlantic cod (Gadus morhua and its significance for monitoring the contaminant situation in marine environments. Polycyclic aromatic hydrocarbons (PAHs are well known toxic and carcinogenic compounds, thus continuous monitoring is required to ensure ecosystem sustainability and human food safety. A sensitive biomarker of PAH exposure in humans is the detection of PAH metabolites bound to albumin in blood. The potential of a similar PAH-albumin biomarker in Atlantic cod was therefore investigated by a desktop bioinformatic study followed by liquid chromatography mass spectrometry/mass spectrometry analysis of plasma from 16 fish. For the first time, an albumin-like protein in plasma of Atlantic cod is described, and the biomarker potential based on PAH-albumin adduct detection is discussed. Due to the detected low abundance of the albumin-like protein, it was found unlikely to be applicable as a new biomarker tool for evaluation of PAH exposure.

  7. Identification of an albumin-like protein in plasma of Atlantic cod (Gadus morhua) and its biomarker potential for PAH contamination.

    Science.gov (United States)

    Enerstvedt, Karianne Skogland; Sydnes, Magne O; Pampanin, Daniela M

    2017-08-01

    Increased research efforts are currently focusing on Atlantic cod (Gadus morhua) and its significance for monitoring the contaminant situation in marine environments. Polycyclic aromatic hydrocarbons (PAHs) are well known toxic and carcinogenic compounds, thus continuous monitoring is required to ensure ecosystem sustainability and human food safety. A sensitive biomarker of PAH exposure in humans is the detection of PAH metabolites bound to albumin in blood. The potential of a similar PAH-albumin biomarker in Atlantic cod was therefore investigated by a desktop bioinformatic study followed by liquid chromatography mass spectrometry/mass spectrometry analysis of plasma from 16 fish. For the first time, an albumin-like protein in plasma of Atlantic cod is described, and the biomarker potential based on PAH-albumin adduct detection is discussed. Due to the detected low abundance of the albumin-like protein, it was found unlikely to be applicable as a new biomarker tool for evaluation of PAH exposure.

  8. Identification and molecular cloning of Atlantic cod (Gadus morhua) activating transcription factor 3 (ATF3) transcript and its induction in spleen following intraperitoneal polyriboinosinic polyribocytidylic acid injection.

    Science.gov (United States)

    Feng, Charles Y; Rise, Matthew L

    2011-09-01

    Activating transcription factor 3 (ATF3) participates in cellular processes to adapt to various extra- and intra-cellular changes including the modulation of immunity to prevent uncontrolled immune responses to pathogens. In teleost fishes, the involvement of ATF3 in immune response has not been documented. In this study, the putative Atlantic cod (Gadus morhua) ATF3 transcript was identified by performing rapid amplification of cDNA ends (RACE) based on unknown expressed sequence tags (ESTs) that are potentially inducible by polyriboinosinic polyribocytidylic acid (pIC, a synthetic double-stranded RNA viral mimic) in Atlantic cod. ATF3-like ESTs were the most abundant unknown transcript (i.e. lacking significant BLAST hits) generated from a previously constructed cDNA library enriched for pIC inducible transcripts in Atlantic cod spleen. The full-length cDNA of cod ATF3 consists of 2329 nucleotides with an open reading frame (ORF) of 735 bp encoding 244 amino acids. The deduced amino acid sequence of Atlantic cod ATF3 shares over 45% identity with its putative orthologs from other vertebrates. In addition, the presence of a conserved basic region leucine zipper (bZIP) domain in the deduced Atlantic cod ATF3-like protein further supports its identity as an ATF3 homolog. In the spleen of Atlantic cod challenged with intraperitoneal (IP) injections of pIC, the time-course transcript expression of ATF3 was studied using quantitative reverse transcription-polymerase chain reaction (QPCR). At 6 h following the pIC injection, the relative expression level of ATF3 mRNA was significantly up-regulated in comparison to a pre-injected control (61.9-fold) and its time-matched saline-injected control (97.3-fold). At 24 h following the pIC injection, the mRNA expression level of cod ATF3 had subsided and was no longer significantly different from its pre-injected control, but significantly higher (1.88-fold) than its time-matched saline-injected control. Collectively, these

  9. Dive to survive: effects of capture depth on barotraumaand post-release survival of Atlantic cod (Gadus morhua)in recreational fisheries

    OpenAIRE

    Ferter, Keno; Weltersbach, Marc Simon; Humborstad, Odd Børre; Fjelldal, Per Gunnar; Sambraus, Florian; Strehlow, Harry Vincent; Vølstad, Jon Helge

    2015-01-01

    - Atlantic cod (Gadus morhua) caught in recreational fisheries are commonly released, often with barotrauma after rapid decompression. Mouth-hooked, non-bleeding cod kept in a floating net pen showed mortalities ≥40% when angled from >50 m depth, likely because of cumulative stress from ongoing barotrauma and exposure to warm surface water. In a natural setting, however, cod have the opportunity to descend after release and are not restricted to the surface. In a follow-up study, 97.8% of ...

  10. Dive to survive: effects of capture depth on barotrauma and post-release survival of Atlantic cod (Gadus morhua) in recreational fisheries

    OpenAIRE

    Ferter, Keno; Weltersbach, Marc Simon; Humborstad, Odd Børre; Fjelldal, Per Gunnar; Sambraus, Florian; Strehlow, Harry Vincent; Vølstad, Jon Helge

    2015-01-01

    Atlantic cod (Gadus morhua) caught in recreational fisheries are commonly released, often with barotrauma after rapid decompression. Mouth-hooked, non-bleeding cod kept in a floating net pen showed mortalities ≥40% when angled from >50 m depth, likely because of cumulative stress from ongoing barotrauma and exposure to warm surface water. In a natural setting, however, cod have the opportunity to descend after release and are not restricted to the surface. In a follow-up study, 97.8% of simil...

  11. Effects of amino acid supplementations on metabolic and physiological parameters in Atlantic cod (Gadus morhua) under stress.

    Science.gov (United States)

    Herrera, Marcelino; Herves, María Antonia; Giráldez, Inmaculada; Skar, Kristin; Mogren, Hanne; Mortensen, Atle; Puvanendran, Velmurugu

    2017-04-01

    The effects of tryptophan (Trp) and phenylalanine (Phe) diet supplementation on the stress and metabolism of the Atlantic cod have been studied. Fish were fed diet supplemented with Trp or Phe or control diet for 1 week. At the end of the feeding trial, fish were subjected to air exposure or heat shock. Following samples of blood, liver and muscle were taken from the fish and were analyzed for stress and metabolic indicators. After an air exposure, plasma cortisol levels in fish fed with Trp and Phe diets were lower compared to the fish fed the control diet. Diets containing both amino acids increased significantly the liver transaminase activities in juvenile cod. During thermal stress, high Trp contents had significant effects on fructose biphosphatase activity though Phe did not. Overall, activities of glucose 6-phosphate dehydrogenase, pyruvate kinase, and phosphofructokinase increased significantly for both amino acid diets. For the thermal stress, fish had the highest values of those activities for the 3Trp diet. Trp content in the diet had significant effects on the transaminase activity in muscle during air stress compared to fish fed control and Phe diets. Muscle alanine transaminase activity for thermal stress in fish fed any diet was not significantly different from the control. Both Trp and Phe supplementations reduced the stress markers in the cod; hence, they could be used as additives for the stress attenuation. However, they also raised the activity of key enzymes in glycolysis and gluconeogenesis, mainly the Trp diets.

  12. Chronic CO2 exposure markedly increases the incidence of cataracts in juvenile Atlantic cod Gadus morhua L

    DEFF Research Database (Denmark)

    Moran, Damian; Tubbs, Lincoln; Støttrup, Josianne G.

    2012-01-01

    A study was undertaken to test the affect of chronic exposure to elevated dissolved carbon dioxide on juvenile Atlantic cod. The CO2 treatment concentrations were designated as low (1–2mgL−1, 1000μatm), medium (8mgL−1, 3500μatm) and high (18mgL−1, 8500μatm), and the fish were reared at 10°C and 20......=757 individuals) using field methods. The most notable difference between CO2 treatments was the prevalence and intensity of lenticular cataracts, which were primarily diffuse rather than nucleated. Nearly 75% of all fish from the high CO2 treatment were found to have some degree of cataractous lesion......, compared with 10–13% for the other treatments. The severity of the cataract was most pronounced at the highest CO2 concentration, with many fish presenting complete bilateral cataracts. These data indicate that chronic exposure to high CO2 concentrations can cause cataracts in juvenile Atlantic cod. To our...

  13. Oil droplet fouling and differential toxicokinetics of polycyclic aromatic hydrocarbons in embryos of Atlantic haddock and cod.

    Science.gov (United States)

    Sørensen, Lisbet; Sørhus, Elin; Nordtug, Trond; Incardona, John P; Linbo, Tiffany L; Giovanetti, Laura; Karlsen, Ørjan; Meier, Sonnich

    2017-01-01

    The impact of crude oil pollution on early life stages (ELS) of fish, including larvae and embryos, has received considerable attention in recent years. Of the organic components present in crude oil, polycyclic aromatic hydrocarbons (PAHs) are considered the main class of compounds responsible for toxic effects in marine organisms. Although evidence suggests that they are more toxic, alkylated PAHs remain much less studied than their unsubstituted congeners. Recently, it was established that embryos of Atlantic haddock (Melanogrammus aeglefinus) are particularly sensitive to dispersed crude oil, and it was hypothesized that this was caused by direct interaction with crude oil droplets, which adhered to the chorion of exposed embryos. Such a phenomenon would increase the potential for uptake of less water-soluble compounds, including alkylated PAHs. In the current study, we compared the uptake of parent and alkylated PAHs in Atlantic cod (Gadus morhua) and haddock embryos exposed to dispersed crude oil at a range of environmentally relevant concentrations (10-600 μg oil/liter seawater). Although the species are biologically very similar, the cod chorion does not become fouled with oil droplets, even when the two species are exposed to dispersions of crude oil droplets under similar conditions. A close correlation between the degree of fouling and toxicological response (heart defects, craniofacial malformation) was observed. Oil droplet fouling in haddock led to both quantitative and qualitative differences in PAH uptake. Finally, kinetic data on a large suite of PAHs showed differential elimination, suggesting differential metabolism of unsubstituted versus alkylated compounds.

  14. Impact of asymptomatic nodavirus carrier state and intraperitoneal viral mimic injection on brain transcript expression in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Rise, Matthew L; Hall, Jennifer R; Rise, Marlies; Hori, Tiago S; Browne, Mitchell J; Gamperl, A Kurt; Hubert, Sophie; Kimball, Jennifer; Bowman, Sharen; Johnson, Stewart C

    2010-07-07

    Nodaviruses and other RNA viruses have a profoundly negative impact on the global aquaculture industry. Nodaviruses target nervous tissue causing viral nervous necrosis, a disease characterized by neurological damage, swimming abnormalities, and morbidity. This study used functional genomic techniques to study the Atlantic cod (Gadus morhua) brain transcript expression responses to asymptomatic high nodavirus carrier state and intraperitoneal injection of polyriboinosinic polyribocytidylic acid (pIC). Reciprocal suppression subtractive hybridization (SSH) cDNA libraries enriched for virus-responsive brain transcripts were constructed and characterized. We generated 1,938 expressed sequence tags (ESTs) from a forward brain SSH library (enriched for transcripts upregulated by nodavirus and/or pIC) and 1,980 ESTs from a reverse brain SSH library (enriched for transcripts downregulated by nodavirus and/or pIC). To examine the effect of nodavirus carrier state on individual brain gene expression in asymptomatic cod, 27 transcripts of interest were selected for quantitative reverse transcription-polymerase chain reaction (QPCR) studies. Transcripts found to be >10-fold upregulated in individuals with a high nodavirus carrier state relative to those in a no/low nodavirus carrier state were identified as ISG15, IL8, DHX58 (alias LGP2), ZNFX1, RSAD2 (alias viperin), and SACS (sacsin, alias spastic ataxia of Charlevoix-Saguenay). These and other SSH-identified transcripts were also found by QPCR to be significantly (P SSH library, including two putative ubiquitination pathway members (HERC4 and SUMO2), were found to be significantly (P < 0.05) downregulated in individuals with a high nodavirus carrier state. Our data shows that Atlantic cod brains have a strong interferon pathway response to asymptomatic high nodavirus carrier state and that many interferon pathway and other immune relevant transcripts are significantly induced in brain by both nodavirus and pIC.

  15. Environmentally realistic exposure to weathered North Sea oil: Sublethal effects in Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus).

    Science.gov (United States)

    Holth, Tor Fredrik; Storset, Audun; Ribeiro, Anne Luise; Ólafsdóttir, Ásdís; Halldórsson, Halldór Pálmar; Hylland, Ketil

    2017-01-01

    With increasing oil and gas activities and transport in the Arctic, there is a need to understand how operational or accidental releases of substances affect marine organisms from a pristine environment. The aim of the current study was to describe and compare the responses of two marine fish species, Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus), following exposure to three levels (low, medium, high) of the water-soluble fraction of a North Sea crude oil for 16 days. The exposure system simulated environmental exposure by allowing clean seawater to percolate through gravel covered in weathered oil before being introduced to aquaria. Both polycyclic aromatic hydrocarbon (PAH) metabolite bile concentrations and cytochrome P4501A (CYP1A) levels and activity increased markedly in comparison with controls in both species, but there were no significant differences between the three exposures. Turbot possessed 4-5-fold higher concentrations of two PAH bile metabolites compared to Atlantic cod by day 8. In contrast, hepatic CYP1A activity in cod was consistently 2-6-fold higher than in turbot with increasing differences over the experimental period. Baseline DNA strand breaks in lymphocytes and kidney cells were low in both species, but was elevated for all treatments by day two. There were no marked indications of the treatments affecting immune functions in either species. This investigation demonstrated that there may be significant differences in responses between species receiving identical exposures and that DNA strand breaks in lymphocytes and kidney cells are sensitive to confinement stress. Data also indicate that some species, such as turbot, may adapt to treatments within days and weeks.

  16. Will you swim into my parlour? In situ observations of Atlantic cod (Gadus morhua) interactions with baited pots, with implications for gear design.

    Science.gov (United States)

    Meintzer, Phillip; Walsh, Philip; Favaro, Brett

    2017-01-01

    Pots (also known as traps) are baited fishing gears widely used in commercial fisheries, and are being considered as a tool for harvesting Atlantic cod (Gadus morhua) in Newfoundland and Labrador, Canada. Pots produce lower environmental impacts than many other fishing gears, but they will only be a viable fishing strategy if they are efficient and selective at catching their target species. To study the behaviour of cod in and around pots, and how those behaviours affect pot efficiency, we used long-duration underwater video cameras to assess two models of cod pot deployed in the nearshore waters of Fogo Island, NL. We examined the number of cod that approached the pot, the number and proportion that successfully completed entries into the pot openings, and the number that exited, and related these factors to the direction of water movement. We observed very few entry attempts relative to the number of approaches by cod, and only 22% of all entry attempts were successful. We observed that 50% of approaches, 70% of entry attempts, and 73% of successful entrances occurred against the current, and 25% of cod were able to exit the pot following capture. Based on our observations, we suggest that future cod pots should have a greater number of entrances, or a mechanism to ensure that entrances rotate in line with the current, in order to maximize their catch efficiency for cod.

  17. Will you swim into my parlour? In situ observations of Atlantic cod (Gadus morhua interactions with baited pots, with implications for gear design

    Directory of Open Access Journals (Sweden)

    Phillip Meintzer

    2017-02-01

    Full Text Available Pots (also known as traps are baited fishing gears widely used in commercial fisheries, and are being considered as a tool for harvesting Atlantic cod (Gadus morhua in Newfoundland and Labrador, Canada. Pots produce lower environmental impacts than many other fishing gears, but they will only be a viable fishing strategy if they are efficient and selective at catching their target species. To study the behaviour of cod in and around pots, and how those behaviours affect pot efficiency, we used long-duration underwater video cameras to assess two models of cod pot deployed in the nearshore waters of Fogo Island, NL. We examined the number of cod that approached the pot, the number and proportion that successfully completed entries into the pot openings, and the number that exited, and related these factors to the direction of water movement. We observed very few entry attempts relative to the number of approaches by cod, and only 22% of all entry attempts were successful. We observed that 50% of approaches, 70% of entry attempts, and 73% of successful entrances occurred against the current, and 25% of cod were able to exit the pot following capture. Based on our observations, we suggest that future cod pots should have a greater number of entrances, or a mechanism to ensure that entrances rotate in line with the current, in order to maximize their catch efficiency for cod.

  18. Pre-digestion of dietary lipids has only minor effects on absorption, retention and metabolism in larval stages of Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Hamre, K; Lukram, I M; Rønnestad, I; Nordgreen, A; Saele, O

    2011-03-01

    The hypothesis of the present study was that cod larvae have a limitation in lipid digestion, and that absorption of lipids would increase by pre-hydrolysation. The diets used were designed to contain 15% lipid, of which 40% was phosphatidylcholine (PC) and 60 % was TAG. Cod larvae (40d post hatch (dph)) were fed a single meal where either PC or TAG was radioactively labelled, and the labelled PC or TAG was either intact or hydrolysed (pre-digested). The larvae were then incubated individually in chambers with collection of CO2 for 10 h. The following fractions were analysed for radioactivity: the incubation water (evacuated feed); the intestine; the body; the CO2 trap. The larvae ate a 16-29 μg diet, equivalent to 3·4-5·2 % of dry body weight. In the whole population, 0-16% of the lipid was evacuated. The larvae that had eaten less than 1·9-2·7 μg lipid absorbed close to 100% of the lipid, absorption being defined conservatively as the amount contained in the carcass and CO2, excluding the intestinal tissue. In these larvae, approximately 100 % of the absorbed lipid was also catabolised. In the larvae that ingested more than 1·9-2·7 μg lipid, there was a linear reduction in lipid absorption to a minimum of 55% at the highest lipid intakes parallel to an increasing retention of lipids in the carcass. There were only minor differences in digestion, absorption, retention and metabolism of lipids between the larvae fed the different diets, and the larvae tended to retain lipid classes as they were present in the feed. The study shows that 40-dph Atlantic cod larvae have an efficient utilisation of dietary lipids supplied as intact PC and TAG.

  19. Molecular Evidence that Only Two Opsin Subfamilies, the Blue Light- (SWS2) and Green Light-Sensitive (RH2), Drive Color Vision in Atlantic Cod (Gadus morhua)

    Science.gov (United States)

    Søviknes, Anne Mette; Drivenes, Øyvind; Helvik, Jon Vidar

    2014-01-01

    Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision) including rod opsin only retinas seen in many deep-sea species to multiple subfamilies of visual opsins in some pelagic species. We have investigated the opsin repertoire of Atlantic cod (Gadus morhua) using information in the recently sequenced cod genome and found that despite cod not being a deep sea species it lacks visual subfamilies sensitive towards the most extreme parts of the light spectra representing UV and red light. Furthermore, we find that Atlantic cod has duplicated paralogs of both blue-sensitive SWS2 and green-sensitive RH2 subfamilies, with members belonging to each subfamily linked in tandem within the genome (two SWS2-, and three RH2A genes, respectively). The presence of multiple cone opsin genes indicates that there have been duplication events in the cod ancestor SWS2 and RH2 opsins producing paralogs that have been retained in Atlantic. Our results are supported by expressional analysis of cone opsins, which further revealed an ontogenetic change in the array of cone opsins expressed. These findings suggest life stage specific programs for opsin regulation which could be linked to habitat changes and available light as the larvae is transformed into an early juvenile. Altogether we provide the first molecular evidence for color vision driven by only two families of cone opsins due to gene loss in a teleost. PMID:25551396

  20. Molecular evidence that only two opsin subfamilies, the blue light- (SWS2 and green light-sensitive (RH2, drive color vision in Atlantic cod (Gadus morhua.

    Directory of Open Access Journals (Sweden)

    Ragnhild Valen

    Full Text Available Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision including rod opsin only retinas seen in many deep-sea species to multiple subfamilies of visual opsins in some pelagic species. We have investigated the opsin repertoire of Atlantic cod (Gadus morhua using information in the recently sequenced cod genome and found that despite cod not being a deep sea species it lacks visual subfamilies sensitive towards the most extreme parts of the light spectra representing UV and red light. Furthermore, we find that Atlantic cod has duplicated paralogs of both blue-sensitive SWS2 and green-sensitive RH2 subfamilies, with members belonging to each subfamily linked in tandem within the genome (two SWS2-, and three RH2A genes, respectively. The presence of multiple cone opsin genes indicates that there have been duplication events in the cod ancestor SWS2 and RH2 opsins producing paralogs that have been retained in Atlantic. Our results are supported by expressional analysis of cone opsins, which further revealed an ontogenetic change in the array of cone opsins expressed. These findings suggest life stage specific programs for opsin regulation which could be linked to habitat changes and available light as the larvae is transformed into an early juvenile. Altogether we provide the first molecular evidence for color vision driven by only two families of cone opsins due to gene loss in a teleost.

  1. Molecular evidence that only two opsin subfamilies, the blue light- (SWS2) and green light-sensitive (RH2), drive color vision in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Valen, Ragnhild; Edvardsen, Rolf Brudvik; Søviknes, Anne Mette; Drivenes, Øyvind; Helvik, Jon Vidar

    2014-01-01

    Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision) including rod opsin only retinas seen in many deep-sea species to multiple subfamilies of visual opsins in some pelagic species. We have investigated the opsin repertoire of Atlantic cod (Gadus morhua) using information in the recently sequenced cod genome and found that despite cod not being a deep sea species it lacks visual subfamilies sensitive towards the most extreme parts of the light spectra representing UV and red light. Furthermore, we find that Atlantic cod has duplicated paralogs of both blue-sensitive SWS2 and green-sensitive RH2 subfamilies, with members belonging to each subfamily linked in tandem within the genome (two SWS2-, and three RH2A genes, respectively). The presence of multiple cone opsin genes indicates that there have been duplication events in the cod ancestor SWS2 and RH2 opsins producing paralogs that have been retained in Atlantic. Our results are supported by expressional analysis of cone opsins, which further revealed an ontogenetic change in the array of cone opsins expressed. These findings suggest life stage specific programs for opsin regulation which could be linked to habitat changes and available light as the larvae is transformed into an early juvenile. Altogether we provide the first molecular evidence for color vision driven by only two families of cone opsins due to gene loss in a teleost.

  2. Functional genomic analysis of the response of Atlantic cod (Gadus morhua) spleen to the viral mimic polyriboinosinic polyribocytidylic acid (pIC).

    Science.gov (United States)

    Rise, Matthew L; Hall, Jennifer; Rise, Marlies; Hori, Tiago; Gamperl, A Kurt; Kimball, Jennifer; Hubert, Sophie; Bowman, Sharen; Johnson, Stewart C

    2008-01-01

    In order to improve our understanding of how Atlantic cod (Gadus morhua) respond to viruses, we characterized immune-related gene expression in spleen tissues following stimulation with a synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid (pIC). We used reciprocal suppression subtractive hybridization (SSH) cDNA libraries and quantitative RTPCR (QPCR) to identify and quantify pIC-responsive transcripts. A total of 3874 expressed sequence tags (ESTs) were generated from SSH libraries enriched for genes responsive to pIC. Thirteen immune-relevant genes from the libraries were subjected to QPCR. Genes confirmed as up-regulated by pIC included interferon stimulated gene 15, a small inducible cytokine, interferon regulatory factors (1, 7, and 10), MHC class I, viperin, and ATP-dependent helicase LGP2. Alpha-1-microglobulin (bikunin) was down-regulated, suggesting that pIC may suppress the acute phase response. Since the SSH libraries built for this study identified genes involved in the antiviral response, they are important resources for studying the responses of Atlantic cod to viruses. Evidence is provided for the existence of a RIG-I-like RNA helicase viral recognition pathway in Atlantic cod. Taken together, our data show that Atlantic cod can recognize double-stranded RNA and mount a rapid and potent interferon pathway response that is similar to that observed in other fish species and higher vertebrates.

  3. In vitro pH-Stat protein hydrolysis of feed ingredients for Atlantic cod, Gadus morhua. 1. Development of the method

    NARCIS (Netherlands)

    Tibbetts, S.; Milley, J.E.; Ross, N.W.; Verreth, J.A.J.; Lall, S.P.

    2011-01-01

    The method described here involves the extraction and partial purification of an enzyme fraction from the dissected pyloric caeca of commercially farmed Atlantic cod, Gadus morhua (1 kg fish) and the development of a pH-Stat method to predict protein digestibility. The various extraction and partial

  4. In vitro pH-Stat protein hydrolysis of feed ingredients for Atlantic cod, Gadus morhua. 2. In vitro protein digestibility of common and alternative feed ingredients

    NARCIS (Netherlands)

    Tibbetts, S.; Verreth, J.A.J.; Lall, S.P.

    2011-01-01

    Using enzyme fractions isolated from the pyloric caeca of farmed Atlantic cod, the in vitro degree of protein hydrolysis (DH) of numerous conventional and novel feed ingredients were measured by a closed-system pH-Stat assay. Regression equations describing the relationship between in vivo apparent

  5. Relative strength of the 2010, 2011 and 2012 year classes, from nearshore surveys of demersal age 0 and 1 Atlantic cod in Newman Sound, Bonavista Bay

    National Research Council Canada - National Science Library

    Gregory, R.S; Morris, C; Newton, B; Sargent, P

    2016-01-01

    We surveyed demersal age 0 and 1 year old Atlantic cod (Gadus morhua) in the nearshore (<10 m deep) during the past 17 seasons using a seine net, to conduct a qualitative assessment of the strength of these year-classes...

  6. Behavioural changes of Atlantic cod (Gadus morhua) after marine boulder reef restoration: Implications for coastal habitat management and Natura 2000 areas

    DEFF Research Database (Denmark)

    Støttrup, Josianne Gatt; Svendsen, Jon Christian; Stenberg, Claus

    2017-01-01

    While marine reefs are degraded globally, the responses of fish to marine reef restoration remain uncertain, particularly in temperate waters. This study measured the effect of marine boulder reef restoration on the behaviour of Atlantic cod, Gadus morhua L., in a Natura 2000 area using acoustic...... telemetry. Cod were tagged and released in the study area before and after the restoration and tracked continuously for six months. A larger fraction of the released fish remained in the study area after restoration (94%) than before (53%). Moreover, throughout the study period, cod spent significantly more...... hours per day and prolonged their residence time in the study area after the restoration. The study indicates that marine reefs subjected to boulder extraction can be restored and function as favourable cod habitats. Temperate marine boulder reef restoration represents a valuable management tool...

  7. Population structure of Atlantic mackerel (Scomber scombrus.

    Directory of Open Access Journals (Sweden)

    Teunis Jansen

    Full Text Available Atlantic mackerel (Scomber scombrus occurs on both sides of the north Atlantic and has traditionally been grouped into 5 spawning components, some of which were thought to be isolated natal homing stocks. Previous studies have provided no evidence for cross Atlantic migration and no or weak support for isolated spawning components within either side of the North Atlantic. We question the de-facto accepted hypothesis of isolation between spawning components on the basis of spawning and age distribution data. The spawning intensities, proxied by larval abundances, are negatively correlated between the North Sea and Celtic Sea, which indicates that the two spawning components may be connected by straying individuals. This finding is based on unique larvae samples collected before the collapse of North Sea component, thus showing that the exchange is not a recent phenomenon due to the collapse. The analyses of old as well as more recent age distributions show that strong year classes spread into other areas where they spawn as adults ("twinning". Our findings are in accordance with the lack of solid evidence for stock separation from previous analyses of tagging data, genetics, ectoparasite infections, otolith shapes, and blood phenotypes. Because no method has been able to identify the origin of spawning mackerel unequivocally from any of the traditional spawning components, and in the light of our results, we conclude that straying outweighs spatial segregation. We propose a new model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic mackerel has important implications for research, assessment and management.

  8. Melanin-concentrating hormone (MCH) and gonadotropin-releasing hormones (GnRH) in Atlantic cod, Gadus morhua: tissue distributions, early ontogeny and effects of fasting.

    Science.gov (United States)

    Tuziak, Sarah M; Volkoff, Hélène

    2013-12-01

    Melanin-concentrating hormone (MCH) is classically known for its role in regulating teleost fish skin color change for environmental adaptation. Recent evidence suggests that MCH also has appetite-stimulating properties. The gonadotropin-releasing hormone (GnRH) peptide family has dual roles in endocrine control of reproduction and energy status in fish. Atlantic cod (Gadus morhua) are a commercially important aquaculture species inhabiting the shores of Atlantic Canada. In this study, we examine MCH and GnRH transcript expression profiles during early development as well as in central and peripheral tissues and quantify juvenile Atlantic cod MCH and GnRH hypothalamic mRNA expressions following food deprivation. MCH and GnRH3 cDNAs are maternally deposited into cod eggs, while MCH has variable expression throughout early development. GnRH2 and GnRH3 mRNAs "turn-on" during mid-segmentation once the brain is fully developed. For both MCH and GnRH, highest expression appears during the exogenous feeding stages, perhaps supporting their functions as appetite regulators during early development. MCH and GnRH transcripts are found in brain regions related to appetite regulation (telencephalon/preoptic area, optic tectum/thalamus, hypothalamus), as well as the pituitary gland and the stomach, suggesting a peripheral function in food intake regulation. Atlantic cod MCH mRNA is upregulated during fasting, while GnRH2 and GnRH3 transcripts do not appear to be influenced by food deprivation. In conclusion, MCH might be involved in stimulating food intake in juvenile Atlantic cod, while GnRHs may play a more significant role in appetite regulation during early development. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Are low but statistically significant levels of genetic differentiation in marine fishes 'biologically meaningful'? A case study of coastal Atlantic cod.

    Science.gov (United States)

    Knutsen, H; Olsen, E M; Jorde, P E; Espeland, S H; André, C; Stenseth, N C

    2011-02-01

    A key question in many genetic studies on marine organisms is how to interpret a low but statistically significant level of genetic differentiation. Do such observations reflect a real phenomenon, or are they caused by confounding factors such as unrepresentative sampling or selective forces acting on the marker loci? Further, are low levels of differentiation biologically trivial, or can they represent a meaningful and perhaps important finding? We explored these issues in an empirical study on coastal Atlantic cod, combining temporally replicated genetic samples over a 10-year period with an extensive capture-mark-recapture study of individual mobility and population size. The genetic analyses revealed a pattern of differentiation between the inner part of the fjord and the open skerries area at the fjord entrance. Overall, genetic differentiation was weak (average F(ST)  = 0.0037), but nevertheless highly statistical significant and did not depend on particular loci that could be subject to selection. This spatial component dominated over temporal change, and temporal replicates clustered together throughout the 10-year period. Consistent with genetic results, the majority of the recaptured fish were found close to the point of release, with <1% of recaptured individuals dispersing between the inner fjord and outer skerries. We conclude that low levels of genetic differentiation in this marine fish can indeed be biologically meaningful, corresponding to separate, temporally persistent, local populations. We estimated the genetically effective sizes (N(e) ) of the two coastal cod populations to 198 and 542 and found a N(e) /N (spawner) ratio of 0.14. © 2010 Blackwell Publishing Ltd.

  10. 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.

  11. The effect of temperature and body size on metabolic scope of activity in juvenile Atlantic cod Gadus morhua L

    DEFF Research Database (Denmark)

    Tirsgaard, Bjørn; Behrens, Jane; Steffensen, John Fleng

    2015-01-01

    Changes in ambient temperature affect the physiology and metabolism and thus the distribution of fish. In this study we used intermittent flow respirometry to determine the effect of temperature (2, 5, 10, 15 and 20 °C) and wet body mass (BM) (~30–460 g) on standard metabolic rate (SMR, mg O2 h−1......), maximum metabolic rate (MMR, mg O2 h−1) and metabolic scope (MS, mg O2 h−1) of juvenile Atlantic cod. SMR increased with BM irrespectively of temperature, resulting in an average scaling exponent of 0.87 (0.82–0.92). Q10 values were 1.8–2.1 at temperatures between 5 and 15 °C but higher (2.6–4.3) between...

  12. Effects of reproduction on growth and survival in Atlantic cod, Gadus morhua, assessed by comparison to triploids

    DEFF Research Database (Denmark)

    Trippel, Edward A.; Butts, Ian; Babin, Amanda

    2014-01-01

    in captive iteroparous, batch-spawning Atlantic cod (Gadus morhua), utilizing diploids and triploids, knowing that triploid females invest little to no energy into gametogenesis. Based on annual specific growth rate, there was no evidence for a somatic cost of reproduction at ages 2 (virgin year) and 4....... years, but there was at age 3. years. At age 2. years, low investment in reproduction likely accounted for the lack of a somatic cost of reproduction, whereas at age 4 the absence was associated with heightened growth post-spawning enabling mature fish to catch up to immature fish. At age 3......, compensatory growth during post-spawning was below that of immature fish. Survival represented a significant component of the cost of reproduction. Laboratory experiments examining the cost of reproduction have traditionally focused on shorter time periods, commonly spanning several months, whereas ours...

  13. Size-dependent social attraction and repulsion explains the decision of Atlantic cod Gadus morhua to enter baited pots.

    Science.gov (United States)

    Anders, N; Fernö, A; Humborstad, O-B; Løkkeborg, S; Rieucau, G; Utne-Palm, A C

    2017-11-15

    The present study tested whether the presence of already retained fishes inside baited fish pots acted as a social attraction and affected the entrance probability of Atlantic cod Gadus morhua in a fjord in northern Norway. Video analysis revealed that the probability of an entrance initially increased with the presence of low numbers of fishes inside the pot, but subsequently decreased at a critical number of caught fishes. The critical number was dependent on the size of the G. morhua attempting to enter. This demonstrates that social attraction and repulsion play a role in G. morhua pot fishing and has important implications for the capture efficiency of fisheries executed with pots. © 2017 The Fisheries Society of the British Isles.

  14. Effects of Hypoxic Exposure during Feeding on SDA and Postprandial Cardiovascular Physiology in the Atlantic Cod, Gadus morhua

    Science.gov (United States)

    Behrens, Jane W.; Axelsson, Michael; Neuenfeldt, Stefan; Seth, Henrik

    2012-01-01

    Some Atlantic cod in the Bornholm Basin undertake vertical foraging migrations into severely hypoxic bottom water. Hypoxic conditions can reduce the postprandial increase in gastrointestinal blood flow (GBF). This could subsequently postpone or reduce the postprandial increase in oxygen consumption (MO2), i.e. the SDA, leading to a disturbed digestion. Additionally, a restricted oxygen uptake could result in an oxygen debt that needs to be compensated for upon return to normoxic waters and this may also affect the ability to process the food. Long-term cardio-respiratory measurements were made on fed G. morhua in order to understand how the cardio-respiratory system of feeding fish respond to a period of hypoxia and a subsequent return to normoxia. These were exposed to 35% water oxygen saturation for 90 minutes, equivalent to the time and oxygen level cod voluntarily endure when searching for food in the Bornholm Basin. We found that i) gastric and intestinal blood flows, cardiac output and MO2 increased after feeding, ii) gastric and intestinal blood flows were spared in hypoxia, and iii) there were no indications of an oxygen debt at the end of the hypoxic period. The magnitude and time course of the measured variables are similar to values obtained from fish not exposed to the hypoxic period. In conclusion, when cod in the field search for and ingest prey under moderate hypoxic conditions they appear to stay within safe limits of oxygen availability as we saw no indications of an oxygen debt, or negative influence on digestive capacity, when simulating field observations. PMID:23049987

  15. Is chemically dispersed oil more toxic to Atlantic cod (Gadus morhua) larvae than mechanically dispersed oil? A transcriptional evaluation

    Science.gov (United States)

    2012-01-01

    Background The use of dispersants can be an effective way to deal with acute oil spills to limit environmental damage, however very little is known about whether chemically dispersed oil have the same toxic effect on marine organisms as mechanically dispersed oil. We exposed Atlantic cod larvae to chemically and mechanically dispersed oil for four days during the first-feeding stage of development, and collected larvae at 14 days post hatch for transcriptional analysis. A genome-wide microarray was used to screen for effects and to assess whether molecular responses to chemically and mechanically dispersed oil were similar, given the same exposure to oil (droplet distribution and concentration) with and without the addition of a chemical dispersant (Dasic NS). Results Mechanically dispersed oil induced expression changes in almost three times as many transcripts compared to chemically dispersed oil (fold change >+/−1.5). Functional analyses suggest that chemically dispersed oil affects partly different pathways than mechanically dispersed oil. By comparing the alteration in gene transcription in cod larvae exposed to the highest concentrations of either chemically or mechanically dispersed oil directly, the chemically dispersed oil affected transcription of genes involved nucleosome regulation, i.e. genes encoding proteins participating in DNA replication and chromatin formation and regulation of cell proliferation, whereas the mechanically dispersed oil most strongly affected genes encoding proteins involved in proteasome-mediated protein degradation. Cyp1a was the transcript that was most strongly affected in both exposure groups, with a 60-fold induction in the two high-exposure groups according to the RT-qPCR data, but no significant difference in transcriptional levels was observed between the two treatments. Conclusions In summary, dispersants do not appear to add to the magnitude of transcriptional responses of oil compounds but rather appear to lower or

  16. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae - can we identify the underlying factors?

    Science.gov (United States)

    Karlsen, Ørjan; van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks.

  17. Is chemically dispersed oil more toxic to Atlantic cod (Gadus morhua larvae than mechanically dispersed oil? A transcriptional evaluation

    Directory of Open Access Journals (Sweden)

    Olsvik Pål A

    2012-12-01

    Full Text Available Abstract Background The use of dispersants can be an effective way to deal with acute oil spills to limit environmental damage, however very little is known about whether chemically dispersed oil have the same toxic effect on marine organisms as mechanically dispersed oil. We exposed Atlantic cod larvae to chemically and mechanically dispersed oil for four days during the first-feeding stage of development, and collected larvae at 14 days post hatch for transcriptional analysis. A genome-wide microarray was used to screen for effects and to assess whether molecular responses to chemically and mechanically dispersed oil were similar, given the same exposure to oil (droplet distribution and concentration with and without the addition of a chemical dispersant (Dasic NS. Results Mechanically dispersed oil induced expression changes in almost three times as many transcripts compared to chemically dispersed oil (fold change >+/−1.5. Functional analyses suggest that chemically dispersed oil affects partly different pathways than mechanically dispersed oil. By comparing the alteration in gene transcription in cod larvae exposed to the highest concentrations of either chemically or mechanically dispersed oil directly, the chemically dispersed oil affected transcription of genes involved nucleosome regulation, i.e. genes encoding proteins participating in DNA replication and chromatin formation and regulation of cell proliferation, whereas the mechanically dispersed oil most strongly affected genes encoding proteins involved in proteasome-mediated protein degradation. Cyp1a was the transcript that was most strongly affected in both exposure groups, with a 60-fold induction in the two high-exposure groups according to the RT-qPCR data, but no significant difference in transcriptional levels was observed between the two treatments. Conclusions In summary, dispersants do not appear to add to the magnitude of transcriptional responses of oil compounds but

  18. Effects of hypoxic exposure during feeding on SDA and postprandial cardiovascular physiology in the Atlantic cod, Gadus morhua.

    Directory of Open Access Journals (Sweden)

    Jane W Behrens

    Full Text Available Some Atlantic cod in the Bornholm Basin undertake vertical foraging migrations into severely hypoxic bottom water. Hypoxic conditions can reduce the postprandial increase in gastrointestinal blood flow (GBF. This could subsequently postpone or reduce the postprandial increase in oxygen consumption (MO(2, i.e. the SDA, leading to a disturbed digestion. Additionally, a restricted oxygen uptake could result in an oxygen debt that needs to be compensated for upon return to normoxic waters and this may also affect the ability to process the food. Long-term cardio-respiratory measurements were made on fed G. morhua in order to understand how the cardio-respiratory system of feeding fish respond to a period of hypoxia and a subsequent return to normoxia. These were exposed to 35% water oxygen saturation for 90 minutes, equivalent to the time and oxygen level cod voluntarily endure when searching for food in the Bornholm Basin. We found that i gastric and intestinal blood flows, cardiac output and MO(2 increased after feeding, ii gastric and intestinal blood flows were spared in hypoxia, and iii there were no indications of an oxygen debt at the end of the hypoxic period. The magnitude and time course of the measured variables are similar to values obtained from fish not exposed to the hypoxic period. In conclusion, when cod in the field search for and ingest prey under moderate hypoxic conditions they appear to stay within safe limits of oxygen availability as we saw no indications of an oxygen debt, or negative influence on digestive capacity, when simulating field observations.

  19. Farmed cod escapees and net-pen spawning left no clear genetic footprint in the local wild cod population

    Directory of Open Access Journals (Sweden)

    Rebekka Varne

    2015-11-01

    Full Text Available This study investigated a potential genetic introgression from farmed to wild cod Gadus morhua L. in the Trondheimsfjord, Norway. During the first 2 yr of operation of a cod farm in the inner part of the fjord, 2 large escape events and extensive pen spawning were reported. Analyses of 4 allozyme markers revealed no significant changes in allele frequencies between samples of wild cod before and after cod farming, although prominent allele frequency differences were demonstrated between wild and farmed samples. Analyses of 10 DNA markers showed a significant change between pre- and post-farming samples, due to contradictory allele frequency differences at Tch11, Pan I and Gmo132. Excluding those 3 markers due to null alleles (Tch11 and selection (Gmo132 and Pan I, the DNA markers paralleled the non-changed allele frequency signal from the allozymes. The topographies of the allozyme- and DNA-based dendrogram of the samples were congruent. Recaptures of tagged and released farmed cod indicated a seemingly random diffusion throughout the fjord and ended after approx. 6 mo. During an ongoing pen spawning, plankton net surveys sampling for cod eggs in the surroundings of the cod farm suggested the eggs originated from the farm. No larvae were present in the plankton samples. The apparent absence of introgression is explained relative to fitness and survival of pen-spawned larvae and adult escapees, and to a purging effect of the estuarine circulation of the Trondheimsfjord.

  20. Oil droplet fouling and differential toxicokinetics of polycyclic aromatic hydrocarbons in embryos of Atlantic haddock and cod

    Science.gov (United States)

    Sørhus, Elin; Nordtug, Trond; Incardona, John P.; Linbo, Tiffany L.; Giovanetti, Laura; Karlsen, Ørjan; Meier, Sonnich

    2017-01-01

    The impact of crude oil pollution on early life stages (ELS) of fish, including larvae and embryos, has received considerable attention in recent years. Of the organic components present in crude oil, polycyclic aromatic hydrocarbons (PAHs) are considered the main class of compounds responsible for toxic effects in marine organisms. Although evidence suggests that they are more toxic, alkylated PAHs remain much less studied than their unsubstituted congeners. Recently, it was established that embryos of Atlantic haddock (Melanogrammus aeglefinus) are particularly sensitive to dispersed crude oil, and it was hypothesized that this was caused by direct interaction with crude oil droplets, which adhered to the chorion of exposed embryos. Such a phenomenon would increase the potential for uptake of less water-soluble compounds, including alkylated PAHs. In the current study, we compared the uptake of parent and alkylated PAHs in Atlantic cod (Gadus morhua) and haddock embryos exposed to dispersed crude oil at a range of environmentally relevant concentrations (10–600 μg oil/liter seawater). Although the species are biologically very similar, the cod chorion does not become fouled with oil droplets, even when the two species are exposed to dispersions of crude oil droplets under similar conditions. A close correlation between the degree of fouling and toxicological response (heart defects, craniofacial malformation) was observed. Oil droplet fouling in haddock led to both quantitative and qualitative differences in PAH uptake. Finally, kinetic data on a large suite of PAHs showed differential elimination, suggesting differential metabolism of unsubstituted versus alkylated compounds. PMID:28678887

  1. Oil droplet fouling and differential toxicokinetics of polycyclic aromatic hydrocarbons in embryos of Atlantic haddock and cod.

    Directory of Open Access Journals (Sweden)

    Lisbet Sørensen

    Full Text Available The impact of crude oil pollution on early life stages (ELS of fish, including larvae and embryos, has received considerable attention in recent years. Of the organic components present in crude oil, polycyclic aromatic hydrocarbons (PAHs are considered the main class of compounds responsible for toxic effects in marine organisms. Although evidence suggests that they are more toxic, alkylated PAHs remain much less studied than their unsubstituted congeners. Recently, it was established that embryos of Atlantic haddock (Melanogrammus aeglefinus are particularly sensitive to dispersed crude oil, and it was hypothesized that this was caused by direct interaction with crude oil droplets, which adhered to the chorion of exposed embryos. Such a phenomenon would increase the potential for uptake of less water-soluble compounds, including alkylated PAHs. In the current study, we compared the uptake of parent and alkylated PAHs in Atlantic cod (Gadus morhua and haddock embryos exposed to dispersed crude oil at a range of environmentally relevant concentrations (10-600 μg oil/liter seawater. Although the species are biologically very similar, the cod chorion does not become fouled with oil droplets, even when the two species are exposed to dispersions of crude oil droplets under similar conditions. A close correlation between the degree of fouling and toxicological response (heart defects, craniofacial malformation was observed. Oil droplet fouling in haddock led to both quantitative and qualitative differences in PAH uptake. Finally, kinetic data on a large suite of PAHs showed differential elimination, suggesting differential metabolism of unsubstituted versus alkylated compounds.

  2. Linking size and age at sexual maturation to body growth, productivity and recruitment of Atlantic cod stocks spanning the North Atlantic

    DEFF Research Database (Denmark)

    Köster, Fritz; Trippel, E.A.; Tomkiewicz, Jonna

    2013-01-01

    Sexual maturation patterns of 22 North Atlantic stocks of cod (Gadus morhua) were examined and related to geographical distribution area, ambient water temperature, growth and surplus production. Four patterns were identified, i.e. sexual maturation early in life at small size, early in life...... at large size, late in life at small size and lastly, late in life at large size. These maturation patterns were geographically clustered and associated with differences in growth and surplus production. Stocks maturing late in life at small size were characterised by slow growth and low surplus production...... (e.g. stocks in the Gulf of St. Lawrence, Labrador/Newfoundland). Stocks maturing early in life at large size exhibited high to intermediate growth and surplus production (e.g. Celtic Sea, North Sea). Stocks maturing late in life at large size had low to intermediate growth rates and surplus...

  3. A moderate increase in ambient temperature modulates the Atlantic cod (Gadus morhua spleen transcriptome response to intraperitoneal viral mimic injection

    Directory of Open Access Journals (Sweden)

    Hori Tiago S

    2012-08-01

    Full Text Available Abstract Background Atlantic cod (Gadus morhua reared in sea-cages can experience large variations in temperature, and these have been shown to affect their immune function. We used the new 20K Atlantic cod microarray to investigate how a water temperature change which, simulates that seen in Newfoundland during the spring-summer (i.e. from 10°C to 16°C, 1°C increase every 5 days impacted the cod spleen transcriptome response to the intraperitoneal injection of a viral mimic (polyriboinosinic polyribocytidylic acid, pIC. Results The temperature regime alone did not cause any significant increases in plasma cortisol levels and only minor changes in spleen gene transcription. However, it had a considerable impact on the fish spleen transcriptome response to pIC [290 and 339 significantly differentially expressed genes between 16°C and 10°C at 6 and 24 hours post-injection (HPI, respectively]. Seventeen microarray-identified transcripts were selected for QPCR validation based on immune-relevant functional annotations. Fifteen of these transcripts (i.e. 88%, including DHX58, STAT1, IRF7, ISG15, RSAD2 and IκBα, were shown by QPCR to be significantly induced by pIC. Conclusions The temperature increase appeared to accelerate the spleen immune transcriptome response to pIC. We found 41 and 999 genes differentially expressed between fish injected with PBS vs. pIC at 10°C and sampled at 6HPI and 24HPI, respectively. In contrast, there were 656 and 246 genes differentially expressed between fish injected with PBS vs. pIC at 16°C and sampled at 6HPI and 24HPI, respectively. Our results indicate that the modulation of mRNA expression of genes belonging to the NF-κB and type I interferon signal transduction pathways may play a role in controlling temperature-induced changes in the spleen’s transcript expression response to pIC. Moreover, interferon effector genes such as ISG15 and RSAD2 were differentially expressed between fish injected with

  4. A moderate increase in ambient temperature modulates the Atlantic cod (Gadus morhua) spleen transcriptome response to intraperitoneal viral mimic injection

    Science.gov (United States)

    2012-01-01

    Background Atlantic cod (Gadus morhua) reared in sea-cages can experience large variations in temperature, and these have been shown to affect their immune function. We used the new 20K Atlantic cod microarray to investigate how a water temperature change which, simulates that seen in Newfoundland during the spring-summer (i.e. from 10°C to 16°C, 1°C increase every 5 days) impacted the cod spleen transcriptome response to the intraperitoneal injection of a viral mimic (polyriboinosinic polyribocytidylic acid, pIC). Results The temperature regime alone did not cause any significant increases in plasma cortisol levels and only minor changes in spleen gene transcription. However, it had a considerable impact on the fish spleen transcriptome response to pIC [290 and 339 significantly differentially expressed genes between 16°C and 10°C at 6 and 24 hours post-injection (HPI), respectively]. Seventeen microarray-identified transcripts were selected for QPCR validation based on immune-relevant functional annotations. Fifteen of these transcripts (i.e. 88%), including DHX58, STAT1, IRF7, ISG15, RSAD2 and IκBα, were shown by QPCR to be significantly induced by pIC. Conclusions The temperature increase appeared to accelerate the spleen immune transcriptome response to pIC. We found 41 and 999 genes differentially expressed between fish injected with PBS vs. pIC at 10°C and sampled at 6HPI and 24HPI, respectively. In contrast, there were 656 and 246 genes differentially expressed between fish injected with PBS vs. pIC at 16°C and sampled at 6HPI and 24HPI, respectively. Our results indicate that the modulation of mRNA expression of genes belonging to the NF-κB and type I interferon signal transduction pathways may play a role in controlling temperature-induced changes in the spleen’s transcript expression response to pIC. Moreover, interferon effector genes such as ISG15 and RSAD2 were differentially expressed between fish injected with pIC at 10°C vs. 16

  5. Precision-cut liver slices of Atlantic cod (Gadus morhua): an in vitro system for studying the effects of environmental contaminants.

    Science.gov (United States)

    Eide, M; Karlsen, O A; Kryvi, H; Olsvik, P A; Goksøyr, A

    2014-08-01

    The Atlantic cod (Gadus morhua) is an economically important species commonly consumed by humans. The widespread distribution of cod in the North Atlantic Ocean makes it vulnerable to effluents from human activities, such as coastal industries and offshore petroleum exploration. It has been demonstrated that many effluents have adverse effects on cod reproduction and health, e.g. by disrupting endocrine signaling pathways. The liver, expressing important components of the biotransformation and the endocrine system, is one of the main target organs. Thus, reliable and reproducible in vitro systems of the liver are important for studying effects of environmental contaminants. The aim of this study was to investigate precision-cut liver slices (PCLS) as an alternative in vitro system for toxicological studies of the Atlantic cod liver. Slices of 8 mm in diameter and 250 μm thickness were prepared and cultivated from immature cod. Several analyses to measure the liver slice viability were performed: enzyme assays, histology, and morphometric analysis, all confirming cell viability for up to 72 h in culture. The liver slices were also exposed to two well-known model environmental contaminants, β-naphthoflavone (BNF) and 17α-ethynylestradiol (EE2), representing established agonists for the aryl hydrocarbon receptor (AHR) and the estrogen receptor (ER), respectively. The results showed increased transcription of the target genes cytochrome P450 1A (CYP1A) and vitellogenin (VTG), both well-established biomarkers for exposure of fish to the selected compounds. In conclusion, PCLS is a promising in vitro system for toxicological studies of cod liver cells. The liver slices are viable in culture for several days and respond to environmental contaminants in a dose- and time-specific manner. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Comparison of the response of Atlantic cod ( Gadus morhua) in the high-latitude regions of the North Atlantic during the warm periods of the 1920s-1960s and the 1990s-2000s

    Science.gov (United States)

    Drinkwater, Ken

    2009-10-01

    Concern about future anthropogenic warming has lead to demands for information on what might happen to fish and fisheries under various climate-change scenarios. One suggestion has been to use past events as a proxy for what will happen in the future. In this paper a comparison between the responses of Atlantic cod ( Gadus morhua) to two major warm periods in the North Atlantic during the 20th century is carried out to determine how reliable the past might be as a predictor of the future. The first warm period began during the 1920s, remained relatively warm through the 1960s, and was limited primarily to the northern regions (>60°N). The second warm period, which again covered the northern regions but also extended farther south (30°N), began in the 1990s and has continued into the present century. During the earlier warm period, the most northern of the cod stocks (West Greenland, Icelandic, and Northeast Arctic cod in the Barents Sea) increased in abundance, individual growth was high, recruitment was strong, and their distribution spread northward. Available plankton data suggest that these cod responses were driven by bottom-up processes. Fishing pressure increased during this period of high cod abundance and the northern cod stocks began to decline, as early as the 1950s in the Barents Sea but during the 1960s elsewhere. Individual growth declined as temperatures cooled and the cod distributions retracted southward. During the warming in the 1990s, the spawning stock biomass of cod in the Barents Sea again increased, recruitment rose, and the stock spread northward, but the individual growth did not improve significantly. Cod off West Greenland also have shown signs of improving recruitment and increasing biomass, albeit they are still very low in comparison to the earlier warming period. The abundance of Icelandic cod, on the other hand, has remained low through the recent warm period and spawning stock biomass and total biomass are at levels near the

  7. Dynamic expression profiles of virus-responsive and putative antimicrobial peptide-encoding transcripts during Atlantic cod (Gadus morhua) embryonic and early larval development.

    Science.gov (United States)

    Rise, Matthew L; Hall, Jennifer R; Alcock, Brian P; Hori, Tiago S

    2012-11-10

    Early life stage mortality is one of the problems faced by Atlantic cod aquaculture. However, our understanding of immunity in early life stage fish is still incomplete, and the information available is restricted to a few species. In the present work we investigated the expression of immune-relevant transcripts in Atlantic cod during early development. The transcripts subjected to QPCR analysis in the present study were previously identified as putative anti-viral or anti-bacterial genes in Atlantic cod using suppression subtractive hybridization (SSH) libraries, QPCR, and/or microarrays. Of the 11 genes involved in this study, only atf3, cxc chemokine and gaduscidin-1 were not detected at the transcript level in all developmental stages investigated from unfertilized egg to early larval stage. Adam22, hamp, il8, irf1, irf7, lgp2, sacsin, and stat1 transcripts were detected in unfertilized egg and 7h post-fertilization (~2-cell stage) embryos, showing maternal contribution of these immune-relevant transcripts to the early embryonic transcriptome. The Atlantic cod genes included in this study presented diverse transcript expression profiles throughout embryonic and early larval development. For example, adam22 and sacsin transcripts rose abruptly during blastula/gastrula stage and were then expressed at relatively high levels through subsequent embryonic and early larval developmental stages. A peak in irf1 and irf7 transcript expression during early segmentation suggests that these interferon pathway genes play developmental stage-specific roles during cod embryogenesis. Stat1 had increasing transcript expression throughout blastula/gastrula, segmentation, and early larval developmental stages. Atf3, cxc chemokine, gaduscidin-1, and il8 transcripts rose approximately 2-3 fold during hatching, supporting the hypothesis that there is preparation at the immune-relevant transcript expression level to deal with environmental pathogens that may be encountered during

  8. Multi-decadal responses of a cod (Gadus morhua) population to human-induced trophic changes, fishing, and climate

    DEFF Research Database (Denmark)

    Eero, Margit; MacKenzie, Brian; Köster, Fritz

    2011-01-01

    significant climate-driven variations in cod recruitment production at multi-annual timescales, which had major impacts on population dynamics and the yields to commercial fisheries. We also quantify the roles of marine mammal predation, eutrophication, and exploitation on the development of the cod...

  9. Growth pattern and growth dependent mortality of larval and pelagic juvenile North Sea cod Gadus morhua

    DEFF Research Database (Denmark)

    Nielsen, Rune; Munk, Peter

    2004-01-01

    We investigated growth patterns and evidence of growth dependent survival for a population of Atlantic cod Gadus morhua using analysis of their otolith microstructure. Central concentrations of a population of cod larvae and juveniles in the north-eastern North Sea were sampled twice (in April...

  10. Correlation between microbiota and growth in Mangrove Killifish (Kryptolebias marmoratus) and Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Forberg, Torunn; Sjulstad, Eli Bjørnø; Bakke, Ingrid; Olsen, Yngvar; Hagiwara, Atsushi; Sakakura, Yoshitaka; Vadstein, Olav

    2016-02-15

    The vertebrate gut is host to large communities of bacteria, and one of the beneficial contributions of this commensal gut microbiota is the increased nutritional gain from feed components that the host cannot degrade on its own. Fish larvae of similar age and under the same rearing conditions often diverge with regards to growth. The underlying reasons for this could be differences in genetic background, feeding behavior or digestive capacity. Both feeding behavior and digestion can be influenced by differences in the microbiota. To investigate possible correlations between the size of fish larvae and their gut microbiota, we analyzed the microbiota small and large genetically homogenous killifish and genetically heterogeneous cod larvae by Bray-Curtis Similarity measures of 16S DNA DGGE patterns. A significant difference in richness (p = 0.037) was observed in the gut microbiota of small and large killifish, but the overall gut microbiota was not found to be significantly different (p = 0.13), indicating strong genetic host selection on microbiota composition at the time of sampling. The microbiota of small and large cod larvae was significantly different with regards to evenness and diversity (p = 0.0001), and a strong correlation between microbiota and growth was observed.

  11. Spatio-temporal dynamics of a fish predator: Density-dependent and hydrographic effects on Baltic Sea cod population.

    Science.gov (United States)

    Bartolino, Valerio; Tian, Huidong; Bergström, Ulf; Jounela, Pekka; Aro, Eero; Dieterich, Christian; Meier, H E Markus; Cardinale, Massimiliano; Bland, Barbara; Casini, Michele

    2017-01-01

    Understanding the mechanisms of spatial population dynamics is crucial for the successful management of exploited species and ecosystems. However, the underlying mechanisms of spatial distribution are generally complex due to the concurrent forcing of both density-dependent species interactions and density-independent environmental factors. Despite the high economic value and central ecological importance of cod in the Baltic Sea, the drivers of its spatio-temporal population dynamics have not been analytically investigated so far. In this paper, we used an extensive trawl survey dataset in combination with environmental data to investigate the spatial dynamics of the distribution of the Eastern Baltic cod during the past three decades using Generalized Additive Models. The results showed that adult cod distribution was mainly affected by cod population size, and to a minor degree by small-scale hydrological factors and the extent of suitable reproductive areas. As population size decreases, the cod population concentrates to the southern part of the Baltic Sea, where the preferred more marine environment conditions are encountered. Using the fitted models, we predicted the Baltic cod distribution back to the 1970s and a temporal index of cod spatial occupation was developed. Our study will contribute to the management and conservation of this important resource and of the ecosystem where it occurs, by showing the forces shaping its spatial distribution and therefore the potential response of the population to future exploitation and environmental changes.

  12. Spatio-temporal dynamics of a fish predator: Density-dependent and hydrographic effects on Baltic Sea cod population.

    Directory of Open Access Journals (Sweden)

    Valerio Bartolino

    Full Text Available Understanding the mechanisms of spatial population dynamics is crucial for the successful management of exploited species and ecosystems. However, the underlying mechanisms of spatial distribution are generally complex due to the concurrent forcing of both density-dependent species interactions and density-independent environmental factors. Despite the high economic value and central ecological importance of cod in the Baltic Sea, the drivers of its spatio-temporal population dynamics have not been analytically investigated so far. In this paper, we used an extensive trawl survey dataset in combination with environmental data to investigate the spatial dynamics of the distribution of the Eastern Baltic cod during the past three decades using Generalized Additive Models. The results showed that adult cod distribution was mainly affected by cod population size, and to a minor degree by small-scale hydrological factors and the extent of suitable reproductive areas. As population size decreases, the cod population concentrates to the southern part of the Baltic Sea, where the preferred more marine environment conditions are encountered. Using the fitted models, we predicted the Baltic cod distribution back to the 1970s and a temporal index of cod spatial occupation was developed. Our study will contribute to the management and conservation of this important resource and of the ecosystem where it occurs, by showing the forces shaping its spatial distribution and therefore the potential response of the population to future exploitation and environmental changes.

  13. Ocean warming and acidification modulate energy budget and gill ion regulatory mechanisms in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Kreiss, C M; Michael, K; Lucassen, M; Jutfelt, F; Motyka, R; Dupont, S; Pörtner, H-O

    2015-10-01

    Ocean warming and acidification are threatening marine ecosystems. In marine animals, acidification is thought to enhance ion regulatory costs and thereby baseline energy demand, while elevated temperature also increases baseline metabolic rate. Here we investigated standard metabolic rates (SMR) and plasma parameters of Atlantic cod (Gadus morhua) after 3-4 weeks of exposure to ambient and future PCO2 levels (550, 1200 and 2200 µatm) and at two temperatures (10, 18 °C). In vivo branchial ion regulatory costs were studied in isolated, perfused gill preparations. Animals reared at 18 °C responded to increasing CO2 by elevating SMR, in contrast to specimens at 10 °C. Isolated gills at 10 °C and elevated PCO2 (≥1200 µatm) displayed increased soft tissue mass, in parallel to increased gill oxygen demand, indicating an increased fraction of gill in whole animal energy budget. Altered gill size was not found at 18 °C, where a shift in the use of ion regulation mechanisms occurred towards enhanced Na(+)/H(+)-exchange and HCO3 (-) transport at high PCO2 (2200 µatm), paralleled by higher Na(+)/K(+)-ATPase activities. This shift did not affect total gill energy consumption leaving whole animal energy budget unaffected. Higher Na(+)/K(+)-ATPase activities in the warmth might have compensated for enhanced branchial permeability and led to reduced plasma Na(+) and/or Cl(-) concentrations and slightly lowered osmolalities seen at 18 °C and 550 or 2200 µatm PCO2 in vivo. Overall, the gill as a key ion regulation organ seems to be highly effective in supporting the resilience of cod to effects of ocean warming and acidification.

  14. Single and mixture effects of aquatic micropollutants studied in precision-cut liver slices of Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Bizarro, Cristina; Eide, Marta; Hitchcock, Daniel J; Goksøyr, Anders; Ortiz-Zarragoitia, Maren

    2016-08-01

    The low concentrations of most contaminants in the aquatic environment individually may not affect the normal function of the organisms on their own. However, when combined, complex mixtures may provoke unexpected effects even at low amounts. Selected aquatic micropollutants such as chlorpyrifos, bis-(2-ethylhexyl)-phthalate (DEHP), perfluorooctanoic acid (PFOA) and 17α-ethinylestradiol (EE2) were tested singly and in mixtures at nM to μM concentrations using precision-cut liver slices (PCLS) of Atlantic cod (Gadus morhua). Fish liver is a target organ for contaminants due to its crucial role in detoxification processes. In order to understand the effects on distinct key liver metabolic pathways, transcription levels of various genes were measured, including cyp1a1 and cyp3a, involved in the metabolism of organic compounds, including toxic ones, and the catabolism of bile acids and steroid hormones; cyp7a1, fabp and hmg-CoA, involved in lipid and cholesterol homeostasis; cyp24a1, involved in vitamin D metabolism; and vtg, a key gene in xenoestrogenic response. Only EE2 had significant effects on gene expression in cod liver slices when exposed singly at the concentrations tested. However, when exposed in combinations, effects not detected in single exposure conditions arose, suggesting complex interactions between studied pollutants that could not be predicted from the results of individual exposure scenarios. Thus, the present work highlights the importance of assessing mixtures when describing the toxic effects of micropollutants to fish liver metabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Characterization and expression analyses of five interferon regulatory factor transcripts (Irf4a, Irf4b, Irf7, Irf8, Irf10) in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Inkpen, Sabrina M; Hori, Tiago S; Gamperl, A Kurt; Nash, Gordon W; Rise, Matthew L

    2015-05-01

    The interferon regulatory factor (IRF) family of genes encodes a group of transcription factors that have important roles not only in regulating the expression of Type I interferons (IFNs) and other genes in the IFN pathway, but also in growth, development and the regulation of oncogenesis. In this study, several IRF family members (Irf4a, Irf4b, Irf7, Irf8, Irf10) in Atlantic cod (Gadus morhua) were characterized at the cDNA and putative amino acid levels, allowing for phylogenetic analysis of these proteins in teleost fish, as well as the development of gene-specific primers used in RT-PCR and quantitative PCR (QPCR) analyses. Two Atlantic cod Irf10 splice variants were identified and their presence confirmed by sequencing of the Irf10 genomic region. RT-PCR showed that Irf7, Irf8 and both Irf10 transcripts were expressed in all 15 cod tissues tested, while Irf4a and Irf4b were absent in some tissues. QPCR analysis of spleen expression expanded upon this, and upon previous work. All IRF transcripts in the study were responsive to stimulation by the viral mimic poly(I:C), and all except Irf4a were responsive to exposure to formalin-killed Aeromonas salmonicida (ASAL). These IRF genes, thus, are likely important in the cod immune response to both viral and bacterial infections. Increased temperature (10 °C to 16 °C) was also observed to modulate the antibacterial responses of all IRF transcripts, and the antiviral responses of Irf4b and Irf10-v2. This research supports earlier studies which reported that elevated temperature modulates the expression of many immune genes in Atlantic cod. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Temperature, paternity and asynchronous hatching influence early developmental characteristics of larval Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Politis, Sebastian Nikitas; Dahlke, Flemming T.; Butts, Ian A.E.

    2014-01-01

    or if they hatched at the end of the hatching period at a specific temperature. Differences in larval morphometrics among temperatures for early hatching larvae decreased or even reversed for later hatching larvae. In light of anticipated global climate change, the present study on cod provides further insight...... (LN), yolk-sac area (AY), and deformities. Larvae hatching on a given day were incubated at the same temperature and sampled at 4days post-hatch (DPH) for growth, yolk utilization rate (YUR) and efficiency (YUE). The mean±SE duration of the hatching window decreased with increasing temperature in both......Offspring, especially during early development, are influenced by both intrinsic properties endowed to them by their parents, extrinsic environmental factors as well as the interplay between genes and the environment. We investigated the effects of paternity (P), temperature (T), and asynchronous...

  17. Life on the edge: O2 binding in Atlantic cod red blood cells near their southern distribution limit is not sensitive to temperature or haemoglobin genotype.

    Science.gov (United States)

    Barlow, Samantha L; Metcalfe, Julian; Righton, David A; Berenbrink, Michael

    2017-02-01

    Atlantic cod are a commercially important species believed to be threatened by warming seas near their southern, equatorward upper thermal edge of distribution. Limitations to circulatory O2 transport, in particular cardiac output, and the geographic distribution of functionally different haemoglobin (Hb) genotypes have separately been suggested to play a role in setting thermal tolerance in this species. The present study assessed the thermal sensitivity of O2 binding in Atlantic cod red blood cells with different Hb genotypes near their upper thermal distribution limit and modelled its consequences for the arterio-venous O2 saturation difference, Sa-vO2 , another major determinant of circulatory O2 supply rate. The results showed statistically indistinguishable red blood cell O2 binding between the three HbI genotypes in wild-caught Atlantic cod from the Irish Sea (53° N). Red blood cells had an unusually low O2 affinity, with reduced or even reversed thermal sensitivity between pH 7.4 and 7.9, and 5.0 and 20.0°C. This was paired with strongly pH-dependent affinity and cooperativity of red blood cell O2 binding (Bohr and Root effects). Modelling of Sa-vO2  at physiological pH, temperature and O2 partial pressures revealed a substantial capacity for increases in Sa-vO2  to meet rising tissue O2 demands at 5.0 and 12.5°C, but not at 20°C. Furthermore, there was no evidence for an increase of maximal Sa-vO2  with temperature. It is suggested that Atlantic cod at such high temperatures may solely depend on increases in cardiac output and blood O2 capacity, or thermal acclimatisation of metabolic rate, for matching circulatory O2 supply to tissue demand. © 2017. Published by The Company of Biologists Ltd.

  18. How may feeding data be integrated into a model for a Norwegian fjord population of cod (Gadus morhua L. ?

    Directory of Open Access Journals (Sweden)

    Torstein Pedersen

    2003-04-01

    Full Text Available We investigate how cod feeding data may be included into a recently developed age-structured model for a coastal cod population in a small fjord in northern Norway. The model integrates data from mark-recapture experiments, trawl-surveys and commercial catches. The fjord population has high biomass density (2-3 tonnes km-2 and low fishing mortality rates (F

  19. An assessment of juvenile Atlantic cod Gadus morhua distribution and growth using diver operated stereo-video surveys.

    Science.gov (United States)

    Elliott, S A M; Ahti, P A; Heath, M R; Turrell, W R; Bailey, D M

    2016-08-01

    Stereo-video scuba transects were conducted during daylight hours from June to September 2013 within a proposed marine protected area (MPA) in the Firth of Clyde, west of Scotland. More juvenile Atlantic cod Gadus morhua of fork length (LF ) range 6-11 cm were observed in substrata containing mixed gravel, including maerl, than in boulder-cobble substrata with high algal cover, or sand with low density seagrass. Community composition was significantly different between substratum types. A decrease in G. morhua abundance was observed over the period of data collection. Over time, mean and variance in G. morhua LF increased, indicating multiple recruitment events. Protecting mixed gravel substrata could be a beneficial management measure to support the survival and recruitment of juvenile G. morhua; other substrata might be important at night given their diel migratory behaviour. Stereo-video cameras provide a useful non-destructive fisheries-independent method to monitor species abundance and length measurements. © 2016 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.

  20. Fertilisation and hatching success of Atlantic cod (Gadus morhua) eggs when exposed to various concentrations of produced water

    Energy Technology Data Exchange (ETDEWEB)

    Wong, D.; Lyons, M.; Burridge, L.; Lee, K. [Fisheries and Oceans Canada, Ottawa, ON (Canada)

    2010-07-01

    This study investigated the fertilization and hatching success of Atlantic cod (Gadus morhua) eggs that were exposed to various dilutions of produced water from a natural gas production platform. A control group of eggs was fertilized in sea water without any produced water. Another set of eggs were fertilized in sea water with 4 different concentrations of produced water and held their respective concentrations for 24 hours to evaluate the success of the fertilization. Viable fertilized eggs were transferred to 96 well plates containing fresh sea water and incubated in the dark at approximately 6 degrees C until hatch. Eggs began hatching about 14 days after fertilization (DPF), peaked at about 17 DPF, then finished hatching by 21 DPF. Analysis of PAH content in the diluted produced water showed that at 0.32 percent, 1.08 percent and 3.6 percent concentrations, the fertilization success was greater than or equal to that of the control group. However, for the 12 percent concentration, there were no viable fertilized eggs present after the 24 hour period. Survivability of eggs during sea water incubation was similar for the 0 percent, 0.32 percent and 1.08 percent treatment groups, but egg mortality increased for the 3.60 percent concentration group, to about 61.5 percent mean cumulative mortality at 6 DPF, then remained constant. The mean hatching success for all dilutions was presented.

  1. Growth of juvenile Atlantic cod Gadus morhua in land-based recirculation systems: Effects of feeding regime, photoperiod and diet

    DEFF Research Database (Denmark)

    Fülberth, Michael; Moran, Damian; Jarlbæk, Henrik

    2009-01-01

    fed Diet B and C also grew best under the LD12:11 and LD6:6 feed/photoperiod regimes (SGR range of 2.41–2.46% d− 1). Conversely, fish kept in the LD24:0 feed/photoperiod regime grew relatively slowly irrespective of diet type (SGR range of 2.26–2.32% d− 1). The feed conversion performance of the feed/photoperiod......The combined effect of feeding regime and photoperiod on the growth of juvenile Atlantic cod Gadus morhua in land-based recirculating aquaculture systems (RAS) was examined using three different commercial diets. Fish of 8–10 g were reared in 1 m3 tanks at an initial density of 10 kg m− 3 for 78 d....... Three RAS units were used to simultaneously test three feed/photoperiod regimes that might be encountered in the wild or aquaculture; LightDark (LD) 24:0, LD12:11 (+ 1 h crepuscular periods) and LD6:6 (+ 12 h crepuscular periods). Feed was administered during the light period every 30 min for a 3 min...

  2. Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Nedelec, Sophie L; Simpson, Stephen D; Morley, Erica L; Nedelec, Brendan; Radford, Andrew N

    2015-10-22

    Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod (Gadus morhua). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width-length ratios. Larvae with lower body width-length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures. © 2015 The Authors.

  3. Multi-decadal responses of a cod (Gadus morhua) population to human-induced trophic changes, fishing, and climate.

    Science.gov (United States)

    Eero, Margit; MacKenzie, Brian R; Köster, Friedrich W; Gislason, Henrik

    2011-01-01

    Understanding how human impacts have interacted with natural variability to affect populations and ecosystems is required for sustainable management and conservation. The Baltic Sea is one of the few large marine ecosystems worldwide where the relative contribution of several key forcings to changes in fish populations can be analyzed with empirical data. In this study we investigate how climate variability and multiple human impacts (fishing, marine mammal hunting, eutrophication) have affected multi-decadal scale dynamics of cod in the Baltic Sea during the 20th century. We document significant climate-driven variations in cod recruitment production at multi-annual timescales, which had major impacts on population dynamics and the yields to commercial fisheries. We also quantify the roles of marine mammal predation, eutrophication, and exploitation on the development of the cod population using simulation analyses, and show how the intensity of these forcings differed over time. In the early decades of the 20th century, marine mammal predation and nutrient availability were the main limiting factors; exploitation of cod was still relatively low. During the 1940s and subsequent decades, exploitation increased and became a dominant forcing on the population. Eutrophication had a relatively minor positive influence on cod biomass until the 1980s. The largest increase in cod biomass occurred during the late 1970s, following a long period of hydrographically related above-average cod productivity coupled to a temporary reduction in fishing pressure. The Baltic cod example demonstrates how combinations of different forcings can have synergistic effects and consequently dramatic impacts on population dynamics. Our results highlight the potential and limitations of human manipulations to influence predator species and show that sustainable management can only be achieved by considering both anthropogenic and naturally varying processes in a common framework.

  4. Harvest Pressure on Coastal Atlantic Cod (Gadus morhua from Recreational Fishing Relative to Commercial Fishing Assessed from Tag-Recovery Data.

    Directory of Open Access Journals (Sweden)

    Alf Ring Kleiven

    Full Text Available Marine recreational fishing is a popular outdoor activity. However, knowledge about the magnitude of recreational catches relative to commercial catches in coastal fisheries is generally sparse. Coastal Atlantic cod (Gadus morhua is a target species for recreational fishers in the North Atlantic. In Norway, recreational fishers are allowed to use a variety of traps and nets as well as long-line and rod and line when fishing for cod. From 2005 to 2013, 9729 cod (mean size: 40 cm, range: 15-93 cm were tagged and released in coastal Skagerrak, southeast Norway. Both high-reward (NOK 500 and low-reward tags (NOK 50 were used in this study. Because some harvested fish (even those posting high-reward tags may go unreported by fishers, reporting rates were estimated from mark-recovery models that incorporate detection parameters in their structure, in addition to survival and mortality estimates. During 2005 to 2013, a total of 1707 tagged cod were recovered and reported by fishers. We estimate the overall annual survival to be 33% (SE 1.5. Recreational rod and line fishing were responsible for 33.7% (SE 2.4 of total mortality, followed by commercial fisheries (15.1% SE 0.8 and recreational fixed gear (6.8% SE 0.4. Natural mortality was 44.4% (SE 2.5 of total mortality. Our findings suggest that recreational fishing-rod and line fishing in particular-is responsible for a substantial part of fishing mortality exerted on coastal cod in southern Norway.

  5. Harvest Pressure on Coastal Atlantic Cod (Gadus morhua) from Recreational Fishing Relative to Commercial Fishing Assessed from Tag-Recovery Data.

    Science.gov (United States)

    Kleiven, Alf Ring; Fernandez-Chacon, Albert; Nordahl, Jan-Harald; Moland, Even; Espeland, Sigurd Heiberg; Knutsen, Halvor; Olsen, Esben Moland

    2016-01-01

    Marine recreational fishing is a popular outdoor activity. However, knowledge about the magnitude of recreational catches relative to commercial catches in coastal fisheries is generally sparse. Coastal Atlantic cod (Gadus morhua) is a target species for recreational fishers in the North Atlantic. In Norway, recreational fishers are allowed to use a variety of traps and nets as well as long-line and rod and line when fishing for cod. From 2005 to 2013, 9729 cod (mean size: 40 cm, range: 15-93 cm) were tagged and released in coastal Skagerrak, southeast Norway. Both high-reward (NOK 500) and low-reward tags (NOK 50) were used in this study. Because some harvested fish (even those posting high-reward tags) may go unreported by fishers, reporting rates were estimated from mark-recovery models that incorporate detection parameters in their structure, in addition to survival and mortality estimates. During 2005 to 2013, a total of 1707 tagged cod were recovered and reported by fishers. We estimate the overall annual survival to be 33% (SE 1.5). Recreational rod and line fishing were responsible for 33.7% (SE 2.4) of total mortality, followed by commercial fisheries (15.1% SE 0.8) and recreational fixed gear (6.8% SE 0.4). Natural mortality was 44.4% (SE 2.5) of total mortality. Our findings suggest that recreational fishing-rod and line fishing in particular-is responsible for a substantial part of fishing mortality exerted on coastal cod in southern Norway.

  6. Discrimination between weaned and unweaned Atlantic cod (Gadus morhua in capture-based aquaculture (CBA by X-ray imaging and radio-frequency metal detector.

    Directory of Open Access Journals (Sweden)

    Ekrem Misimi

    Full Text Available The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg in the small scale capture-based aquaculture (CBA. Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60-70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups - unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented.

  7. Discrimination between Weaned and Unweaned Atlantic Cod (Gadus morhua) in Capture-Based Aquaculture (CBA) by X-Ray Imaging and Radio-Frequency Metal Detector

    Science.gov (United States)

    Misimi, Ekrem; Martinsen, Svein; Mathiassen, John Reidar; Erikson, Ulf

    2014-01-01

    The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60–70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups – unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented. PMID:24743448

  8. Discrimination between weaned and unweaned Atlantic cod (Gadus morhua) in capture-based aquaculture (CBA) by X-ray imaging and radio-frequency metal detector.

    Science.gov (United States)

    Misimi, Ekrem; Martinsen, Svein; Mathiassen, John Reidar; Erikson, Ulf

    2014-01-01

    The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60-70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups - unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented.

  9. The hypoxia avoidance behaviour of juvenile Atlantic cod (Gadus morhua L.) depends on the provision and pressure level of an O2 refuge

    DEFF Research Database (Denmark)

    Herbert, Neill A.; Skjaeraasen, Jon E.; Nilsen, Trygve

    2011-01-01

    The frequency of low O(2) (hypoxia) has increased in coastal marine areas but how fish avoid deleterious water masses is not yet clear. To assess whether the presence and oxygen pressure (PO(2)) level of an O(2) refuge affects the hypoxia avoidance behaviour of fish, individual Atlantic cod (Gadus...... morhua L.) were exposed to a range of O(2) choices in a 2-way choice chamber at 11.4 degrees C over two different experiments. Cod in the first experiment were allowed access to a fixed O(2) refuge (fully air-saturated seawater) whilst oxygen pressure (PO(2)) on the other side was reduced in steps...... to a critically low level, i.e. 4.3 kPa-a point where cod can no longer regulate O(2) consumption. Under these conditions, cod did not avoid any level of hypoxia and fish swimming speed also remained unchanged. In contrast, strong avoidance reactions were exhibited in a second experiment when fish were again...

  10. Effect of replacement of fish oil with camelina (Camelina sativa) oil on growth, lipid class and fatty acid composition of farmed juvenile Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Hixson, Stefanie M; Parrish, Christopher C; Anderson, Derek M

    2013-12-01

    Camelina (Camelina sativa) oil was tested as a replacement for fish oil in diets for farmed Atlantic cod (Gadus morhua). Camelina differs from other plant oilseeds previously used in aquaculture with high lipid (40 %), α-linolenic acid (40 %), antioxidants and low proportions of saturated fats. Dietary treatments were fed to cod (19 g fish⁻¹ initial weight) for 9 weeks and included a fish oil control (FO), 40 % (CO40) and 80 % (CO80) replacement of fish oil with camelina oil. There was no effect of replacing fish oil with camelina oil included at levels up to 80 % on the growth performance. Cod fed CO80 stored more lipid in the liver (p CO40 > CO80; p Camelina oil can reduce the amount of fish oil needed to meet lipid requirements, although replacing 80 % of fish oil reduced LC PUFAs in both tissues. A comparison of BF₃ and H₂SO₄ as catalysts to transmethylate cod liver and muscle lipids revealed small but significant differences in some fatty acid proportions.

  11. Global transcriptome analysis of Atlantic cod (Gadus morhua) liver after in vivo methylmercury exposure suggests effects on energy metabolism pathways.

    Science.gov (United States)

    Yadetie, Fekadu; Karlsen, Odd Andre; Lanzén, Anders; Berg, Karin; Olsvik, Pål; Hogstrand, Christer; Goksøyr, Anders

    2013-01-15

    Methylmercury (MeHg) is a widely distributed contaminant polluting many aquatic environments, with health risks to humans exposed mainly through consumption of seafood. The mechanisms of toxicity of MeHg are not completely understood. In order to map the range of molecular targets and gain better insights into the mechanisms of toxicity, we prepared Atlantic cod (Gadus morhua) 135k oligonucleotide arrays and performed global analysis of transcriptional changes in the liver of fish treated with MeHg (0.5 and 2 mg/kg of body weight) for 14 days. Inferring from the observed transcriptional changes, the main pathways significantly affected by the treatment were energy metabolism, oxidative stress response, immune response and cytoskeleton remodeling. Consistent with known effects of MeHg, many transcripts for genes in oxidative stress pathways such as glutathione metabolism and Nrf2 regulation of oxidative stress response were differentially regulated. Among the differentially regulated genes, there were disproportionate numbers of genes coding for enzymes involved in metabolism of amino acids, fatty acids and glucose. In particular, many genes coding for enzymes of fatty acid beta-oxidation were up-regulated. The coordinated effects observed on many transcripts coding for enzymes of energy pathways may suggest disruption of nutrient metabolism by MeHg. Many transcripts for genes coding for enzymes in the synthetic pathways of sulphur containing amino acids were also up-regulated, suggesting adaptive responses to MeHg toxicity. By this toxicogenomics approach, we were also able to identify many potential biomarker candidate genes for monitoring environmental MeHg pollution. These results based on changes on transcript levels, however, need to be confirmed by other methods such as proteomics. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Biological effects of polycyclic aromatic hydrocarbons (PAH) and their first metabolic products in in vivo exposed Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Pampanin, Daniela M; Le Goff, Jeremie; Skogland, Karianne; Marcucci, Cristian R; Øysæd, Kjell Birger; Lorentzen, Marianne; Jørgensen, Kåre B; Sydnes, Magne O

    2016-01-01

    The monitoring of the presence of polycyclic aromatic hydrocarbons (PAH) in the aquatic environment is a worldwide activity since some of these compounds are well-established carcinogens and mutagens. Contaminants in this class are in fact regarded as priority hazardous substances for environmental pollution (Water Framework Directive 2000/60/EC). In this study, Atlantic cod (Gadus morhua) was selected to assess in vivo effects of two PAH and their first metabolic products, namely, the corresponding trans-dihydrodiols, using biological markers. Fish were exposed for 1 wk to a single PAH (naphthalene or chrysene) and its synthetic metabolites ((1R,2R)-1,2-dihydronaphthalene-1,2-diol and (1R,2R)-1,2-dihydrochrysene-1,2-diol) by intraperitoneal injection in a continuous seawater flow system. After exposure, PAH metabolism including PAH metabolites in bile and ethoxyresorufin O-deethylase (EROD) activity, oxidative stress glutathione S-transferases (GST) and catalase (CAT) activities, and genotoxicity such as DNA adducts were evaluated, as well as general health conditions including condition index (CI), hepatosomatic index (HSI), and gonadosomatic index (GSI). PAH metabolite values were low and not significantly different when measured with the fixed-wavelength fluorescence screening method, while the gas chromatography-mass spectroscopy (GC-MS) method showed an apparent dose response in fish exposed to naphthalene. DNA adduct levels ≥0.16 × 10(-8) relative adduct level (RAL) were detected. It should be noted that 0.16 × 10(-8) RAL is considered the maximal acceptable background level for this species. The other biomarkers activities of catalase, GST, and EROD did not display a particular compound- or dose-related response. The GSI values were significantly lower in some chrysene- and in both naphthalene- and naphthalene diol-exposed groups compared to control.

  13. Optimization and comparison of miniaturized extraction techniques for PAHs from crude oil exposed Atlantic cod and haddock eggs.

    Science.gov (United States)

    Sørensen, Lisbet; Silva, Marta S; Booth, Andy M; Meier, Sonnich

    2016-02-01

    Two miniaturized extraction methods for a wide range of 2-6 ring polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues in small lipid-rich biota samples (≤100 mg) have been developed. Both methods utilize liquid extraction (LE) prior to a clean-up step using either normal phase solid phase extraction (SPE) or mixed-phase dispersive SPE (dSPE). Optimization of the methods was achieved by comparing the type and amount of sorbents, drying agents, and solvents used. In order to improve the limits of detection (LOD) of target PAHs under high sensitivity gas chromatography-tandem mass spectrometry analysis, specific emphasis was given to minimizing lipid co-extraction. The optimized LE-SPE method comprised extraction with dichloromethane/n-hexane (1:1, v/v) and clean-up by silica SPE, whereas the optimized LE-dSPE method comprised extraction with acetonitrile and clean-up with PSA and C18 sorbents. The methods were validated and directly compared through the analysis of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) eggs exposed to oil. The LE-SPE method resulted in lower levels of co-extracted lipids (14.1 ± 1.7 ng/μL) than the LE-dSPE method (60 ± 14 ng/μL). Achieved PAH LODs for the LE-SPE method were typically an order of magnitude lower (fish eggs (~100 mg) exposed to small quantities of crude oil (~1-10 μg/L total PAHs).

  14. Where does the cod come from? Panels of gene‐associated markers provide vastly improved origin assignment in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Hansen, Jakob Hemmer; Taylor, Martin

    2012-01-01

    Methods for determining the geographical origin of individual fish are in high demand for fighting illegal, unreported, and unregulated (IUU) fishing and for independent control of catch certificates and “eco‐labels”. Hitherto, genetic origin assignment of marine fish has been hampered by the gen...... relevant for controlling illegal fishing, ecolabels, and fisheries management. Our results demonstrate how application of gene‐associated markers will probably revolutionize origin assignment in cod by providing faster, cheaper, and more reliable tools for origin assignment...

  15. A review of the contributions of fisheries and climate variability to contrasting dynamics in two Arcto-boreal Atlantic cod (Gadus morhua) stocks: Persistent high productivity in the Barents Sea and collapse on the Newfoundland and Labrador Shelf

    Science.gov (United States)

    Lilly, George R.; Nakken, Odd; Brattey, John

    2013-07-01

    Stocks of Atlantic cod (Gadus morhua) across the North Atlantic and adjacent seas have been fished intensively for years, and many are now severely depleted. In order to promote recovery and sustainable harvesting, it is essential to understand factors that have contributed to the declines and to variability in rates of recovery. Considerable insight may be gleaned by comparing and contrasting the histories of the Northeast Arctic (NEA) cod in the Barents Sea - Svalbard area of the northeast Atlantic and the “northern cod” on the Newfoundland and Labrador (NL) shelf in the northwest Atlantic. These two stocks, which were among the 3 largest cod stocks during the middle of the 20th century, are Arcto-boreal, and have many species of prey and predators in common. The biomass of NEA cod has varied considerably over time, and in 2009 was a little above 60% of its maximum observed level, which occurred in the late 1940s and early 1950s. In contrast, the biomass of NL cod decreased steadily from the early 1960s to the late 1970s, increased somewhat during the 1980s, and crashed during the early 1990s to an extremely low level, at which it remained for a decade before showing recent indications of improvement. Although both stocks were influenced by similar changes in harvesting strategies and environmental circumstances, both biotic and abiotic, there are two events which stand out as being particularly influential. First, crises developed in the management of both stocks in the late 1980s. For NEA cod, the crisis was environmental, caused by the collapse of capelin (Mallotus villosus), the main food for adult cod, whereas for NL cod the crisis was caused by a sudden large reduction in scientific perception of stock size. The difference in response to these crises strongly influenced subsequent stock dynamics. Catches of NEA cod were reduced considerably, preventing severe overharvesting of the cod that at that time experienced low productivity, whereas catches of NL

  16. Seals, cod and forage fish: A comparative exploration of variations in the theme of stock collapse and ecosystem change in four Northwest Atlantic ecosystems

    Science.gov (United States)

    Bundy, Alida; Heymans, Johanna J.; Morissette, Lyne; Savenkoff, Claude

    2009-04-01

    The facts: four Northwest Atlantic ecosystems, three cod stock collapses 15 years ago (plus one severely depleted), seals now top predator in all ecosystems, all had cod as a top predator before collapse, groundfish declines in all areas, forage base increased in most systems. No recovery in any system. Have these ecosystems fundamentally changed? Why? The challenge: compare and contrast these four ecosystems. The answer: using mass balance models, empirical data and a suite of ecosystem indicators, we explore how and why these systems have changed over time. At the ecosystem and community level, we see broad similarities between ecosystems. However, structurally and functionally these systems have shifted to an alternate state, with changes in predator structure, trophic structure and flow.

  17. Forecasting the Major Influences of Predation and Environment on Cod Recovery in the Northern Gulf of St. Lawrence

    OpenAIRE

    Nicolas Bousquet; Emmanuel Chassot; Duplisea, Daniel E.; Mike O Hammill

    2014-01-01

    The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring thi...

  18. Validation of reference genes for quantitative RT-qPCR studies of gene expression in Atlantic cod (Gadus morhua l. during temperature stress

    Directory of Open Access Journals (Sweden)

    Karlsen Hans E

    2011-04-01

    Full Text Available Abstract Background One important physiological response to environmental stress in animals is change in gene expression. To obtain reliable data from gene expression studies using RT-qPCR it is important to evaluate a set of possible reference genes as normalizers for expression. The expression of these candidate genes should be analyzed in the relevant tissues during normal and stressed situations. To find suitable reference genes it was crucial that the genes were stably expressed also during a situation of physiological stress. For poikilotermic animals like cod, changes in temperature are normal, but if the changes are faster than physiological compensation, the animals respond with typical stress responses. It has previously been shown that Atlantic cod show stress responses when elevation of water temperature is faster than 1 degree/day, for this reason we chose hyperthermia as stress agent for this experiment. Findings We here describe the expression of eight candidate reference genes from Atlantic cod (Gadus morhua l. and their stability during thermal stress (temperature elevation of one degree C/day for 5 days. The genes investigated were: Eukaryotic elongation factor 1 alpha, ef1a; 18s ribosomal RNA; 18s, Ubiquitin conjugate protein; ubiq, cytoskeletal beta-actin; actb, major histcompatibility complex I; MHC-I light chain, beta-2 -microglobulin; b2m, cytoskeletal alpha-tubulin; tba1c, acidic ribosomal phosphoprotein; rplp1, glucose-6-phosphate dehydrogenase; g6pd. Their expression were analyzed in 6 tissues (liver, head kidney, intestine, spleen, heart and gills from cods exposed to elevated temperature and compared to a control group. Although there were variations between tissues with respect to reference gene stability, four transcripts were more consistent than the others: ubiq, ef1a, 18s and rplp1. We therefore used these to analyze the expression of stress related genes (heat shock proteins induced during hyperthermia. We found

  19. Seasonal variation in biomarkers in blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua)-Implications for environmental monitoring in the Barents Sea

    Energy Technology Data Exchange (ETDEWEB)

    Nahrgang, J., E-mail: jasmine.m.nahrgang@uit.no [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Brooks, S.J. [Norwegian Institute for Water Research (NIVA), NO-0349 Oslo (Norway); Evenset, A. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Camus, L. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University Centre In Svalbard (UNIS), NO-9171 Longyearbyen (Norway); Jonsson, M.; Smith, T.J. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Lukina, J. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University of Tromso, Faculty of Biosciences, Fisheries and Economics, Department of Arctic and Marine Biosciences, NO-9037 Tromso (Norway); Frantzen, M. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); Giarratano, E. [Centro Nacional Patagonico (CENPAT-CONICET), AR-9120 Puerto Madryn (Argentina); Renaud, P.E. [Akvaplan-niva, FRAM Centre, NO-9296 Tromso (Norway); University Centre In Svalbard (UNIS), NO-9171 Longyearbyen (Norway)

    2013-02-15

    In the Barents Sea, the limited data on biological relevant indicators and their responses to various anthropogenic stressors have hindered the development of a consistent scientific basis for selecting indicator species and developing practical procedures for environmental monitoring. Accordingly, the main aim of the present study was to develop a common set of baseline values for contaminants and biomarkers in three species, and to identify their strengths and limitations in monitoring of the Barents Sea. Blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua) were sampled from a north Norwegian fjord in March, June, September and December 2010. Digestive glands from the bivalve species and liver from Atlantic cod were analysed for biomarkers of oxidative stress (catalase [CAT], glutathione peroxidase [GPX], glutathione-S-transferase activities [GST], lipid peroxidation as thiobarbituric reactive substances [TBARS] and total oxyradical scavenging capacity [TOSC]), biotransformation (ethoxyresorufine-O-deethylase activity [EROD]) and general stress (lysosomal membrane stability [LMS]). Concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals in the bivalves and PAH metabolites in fish bile were quantified. Finally, energy reserves (total lipids, proteins and carbohydrates) and electron transport system (ETS) activity in the digestive gland of the bivalves and liver of Atlantic cod provided background information for reproductive cycle and general physiological status of the organisms. Blue mussel and Icelandic scallop showed very similar trends in biological cycle, biomarker expression and seasonality. Biomarker baselines in Atlantic cod showed weaker seasonal variability. However, important biological events may have been undetected due to the large time intervals between sampling occasions. Physiological biomarkers such as energy reserves and ETS activity were recommended as complementary parameters to the

  20. Extracellular glucose supports lactate production but not aerobic metabolism in cardiomyocytes from both normoglycemic Atlantic cod and low glycemic short-horned sculpin.

    Science.gov (United States)

    Clow, Kathy A; Short, Connie E; Driedzic, William R

    2016-05-01

    Fish exhibit a wide range of species-specific blood glucose levels. How this relates to glucose utilization is yet to be fully realized. Here, we assessed glucose transport and metabolism in myocytes isolated from Atlantic cod (Gadus morhua) and short-horned sculpin (Myoxocephalus scorpius), species with blood glucose levels of 3.7 and 0.57 mmol l(-1), respectively. Glucose metabolism was assessed by the production of (3)H2O from [2-(3)H]glucose. Glucose metabolism was 3.5- to 6-fold higher by myocytes from Atlantic cod than by those from short-horned sculpin at the same level of extracellular glucose. In Atlantic cod myocytes, glucose metabolism displayed what appears to be a saturable component with respect to extracellular glucose, and cytochalasin B inhibited glucose metabolism. These features revealed a facilitated glucose diffusion mechanism that accounts for between 30% and 55% of glucose entry at physiological levels of extracellular glucose. Facilitated glucose diffusion appears to be minimal in myocytes for short-horned sculpin. Glucose entry by simple diffusion occurs in both cell types with the same linear relationship between glucose metabolism and extracellular glucose concentration, presumably due to similarities in membrane composition. Oxygen consumption by myocytes incubated in medium containing physiological levels of extracellular glucose (Atlantic cod 5 mmol l(-1), short-horned sculpin 0.5 mmol l(-1)) was similar in the two species and was not decreased by cytochalasin B, suggesting that these cells have the capability of oxidizing alternative on-board metabolic fuels. Cells produced lactate at low rates but glycogen levels did not change during the incubation period. In cells from both species, glucose utilization assessed by both simple chemical analysis of glucose disappearance from the medium and (3)H2O production was half the rate of lactate production and as such extracellular glucose was not available for oxidative metabolism

  1. Diel vertical interactions between Atlantic cod Gadus morhua and sprat Sprattus sprattus in a stratified water column

    DEFF Research Database (Denmark)

    Andersen, Niels Gerner; Lundgren, Bo; Neuenfeldt, Stefan

    2017-01-01

    , respectively. Cod resided close to the bottom outside these temporal predation windows. Sprat schools were located at the same depth as cod in the daylight hours, whereas at night dispersed sprat were situated higher in the water column. These vertical dynamics could be explained by fitness optimization using...... bioenergetics and trade-offs between temperature, oxygen saturation of the water and predation risk. This study forms a first step towards providing a mechanistic background for the predatory impact of cod at the basin scale and beyond...

  2. Regional changes in vertebra morphology during ontogeny reflect the life history of Atlantic cod (Gadus morhua L.)

    Science.gov (United States)

    Fjelldal, Per G; Totland, Geir K; Hansen, Tom; Kryvi, Harald; Wang, Xiyuan; Søndergaard, Jens L; Grotmol, Sindre

    2013-01-01

    This study examined vertebra formation, morphology, regional characters, and bending properties of the vertebral column of Atlantic cod throughout its life cycle (0–6 years). The first structure to form was the foremost neural arch, 21 days post hatching (dph), and the first vertebra centrum to form – as a chordacentrum – was the 3rd centrum at 28 dph. Thereafter, the notochord centra developed in a regular sequence towards the head and caudal fin. All vertebrae were formed within 50 dph. The vertebral column consisted of 52 (± 2) vertebrae (V) and could be divided into four distinct regions: (i) the cervical region (neck) (V1 and V2), characterized by short vertebra centra, prominent neural spines and absence of articulations with ribs; (ii) the abdominal region (trunk) (V3–V19), characterized by vertebrae with wing-shaped transverse processes (parapophyses) that all articulate with a rib; (iii) the caudal region (tail) (V20–V40), where the vertebra centra have haemal arches with prominent haemal spines; (iv) the ural region (V41 to the last vertebra), characterized by broad neural and haemal spines, providing sites of origin for muscles inserting on the fin rays – lepidotrichs – of the tail fin. The number of vertebrae in the cervical, abdominal and caudal regions was found to be constant, whereas in the ural region, numbers varied from 12 to 15. Geometric modelling based on combination of vertebra lengths, diameters and intervertebral distances showed an even flexibility throughout the column, except in the ural region, where flexibility increased. Throughout ontogeny, the vertebra centra of the different regions followed distinct patterns of growth; the relative length of the vertebrae increased in the cervical and abdominal regions, and decreased in the caudal and ural regions with increasing age. This may reflect changes in swimming mode with age, and/or that the production of large volumes of gametes during sexual maturation requires a

  3. HLA genes in Atlantic Celtic populations: are Celts Iberians? | Arnaiz ...

    African Journals Online (AJOL)

    Atlantic Europe populations were analyzed with HLA genes in order to establish their relationship among themselves and with other populations. Standard genetic and statistical software analyses were used. Celtic populations (British Isles and French Bretons) have genetically been found close together: Irish, Welsh, ...

  4. A new method for the rapid detection of Atlantic cod (Gadus morhua), Pacific cod (Gadus macrocephalus), Alaska pollock (Gadus chalcogrammus) and ling (Molva molva) using a lateral flow dipstick assay.

    Science.gov (United States)

    Taboada, Ledicia; Sánchez, Ana; Pérez-Martín, Ricardo I; Sotelo, Carmen G

    2017-10-15

    Species-specific lateral flow dipstick (LFD) assays for the identification of Atlantic cod (Gadus morhua), Pacific cod (Gadus macrocephalus), Alaska pollock (Gadus chalcogrammus) and ling (Molva molva) in food products were developed. The method comprises a PCR system with four sets of specific primers, for each target species. This step was also devised to dual-labeling of PCR products with biotin and 6-FAM, which are then easily read on a lateral flow dipstick, upon which these products are immobilized by a fixed biotin-ligand and visualized with anti-FAM antibody-coated gold nanoparticles. Sensitivity and selectivity were determined for each of the developed assays. Validation of the assays was performed with DNA extracted from commercial fish products, the identification of all samples by PCR-LFD was coherent with the results found with DNA sequencing. Target species were successfully detected in analyzed commercial samples, demonstrating the applicability of this method to the rapid analysis of food products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Historical changes in genotypic frequencies at the Pantophysin locus in Atlantic cod (Gadus morhua) in Icelandic waters: evidence of fisheries-induced selection?

    Science.gov (United States)

    Jakobsdóttir, Klara B; Pardoe, Heidi; Magnússon, Árni; Björnsson, Höskuldur; Pampoulie, Christophe; Ruzzante, Daniel E; Marteinsdóttir, Guðrún

    2011-01-01

    The intense fishing mortality imposed on Atlantic cod in Icelandic waters during recent decades has resulted in marked changes in stock abundance, as well as in age and size composition. Using a molecular marker known to be under selection (Pan I) along with a suite of six neutral microsatellite loci, we analysed an archived data set and revealed evidence of distinct temporal changes in the frequencies of genotypes at the Pan I locus among spawning Icelandic cod, collected between 1948 and 2002, a period characterized by high fishing pressure. Concurrently, temporal stability in the composition of the microsatellite loci was established within the same data set. The frequency of the Pan IBB genotype decreased over a period of six decades, concomitant with considerable spatial and technical changes in fishing effort that resulted in the disappearance of older individuals from the fishable stock. Consequently, these changes have likely led to a change in the genotype frequencies at this locus in the spawning stock of Icelandic cod. The study highlights the value of molecular genetic approaches that combine functional and neutral markers examined in the same set of individuals for investigations of the selective effects of harvesting and reiterates the need for an evolutionary dimension to fisheries management. PMID:25568005

  6. Historical changes in genotypic frequencies at the Pantophysin locus in Atlantic cod (Gadus morhua) in Icelandic waters: evidence of fisheries-induced selection?

    Science.gov (United States)

    Jakobsdóttir, Klara B; Pardoe, Heidi; Magnússon, Árni; Björnsson, Höskuldur; Pampoulie, Christophe; Ruzzante, Daniel E; Marteinsdóttir, Guðrún

    2011-07-01

    The intense fishing mortality imposed on Atlantic cod in Icelandic waters during recent decades has resulted in marked changes in stock abundance, as well as in age and size composition. Using a molecular marker known to be under selection (Pan I) along with a suite of six neutral microsatellite loci, we analysed an archived data set and revealed evidence of distinct temporal changes in the frequencies of genotypes at the Pan I locus among spawning Icelandic cod, collected between 1948 and 2002, a period characterized by high fishing pressure. Concurrently, temporal stability in the composition of the microsatellite loci was established within the same data set. The frequency of the Pan I(BB) genotype decreased over a period of six decades, concomitant with considerable spatial and technical changes in fishing effort that resulted in the disappearance of older individuals from the fishable stock. Consequently, these changes have likely led to a change in the genotype frequencies at this locus in the spawning stock of Icelandic cod. The study highlights the value of molecular genetic approaches that combine functional and neutral markers examined in the same set of individuals for investigations of the selective effects of harvesting and reiterates the need for an evolutionary dimension to fisheries management.

  7. Population Structuring and Migration Pathway of Atlantic bonito Sarda sarda

    Directory of Open Access Journals (Sweden)

    Cemal Turan

    2016-09-01

    Full Text Available Population structure of Atlantic Bonito Sarda sarda in the Mediterranean Sea and possible pathway of migration for spawning and feeding was discussed on the bases of genetic and morphological dataset. The effects of topographic and hydrographic factors on the connectivity and migration pattern of Atlantic Bonito in Turkish, Bulgarian and Croatian marine waters and fishery management implications of putative stocks were correspondingly referred

  8. Trophic relations of capelin Mallotus villosus and polar cod Boreogadus saida in the Barents Sea as a factor of impact on the ecosystem

    Science.gov (United States)

    Orlova, Emma L.; Dolgov, Andrey V.; Rudneva, Galina B.; Oganin, Ivan A.; Konstantinova, Ludmila L.

    2009-10-01

    The purpose of the study is to assess the role of trophic relations of the dominant pelagic fishes capelin and polar cod in the Barents Sea with regard to distribution and accessibility as prey for the Atlantic cod in warm years (2004-2005). Unlike in the previous period, during these warm years a dramatic increase of the polar cod population resulted in a northwards expansion of the feeding grounds where overlapping of polar cod and capelin concentrations was observed. This caused an increased competition for copepods, which are the main food item for young fish. In the areas dominated by polar cod the shortage of copepods forced immature capelin to switch to the chaetognath Sagitta, which affected their fatness negatively. During the warm years the feeding grounds of Atlantic cod also expanded, to a large degree caused by the shortage of their main food, the capelin. In 2004-2005 the cod formed feeding concentrations in the north and northeast Barents Sea where they fed on the capelin. In this area the consumption of polar cod by cod increased, and in some local areas the polar cod practically replaced the capelin in the diet of cod. In general polar cod in the diet of Atlantic cod were more important in the northern than in the southern part of the Barents Sea. The fatness of cod was extremely low during the whole spring-summer period (until August), and after the feeding period the fatness index of the Atlantic cod became lower than the average long-term autumn value.

  9. Northeast Regional Cod Tagging Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientific justification: Canadian and US stock assessments for Atlantic cod indicate considerable fluctuation in stock abundance and recruitment over the last 20...

  10. Industry Based Survey (IBS) Cod

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Gulf of Maine Atlantic Cod Industry-Based Survey" was a collaboration of the Massachusetts Division of Marine Fisheries and the fishing industry, with support...

  11. Conditions for instant electrical stunning of farmed Atlantic cod after de-watering, maintenance of unconsciousness, effects of stress, and fillet quality — A comparison with AQUI-S™

    NARCIS (Netherlands)

    Erikson, U.; Lambooij, E.; Digre, H.; Reimert, H.G.M.; Bondø, M.; Vis, van de H.

    2012-01-01

    Electrical stunning of farmed Atlantic cod is a method used to render the fish unconscious before further processing. However, evaluations of the stunning method at plants have shown that the electrical parameters need to be optimized to achieve instant stunning and prolonged duration of

  12. Characterization and expression analyses of anti-apoptotic Bcl-2-like genes NR-13, Mcl-1, Bcl-X1, and Bcl-X2 in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Feng, Charles Y; Rise, Matthew L

    2010-01-01

    NR-13, Mcl-1, and BCL-X(L), are conserved anti-apoptotic proteins that belong to the anti-apoptotic Bcl-2 sub-family, which inhibits cell death by preventing mitochondrial membrane permeabilization (MMP). Given the anti-apoptotic functions of these proteins in vertebrates (e.g. human, mouse, and zebrafish) and the involvement of apoptotic regulation in immune responses, we studied the sequences of these genes and their transcript expression in Atlantic cod (Gadus morhua) during innate immune responses to viral and bacterial stimuli. Based on previously generated Atlantic cod expressed sequence tags (ESTs), we identified partial cDNA sequences of putative orthologues of Atlantic cod NR-13, Mcl-1, and Bcl-X, and obtained the full-length cDNA, genomic, and promoter region sequences for these genes. The analyses of Atlantic cod cDNA sequences, and comparisons of the cod deduced amino acid sequences to putative orthologues in other species, revealed the presence of highly conserved Bcl-2 homology (BH) and transmembrane (TM) domains in the Atlantic cod sequences. Analysis of gene structure revealed conserved intron/exon boundaries within the coding regions of human and Atlantic cod putative orthologues. We found that an intron/exon boundary immediately following the codon for the 8th residue (tryptophan) of the BH2 domain exists in all anti-apoptotic Bcl-2 sub-family genes regardless of vast evolutionary distance. We also identified a non-coding exon in the Atlantic cod NR-13-like gene, which appears to be absent in its putative mammalian orthologues. Quantitative reverse transcription-polymerase chain reaction (QPCR) was used to study constitutive gene expression in six tissues (blood, brain, gill, head kidney, pyloric caecum, and spleen) of non-stressed juvenile cod; NR-13 and Bcl-X2 were most highly expressed in gill, whereas Mcl-1 and Bcl-X1 were most highly expressed in blood. In cod challenged with intraperitoneal (IP) injections of the viral mimic polyriboinosinic

  13. Substitution of fish oil with camelina oil and inclusion of camelina meal in diets fed to Atlantic cod (Gadus morhua) and their effects on growth, tissue lipid classes, and fatty acids.

    Science.gov (United States)

    Hixson, S M; Parrish, C C

    2014-03-01

    Developing a commercially relevant Atlantic cod aquaculture industry will require improvements in feed sustainability. Camelina oil and meal are potential replacements of fish oil and fish meal in aquaculture feeds. Camelina oil is high in 18:3ω3 (30%), with an ω3/ω6 ratio > 1. Camelina meal has a considerable crude protein level (38%), which includes significant amounts of methionine and phenylalanine. Four diets were tested; each diet was fed to triplicate tanks (3 tanks per diet) of Atlantic cod (14.4 g/fish; 70 fish per tank) for 13 wk. The diets included a fish oil/fish meal control (FO) and three diets which replaced 100% of fish oil with camelina oil: one diet contained fish meal (100CO), another solvent extracted fish meal (100COSEFM), and another had fish meal partially reduced by 15% inclusion of camelina meal (100CO15CM). Growth was measured (length and weight) and tissue samples were collected for lipid analysis (muscle, liver, brain, gut, spleen, skin, and carcass) at wk 0 (before feeding the experimental diet) and at wk 13. Cod fed camelina oil had a lower (P cod fed the FO diet (50.8 ± 10.3 g/fish). Cod fed 100CO15CM had a lower (P Cod tissues in the 100COSEFM treatment were most impacted by dietary fatty acid profile. Multivariate statistics revealed that FO and 100COSEFM tissue fatty acid profiles were 21 to 31% different, depending on tissue type. The full replacement of fish oil with camelina oil, plus solvent extracted fish meal had an overarching effect on the entire fatty acid profile of the whole animal. Fatty acid mass balance calculations indicated that cod fed 100COSEFM elongated 13% of 18:3ω3 to 20:3ω3 and oxidized the remaining 87%, whereas cod fed fish oil showed a much lower (P cod fed 100COSEFM deposited the most energy throughout the trial (60 kJ/fish; P = 0.019), mostly in the liver (90%). Excess camelina lipids were not necessarily utilized for energy, which likely impacted growth. Feeding 100% camelina oil to Atlantic cod

  14. Effects of dietary fatty acids on the production and quality of eggs and larvae of Atlantic cod (Gadus morhua L.)

    DEFF Research Database (Denmark)

    Røjbek, Maria; Støttrup, Josianne; Jacobsen, Charlotte

    2014-01-01

    –173% higher in eggs than in diets. Cod fed the diet with the lowest EPA/ARA ratio had the greatest egg production. Eggs from fish on a diet with high ARA level had significantly higher fertilization and hatching success than those fed low levels of ARA. This diet produced on average 71 viable eggs g 1 female...

  15. The third serine proteinase with chymotrypsin specificity isolated from Atlantic cod (Gadus morhua) is a type-II elastase

    DEFF Research Database (Denmark)

    Asgeirsson, B; Leth-Larsen, Rikke; Thórólfsson, M

    1998-01-01

    efficiency of elastase C. The effects of several inhibitors on cod elastase C were identical to effects on chymotrypsins variants A and B, but dissimilar when compared with porcine pancreatic elastase. On the basis of the specificity and amino acid sequence, we conclude that the enzyme under study is most...

  16. Biomarker candidate discovery in Atlantic cod (Gadus morhua) continuously exposed to North Sea produced water from egg to fry

    DEFF Research Database (Denmark)

    Bohne-Kjersem, Anneli; Bache, Nicolai; Meier, Sonnich

    2010-01-01

    spectrometry, using a newly developed cod EST database and the NCBI database. Many of the protein changes occurred at low levels (0.01% and 0.1% PW) of exposure, indicating putative biological responses at lower levels than previously detected. Using discriminant analysis, we identified a set of protein...

  17. Differential Survival among Batches of Atlantic Cod (Gadus morhua L. from Fertilisation through to Post-Metamorphosis.

    Directory of Open Access Journals (Sweden)

    Petra E Petersen

    Full Text Available Aquaculture production of cod has decreased from over 20,000 tonnes in 2009 to less than 2,000 tonnes in 2014 and the industry faces many challenges, one of which is high and unpredictably variable mortality rates in the early life stages. Hence, full-cycle farming with hatchery produced juveniles is still considered unprofitable compared to fisheries and on-growing of wild cod. In the present study, potential batch differences in progeny survival of wild-caught, hatchery-spawned Faroe Bank cod (Gadus morhua L. were investigated at two defined periods during early life history; i the embryo stage (60 day degrees post fertilisation and ii the fry stage (110 days post hatch, post metamorphosis. The fry stage experiment was conducted in three replicates (N = 300 per replicate, and a panel of three polymorphic microsatellite markers was used for parental analysis. Mean survival rate at the embryo stage was 69% (± 20% SD. Survival was positively associated with egg diameter (P < 0.01, explaining 90% of the variation in egg survival rates. The data were too scarce to conclude either way concerning a possible correlation between survival rates between the two periods (P < 0.10. Offspring from three batches (from a total of eight dominated in the fry stage, contributing over 90% of the progeny, and results were consistent over all three replicate tanks. The skewed batch representation observed may be of relevance to the effective management of selective breeding programmes for cod.

  18. Differential Survival among Batches of Atlantic Cod (Gadus morhua L.) from Fertilisation through to Post-Metamorphosis.

    Science.gov (United States)

    Petersen, Petra E; Penman, David J; Dahle, Geir; Patursson, Øystein; Taggart, John B

    2016-01-01

    Aquaculture production of cod has decreased from over 20,000 tonnes in 2009 to less than 2,000 tonnes in 2014 and the industry faces many challenges, one of which is high and unpredictably variable mortality rates in the early life stages. Hence, full-cycle farming with hatchery produced juveniles is still considered unprofitable compared to fisheries and on-growing of wild cod. In the present study, potential batch differences in progeny survival of wild-caught, hatchery-spawned Faroe Bank cod (Gadus morhua L.) were investigated at two defined periods during early life history; i) the embryo stage (60 day degrees post fertilisation) and ii) the fry stage (110 days post hatch), post metamorphosis. The fry stage experiment was conducted in three replicates (N = 300 per replicate), and a panel of three polymorphic microsatellite markers was used for parental analysis. Mean survival rate at the embryo stage was 69% (± 20% SD). Survival was positively associated with egg diameter (P < 0.01), explaining 90% of the variation in egg survival rates. The data were too scarce to conclude either way concerning a possible correlation between survival rates between the two periods (P < 0.10). Offspring from three batches (from a total of eight) dominated in the fry stage, contributing over 90% of the progeny, and results were consistent over all three replicate tanks. The skewed batch representation observed may be of relevance to the effective management of selective breeding programmes for cod.

  19. New England Cod Collapse and the Climate.

    Directory of Open Access Journals (Sweden)

    Kyle C Meng

    Full Text Available To improve fishery management, there is an increasing need to understand the long-term consequences of natural and anthropogenic climate variability for ecological systems. New England's iconic cod populations have been in decline for several decades and have recently reached unprecedented lows. We find that 17% of the overall decline in Gulf of Maine cod biomass since 1980 can be attributed to positive phases of the North Atlantic Oscillation (NAO. This is a consequence of three results: i a 1-unit increase in the NAO winter index is associated with a 17% decrease in the spring biomass of age-1 cod the following year; ii this NAO-driven decrease persists as the affected cohort matures; iii fishing practices appear to exacerbate NAO's direct biological effect such that, since 1913, a 1-unit increase in the NAO index lowers subsequent cod catch for up to 19 years. The Georges Bank cod stock displays similar patterns. Because we statistically detect a delay between the NAO and subsequent declines in adult biomass, our findings imply that observed current NAO conditions can be used in stock forecasts, providing lead time for adaptive policy. More broadly, our approach can inform forecasting efforts for other fish populations strongly affected by natural and anthropogenic climatic variation.

  20. Changes in regional brain monoaminergic activity and temporary down-regulation in stress response from dietary supplementation with l-tryptophan in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Basic, D.; Schjolden, J.; Krogdahl, A.

    2013-01-01

    or four times the Trp levels in commercial feed, last in juvenile Atlantic cod (Gadus morhua) when the fish are reintroduced to a diet with standard amino acid composition. We also wanted to determine whether Trp supplementation induced changes in brain monoaminergic neurochemistry in those forebrain...... structures innervated by DA- and 5-HTergic neurons, by measuring regional activity of DA and 5-HT in the lateral pallial regions (Dl) of the telencephalon and nucleus lateralis tuberis (NLT) of the hypothalamus. Dietary Trp resulted in a dose-dependent suppression in plasma cortisol among fish exposed...... to confinement stress on the first day following experimental diet; however, such an effect was not observed at 2 or 6 d after Trp treatment. Feeding the fish with moderate Trp doses also evoked a general increase in DA and 5-HT-ergic activity, suggesting that these neural circuits within the NLT and Dl may...

  1. Cortisol levels and expression of selected stress- and apoptosis-related genes in the embryos of Atlantic cod, Gadus morhua following short-term exposure to air

    DEFF Research Database (Denmark)

    Marlowe, Christopher; Caipang, A.; Fagutao, Ferdinand F.

    2015-01-01

    Embryos (morula stage) of Atlantic cod, Gadus morhua L., were collected and subjected to air exposure for 2 min. followed by recovery at ambient conditions in the rearing container. Total immunoreactive cortisol and transcription of selected stress- and apoptosis-related genes of the embryos were...... determined before the application of the stressor and at 0.5, 1 and 24 h post-exposure. There was no significant difference in the total cortisol levels of the fertilized eggs before and after handling stress. There was high expression level of hsp70 and sod before application of the stressor...... and significantly increased at 0.5 h postexposure. The expression levels of cat and gpx were weak to moderate and were not affected by the stressor. The apoptotic genes, mcl1 and NR-13 were highly expressed and significantly increased after exposure to air. Bcl-X1 and Bcl-X2 were moderately expressed in the control...

  2. Identification of Atlantic cod (Gadus morhua), ling (Molva molva), and Alaska pollock (Gadus chalcogrammus) by PCR-ELISA using duplex PCR.

    Science.gov (United States)

    Taboada, Ledicia; Sánchez, Ana; Velasco, Amaya; Santaclara, Francisco J; Pérez-Martín, Ricardo I; Sotelo, Carmen G

    2014-06-18

    Species-specific PCR-ELISA assays for the identification of Atlantic cod (Gadus morhua), Alaska pollock (Gadus chalcogrammus), and ling (Molva molva) in food products have been developed. The method, comprising a set of primers common to the first two species, a set of primers for M. molva, and a probe for each species, was designed using ND4 and cytochrome b genes as molecular markers. The sensitivity and selectivity were then determined for each assay. These assays were afterward used to analyze DNA extracted from commercial fish products. The presence of the target species was successfully detected in all analyzed samples, demonstrating the applicability of this method to the analysis of food products.

  3. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae — can we identify the underlying factors?

    Science.gov (United States)

    van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F.; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks. PMID:26038712

  4. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L. larvae — can we identify the underlying factors?

    Directory of Open Access Journals (Sweden)

    Ørjan Karlsen

    2015-05-01

    Full Text Available The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1, groups of cod larvae were fed either (a natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b enriched rotifers followed by Artemia (the intensive group. In the second experiment (Exp-2, two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5 after the fish had been fed the same formulated diet for approximately 2 weeks.

  5. Seasonal trends in adenylate nucleotide content in eggs of recruit and repeat spawning Atlantic cod (Gadus morhua L.) and implications for egg quality and buoyancy

    Science.gov (United States)

    Jung, Kyung-Mi; Svardal, Asbjørn M.; Eide, Torunn; Thorsen, Anders; Kjesbu, Olav Sigurd

    2012-10-01

    Seasonal and ontogenetic variation in egg buoyancy (egg specific gravity; ρ) (n = 63) and nucleotide content (n = 46) were examined for wild-caught Atlantic (Barents Sea) cod (Gadus morhua) held in captivity over two successive spawning seasons, i.e. each female (n = 5) was studied both as recruit and repeat spawner. All eggs were naturally spawned and fertilized, and incubated under optimal condition in flow-through aquaria. Egg diameter and egg dry weight declined steadily during the spawning period, while stage-specific ρ was approximately constant between egg batches (typically around 15 in total). Within each egg batch, i.e. during egg incubation, ρ significantly decreased from the time of gastrulation to before hatching, accompanied by increased contents of ATP and ADP. Altogether, we found that adenylate energy charge (EC) (EC = ([ATP] + 0.5 [ADP]) / ([ATP] + [ADP] + [AMP]) positively affected egg buoyancy (P = 0.013) in concert with egg developmental stage (P cod eggs in the field would show comparably similar trends in ρ and levels of nucleotides.

  6. Quantitative proteomics analysis reveals perturbation of lipid metabolic pathways in the liver of Atlantic cod (Gadus morhua) treated with PCB 153.

    Science.gov (United States)

    Yadetie, Fekadu; Oveland, Eystein; Døskeland, Anne; Berven, Frode; Goksøyr, Anders; Karlsen, Odd André

    2017-04-01

    PCB 153 is one of the most abundant PCB congeners detected in biological samples. It is a persistent compound that is still present in the environment despite the ban on production and use of PCBs in the late 1970s. It has strong tendencies to bioaccumulate and biomagnify in biota, and studies have suggested that it is an endocrine and metabolic disruptor. In order to study mechanisms of toxicity, we exposed Atlantic cod (Gadus morhua) to various doses of PCB 153 (0, 0.5, 2 and 8mg/kg body weight) for two weeks and examined the effects on expression of liver proteins using label-free quantitative proteomics. Label-free liquid chromatography-mass spectrometry analysis of the liver proteome resulted in the quantification of 1272 proteins, of which 78 proteins were differentially regulated in the PCB 153-treated dose groups compared to the control group. Functional enrichment analysis showed that pathways significantly affected are related to lipid metabolism, cytoskeletal remodeling, cell cycle and cell adhesion. Importantly, the main effects appear to be on lipid metabolism, with up-regulation of enzymes in the de novo fatty acid synthesis pathway, consistent with previous transcriptomics results. Increased plasma triglyceride levels were also observed in the PCB 153 treated fish, in agreement with the induction of the lipogenic genes and proteins. The results suggest that PCB 153 perturbs lipid metabolism in the Atlantic cod liver. Elevated levels of lipogenic enzymes and plasma triglycerides further suggest increased synthesis of fatty acids and triglycerides. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Early life of key fish species, capelin Mallotus villosus and Atlantic cod Gadus morhua, in West Greenland

    DEFF Research Database (Denmark)

    Malanski, Evandro

    feeding on prey sizes of about 5% of their own size (Paper I) and consequently the prey preference spectra covered calanoid nauplii, cladocerans and calanoid copepodites with increasing larval size. In the Godthåbsfjord system and Fyllas Bank area, 4 hydrographic zones were defined; in each zone distinct...... of preference – and of importance as biomass consumed – were calanoid nauplii and cyclopoid copepodites. The findings indicate that capelin and cod larvae were not competing for food as their prey size spectra do not overlap. While cod is preying on larger organisms as they develop, the increase in maximally...... is linked to the break-up of ice cover and the subsequent irradiance increase in the water column, climatic changes in Arctic regions could lead to a mismatch between larval emergence and optimal conditions for their feeding and growth. Thus it would be feasible to investigate the capelin stock genetic...

  8. The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L.).

    Science.gov (United States)

    Le, Hoang T M D; Angotzi, Anna Rita; Ebbesson, Lars O E; Karlsen, Ørjan; Rønnestad, Ivar

    2016-01-01

    Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART) in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization. Differential temporal and spatial expression patterns for each appetite regulator were found from first feeding (4 days post hatch; dph) to juvenile stage (76 dph). Neurons expressing NPY mRNA were detected in the telencephalon (highest expression), diencephalon, and optic tectum from 4 dph onward. CART mRNA expression had a wider distribution along the anterior-posterior brain axis, including both telencephalon and diencephalon from 4 dph. From 46 dph, CART transcripts were also detected in the olfactory bulb, region of the nucleus of medial longitudinal fascicle, optic tectum and midbrain tegmentum. At 4 and 20 dph, pOX mRNA expression was exclusively found in the preoptic region, but extended to the hypothalamus at 46 and 76 dph. Co-expression of both CART and pOX genes were also observed in several hypothalamic neurons throughout larval development. Our results show that both orexigenic and anorexigenic factors are present in the telencephalon, diencephalon and mesencephalon in cod larvae. The telencephalon mostly contains key factors of hunger control (NPY), while the diencephalon, and particularly the hypothalamus may have a more complex role in modulating the multifunctional control of appetite in this species. As the larvae develop, the overall progression in temporal and

  9. The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L..

    Directory of Open Access Journals (Sweden)

    Hoang T M D Le

    Full Text Available Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization. Differential temporal and spatial expression patterns for each appetite regulator were found from first feeding (4 days post hatch; dph to juvenile stage (76 dph. Neurons expressing NPY mRNA were detected in the telencephalon (highest expression, diencephalon, and optic tectum from 4 dph onward. CART mRNA expression had a wider distribution along the anterior-posterior brain axis, including both telencephalon and diencephalon from 4 dph. From 46 dph, CART transcripts were also detected in the olfactory bulb, region of the nucleus of medial longitudinal fascicle, optic tectum and midbrain tegmentum. At 4 and 20 dph, pOX mRNA expression was exclusively found in the preoptic region, but extended to the hypothalamus at 46 and 76 dph. Co-expression of both CART and pOX genes were also observed in several hypothalamic neurons throughout larval development. Our results show that both orexigenic and anorexigenic factors are present in the telencephalon, diencephalon and mesencephalon in cod larvae. The telencephalon mostly contains key factors of hunger control (NPY, while the diencephalon, and particularly the hypothalamus may have a more complex role in modulating the multifunctional control of appetite in this species. As the larvae develop, the overall progression in

  10. Maturation trends indicative of rapid evolution preceded the collapse of northern cod.

    Science.gov (United States)

    Olsen, Esben M; Heino, Mikko; Lilly, George R; Morgan, M Joanne; Brattey, John; Ernande, Bruno; Dieckmann, Ulf

    2004-04-29

    Northern cod, comprising populations of Atlantic cod (Gadus morhua) off southern Labrador and eastern Newfoundland, supported major fisheries for hundreds of years. But in the late 1980s and early 1990s, northern cod underwent one of the worst collapses in the history of fisheries. The Canadian government closed the directed fishing for northern cod in July 1992, but even after a decade-long offshore moratorium, population sizes remain historically low. Here we show that, up until the moratorium, the life history of northern cod continually shifted towards maturation at earlier ages and smaller sizes. Because confounding effects of mortality changes and growth-mediated phenotypic plasticity are accounted for in our analyses, this finding strongly suggests fisheries-induced evolution of maturation patterns in the direction predicted by theory. We propose that fisheries managers could use the method described here as a tool to provide warning signals about changes in life history before more overt evidence of population decline becomes manifest.

  11. Population structure of long-finned pilot whales in the North Atlantic: a correlation with sea surface temperature?

    Science.gov (United States)

    Fullard, K J; Early, G; Heide-Jorgensen, M P; Bloch, D; Rosing-Asvid, A; Amos, W

    2000-07-01

    The long-finned pilot whale, Globicephala melas, is a social, pelagic odontocete distributed widely in the cold temperate waters of the North Atlantic. Despite genetic, morphometric, physiological and observational studies, it remains unclear whether any population substructure exists. We have used eight highly polymorphic microsatellite loci to analyse samples from four disparate sampling sites: USA East Coast (Cape Cod), West Greenland, the Faeroe Islands and the UK. Our results indicate that substructure does exist, and is particularly pronounced between West Greenland and other sites. The magnitudes of the various pairwise comparisons do not support a simple isolation-by-distance model. Instead, the patterns of genetic differentiation suggest that population isolation occurs between areas of the ocean which differ in sea surface temperature. Such a mechanism is supported by the observation that temperature is a primary factor determining the relative distributions of two short-finned pilot whale (G. macrorhynchus) populations off the Pacific coast of Japan.

  12. Effect of sub-lethal exposure to ultraviolet radiation on the escape performance of Atlantic cod larvae (Gadus morhua.

    Directory of Open Access Journals (Sweden)

    Yuichi Fukunishi

    Full Text Available The amount of ultraviolet (UV radiation reaching the earth's surface has increased due to depletion of the ozone layer. Several studies have reported that UV radiation reduces survival of fish larvae. However, indirect and sub-lethal impacts of UV radiation on fish behavior have been given little consideration. We observed the escape performance of larval cod (24 dph, SL: 7.6±0.2 mm; 29 dph, SL: 8.2±0.3 mm that had been exposed to sub-lethal levels of UV radiation vs. unexposed controls. Two predators were used (in separate experiments: two-spotted goby (Gobiusculus flavescens; a suction predator and lion's mane jellyfish (Cyanea capillata; a "passive" ambush predator. Ten cod larvae were observed in the presence of a predator for 20 minutes using a digital video camera. Trials were replicated 4 times for goby and 5 times for jellyfish. Escape rate (total number of escapes/total number of attacks ×100, escape distance and the number of larvae remaining at the end of the experiment were measured. In the experiment with gobies, in the UV-treated larvae, both escape rate and escape distance (36%, 38±7.5 mm respectively were significantly lower than those of control larvae (75%, 69±4.7 mm respectively. There was a significant difference in survival as well (UV: 35%,63%. No apparent escape response was observed, and survival rate was not significantly different, between treatments (UV: 66%,74% in the experiment with jellyfish. We conclude that the effect and impact of exposure to sub-lethal levels of UV radiation on the escape performance of cod larvae depends on the type of predator. Our results also suggest that prediction of UV impacts on fish larvae based only on direct effects are underestimations.

  13. Response of branchial Na(+)/K(+) ATPase to changes in ambient temperature in Atlantic cod (Gadus morhua) and whiting (Merlangius merlangus).

    Science.gov (United States)

    Michael, Katharina; Koschnick, Nils; Pörtner, Hans-O; Lucassen, Magnus

    2016-05-01

    The maintenance of ion and pH homeostasis despite changes in ambient temperature is crucial for ectothermic organisms. Thermal sensitivity of Na(+)/K(+) ATPase mRNA expression, protein expression and activity was determined in gills of North Sea cod (NC) and Northeastern Arctic cod (NEAC), acclimated for 6 weeks at 4 and 10 °C and compared to field samples of North Sea cod (sNC), acclimatized to early spring (4 °C) and summer (18 °C) conditions. The same analyses were conducted in gills of the confamiliar whiting, acclimated at 4 and 10 °C. Branchial Na(+)/K(+) ATPase capacities remained uncompensated at functional and protein levels in NC and NEAC at both acclimation temperatures. Na(+)/K(+) ATPase mRNA expression in NEAC acclimated at 10 °C was about twofold higher compared to NC, indicating some population-specific differentiation at this level. Lower Na(+)/K(+) ATPase capacities in gills of warm-acclimatized sNC at common assay temperatures indicate thermal compensation between seasonal extremes, and post-translational modifications contributed to this mitigation at high assay temperature. Together, cod compensates Na(+)/K(+) ATPase capacities on the warm edge of the thermal window and below 4 °C, respectively. In contrast, whiting Na(+)/K(+) ATPase capacities were cold compensated at 4 °C, supported by 1.5-fold higher mRNA and protein expression. Besides, capacities were lower in whiting compared to NC and NEAC at optimum temperature, which may be advantageous in terms of reduced maintenance cost, but at temperatures ≤4 °C, compensation may represent an energy trade-off to maintain homeostasis. The species-specific response of gadid Na(+)/K(+) ATPase indicates certain threshold temperatures beyond which compensation of the pump is elicited, possibly related to the different biogeography of these species.

  14. Movements of Atlantic Sturgeon of the Gulf of Maine inside and outside the geographically defined Distinct Population Segment

    Science.gov (United States)

    Wippelhauser, Gail S.; Sulikowski, James; Zydlewski, Gayle B.; Altenritter, Megan; Kieffer, Micah; Kinnison, Michael T.

    2017-01-01

    Identification of potential critical habitat, seasonal distributions, and movements within and between river systems is important for protecting the Gulf of Maine (GOM) Distinct Population Segment of Atlantic Sturgeon. To accomplish these objectives, we captured Atlantic Sturgeon in four GOM rivers (Penobscot, Kennebec system, Saco, and Merrimack), and tagged 144 (83.3–217.4 cm TL) internally with uniquely coded acoustic transmitters. Tagged fish were detected between 2006 to 2014 by primary receiver arrays deployed in the four GOM rivers or opportunistically on a secondary group of receivers deployed within the GOM and along the continental shelf. Atlantic Sturgeon tagged in the four rivers were documented at three spawning areas in the Kennebec system in June and July, including one that became accessible in 1999 when the Edwards Dam was removed. After being tagged, the majority (74%) of Atlantic sturgeon were detected in the estuaries of the four GOM rivers, primarily from May through October. Tagged fish spent most of their time in saline water in the Saco River and Merrimack River, moved into brackish water in the Penobscot River, and were found in saline, brackish, and fresh water in the Kennebec system. Approximately 70% of the tagged fish were detected in GOM coastal waters, and aggregated in the Bay of Fundy (May–January), offshore of the Penobscot River (September-February and May), offshore of the Kennebec River (September–February), in Saco Bay and the Scarborough River (July–November), and along the eastern Massachusetts coast between Cape Ann and Cape Cod (April–February). Nine tagged Atlantic sturgeon (7%) left the GOM, three of which moved as far north as Halifax in Canada and six moved as far south as the James River in Virginia. Information from this study will be used to make recommendations to avoid, reduce or mitigate the impacts of in-water projects and on Atlantic sturgeon.

  15. Molecular identification and transmission studies of X-cell parasites from Atlantic cod Gadus morhua (Gadiformes: Gadidae and the northern black flounder Pseudopleuronectes obscurus (Pleuronectiformes: Pleuronectidae

    Directory of Open Access Journals (Sweden)

    Watanabe K

    2011-02-01

    Full Text Available Abstract Background Epidermal pseudotumours from Hippoglossoides dubius and Acanthogobius flavimanus in Japan and gill lesions in Limanda limanda from the UK have been shown to be caused by phylogenetically related protozoan parasites, known collectively as X-cells. However, the phylogenetic position of the X-cell group is not well supported within any of the existing protozoan phyla and they are currently thought to be members of the Alveolata. Ultrastructural features of X-cells in fish pseudotumours are somewhat limited and no typical environmental stages, such as spores or flagellated cells, have been observed. The life cycles for these parasites have not been demonstrated and it remains unknown how transmission to a new host occurs. In the present study, pseudobranchial pseudotumours from Atlantic cod, Gadus morhua, in Iceland and epidermal pseudotumours from the northern black flounder, Pseudopleuronectes obscurus, in Japan were used in experimental transmission studies to establish whether direct transmission of the parasite is achievable. In addition, X-cells from Atlantic cod were sequenced to confirm whether they are phylogenetically related to other X-cells and epidermal pseudotumours from the northern black flounder were analysed to establish whether the same parasite is responsible for infecting different flatfish species in Japan. Results Phylogenetic analyses of small subunit ribosomal DNA (SSU rDNA sequence data from Atlantic cod X-cells show that they are a related parasite that occupies a basal position to the clade containing other X-cell parasites. The X-cell parasite causing epidermal pseudotumours in P. obscurus is the same parasite that causes pseudotumours in H. dubius. Direct, fish to fish, transmission of the X-cell parasites used in this study, via oral feeding or injection, was not achieved. Non-amoeboid X-cells are contained within discrete sac-like structures that are loosely attached to epidermal pseudotumours in

  16. Suspended matter in surface waters of the Atlantic continental margin from Cape Cod to the Florida keys

    Science.gov (United States)

    Manheim, F. T.; Meade, R.H.; Bond, G.C.

    1970-01-01

    Appreciable amounts of suspended matter (> 1.0 milligram per liter) in surface waters are restricted to within a few kilometers of the Atlantic coast. Particles that escape estuaries or are discharged by rivers into the shelf region tend to travel longshoreward rather than seaward. Suspended matter farther offshore, chiefly amorphous organic particles, totals 0.1 milligram per liter or less. Soot, fly ash, processed cellulose, and other pollutants are widespread.

  17. Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study

    Science.gov (United States)

    Winberg, Anna; West, Christina E; Strinnholm, Åsa; Nordström, Lisbeth; Hedman, Linnea; Rönmark, Eva

    2015-01-01

    Objectives Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren. Methods In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited) completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695). Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges. Results In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%), outgrown allergy (19%), lactose intolerance (40%), and unclear (12%). Conclusions There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy. PMID:26134827

  18. Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study.

    Directory of Open Access Journals (Sweden)

    Anna Winberg

    Full Text Available Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren.In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695. Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges.In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%, outgrown allergy (19%, lactose intolerance (40%, and unclear (12%.There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy.

  19. Effects of hypoxic exposure during feeding on SDA and postprandial cardiovascular physiology in the Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Behrens, Jane; Axelsson, Michael; Neuenfeldt, Stefan

    2012-01-01

    (MO2), i.e. the SDA, leading to a disturbed digestion. Additionally, a restricted oxygen uptake could result in an oxygen debt that needs to be compensated for upon return to normoxic waters and this may also affect the ability to process the food. Long-term cardio-respiratory measurements were made...... on fed G. morhua in order to understand how the cardio-respiratory system of feeding fish respond to a period of hypoxia and a subsequent return to normoxia. These were exposed to 35% water oxygen saturation for 90 minutes, equivalent to the time and oxygen level cod voluntarily endure when searching...... of an oxygen debt, or negative influence on digestive capacity, when simulating field observations...

  20. THE EFFECT OF HYPOXIA ON THE MAXIMUM MATABOLIC RATE AND SPECIFIC DYNAMIC ACTION IN ATLANTIC COD Gadus morhua

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2010-01-01

    of hypoxia compared. Maximum metabolic rate compared to standard metabolic rate is termed the Scope for Activity. The results showed that hypoxia at 6.3 kPa does influence the SDA. The effect on the SDA curve on cod fed 5 % of the wet body mass was that the peak metabolic rate was significantly depressed (44...... and fish kept at high densities. Feeding is followed by an increase in the metabolic rate. termed the specific dynamic action (SDA). SDA integrates all the energetic expenditures involved in feeding. It is generally agreed that the increased metabolic rate is caused by biochemical transformation of food...... the fi sh. The fish were fed single rations of fillets of herring, equivalent to 5 % wet body mass. Hypoxia was controlled by an oxygen regulator injecting compressed nitrogen in the water via a solenoid valve. In addition the maximum metabolic rate of starved fish was measured in normoxia and 4 levels...

  1. Characterization of the fatty acyl elongase (elovl) gene family, and hepatic elovl and delta-6 fatty acyl desaturase transcript expression and fatty acid responses to diets containing camelina oil in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Xue, Xi; Feng, Charles Y; Hixson, Stefanie M; Johnstone, Kim; Anderson, Derek M; Parrish, Christopher C; Rise, Matthew L

    2014-09-01

    For aquaculture to become sustainable, there is a need to substitute fish oil [FO, rich in ω3 long chain polyunsaturated fatty acids (LC-PUFA) such as 20:5ω3 (EPA) and 22:6ω3 (DHA)] in aquafeed with plant oils such as camelina oil [CO, rich in C18 PUFA such as 18:3ω3 (ALA) and 18:2ω6 (LNA)]. The LC-PUFA are essential components in fish diets for maintaining optimal health, physiology and growth. However, most marine fish including Atlantic cod are inefficient at producing LC-PUFA from shorter chain precursors. Since elovl genes encode enzymes that play key roles in fatty acid biosynthesis, we hypothesized that they may be involved in Atlantic cod responses to diets rich in 18:3ω3 and 18:2ω6. Ten members of the cod elovl gene family were characterized at the mRNA level. RT-PCR was used to study constitutive expression of elovl transcripts in fifteen tissues. Some transcripts (e.g. elovl5) were ubiquitously expressed, while others had tissue-specific expression (e.g. elovl4a in brain and eye). Cod fed a CO-containing diet (100% CO replacement of FO and including solvent-extracted fish meal) had significantly lower weight gain, with significant up-regulation of elovl5 and fadsd6 transcripts in the liver as shown by QPCR analysis, compared with cod on a FO control diet after a 13-week trial. Multivariate statistical analyses (SIMPER and PCA) indicated that high 18:3ω3 and/or low ω3 LC-PUFA levels in the liver were associated with the up-regulation of elovl5 and fadsd6, which are involved in LC-PUFA biosynthesis in cod. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Atlantic cod (Gadus morhua) larvae can biosynthesis phospholipid de novo from 2-oleoyl-glycerol and glycerol precursors.

    Science.gov (United States)

    Li, Keshuai; Olsen, Rolf Erik; Østensen, Mari-Ann; Altin, Dag; Kjørsvik, Elin; Olsen, Yngvar

    2016-02-01

    The dietary requirement of phospholipid (PL) of fish larvae has been suggested to originate in an inefficient ability for de novo biosynthesis of PL based on dietary triacylglycerol (TAG). The main objective of the present study was to investigate whether cod larvae could synthesis PL from sn-2-monoacylglycerol (2-MAG) and glycerol precursors. A tube feeding method was used to deliver equal molar aliquots of 2-oleoyl-[1,2,3-(3)H]glycerol and [U-(14)C] glycerol together with bovine serum albumin (BSA) bound 16:0 (palmitic acid) and 22:6n-3 (docosahexaenoic acid, DHA), with or without choline chloride to the foregut of anesthetized cod larvae and thereafter monitoring the metabolism of these components in the larvae through 4 h following injection. Our results showed that both 2-MAG and glycerol precursors contributed to the de novo synthesis of phosphatidylcholine (PC) and the 2-MAG pathway predominated over the G-3-P (glycerol-3-phosphate) pathway in the synthesis of TAG and PC. The molecular ratio of PC/TAG obtained from the 2-MAG and the G-3-P pathways was 0.44-0.74 and 1.02-2.06 within the first hour of tube feeding, suggesting they might have comparable biosynthesis ability of PC and TAG under the conditions of the present study. Furthermore, supplementation of choline chloride significantly increased PC/TAG ratio (p < 0.05) for both pathways. However, further studies are needed to quantify the enzyme activity involved in the CDP-choline (cytidine diphosphate choline) pathway, and the function of choline either in simulating PC synthesis or TAG catabolism or both needs further investigation.

  3. Discovery of miRNAs and Their Corresponding miRNA Genes in Atlantic Cod (Gadus morhua): Use of Stable miRNAs as Reference Genes Reveals Subgroups of miRNAs That Are Highly Expressed in Particular Organs.

    Science.gov (United States)

    Andreassen, Rune; Rangnes, Fredrik; Sivertsen, Maria; Chiang, Michelle; Tran, Michelle; Worren, Merete Molton

    2016-01-01

    Atlantic cod (Gadus morhua) is among the economically most important species in the northern Atlantic Ocean and a model species for studying development of the immune system in vertebrates. MicroRNAs (miRNAs) are an abundant class of small RNA molecules that regulate fundamental biological processes at the post-transcriptional level. Detailed knowledge about a species miRNA repertoire is necessary to study how the miRNA transcriptome modulate gene expression. We have therefore discovered and characterized mature miRNAs and their corresponding miRNA genes in Atlantic cod. We have also performed a validation study to identify suitable reference genes for RT-qPCR analysis of miRNA expression in Atlantic cod. Finally, we utilized the newly characterized miRNA repertoire and the dedicated RT-qPCR method to reveal miRNAs that are highly expressed in certain organs. The discovery analysis revealed 490 mature miRNAs (401 unique sequences) along with precursor sequences and genomic location of the miRNA genes. Twenty six of these were novel miRNA genes. Validation studies ranked gmo-miR-17-1-5p or the two-gene combination gmo-miR25-3p and gmo-miR210-5p as most suitable qPCR reference genes. Analysis by RT-qPCR revealed 45 miRNAs with significantly higher expression in tissues from one or a few organs. Comparisons to other vertebrates indicate that some of these miRNAs may regulate processes like growth, lipid metabolism, immune response to microbial infections and scar damage repair. Three teleost-specific and three novel Atlantic cod miRNAs were among the differentially expressed miRNAs. The number of known mature miRNAs was considerably increased by our identification of miRNAs and miRNA genes in Atlantic cod. This will benefit further functional studies of miRNA expression using deep sequencing methods. The validation study showed that stable miRNAs are suitable reference genes for RT-qPCR analysis of miRNA expression. Applying RT-qPCR we have identified several mi

  4. Discovery of miRNAs and Their Corresponding miRNA Genes in Atlantic Cod (Gadus morhua: Use of Stable miRNAs as Reference Genes Reveals Subgroups of miRNAs That Are Highly Expressed in Particular Organs.

    Directory of Open Access Journals (Sweden)

    Rune Andreassen

    Full Text Available Atlantic cod (Gadus morhua is among the economically most important species in the northern Atlantic Ocean and a model species for studying development of the immune system in vertebrates. MicroRNAs (miRNAs are an abundant class of small RNA molecules that regulate fundamental biological processes at the post-transcriptional level. Detailed knowledge about a species miRNA repertoire is necessary to study how the miRNA transcriptome modulate gene expression. We have therefore discovered and characterized mature miRNAs and their corresponding miRNA genes in Atlantic cod. We have also performed a validation study to identify suitable reference genes for RT-qPCR analysis of miRNA expression in Atlantic cod. Finally, we utilized the newly characterized miRNA repertoire and the dedicated RT-qPCR method to reveal miRNAs that are highly expressed in certain organs.The discovery analysis revealed 490 mature miRNAs (401 unique sequences along with precursor sequences and genomic location of the miRNA genes. Twenty six of these were novel miRNA genes. Validation studies ranked gmo-miR-17-1-5p or the two-gene combination gmo-miR25-3p and gmo-miR210-5p as most suitable qPCR reference genes. Analysis by RT-qPCR revealed 45 miRNAs with significantly higher expression in tissues from one or a few organs. Comparisons to other vertebrates indicate that some of these miRNAs may regulate processes like growth, lipid metabolism, immune response to microbial infections and scar damage repair. Three teleost-specific and three novel Atlantic cod miRNAs were among the differentially expressed miRNAs.The number of known mature miRNAs was considerably increased by our identification of miRNAs and miRNA genes in Atlantic cod. This will benefit further functional studies of miRNA expression using deep sequencing methods. The validation study showed that stable miRNAs are suitable reference genes for RT-qPCR analysis of miRNA expression. Applying RT-qPCR we have identified

  5. Changes in regional brain monoaminergic activity and temporary down-regulation in stress response from dietary supplementation with l-tryptophan in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Basic, Dean; Schjolden, Joachim; Krogdahl, Ashild; von Krogh, Kristine; Hillestad, Marie; Winberg, Svante; Mayer, Ian; Skjerve, Eystein; Höglund, Erik

    2013-06-28

    The brain monoamines serotonin (5-hydroxytryptamine; 5-HT) and dopamine (DA) both play an integrative role in behavioural and neuroendocrine responses to challenges, and comparative models suggest common mechanisms for dietary modulation of transmission by these signal substances in vertebrates. Previous studies in teleosts demonstrate that 7 d of dietary administration with L-tryptophan (Trp), the direct precursor of 5-HT, suppresses the endocrine stress response. The present study investigated how long the suppressive effects of a Trp-enriched feed regimen, at doses corresponding to two, three or four times the Trp levels in commercial feed, last in juvenile Atlantic cod (Gadus morhua) when the fish are reintroduced to a diet with standard amino acid composition. We also wanted to determine whether Trp supplementation induced changes in brain monoaminergic neurochemistry in those forebrain structures innervated by DA and 5-HTergic neurons, by measuring regional activity of DA and 5-HT in the lateral pallial regions (Dl) of the telencephalon and nucleus lateralis tuberis (NLT) of the hypothalamus. Dietary Trp resulted in a dose-dependent suppression in plasma cortisol among fish exposed to confinement stress on the first day following experimental diet; however, such an effect was not observed at 2 or 6 d after Trp treatment. Feeding the fish with moderate Trp doses also evoked a general increase in DA and 5-HT-ergic activity, suggesting that these neural circuits within the NLT and Dl may be indirectly involved in regulating the acute stress response.

  6. Understanding climate impacts on recruitment and spatial dynamics of Atlantic cod in the Gulf of Maine: Integration of observations and modeling

    Science.gov (United States)

    Runge, Jeffrey A.; Kovach, Adrienne I.; Churchill, James H.; Kerr, Lisa A.; Morrison, John R.; Beardsley, Robert C.; Berlinsky, David L.; Chen, Changsheng; Cadrin, Steven X.; Davis, Cabell S.; Ford, Kathryn H.; Grabowski, Jonathan H.; Howell, W. Huntting; Ji, Rubao; Jones, Rebecca J.; Pershing, Andrew J.; Record, Nicholas R.; Thomas, Andrew C.; Sherwood, Graham D.; Tallack, Shelly M. L.; Townsend, David W.

    2010-10-01

    We put forward a combined observing and modeling strategy for evaluating effects of environmental forcing on the dynamics of spatially structured cod populations spawning in the western Gulf of Maine. Recent work indicates at least two genetically differentiated complexes in this region: a late spring spawning, coastal population centered in Ipswich Bay, and a population that spawns in winter inshore and on nearshore banks in the Gulf of Maine and off southern New England. The two populations likely differ in trophic interactions and in physiological and behavioral responses to different winter and spring environments. Coupled physical-biological modeling has advanced to the point where within-decade forecasting of environmental conditions for recruitment to each of the two populations is feasible. However, the modeling needs to be supported by hydrographic, primary production and zooplankton data collected by buoys, and by data from remote sensing and fixed station sampling. Forecasts of environmentally driven dispersal and growth of planktonic early life stages, combined with an understanding of possible population-specific predator fields, usage of coastal habitat by juveniles and adult resident and migratory patterns, can be used to develop scenarios for spatially explicit population responses to multiple forcings, including climate change, anthropogenic impacts on nearshore juvenile habitat, connectivity among populations and management interventions such as regional fisheries closures.

  7. Collapse and conservation of shark populations in the Northwest Atlantic.

    Science.gov (United States)

    Baum, Julia K; Myers, Ransom A; Kehler, Daniel G; Worm, Boris; Harley, Shelton J; Doherty, Penny A

    2003-01-17

    Overexploitation threatens the future of many large vertebrates. In the ocean, tunas and sea turtles are current conservation concerns because of this intense pressure. The status of most shark species, in contrast, remains uncertain. Using the largest data set in the Northwest Atlantic, we show rapid large declines in large coastal and oceanic shark populations. Scalloped hammerhead, white, and thresher sharks are each estimated to have declined by over 75% in the past 15 years. Closed-area models highlight priority areas for shark conservation, and the need to consider effort reallocation and site selection if marine reserves are to benefit multiple threatened species.

  8. Differential impacts of elevated CO2 and acidosis on the energy budget of gill and liver cells from Atlantic cod, Gadus morhua.

    Science.gov (United States)

    Stapp, L S; Kreiss, C M; Pörtner, H O; Lannig, G

    2015-09-01

    Ocean acidification impacts fish and other marine species through increased seawater PCO2 levels (hypercapnia). Knowledge of the physiological mechanisms mediating effects in various tissues of fish is incomplete. Here we tested the effects of extracellular hypercapnia and acidosis on energy metabolism of gill and liver cells of Atlantic cod. Exposure media mimicked blood conditions in vivo, either during normo- or hypercapnia and at control or acidic extracellular pH (pHe). We determined metabolic rate and energy expenditure for protein biosynthesis, Na(+)/K(+)-ATPase and H(+)-ATPase and considered nutrition status by measurements of metabolic rate and protein biosynthesis in media with and without free amino acids (FAA). Addition of FAA stimulated hepatic but not branchial oxygen consumption. Normo- and hypercapnic acidosis as well as hypercapnia at control pHe depressed metabolic stimulation of hepatocytes. In gill cells, acidosis depressed respiration independent of PCO2 and FAA levels. For both cell types, depressed respiration was not correlated with the same reduction in energy allocated to protein biosynthesis or Na(+)/K(+)-ATPase. Hepatic energy expenditure for protein synthesis and Na(+)/K(+)-ATPase was even elevated at acidic compared to control pHe suggesting increased costs for ion regulation and cellular reorganization. Hypercapnia at control pHe strongly reduced oxygen demand of branchial Na(+)/K(+)-ATPase with a similar trend for H(+)-ATPase. We conclude that extracellular acidosis triggers metabolic depression in gill and metabolically stimulated liver cells. Additionally, hypercapnia itself seems to limit capacities for metabolic usage of amino acids in liver cells while it decreases the use and costs of ion regulatory ATPases in gill cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Impact of long-term moderate hypercapnia and elevated temperature on the energy budget of isolated gills of Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Kreiss, Cornelia M; Michael, Katharina; Bock, Christian; Lucassen, Magnus; Pörtner, Hans-O

    2015-04-01

    Effects of severe hypercapnia have been extensively studied in marine fishes, while knowledge on the impacts of moderately elevated CO2 levels and their combination with warming is scarce. Here we investigate ion regulation mechanisms and energy budget in gills from Atlantic cod acclimated long-term to elevated PCO2 levels (2500 μatm) and temperature (18°C). Isolated perfused gill preparations were established to determine gill thermal plasticity during acute exposures (10-22°C) and in vivo costs of Na(+)/K(+)-ATPase activity, protein and RNA synthesis. Maximum enzyme capacities of F1Fo-ATPase, H(+)-ATPase and Na(+)/K(+)-ATPase were measured in vitro in crude gill homogenates. After whole animal acclimation to elevated PCO2 and/or warming, branchial oxygen consumption responded more strongly to acute temperature change. The fractions of gill respiration allocated to protein and RNA synthesis remained unchanged. In gills of fish CO2-exposed at both temperatures, energy turnover associated with Na(+)/K(+)-ATPase activity was reduced by 30% below rates of control fish. This contrasted in vitro capacities of Na(+)/K(+)-ATPase, which remained unchanged under elevated CO2 at 10°C, and earlier studies which had found a strong upregulation under severe hypercapnia. F1Fo-ATPase capacities increased in hypercapnic gills at both temperatures, whereas Na(+)/K(+)ATPase and H(+)-ATPase capacities only increased in response to elevated CO2 and warming indicating the absence of thermal compensation under CO2. We conclude that in vivo ion regulatory energy demand is lowered under moderately elevated CO2 levels despite the stronger thermal response of total gill respiration and the upregulation of F1Fo-ATPase. This effect is maintained at elevated temperature. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Microevolution in time and space: SNP analysis of historical DNA reveals dynamic signatures of selection in Atlantic cod

    DEFF Research Database (Denmark)

    Therkildsen, Nina Overgaard; Hansen, Jakob Hemmer; Als, Thomas Damm

    2013-01-01

    suggested that temporal allele frequency shifts at certain loci may correlate with local temperature variation and with life history changes suggested to be fisheries induced. Interestingly, however, largely nonoverlapping sets of loci were temporal outliers in the different populations and outliers from...... the 1928 to 1960 period showed almost complete stability during later decades. The contrasting microevolutionary trajectories among populations resulted in sequential shifts in spatial outliers, with no locus maintaining elevated spatial differentiation throughout the study period. Simulations of migration...... coupled with observations of temporally stable spatial structure at neutral loci suggest that population replacement or gene flow alone could not explain all the observed allele frequency variation. Thus, the genetic changes are likely to at least partly be driven by highly dynamic temporally...

  11. Understanding the release efficiency of Atlantic cod (Gadus morhua) from trawls with a square mesh panel: effects of panel area, panel position, and stimulation of escape response

    DEFF Research Database (Denmark)

    Herrmann, Bent; Wienbeck, Harald; Karlsen, Junita Diana

    2015-01-01

    Based on size selectivity data for more than 25 000 cod (Gadus morhua) collected during experimental trawl fishing with six different codends, all of which included a square mesh panel,we investigated the effect on cod-release efficiency based on the size of the square mesh panel area, position...... of the square mesh panel, and stimulation of the escape response. Based on the results, we were able to explain why the BACOMAcodend, applied in the Baltic Sea cod directed trawl fishery, releases juvenile cod efficiently, whereas other designs, including a squaremesh panel with similar mesh size, are less...... the catch-accumulation zone. Our findings demonstrated that this release was as efficient as for a panel mounted in the catch-accumulation zone of the codend. Devices that stimulate behaviour may improve the release efficiency of cod through square mesh panels in other fisheries where this is a problem...

  12. How cod shapes its world

    NARCIS (Netherlands)

    van Leeuwen, A.; de Roos, A.M.; Persson, L.

    2008-01-01

    Cod stocks in the North West Atlantic and the Baltic Sea have shown similar dynamics in recent decades with a rapid decline in abundance and a lack of stock recovery following a period of large biomass. We explore whether the lack of recovery can be ascribed to an emergent Allee effect, which is a

  13. Northwest Atlantic grey seal population trends, 1960-2012: Tendances de la population de phoques gris de l'Atlantique Nord-Ouest, 1960-2012

    National Research Council Canada - National Science Library

    Hammill, M.O; Bowen, W.D; den Hyer, C

    2014-01-01

    A model of Northwest Atlantic grey seal population dynamics was fitted to available pup production data to provide estimates of the Canadian component of the Northwest Atlantic grey seal population from 1960-2012...

  14. Evaluation of the impact of camelina oil-containing diets on the expression of genes involved in the innate anti-viral immune response in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Booman, Marije; Xu, Qingheng; Rise, Matthew L

    2014-11-01

    To improve sustainability of aquaculture, especially for carnivorous species like Atlantic cod, replacement of fish oil-based diets with vegetable oil-based diets has been studied. The use of vegetable oil in fish feeds can significantly change the fatty acid composition of fish tissues, and given the importance of fatty acids in inflammation and immunity, this change could potentially impact the immune response and health of the fish. The oilseed Camelina sativa is a promising source for this vegetable oil, because of the high oil content of its seeds (40%), a higher n-3 fatty acid content than most other oilseeds, and a high amount of γ-tocopherol. This study aims to investigate the effect of the replacement of dietary fish oil with oil from Camelina sativa on the immune response of Atlantic cod, as measured by the gene expression in spleen. Juvenile cod were fed on a fish oil-based diet (FO) or one of two diets in which camelina oil replaced 40% or 80% of fish oil (40CO and 80CO respectively) for 67 days, after which they were injected with either the viral mimic polyriboinosinic polyribocytidylic acid (pIC), or phosphate-buffered saline (PBS) as a control. Microarray analysis was used to determine the effect of the diet on the basal spleen transcriptome (pre-injection), and on the response to pIC (24 h post-injection). No marked differences in the spleen transcriptome were found between the three diets, either before or after injection with pIC. All fish, regardless of diet, showed a strong anti-viral response 24 h after pIC injection, with more than 500 genes having a significant difference of expression of 2-fold or higher compared to the PBS-injected fish for the FO, 40CO and 80CO diets. Gene Ontology annotation analysis of the three pIC-responsive gene lists indicated they were highly similar, and that the term 'immune system process' was significantly enriched in the pIC-responsive gene lists for all three diets. QPCR analysis for 5 genes with a known

  15. Seasonal and annual variation in the diet of Atlantic cod (Gadus morhua) in relation to the abundance of capelin (Mallotus villosus) off eastern Newfoundland, Canada

    Science.gov (United States)

    Methven, David A.; Piatt, John F.

    1989-01-01

    The importance of capelin as prey for cod has long been known (Thompson, 1943; and see Lilly (1987) for a review); however, no studies have been conducted on how the highly dynamic seasonal and yearly variations in capelin abundance affect cod diet. We studied the occurrence of capelin in cod stomachs in relation to the relative abundance of capelin at Witless Bay, Newfoundland (47°15’N 52°46’W), during June, July and August, 1982-1984. The mean number of capelin per stomach and the per cent occurrence of stomachs containing capelin were determined for each collection of stomachs. A total of 680 stomachs were examined. Cod were sampled from those caught in gillnets by fishermen and averaged 66 cm ± 8 (s.d.) in 1983 and 62 cm ± 8 (s.d.) in 1984. Relative abundance of capelin in the local habitat was determined by conducting hydroacoustic surveys around Gull Island in Witless Bay, the same area where cod were collected for stomach content analysis. Only hydroacoustic surveys conducted within three days of cod stomach collections were analyzed. Further details of hydroacoustic surveys including quantifications of acoustic echograms are described in Piatt (1989).

  16. [Genetic variation at the pantophysin (PanI) locus in North-East Arctic cod Gadus morhua L. (Gadiformes: Gadidae) population in the Barents Sea and adjacent waters].

    Science.gov (United States)

    Makeenko, G A; Volkov, A A; Mugue, N S; Zelenina, D A

    2014-12-01

    We investigated polymorphisms in the pantophysin gene (Pan I locus) in a population of North-East Arctic cod, Gadus morhua L., throughout its foraging area in the Barents Sea and adjacent waters. Correlations between the frequencies of Pan I alleles and habitat conditions, such as depth and temperature, were explored. This study was based on a large number of specimens (2210 individuals) of different age and wide geographic sampling coverage. The frequency of the Pan I(A) allele, a known genetic marker of coastal cod, varied from zero to 0.47. Allele frequencies correlated with depth at the sampling location but not with bottom water temperatures. We observed variations in Pan I(A) frequencies among different age cohorts from the same area. The most prominent shift in Pan I polymorphism was detected at the early stages of the fish life cycle, between pelagic juveniles and benthic cod. We found that the Pan I(A) allele frequency in pelagic yearling cod was essentially same throughout the studied areas in the Barents Sea. In turn, juveniles settling at the northern and deep water locations showed a significant decrease in the allele frequency. In contrast, the frequency of the Pan I(A) allele remained constant in juveniles settling in shallow waters when compared to the pelagic stage. These results confirm the selective nature of the cod Pan I locus and indicate that selection process acting on individuals with different genotypes at the Pan I locus leads to the formation of a stable spatial distribution of allele frequencies observed in adult cod.

  17. β-naphthoflavone interferes with cyp1c1, cox2 and IL-8 gene transcription and leukotriene B4 secretion in Atlantic cod (Gadus morhua) head kidney cells during inflammation.

    Science.gov (United States)

    Holen, Elisabeth; Olsvik, Pål A

    2016-07-01

    The objective of this study was to evaluate how β-naphthoflavone interacts with lipopolysaccharide (LPS) and polyinosinic acid: polycytidylic acid (poly I: C) induced innate immune parameters as well as phase I and phase II detoxification enzymes in head kidney cells isolated from Atlantic cod. β-naphthoflavone is a pure agonist of aryl hydrocarbon receptor (AhR) while LPS and poly I: C are not. β-naphthoflavone was added to head kidney leukocytes alone or together with LPS or poly I: C and the responses were evaluated in terms of protein and gene expression. The results showed that β-naphthoflavone (25 nM), with and without LPS, significantly induced cytochrome P450 (cyp1c) transcription in cod head kidney cells. β-naphthoflavone (100 nM) in the presence of the virus mimic, poly I: C, also increased cyp1c1transcription. LPS induced cyp1c1, cyclooxygenase 2 (cox2), interleukin 1β (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8) transcription, genes that were not affected by the tested β-naphthoflavone concentrations alone. However, β-naphthoflavone (25 and 50 nM) strengthened LPS induced cox2 and IL-8 transcription. Cod head kidney cells exposed to β-naphthoflavone concentrations ranging from 25 to 100 nM, with and without LPS or poly I: C, expressed AhR protein. LPS or β-naphthoflavone (5-50 nM) significantly induced leukotriene B4 (LTB4) secretion compared to control. In conclusion, this study suggests that β-naphthoflavone could interfere with LPS induced immune cell signaling in cod head kidney cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Ocelot Population Status in Protected Brazilian Atlantic Forest.

    Directory of Open Access Journals (Sweden)

    Rodrigo Lima Massara

    Full Text Available Forest fragmentation and habitat loss are detrimental to top carnivores, such as jaguars (Panthera onca and pumas (Puma concolor, but effects on mesocarnivores, such as ocelots (Leopardus pardalis, are less clear. Ocelots need native forests, but also might benefit from the local extirpation of larger cats such as pumas and jaguars through mesopredator release. We used a standardized camera trap protocol to assess ocelot populations in six protected areas of the Atlantic forest in southeastern Brazil where over 80% of forest remnants are < 50 ha. We tested whether variation in ocelot abundance could be explained by reserve size, forest cover, number of free-ranging domestic dogs and presence of top predators. Ocelot abundance was positively correlated with reserve size and the presence of top predators (jaguar and pumas and negatively correlated with the number of dogs. We also found higher detection probabilities in less forested areas as compared to larger, intact forests. We suspect that smaller home ranges and higher movement rates in smaller, more degraded areas increased detection. Our data do not support the hypothesis of mesopredator release. Rather, our findings indicate that ocelots respond negatively to habitat loss, and thrive in large protected areas inhabited by top predators.

  19. Climate and ecosystem linkages explain widespread declines in North American Atlantic salmon populations.

    Science.gov (United States)

    Mills, Katherine E; Pershing, Andrew J; Sheehan, Timothy F; Mountain, David

    2013-10-01

    North American Atlantic salmon (Salmo salar) populations experienced substantial declines in the early 1990s, and many populations have persisted at low abundances in recent years. Abundance and productivity declined in a coherent manner across major regions of North America, and this coherence points toward a potential shift in marine survivorship, rather than local, river-specific factors. The major declines in Atlantic salmon populations occurred against a backdrop of physical and biological shifts in Northwest Atlantic ecosystems. Analyses of changes in climate, physical, and lower trophic level biological factors provide substantial evidence that climate conditions directly and indirectly influence the abundance and productivity of North American Atlantic salmon populations. A major decline in salmon abundance after 1990 was preceded by a series of changes across multiple levels of the ecosystem, and a subsequent population change in 1997, primarily related to salmon productivity, followed an unusually low NAO event. Pairwise correlations further demonstrate that climate and physical conditions are associated with changes in plankton communities and prey availability, which are ultimately linked to Atlantic salmon populations. Results suggest that poor trophic conditions, likely due to climate-driven environmental factors, and warmer ocean temperatures throughout their marine habitat area are constraining the productivity and recovery of North American Atlantic salmon populations. © 2013 John Wiley & Sons Ltd.

  20. Heat-shock responsive genes identified and validated in Atlantic cod (Gadus morhua) liver, head kidney and skeletal muscle using genomic techniques.

    Science.gov (United States)

    Hori, Tiago S; Gamperl, A Kurt; Afonso, Luis Ob; Johnson, Stewart C; Hubert, Sophie; Kimball, Jennifer; Bowman, Sharen; Rise, Matthew L

    2010-01-28

    Daily and seasonal changes in temperature are challenges that fish within aquaculture settings cannot completely avoid, and are known to elicit complex organismal and cellular stress responses. We conducted a large-scale gene discovery and transcript expression study in order to better understand the genes that are potentially involved in the physiological and cellular aspects of stress caused by heat-shock. We used suppression subtractive hybridization (SSH) cDNA library construction and characterization to identify transcripts that were dysregulated by heat-shock in liver, skeletal muscle and head kidney of Atlantic cod. These tissues were selected due to their roles in metabolic regulation, locomotion and growth, and immune function, respectively. Fish were exposed for 3 hours to an 8 degrees C elevation in temperature, and then allowed to recover for 24 hours at the original temperature (i.e. 10 degrees C). Tissue samples obtained before heat-shock (BHS), at the cessation of heat-shock (CS), and 3, 12, and 24 hours after the cessation of heat-shock (ACS), were used for reciprocal SSH library construction and quantitative reverse transcription - polymerase chain reaction (QPCR) analysis of gene expression using samples from a group that was transferred but not heat-shocked (CT) as controls. We sequenced and characterized 4394 ESTs (1524 from liver, 1451 from head kidney and 1419 from skeletal muscle) from three "forward subtracted" libraries (enriched for genes up-regulated by heat-shock) and 1586 from the liver "reverse subtracted" library (enriched for genes down-regulated by heat-shock), for a total of 5980 ESTs. Several cDNAs encoding putative chaperones belonging to the heat-shock protein (HSP) family were found in these libraries, and "protein folding" was among the gene ontology (GO) terms with the highest proportion in the libraries. QPCR analysis of HSP90alpha and HSP70-1 (synonym: HSPA1A) mRNA expression showed significant up-regulation in all three

  1. Heat-shock responsive genes identified and validated in Atlantic cod (Gadus morhua liver, head kidney and skeletal muscle using genomic techniques

    Directory of Open Access Journals (Sweden)

    Kimball Jennifer

    2010-01-01

    Full Text Available Abstract Background Daily and seasonal changes in temperature are challenges that fish within aquaculture settings cannot completely avoid, and are known to elicit complex organismal and cellular stress responses. We conducted a large-scale gene discovery and transcript expression study in order to better understand the genes that are potentially involved in the physiological and cellular aspects of stress caused by heat-shock. We used suppression subtractive hybridization (SSH cDNA library construction and characterization to identify transcripts that were dysregulated by heat-shock in liver, skeletal muscle and head kidney of Atlantic cod. These tissues were selected due to their roles in metabolic regulation, locomotion and growth, and immune function, respectively. Fish were exposed for 3 hours to an 8°C elevation in temperature, and then allowed to recover for 24 hours at the original temperature (i.e. 10°C. Tissue samples obtained before heat-shock (BHS, at the cessation of heat-shock (CS, and 3, 12, and 24 hours after the cessation of heat-shock (ACS, were used for reciprocal SSH library construction and quantitative reverse transcription - polymerase chain reaction (QPCR analysis of gene expression using samples from a group that was transferred but not heat-shocked (CT as controls. Results We sequenced and characterized 4394 ESTs (1524 from liver, 1451 from head kidney and 1419 from skeletal muscle from three "forward subtracted" libraries (enriched for genes up-regulated by heat-shock and 1586 from the liver "reverse subtracted" library (enriched for genes down-regulated by heat-shock, for a total of 5980 ESTs. Several cDNAs encoding putative chaperones belonging to the heat-shock protein (HSP family were found in these libraries, and "protein folding" was among the gene ontology (GO terms with the highest proportion in the libraries. QPCR analysis of HSP90α and HSP70-1 (synonym: HSPA1A mRNA expression showed significant up

  2. The role of extracellular matrix components in pin bone attachments during storage-a comparison between farmed Atlantic salmon (Salmo salar) and cod (Gadus morhua L.).

    Science.gov (United States)

    Rønning, Sissel B; Østbye, Tone-Kari; Krasnov, Aleksei; Vuong, Tram T; Veiseth-Kent, Eva; Kolset, Svein O; Pedersen, Mona E

    2017-04-01

    Pin bones represent a major problem for processing and quality of fish products. Development of methods of removal requires better knowledge of the pin bones' attachment to the muscle and structures involved in the breakdown during loosening. In this study, pin bones from cod and salmon were dissected from fish fillets after slaughter or storage on ice for 5 days, and thereafter analysed with molecular methods, which revealed major differences between these species before and after storage. The connective tissue (CT) attaches the pin bone to the muscle in cod, while the pin bones in salmon are embedded in adipose tissue. Collagens, elastin, lectin-binding proteins and glycosaminoglycans (GAGs) are all components of the attachment site, and this differ between salmon and cod, resulting in a CT in cod that is more resistant to enzymatic degradation compared to the CT in salmon. Structural differences are reflected in the composition of transcriptome. Microarray analysis comparing the attachment sites of the pin bones with a reference muscle sample showed limited differences in salmon. In cod, on the other hand, the variances were substantial, and the gene expression profiles suggested difference in myofibre structure, metabolism and cell processes between the pin bone attachment site and the reference muscle. Degradation of the connective tissue occurs closest to the pin bones and not in the neighbouring tissue, which was shown using light microscopy. This study shows that the attachment of the pin bones in cod and salmon is different; therefore, the development of methods for removal should be tailored to each individual species.

  3. Comparison of protein expression in plasma from nonylphenol and bisphenol A-exposed Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) by use of SELDI-TOF

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Bodil K. [International Research Institute of Stavanger (IRIS) AS, Mekjarvik 12, N-4070 Randaberg (Norway)]. E-mail: Bodil.larsen@irisresearch.no; Bjornstad, Anne [International Research Institute of Stavanger (IRIS) AS, Mekjarvik 12, N-4070 Randaberg (Norway); Sundt, Rolf C. [International Research Institute of Stavanger (IRIS) AS, Mekjarvik 12, N-4070 Randaberg (Norway); Taban, Ingrid C. [International Research Institute of Stavanger (IRIS) AS, Mekjarvik 12, N-4070 Randaberg (Norway); Pampanin, Daniela M. [International Research Institute of Stavanger (IRIS) AS, Mekjarvik 12, N-4070 Randaberg (Norway); Andersen, Odd Ketil [International Research Institute of Stavanger (IRIS) AS, Mekjarvik 12, N-4070 Randaberg (Norway)

    2006-06-01

    The overall objective of this study was to compare the expression of plasma proteins in juvenile cod and turbot after a 3 week exposure to two different chemicals known to be estrogenic: 4-nonylphenol (NP, 29 {mu}g/L) and bisphenol A (BPA, 59 {mu}g/L). ProteinChip[reg] array technology in combination with surfaced enhanced laser desorption ionisation-time of flight (SELDI-TOF) was used to investigate general responses in plasma proteins. In addition, an indirect enzyme-linked immunosorbent assay (ELISA) was used to analyse two specific biomarkers of estrogenic exposure, vitellogenin (Vtg) and zona radiata protein (Zrp) in plasma. Both methods revealed clear species specific responses. In cod, 67% of significantly altered proteins showed the same response (up or down regulated) in NP and BPA exposed animals (males and females combined). The rest were either specific to NP (10%), BPA (19%) or they showed opposite responses to the two chemicals (4%). In contrast, only 20% of significantly altered proteins were common for NP and BPA exposed turbot: 60% were altered only in NP and 17% only in BPA. Furthermore, in BPA exposed cod, 77% of the responses were common for male and females, whereas turbot showed only 21% similarity for the two genders. However, NP exposed male and female turbot showed 88% similarity in responses. As gender was not determined in NP exposed cod, gender specific responses could not be determined. ELISA results supported that cod responded clearly to both chemicals as a large increase was observed in Vtg and Zrp levels. Turbot responded strongly to NP, but seemed only slightly affected by BPA. Overall, the results indicated that cod are more sensitive or respond with less specificity to estrogenic chemicals than turbot. The relatively large degree of common responses in NP and BPA exposed cod may indicate that in cod BPA have similar mode of action as NP. Generally, the results show the potential of SELDI-TOF as a tool for comparing multiple

  4. Atlantic bluefin tuna: a novel multistock spatial model for assessing population biomass.

    Directory of Open Access Journals (Sweden)

    Nathan G Taylor

    Full Text Available Atlantic bluefin tuna (Thunnus thynnus is considered to be overfished, but the status of its populations has been debated, partly because of uncertainties regarding the effects of mixing on fishing grounds. A better understanding of spatial structure and mixing may help fisheries managers to successfully rebuild populations to sustainable levels while maximizing catches. We formulate a new seasonally and spatially explicit fisheries model that is fitted to conventional and electronic tag data, historic catch-at-age reconstructions, and otolith microchemistry stock-composition data to improve the capacity to assess past, current, and future population sizes of Atlantic bluefin tuna. We apply the model to estimate spatial and temporal mixing of the eastern (Mediterranean and western (Gulf of Mexico populations, and to reconstruct abundances from 1950 to 2008. We show that western and eastern populations have been reduced to 17% and 33%, respectively, of 1950 spawning stock biomass levels. Overfishing to below the biomass that produces maximum sustainable yield occurred in the 1960s and the late 1990s for western and eastern populations, respectively. The model predicts that mixing depends on season, ontogeny, and location, and is highest in the western Atlantic. Assuming that future catches are zero, western and eastern populations are predicted to recover to levels at maximum sustainable yield by 2025 and 2015, respectively. However, the western population will not recover with catches of 1750 and 12,900 tonnes (the "rebuilding quotas" in the western and eastern Atlantic, respectively, with or without closures in the Gulf of Mexico. If future catches are double the rebuilding quotas, then rebuilding of both populations will be compromised. If fishing were to continue in the eastern Atlantic at the unregulated levels of 2007, both stocks would continue to decline. Since populations mix on North Atlantic foraging grounds, successful rebuilding

  5. Genetic variation in time and space : Microsatellite analysis of extinct and extant populations of Atlantic salmon

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Hansen, Michael Møller; Loeschcke, V.

    1999-01-01

    Information on genetic composition of past and present populations may be obtained by analyzing DNA from archival samples. A study is presented on the genetic population structure of extant and extinct local populations of Atlantic salmon from 1913 to 1989 using dried scales as a source of DNA...

  6. CHARACTERIZATION OF WESTERN NORTH ATLANTIC RIGHT WHALE SPRING FEEDING HABITAT

    Science.gov (United States)

    The Great South Channel region of the southwestern Gulf of Maine, between George's Bank and Cape Cod, is the primary spring feeding ground for the western North Atlantic population of the I northern right whale, E. glacialis .Since this whale is so endangered, it is critical to i...

  7. Temporal trends in age and size at maturation of four North Sea gadid populations: cod, haddock, whiting, and Norway pout

    DEFF Research Database (Denmark)

    Marty, Lise; Rochet, Marie-Joëlle; Ernande, Bruno

    2014-01-01

    , phenotypic plasticity, and evolution to these trends were assessed. First, maturation trends were extricated from demographic effects and growth-dependent plasticity by estimating probabilistic maturation reaction norms (PMRNs). PMRN midpoints have significantly shifted downwards at most ages for cod......, haddock, and whiting, but not for Norway pout. Second, increased temperature and food abundance, loosened trophic competition, and relaxed social pressure may also trigger growth-independent plasticity in maturation. Principal component regression of PMRN midpoints on annual estimates of relevant...... environmental variables exhibiting a temporal trend suggest that, despite some evidence of environmental effects, PMRN trends were mostly independent of growth-independent plasticity in haddock, whiting, and male cod, but not in female cod. According to these findings, evolution of maturation, potentially...

  8. Uptake and tissue distribution of C{sub 4}-C{sub 7} alkylphenols in Atlantic cod (Gadus morhua): Relevance for biomonitoring of produced water discharges from oil production

    Energy Technology Data Exchange (ETDEWEB)

    Sundt, Rolf C. [IRIS-International Research Institute of Stavanger, P.O. Box 8046, N-4068 Stavanger (Norway)], E-mail: rolf.sundt@iris.no; Baussant, Thierry [IRIS-International Research Institute of Stavanger, P.O. Box 8046, N-4068 Stavanger (Norway); Beyer, Jonny [IRIS-International Research Institute of Stavanger, P.O. Box 8046, N-4068 Stavanger (Norway); University of Stavanger, N-4036 Stavanger (Norway)

    2009-01-15

    The sensitivity of different tissues for assessment of chronic low-dose environmental exposure of fish to alkylphenols (APs) was investigated. We exposed Atlantic cod (Gadus morhua) in the laboratory to tritium labelled 4-tert-butylphenol, 4n-pentylphenol, 4n-hexylphenol, and 4n-heptylphenol via seawater (8 ng/l) and via contaminated feed (5 {mu}g/kg fish per day). Measurements of different fish tissues during eight days of exposure and eight subsequent days of recovery revealed that APs administered via spiked seawater were readily taken up whereas the uptake was far less efficient when APs were administered in spiked feed. AP residues were mainly located in the bile fluid whereas the concentrations in liver were very low, indicating a rapid excretion and the liver-bile axis to be the major route of elimination. The biological half-life of APs in the exposed cod was short, between 10 and 20 h. Our study shows that in connection with biomonitoring of AP exposure in fish, assessment of AP metabolites in bile fluid is a more sensitive tool than detection of parent AP levels in liver or other internal tissues.

  9. Fundamental differences in diversity and genomic population structure between Atlantic and Pacific Prochlorococcus.

    Science.gov (United States)

    Kashtan, Nadav; Roggensack, Sara E; Berta-Thompson, Jessie W; Grinberg, Maor; Stepanauskas, Ramunas; Chisholm, Sallie W

    2017-09-01

    The Atlantic and Pacific Oceans represent different biogeochemical regimes in which the abundant marine cyanobacterium Prochlorococcus thrives. We have shown that Prochlorococcus populations in the Atlantic are composed of hundreds of genomically, and likely ecologically, distinct coexisting subpopulations with distinct genomic backbones. Here we ask if differences in the ecology and selection pressures between the Atlantic and Pacific are reflected in the diversity and genomic composition of their indigenous Prochlorococcus populations. We applied large-scale single-cell genomics and compared the cell-by-cell genomic composition of wild populations of co-occurring cells from samples from Station ALOHA off Hawaii, and from Bermuda Atlantic Time Series Station off Bermuda. We reveal fundamental differences in diversity and genomic structure of populations between the sites. The Pacific populations are more diverse than those in the Atlantic, composed of significantly more coexisting subpopulations and lacking dominant subpopulations. Prochlorococcus from the two sites seem to be composed of mostly non-overlapping distinct sets of subpopulations with different genomic backbones-likely reflecting different sets of ocean-specific micro-niches. Furthermore, phylogenetically closely related strains carry ocean-associated nutrient acquisition genes likely reflecting differences in major selection pressures between the oceans. This differential selection, along with geographic separation, clearly has a significant role in shaping these populations.

  10. The role of extracellular matrix components in pin bone attachments during storage—a comparison between farmed Atlantic salmon (Salmo salar) and cod (Gadus morhua L.)

    OpenAIRE

    Rønning, Sissel Beate; Østbye, Tone-Kari K; Krasnov, Aleksei; Vuong, Tram Thu; Veiseth-Kent, Eva; Kolset, Svein Olav; Pedersen, Mona Elisabeth

    2016-01-01

    Pin bones represent a major problem for processing and quality of fish products. Development of methods of removal requires better knowledge of the pin bones? attachment to the muscle and structures involved in the breakdown during loosening. In this study, pin bones from cod and salmon were dissected from fish fillets after slaughter or storage on ice for 5?days, and thereafter analysed with molecular methods, which revealed major differences between these species before and after storage. T...

  11. Effects of temperature and population density on von Bertalanffy growth parameters in Atlantic herring: a macro-ecological analysis

    NARCIS (Netherlands)

    Brunel, T.P.A.; Dickey-Collas, M.

    2010-01-01

    The effect of temperature and population density on the growth of Atlantic herring Clupea harengus was studied using a comparative approach applied to 15 North Atlantic populations. The von Bertalanffy (VB) equation was applied to describe mean growth of individuals in each population, both averaged

  12. Microsatellite DNA reveals population genetic differentiation among sprat (Sprattus sprattus) sampled throughout the Northeast Atlantic, including Norwegian fjords

    DEFF Research Database (Denmark)

    Glover, Kevin A.; Skaala, Øystein; Limborg, Morten

    2011-01-01

    Glover, K. A., Skaala, Ø., Limborg, M., Kvamme, C., and Torstensen, E. Microsatellite DNA reveals population genetic differentiation among sprat (Sprattus sprattus) sampled throughout the Northeast Atlantic, including Norwegian fjords. – ICES Journal of Marine Science, 68: 2145–2151. Sprat (Sprat...... display population genetic differentiation throughout the Northeast Atlantic, and there may be limited connectivity between Norwegian fjord and sea-going populations....

  13. Phylogeography and population dynamics of the white-sided dolphin (Lagenorhynchus acutus) in the North Atlantic

    KAUST Repository

    Banguera-Hinestroza, E.

    2014-02-27

    Highly mobile species in the marine environment may be expected to show little differentiation at the population level, but this is often not the case. Instead cryptic population structure is common, and effective conservation will require an understanding of how these patterns evolve. Here we present an assessment from both sides of the North Atlantic of differentiation among populations of a dolphin species that inhabits mainly pelagic waters, the Atlantic white-sided dolphin. We compare eleven putative populations in the western and eastern North Atlantic at mtDNA and microsatellite DNA loci and find reduced nucleotide diversity and signals for historical bottlenecks and post-bottleneck expansions in all regions. We calculate expansion times to have occurred during the early Holocene, following the last glacial maximum (LGM). We find evidence for connectivity among populations from either side of the North Atlantic, and differentiation between putative populations in the far northeast compared with all other areas sampled. Some data suggest the possibility of separate refugia during the LGM explaining this pattern, although ongoing ecological processes may also be a factor. We discuss the implications for developing effective programs of conservation and management in the context of ongoing anthropogenic impact. © 2014 Springer Science+Business Media Dordrecht.

  14. Population structure of humpback whales from their breeding grounds in the South Atlantic and Indian Oceans.

    Science.gov (United States)

    Rosenbaum, Howard C; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S; Best, Peter B; Findlay, Ken P; Minton, Gianna; Ersts, Peter J; Collins, Timothy; Engel, Marcia H; Bonatto, Sandro L; Kotze, Deon P G H; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-10-08

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region.

  15. Population Structure of Humpback Whales from Their Breeding Grounds in the South Atlantic and Indian Oceans

    Science.gov (United States)

    Rosenbaum, Howard C.; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S.; Best, Peter B.; Findlay, Ken P.; Minton, Gianna; Ersts, Peter J.; Collins, Timothy; Engel, Marcia H.; Bonatto, Sandro L.; Kotze, Deon P. G. H.; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-01-01

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region. PMID:19812698

  16. Regime shifts, resilience and recovery of a cod stock

    DEFF Research Database (Denmark)

    Lindegren, Martin; Diekmann, Rabea; Möllmann, Christian

    2010-01-01

    In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...... of the local cod stock to environmental change. The recovery and healthy condition of the Sound cod stock illustrate the need for adaptive marine management strategies that maximize ecosystem resilience....

  17. Recent trends in the abundance of plaice Pleuronectes platessa and cod Gadus morhua in shallow coastal waters of the Northeastern Atlantic continental shelf – a review

    DEFF Research Database (Denmark)

    Dutz, Jörg; Støttrup, Josianne Gatt; Stenberg, Claus

    2016-01-01

    responsible for any trends. At present, only a few studies exist on the trends of abundance of plaice or cod, namely from the Bay of Biscay, the North Sea and the Skagerrak/Kattegat. They suggest a declining abundance in coastal, shallow areas and – at least for plaice – a latitudinal gradient with an erosion...... of juveniles and adult fish to increasing seawater temperature are the main hypotheses for changes in distribution and abundance of both fish species in the North Sea/Bay of Biscay. However, temperature alone cannot explain the observed decline of fish in coastal areas, and the causes may be more complex...

  18. Flesh quality and biochemistry of light-manipulated Atlantic cod (Gadus morhua) and the significance of collagen cross-links on fillet firmness and gaping.

    Science.gov (United States)

    Hagen, Ørjan; Johnsen, Chris André

    2016-01-01

    The aim of our study was to investigate whether light-manipulation, causing accelerated or delayed maturation, could be used as a tool to improve fillet gaping score and texture of farmed cod (Gadus morhua L.) harvested during summer. Control and accelerated groups had completed spawning by the time of harvest, and expressed sexual dimorphism in various biometric and flesh quality parameters. Pyridinoline cross-links, a key biochemical parameter investigated, were positively correlated with texture (r(2) = 0.4), as also were cathepsin B&L and sex. Gaping was also impacted by pyridinoline cross-links, together with body mass and maturation. Interestingly, the level of gaping was significantly reduced with a pyridinoline cross-link concentration of >2500 pmols g(-1) dry mass. In conclusion, light-manipulation can be used as a tool to improve flesh texture of farmed cod with a low gaping score, but with compromise of increased dress out percentage for the accelerated group. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Cod Liver Oil

    Science.gov (United States)

    Cod liver oil can be obtained from eating fresh cod liver or by taking supplements. Cod liver oil is used as a source of vitamin ... condition called macular degeneration. Some people put cod liver oil on their skin to speed healing of ...

  20. Transcriptional responses in juvenile Atlantic cod (Gadus morhua) after exposure to mercury-contaminated sediments obtained near the wreck of the German WW2 submarine U-864, and from Bergen Harbor, Western Norway.

    Science.gov (United States)

    Olsvik, Pål A; Brattås, Marianne; Lie, Kai K; Goksøyr, Anders

    2011-04-01

    The main aim of the present work was to investigate the effects of mercury (Hg)-enriched sediments on fish. Sediments near the sunken German WW2 submarine U-864, which according to historical documents included 67 tons of metallic Hg in its cargo, are enriched of Hg leaking from the wreckage. Juvenile Atlantic cod (Gadus morhua) were exposed to two field-collected polluted sediments (U-864: inorganic Hg and Bergen Harbor (Vågen): inorganic Hg, PCB and PAH) or two comparable reference sediments for 5 weeks in the laboratory, and transcriptional responses evaluated in gills and liver. Gills of fish exposed to the Hg-enriched sunken WW2 submarine U-864 sediment contained four fold higher Hg levels compared to the control fish. An increase in Hg content in liver in the U-864 fish was also observed. The transcriptional results showed that calreticulin, HSP70 and heme oxygenase mRNA were significantly up-regulated in gills in fish exposed to the Hg-enriched sediments, whereas calreticulin, heme oxygenase, transferrin and WAP65 were significantly up-regulated and glutathione peroxidase 4B and zona pellucida 3 were significantly down-regulated in liver tissue. In gills and liver of cod exposed to the mixed-contaminated Vågen sediment, CYP1A showed the highest induction. In conclusion, the experiment shows that sediment-bound Hg is available to the fish and affects the transcription of oxidative stress responsive enzymes, suggesting that the Hg-enriched sediments may negatively affect the local wildlife. Furthermore, the mixed contaminated sediments of Vågen affected similar responses in addition to Ah-receptor mediated responses reflecting exposure to PAHs and PCBs. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Transcriptome profiling reveals that feeding wild zooplankton to larval Atlantic cod (Gadus morhua) influences suites of genes involved in oxidation-reduction, mitosis, and selenium homeostasis.

    Science.gov (United States)

    Rise, Matthew L; Hall, Jennifer R; Nash, Gordon W; Xue, Xi; Booman, Marije; Katan, Tomer; Gamperl, A Kurt

    2015-11-26

    Larval nutrition and growth are key issues for wild and cultured cod. While it was shown previously that larval cod fed wild zooplankton grow faster than those fed only rotifers, the mechanisms involved in this enhanced growth are not completely understood. We used microarrays to identify larval cod transcripts that respond to feeding with small amounts of wild zooplankton (5-10 % of live prey items). The larval transcriptome was compared between 3 treatment groups [fed rotifers (RA), rotifers with protein hydrolysate (RA-PH), or rotifers with zooplankton (RA-Zoo)] at 9-10 mm length [26-30 days post-hatch (dph)] to identify a robust suite of zooplankton-responsive genes (i.e. differentially expressed between RA-Zoo and both other groups). The microarray experiment identified 147 significantly up-regulated and 156 significantly down-regulated features in RA-Zoo compared with both RA and RA-PH. Gene ontology terms overrepresented in the RA-Zoo responsive gene set included "response to selenium ion" and several related to cell division and oxidation-reduction. Ten selenoprotein-encoding genes, and 2 genes involved in thyroid hormone generation, were up-regulated in RA-Zoo compared with both other groups. Hierarchical clustering of RA-Zoo responsive genes involved in oxidation-reduction and selenium homeostasis demonstrated that only the zooplankton treatment had a considerable and consistent impact on the expression of these genes. Fourteen microarray-identified genes were selected for QPCR involving 9-13 mm larvae, and 13 of these were validated as differentially expressed between RA-Zoo and both other groups at ~9 mm. In contrast, in age-matched (34-35 dph; ~11 mm RA and RA-PH, ~13 mm RA-Zoo) and size-matched (~13 mm) older larvae, only 2 and 3 genes, respectively, showed the same direction of RA-Zoo-responsive change as in ~9 mm larvae. The modulation of genes involved in selenium binding, redox homeostasis, and thyroid hormone generation in ~9 mm RA-Zoo larvae in

  2. Infection levels and species diversity of ascaridoid nematodes in Atlantic cod, Gadus morhua, are correlated with geographic area and fish size

    DEFF Research Database (Denmark)

    Gay, M.; Bao, M.; MacKenzie, K.

    2018-01-01

    2012-2014.Prevalences for Anisakis in whole fish and in fillets in the different fishing areas varied from 16 to 100% and from 12 to 90% respectively. Abundance was also greatly influenced by the sampling area. Generalized additive model results indicate higher numbers of Anisakis in the North Sea......, even after the larger body size was accounted for. Numbers and prevalence of Anisakis were positively related to fish length or weight. The prevalence of parasites in whole fish and in fillets was also influenced by the season, with the spring displaying a peak for the prevalence in whole fish and......, at the same time, a drop for the prevalence in fillets. Whereas 46% of cod had Anisakis larvae in their fillets, the majority (39%) had parasites mainly in the ventral part of the fillet and only 12% had parasites in their dorsal part. This observation is of importance for the processing of the fish. Indeed...

  3. Population genetic structure of the abyssal grenadier (Coryphaenoides armatus) around the mid-Atlantic ridge

    Science.gov (United States)

    Ritchie, H.; Cousins, N. J.; Cregeen, S. J.; Piertney, S. B.

    2013-12-01

    Understanding the factors that affect the levels and distribution of genetic diversity in oceanic and deep sea environments is a central focus in marine population genetics. Whilst it has been considered that the oceans represent a homogenous environment that would facilitate dispersal and minimise population structure, it is now clear that topographical features and current patterns can influence the extent of spatial gene flow and promote significant population genetic divergence even at local scales. Here we examine patterns of population genetic structure among N. Atlantic populations of the cosmopolitan abyssal grenadier Coryphaenoides armatus in relation to two hypothesised barriers to gene flow-the mid-Atlantic Ridge and the Charlie-Gibbs Fracture Zone/Sub-Polar Front. A suite of microsatellite markers were developed to examine the spatial pattern of allelic variation among 210 individuals from ten sampling locations encompassing sites east and west of the MAR and north and south of the CGFZ, plus a geographically distinct sample of individuals from the Crozet Islands in the Indian Ocean. Considerable genetic diversity was detected among individuals (na=5-13 and HO=0.46-0.69 across populations) but with an overall lack of genetic divergence between populations. Pairwise estimates of divergence among NE Atlantic samples were small and non-significant (max FST=0.04) and Structure-based Bayesian analysis of genetic clusters returned no distinct population structure. The only indication of genetic structure was between the Atlantic and Indian Oceans, with FST estimates of ca. 0.05. Patterns of genetic diversity and divergence are discussed in relation to what has been resolved in Coryphaenoides congeners, and what is known about the life history and ecology of C. armatus.

  4. Footprints of directional selection in wild Atlantic salmon populations: evidence for parasite-driven evolution?

    Science.gov (United States)

    Zueva, Ksenia J; Lumme, Jaakko; Veselov, Alexey E; Kent, Matthew P; Lien, Sigbjørn; Primmer, Craig R

    2014-01-01

    Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved.

  5. North Atlantic ecosystem shifts revealed by cod otolith δ15N and δ13C chronologies

    DEFF Research Database (Denmark)

    Pedersen, Jens Brøgger; Nielsen, Jens Munk; Steingrund, Petur

    annual mean values over time were seen in both ecosystems, suggesting δ15N & δ13C values were affected by the same overall processes. There were significant effects of climate variables (temperature, Atlantic Multi-decadal Oscillation (AMO) and Sub Polar Gyre index) on δ15N and δ13C chronologies in both...... catches. This indicates a large ecosystem shift in the Nuuk Fjord around 1970 and a smaller in 1995 and is further supported by the δ15N & δ13C bi-plot that shows a clear separation in signatures before and after 1970. To separate baseline shifts from trophic shifts new δ15N and δ13C chronologies...

  6. Genetic structure of European populations of Salmo salar L (Atlantic salmon) inferred from mitochondrial DNA

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Hansen, Michael Møller; Loeschcke, V.

    1996-01-01

    The genetic relationships between the only natural population of Atlantic salmon (Salmo salar L.) in Denmark and seven other European salmon populations were studied using RFLP analysis of PCR amplified mitochondrial DNA segments. Six different haplotypes were detected by restriction enzyme...... analyses of the NADH dehydrogenase 1 segment, employing four endonucleases. Significant genetic differentiation was observed among populations. A hierarchical analysis of the distribution of the mtDNA variability revealed that only a small part was distributed among geographical groups within the study...

  7. The Population Consequences of Disturbance Model Application to North Atlantic Right Whales (Eubalaena glacialis)

    Science.gov (United States)

    2015-09-30

    physiology , and the revised approach is called PCOD (Population Consequences Of Disturbance). In North Atlantic right whales (Eubalaena glacialis...Bayesian Model to assess right whale biology, 2) assess the relationship between health indicators and reproduction and mortality in right whales, and 3...assess the effects of fishing gear entanglements and sub-lethal vessel strikes on reproduction and mortality in right whales. The objective for FY

  8. Genetic Analysis of a Population of Atlantic salmon (Salmo salar, L.)in the Rhine System

    OpenAIRE

    Papa, Laura

    2009-01-01

    The present study was developed under the guidelines of a regional project to support the management of the anadromous salmonids in the Rhine, particularly the reintroduction of the Atlantic salmon (Salmo salar, L.) The main aim was to assign the salmons ascending to the Iffezheim lock to salmons used for reintroduction in the Rhine. It was analysed if such an assignment was reasonably possible. Furthermore, we wanted to find out if an established Rhine population already exists. The Ph.D. st...

  9. Environmental contaminants in fillets of sea-run Atlantic salmon (Salmo salar) from the Gulf of Maine Distinct Population Segment

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Between 2008 and 2010, skin‐on fillets from seven dead adult sea‐run Atlantic salmon from the Gulf of Maine Distinct Population Segment (GOM DPS) were analyzed for...

  10. Ancient DNA reveals the Arctic origin of Viking Age cod from Haithabu, Germany.

    Science.gov (United States)

    Star, Bastiaan; Boessenkool, Sanne; Gondek, Agata T; Nikulina, Elena A; Hufthammer, Anne Karin; Pampoulie, Christophe; Knutsen, Halvor; André, Carl; Nistelberger, Heidi M; Dierking, Jan; Petereit, Christoph; Heinrich, Dirk; Jakobsen, Kjetill S; Stenseth, Nils Chr; Jentoft, Sissel; Barrett, James H

    2017-08-22

    Knowledge of the range and chronology of historic trade and long-distance transport of natural resources is essential for determining the impacts of past human activities on marine environments. However, the specific biological sources of imported fauna are often difficult to identify, in particular if species have a wide spatial distribution and lack clear osteological or isotopic differentiation between populations. Here, we report that ancient fish-bone remains, despite being porous, brittle, and light, provide an excellent source of endogenous DNA (15-46%) of sufficient quality for whole-genome reconstruction. By comparing ancient sequence data to that of modern specimens, we determine the biological origin of 15 Viking Age (800-1066 CE) and subsequent medieval (1066-1280 CE) Atlantic cod ( Gadus morhua ) specimens from excavation sites in Germany, Norway, and the United Kingdom. Archaeological context indicates that one of these sites was a fishing settlement for the procurement of local catches, whereas the other localities were centers of trade. Fish from the trade sites show a mixed ancestry and are statistically differentiated from local fish populations. Moreover, Viking Age samples from Haithabu, Germany, are traced back to the North East Arctic Atlantic cod population that has supported the Lofoten fisheries of Norway for centuries. Our results resolve a long-standing controversial hypothesis and indicate that the marine resources of the North Atlantic Ocean were used to sustain an international demand for protein as far back as the Viking Age.

  11. Ancient DNA reveals the Arctic origin of Viking Age cod from Haithabu, Germany

    Science.gov (United States)

    Star, Bastiaan; Boessenkool, Sanne; Gondek, Agata T.; Nikulina, Elena A.; Hufthammer, Anne Karin; Pampoulie, Christophe; Knutsen, Halvor; André, Carl; Nistelberger, Heidi M.; Dierking, Jan; Petereit, Christoph; Heinrich, Dirk; Jakobsen, Kjetill S.; Stenseth, Nils Chr.; Jentoft, Sissel

    2017-01-01

    Knowledge of the range and chronology of historic trade and long-distance transport of natural resources is essential for determining the impacts of past human activities on marine environments. However, the specific biological sources of imported fauna are often difficult to identify, in particular if species have a wide spatial distribution and lack clear osteological or isotopic differentiation between populations. Here, we report that ancient fish-bone remains, despite being porous, brittle, and light, provide an excellent source of endogenous DNA (15–46%) of sufficient quality for whole-genome reconstruction. By comparing ancient sequence data to that of modern specimens, we determine the biological origin of 15 Viking Age (800–1066 CE) and subsequent medieval (1066–1280 CE) Atlantic cod (Gadus morhua) specimens from excavation sites in Germany, Norway, and the United Kingdom. Archaeological context indicates that one of these sites was a fishing settlement for the procurement of local catches, whereas the other localities were centers of trade. Fish from the trade sites show a mixed ancestry and are statistically differentiated from local fish populations. Moreover, Viking Age samples from Haithabu, Germany, are traced back to the North East Arctic Atlantic cod population that has supported the Lofoten fisheries of Norway for centuries. Our results resolve a long-standing controversial hypothesis and indicate that the marine resources of the North Atlantic Ocean were used to sustain an international demand for protein as far back as the Viking Age. PMID:28784790

  12. Population genetic structure in Atlantic and Pacific Ocean common murres (Uria aalge): natural replicate tests of post-Pleistocene evolution.

    Science.gov (United States)

    Morris-Pocock, J A; Taylor, S A; Birt, T P; Damus, M; Piatt, J F; Warheit, K I; Friesen, V L

    2008-11-01

    Understanding the factors that influence population differentiation in temperate taxa can be difficult because the signatures of both historic and contemporary demographics are often reflected in population genetic patterns. Fortunately, analyses based on coalescent theory can help untangle the relative influence of these historic and contemporary factors. Common murres (Uria aalge) are vagile seabirds that breed in the boreal and low arctic waters of the Northern Hemisphere. Previous analyses revealed that Atlantic and Pacific populations are genetically distinct; however, less is known about population genetic structure within ocean basins. We employed the mitochondrial control region, four microsatellite loci and four intron loci to investigate population genetic structure throughout the range of common murres. As in previous studies, we found that Atlantic and Pacific populations diverged during the Pleistocene and do not currently exchange migrants. Therefore, Atlantic and Pacific murre populations can be used as natural replicates to test mechanisms of population differentiation. While we found little population genetic structure within the Pacific, we detected significant east-west structuring among Atlantic colonies. The degree that population genetic structure reflected contemporary population demographics also differed between ocean basins. Specifically, while the low levels of population differentiation in the Pacific are at least partially due to high levels of contemporary gene flow, the east-west structuring of populations within the Atlantic appears to be the result of historic fragmentation of populations rather than restricted contemporary gene flow. The contrasting results in the Atlantic and Pacific Oceans highlight the necessity of carefully considering multilocus nonequilibrium population genetic approaches when reconstructing the demographic history of temperate Northern Hemisphere taxa.

  13. Cod Gadus morhua and climate change: processes, productivity and prediction

    DEFF Research Database (Denmark)

    Brander, Keith

    2010-01-01

    the causes. Investigation of cod Gadus morhua populations across the whole North Atlantic Ocean has shown large-scale patterns of change in productivity due to lower individual growth and condition, caused by large-scale climate forcing. If a population is being heavily exploited then a drop in productivity......Environmental factors act on individual fishes directly and indirectly. The direct effects on rates and behaviour can be studied experimentally and in the field, particularly with the advent of ever smarter tags for tracking fishes and their environment. Indirect effects due to changes in food......, predators, parasites and diseases are much more difficult to estimate and predict. Climate can affect all life-history stages through direct and indirect processes and although the consequences in terms of growth, survival and reproductive output can be monitored, it is often difficult to determine...

  14. COD::CIF::Parser

    Science.gov (United States)

    Merkys, Andrius; Vaitkus, Antanas; Butkus, Justas; Okulič-Kazarinas, Mykolas; Kairys, Visvaldas; Gražulis, Saulius

    2016-02-01

    A syntax-correcting CIF parser, COD::CIF::Parser , is presented that can parse CIF 1.1 files and accurately report the position and the nature of the discovered syntactic problems. In addition, the parser is able to automatically fix the most common and the most obvious syntactic deficiencies of the input files. Bindings for Perl, C and Python programming environments are available. Based on COD::CIF::Parser , the cod-tools package for manipulating the CIFs in the Crystallography Open Database (COD) has been developed. The cod-tools package has been successfully used for continuous updates of the data in the automated COD data deposition pipeline, and to check the validity of COD data against the IUCr data validation guidelines. The performance, capabilities and applications of different parsers are compared.

  15. Genetic structure analysis of Eufriesea violacea (Hymenoptera, Apidae populations from southern Brazilian Atlantic rainforest remnants

    Directory of Open Access Journals (Sweden)

    Silvia H. Sofia

    2005-09-01

    Full Text Available Random amplified polymorphic DNA (RAPD markers were used to analyze the genetic structure of Eufriesea violacea populations in three fragments (85.47, 832.58 and 2800 ha of Atlantic rainforest located in the north of the Brazilian state of Paraná. A total of twelve primers produced 206 loci, of which 129 were polymorphic (95% criterion. The proportions of polymorphic loci in each population ranged from 57.28% to 59.2%, revealing very similar levels of genetic variability in the groups of bees from each fragment. Unbiased genetic distances between groups ranged from 0.0171 to 0.0284, the smallest genetic distance occurring between bees from the two larger fragments. These results suggest that the E. violacea populations from the three fragments have maintained themselves genetically similar to native populations of this species originally present in northern Paraná.

  16. Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales.

    Science.gov (United States)

    Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M; Kinze, Carl; Lockyer, Christina H; Vighi, Morgana; Aguilar, Alex

    2013-01-01

    In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly highly mobile, shows indication of structuring in the eastern North Atlantic, an ocean basin in which a single population is believed to occur. To do so, we examined stable isotope values in sequential growth layer groups of teeth from individuals sampled in Denmark and NW Spain. In each layer we measured oxygen- isotope ratios (δ(18)O) in the inorganic component (hydroxyapatite), and nitrogen and carbon isotope ratios (δ(15)N: δ(13)C) in the organic component (primarily collagenous). We found significant differences between Denmark and NW Spain in δ(15)N and δ(18)O values in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in δ(15)N, δ(13)C and δ(18)O values in the period up to age 20, and in the ontogenetic variation of δ(15)N and δ(18)O values. These differences evidence that diet composition, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted.

  17. Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales.

    Directory of Open Access Journals (Sweden)

    Asunción Borrell

    Full Text Available In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly highly mobile, shows indication of structuring in the eastern North Atlantic, an ocean basin in which a single population is believed to occur. To do so, we examined stable isotope values in sequential growth layer groups of teeth from individuals sampled in Denmark and NW Spain. In each layer we measured oxygen- isotope ratios (δ(18O in the inorganic component (hydroxyapatite, and nitrogen and carbon isotope ratios (δ(15N: δ(13C in the organic component (primarily collagenous. We found significant differences between Denmark and NW Spain in δ(15N and δ(18O values in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in δ(15N, δ(13C and δ(18O values in the period up to age 20, and in the ontogenetic variation of δ(15N and δ(18O values. These differences evidence that diet composition, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted.

  18. Potential for restoration of the Roanoke River population of Atlantic sturgeon

    Science.gov (United States)

    Armstrong, J.L.; Hightower, J.E.

    2002-01-01

    The Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) was historically abundant within Albemarie Sound and the Roanoke River in North Carolina, but declined dramatically in the late 1800s in response to intensive fishing. Recent evidence suggests that the population may be recovering, following a statewide prohibition on harvest in 1991. A recruitment index generally increased from 1992 through 2001. Estuarine habitat for juveniles appears to be suitable, resulting in mean growth rates for age 1 fish ranging from 0.59 to 0.81 mm day-1. A restoration goal of 7000-21 000 subadult and adult Atlantic sturgeon was developed for the Roanoke River, based on historical landings records. Bycatch mortality because of commercial gill-netting in Albermarle Sound could affect recovery. Telemetry and netting data indicate that juvenile Atlantic sturgeon in the sound are most abundant in shallow nearshore areas where commercial gill-netting is concentrated. However, immediate mortality rates from survey and commercial gill-netting in Albemarle Sound were only 0-2%. Additional field studies are needed to refine estimates of immediate- and longer-term mortality associated with gill-net bycatch.

  19. Implications of stock recovery for a neighbouring management unit: experience from the Baltic cod

    DEFF Research Database (Denmark)

    Eero, Margit; Hansen, Jakob Hemmer; Hüssy, Karin

    2014-01-01

    Cod in the Baltic Sea is assessed and managed as two separate stocks, i.e. eastern and western Baltic cod. The eastern Baltic cod has recently started to recover after several decades of severe depletion. In the present study, we suggest that the recovery of the eastern Baltic cod population has ...

  20. Historical Arctic Logbooks Provide Insights into Past Diets and Climatic Responses of Cod.

    Directory of Open Access Journals (Sweden)

    Bryony L Townhill

    Full Text Available Gadus morhua (Atlantic cod stocks in the Barents Sea are currently at levels not seen since the 1950s. Causes for the population increase last century, and understanding of whether such large numbers will be maintained in the future, are unclear. To explore this, we digitised and interrogated historical cod catch and diet datasets from the Barents Sea. Seventeen years of catch data and 12 years of prey data spanning 1930-1959 cover unexplored spatial and temporal ranges, and importantly capture the end of a previous warm period, when temperatures were similar to those currently being experienced. This study aimed to evaluate cod catch per unit effort and prey frequency in relation to spatial, temporal and environmental variables. There was substantial spatio-temporal heterogeneity in catches through the time series. The highest catches were generally in the 1930s and 1940s, although at some localities more cod were recorded late in the 1950s. Generalized Additive Models showed that environmental, spatial and temporal variables are all valuable descriptors of cod catches, with the highest occurring from 15-45°E longitude and 73-77°N latitude, at bottom temperatures between 2 and 4°C and at depths between 150 and 250 m. Cod diets were highly variable during the study period, with frequent changes in the relative frequencies of different prey species, particularly Mallotus villosus (capelin. Environmental variables were particularly good at describing the importance of capelin and Clupea harengus (herring in the diet. These new analyses support existing knowledge about how the ecology of the region is controlled by climatic variability. When viewed in combination with more recent data, these historical relationships will be valuable in forecasting the future of Barents Sea fisheries, and in understanding how environments and ecosystems may respond.

  1. Historical Arctic Logbooks Provide Insights into Past Diets and Climatic Responses of Cod.

    Science.gov (United States)

    Townhill, Bryony L; Maxwell, David; Engelhard, Georg H; Simpson, Stephen D; Pinnegar, John K

    2015-01-01

    Gadus morhua (Atlantic cod) stocks in the Barents Sea are currently at levels not seen since the 1950s. Causes for the population increase last century, and understanding of whether such large numbers will be maintained in the future, are unclear. To explore this, we digitised and interrogated historical cod catch and diet datasets from the Barents Sea. Seventeen years of catch data and 12 years of prey data spanning 1930-1959 cover unexplored spatial and temporal ranges, and importantly capture the end of a previous warm period, when temperatures were similar to those currently being experienced. This study aimed to evaluate cod catch per unit effort and prey frequency in relation to spatial, temporal and environmental variables. There was substantial spatio-temporal heterogeneity in catches through the time series. The highest catches were generally in the 1930s and 1940s, although at some localities more cod were recorded late in the 1950s. Generalized Additive Models showed that environmental, spatial and temporal variables are all valuable descriptors of cod catches, with the highest occurring from 15-45°E longitude and 73-77°N latitude, at bottom temperatures between 2 and 4°C and at depths between 150 and 250 m. Cod diets were highly variable during the study period, with frequent changes in the relative frequencies of different prey species, particularly Mallotus villosus (capelin). Environmental variables were particularly good at describing the importance of capelin and Clupea harengus (herring) in the diet. These new analyses support existing knowledge about how the ecology of the region is controlled by climatic variability. When viewed in combination with more recent data, these historical relationships will be valuable in forecasting the future of Barents Sea fisheries, and in understanding how environments and ecosystems may respond.

  2. Remarkably low mtDNA control-region diversity and shallow population structure in Pacific cod Gadus macrocephalus.

    Science.gov (United States)

    Liu, M; Lu, Z C; Gao, T X; Yanagimoto, T; Sakurai, Y

    2010-10-01

    To investigate the genetic diversity and describe the population structure in Gadus macrocephalus, a 452 base pair (bp) fragment of the mitochondrial DNA control region was analysed in 259 individuals. The results showed remarkably low nucleotide diversity and a lack of genealogical structure. Small but significant genetic differentiations, however, were detected among north-western Pacific populations, but no large-scale regional differences were detected. These results indicate that populations of G. macrocephalus in the north-western Pacific are genetically subdivided and represent evolutionary lineages that should be managed individually. © 2010 The Authors. Journal compilation © 2010 The Fisheries Society of the British Isles.

  3. Cod reproductive ecology

    DEFF Research Database (Denmark)

    Røjbek, Maria

    reproduction. The overall objective of the thesis is to investigate the role of lipids in reproduction of cod (Gadus morhua) in the Central Baltic Sea. The first objective is to examine the seasonal variation in content of lipid and EFA in whole prey species of cod (Paper I). The second objective...... is to investigate the variation in lipid content, EFA and antioxidants of female Baltic cod gonads and livers during the reproductive cycle (Paper II) and to examine whether there is a deficiency in lipid energy and dietary EFA that could explain the delayed spawning time observed in the Baltic cod (Paper III...

  4. Prehistoric versus modern Baltic Sea cod fisheries: selectivity across the millennia.

    Science.gov (United States)

    Limburg, Karin E; Walther, Yvonne; Hong, Bongghi; Olson, Carina; Storå, Jan

    2008-12-07

    Combining Stone Age and modern data provides unique insights for management, extending beyond contemporary problems and shifting baselines. Using fish chronometric parts, we compared demographic characteristics of exploited cod populations from the Neolithic Period (4500 BP) to the modern highly exploited fishery in the central Baltic Sea. We found that Neolithic cod were larger (mean 56.4 cm, 95% confidence interval (CI)+/-0.9) than modern fish (weighted mean length in catch =49.5+/-0.2 cm in 1995, 48.2+/-0.2 cm in 2003), and older (mean ages=4.7+/-0.11, 3.1+/-0.02 and 3.6+/-0.02 years for Neolithic, 1995, and 2003 fisheries, respectively). Fishery-independent surveys in 1995 and 2003 show that mean sizes in the stock are 16-17 cm smaller than reflected in the fishery, and mean ages approximately 1-1.5 years younger. Modelled von Bertalanffy growth and back-calculated lengths indicated that Neolithic cod grew to smaller asymptotic lengths, but were larger at younger ages, implying rapid early growth. Very small Neolithic cod were absent and large individuals were rare as in modern times. This could be owing to selective harvests, the absence of small and large fish in the area or a combination. Comparing modern and prehistoric times, fishery selection is evident, but apparently not as great as in the North Atlantic proper.

  5. Evidence of segregated spawning in a single marine fish stock: Sympatric divergence of ecotypes in icelandic cod?

    Science.gov (United States)

    Grabowski, T.B.; Thorsteinsson, Vilhjalmur; McAdam, B.J.; Marteinsdottir, G.

    2011-01-01

    There is increasing recognition of intraspecific diversity and population structure within marine fish species, yet there is little direct evidence of the isolating mechanisms that maintain it or documentation of its ecological extent. We analyzed depth and temperature histories collected by electronic data storage tags retrieved from 104 Atlantic cod at liberty ???1 year to evaluate a possible isolating mechanisms maintaining population structure within the Icelandic cod stock. This stock consists of two distinct behavioral types, resident coastal cod and migratory frontal cod, each occurring within two geographically distinct populations. Despite being captured together on the same spawning grounds, we show the behavioral types seem reproductively isolated by fine-scale differences in spawning habitat selection, primarily depth. Additionally, the different groups occupied distinct seasonal thermal and bathymetric niches that generally demonstrated low levels of overlap throughout the year. Our results indicate that isolating mechanisms, such as differential habitat selection during spawning, might contribute to maintaining diversity and fine-scale population structure in broadcast-spawning marine fishes.

  6. Evidence of segregated spawning in a single marine fish stock: sympatric divergence of ecotypes in Icelandic cod?

    Directory of Open Access Journals (Sweden)

    Timothy B Grabowski

    Full Text Available There is increasing recognition of intraspecific diversity and population structure within marine fish species, yet there is little direct evidence of the isolating mechanisms that maintain it or documentation of its ecological extent. We analyzed depth and temperature histories collected by electronic data storage tags retrieved from 104 Atlantic cod at liberty ≥1 year to evaluate a possible isolating mechanisms maintaining population structure within the Icelandic cod stock. This stock consists of two distinct behavioral types, resident coastal cod and migratory frontal cod, each occurring within two geographically distinct populations. Despite being captured together on the same spawning grounds, we show the behavioral types seem reproductively isolated by fine-scale differences in spawning habitat selection, primarily depth. Additionally, the different groups occupied distinct seasonal thermal and bathymetric niches that generally demonstrated low levels of overlap throughout the year. Our results indicate that isolating mechanisms, such as differential habitat selection during spawning, might contribute to maintaining diversity and fine-scale population structure in broadcast-spawning marine fishes.

  7. Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales

    DEFF Research Database (Denmark)

    Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M.

    2013-01-01

    In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly...... in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in delta N-15, delta C-13 and delta O-18 values in the period up to age 20, and in the ontogenetic variation of delta N-15 and delta O-18 values. These differences evidence that diet composition......, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted....

  8. High Connectivity among Blue Crab (Callinectes sapidus) Populations in the Western South Atlantic.

    Science.gov (United States)

    Lacerda, Ana Luzia Figueiredo; Kersanach, Ralf; Cortinhas, Maria Cristina Silva; Prata, Pedro Fernandes Sanmartin; Dumont, Luiz Felipe Cestari; Proietti, Maíra Carneiro; Maggioni, Rodrigo; D'Incao, Fernando

    2016-01-01

    Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48), and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes.

  9. High Connectivity among Blue Crab (Callinectes sapidus Populations in the Western South Atlantic.

    Directory of Open Access Journals (Sweden)

    Ana Luzia Figueiredo Lacerda

    Full Text Available Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48, and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes.

  10. Early life of an inshore population of West Greenlandic cod Gadus morhua: spatial and temporal aspects of growth and survival

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus; Nielsen, Torkel Gissel; Thompson, A. R.

    2016-01-01

    Understanding the processes that affect fish larval survival and recruitment is a fundamental tenant of fisheries science. Small, isolated fjords are ideal study systems for elucidating early life history processes, as population dynamics are well traced in these partially closed systems. We...

  11. Forecasting the major influences of predation and environment on cod recovery in the northern Gulf of St. Lawrence.

    Science.gov (United States)

    Bousquet, Nicolas; Chassot, Emmanuel; Duplisea, Daniel E; Hammill, Mike O

    2014-01-01

    The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010-2040) to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus) abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry.

  12. Forecasting the major influences of predation and environment on cod recovery in the northern Gulf of St. Lawrence.

    Directory of Open Access Journals (Sweden)

    Nicolas Bousquet

    Full Text Available The northern Gulf of St. Lawrence (NGSL stock of Atlantic cod (Gadus morhua, historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010-2040 to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry.

  13. Population structure and gene flow of the Atlantic walrus ( Odobenus rosmarus rosmarus ) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation

    DEFF Research Database (Denmark)

    Andersen, L.W.; Born, E.W.; Gjertz, I.

    1998-01-01

    flow (Nm) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic...... microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land-Svalbard population, which were connected by moderate gene flow...... individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene...

  14. Low clonal propagation in Atlantic and Mediterranean populations of the red gorgonian Paramuricea clavata (Octocorallia

    Directory of Open Access Journals (Sweden)

    Joanna Pilczynska

    2017-03-01

    Full Text Available Clonal propagation is a common feature of benthic marine organisms. In the present study, we investigated the contribution of clonal reproduction in the red gorgonian Paramuricea clavata. Mediterranean populations of P. clavata were severely affected by mass mortality events caused by increased water temperature in 1999 and 2003. The populations are characterized by slow growth and episodic recruitment, but after the observed mortalities, an unexpectedly high recovery rate was observed in the severely affected populations from the Ligurian Sea, NW Mediterranean. Ten years after the last mortality event, we investigated the contribution of clonal propagation in populations from the Ligurian Sea, where some populations were highly affected by mass mortality events, and from the Atlantic, where mortality was never observed. All individuals were genotyped for nine microsatellite loci. The contribution of clonal reproduction varied from 0% to 13% and did not differ significantly between affected and unaffected populations. We confirm by using genetic markers that clonal propagation in P. clavata is not common, and that the contribution of clones is too low to play an important role in red gorgonian reproduction and cannot contribute to population recovery at sites that have been affected by mass mortality events.

  15. Population structure of Atlantic swordfish (Xiphias gladius L. 1758 (Teleostea, Xiphiidae using mitochondrial DNA analysis: implicationsfor fisheries management

    Directory of Open Access Journals (Sweden)

    Garcia, A.

    2011-06-01

    Full Text Available Recent studies on Atlantic swordfish (Xiphias gladius L. 1758 genetic structure have demonstrated significant heterogeneity but the precise boundary between populations remains to be identified. In this context, genetic diversity was investigated by PCR-RFLP analysis at the control region of mitochondrial DNA (D-loop from 274 swordfish specimens collected from five different areas of the Atlantic Ocean. The analysis of molecular variance (AMOVA showed that genetic variation was mainly due to differences within rather than between the studied areas. Additionally, the phylogenetic analysis did not show evident relationships among haplotypes from all areas. However, low but significant FST values were recorded when comparing Equatorial samples with those from the north central and north tropical Atlantic. These results do not support a need for changing the current management boundary for the Atlantic fishery.

  16. Could seals prevent cod recovery in the Baltic Sea?

    DEFF Research Database (Denmark)

    MacKenzie, Brian; Eero, Margit; Ojaveer, Henn

    2011-01-01

    in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows...... that the cod population could reach high levels well above the long-term average. Scenarios with similar seal and fishing levels but with 15% lower salinity suggest that the Baltic will still be able to support a cod population which can sustain a fishery, but biomass and yields will be lower. At present...... knowledge of cod and seal interactions, seal predation was found to have much lower impact on cod recovery, compared to the effects of exploitation and salinity. These results suggest that dual management objectives (recovery of both seal and cod populations) are realistic but success in achieving...

  17. Small mammal populations of an agroecosystem in the Atlantic Forest domain, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    PS. D’Andrea

    Full Text Available This study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. The study was conducted in a rural area of the Atlantic Forest, in Sumidouro, Rio de Janeiro State, Brazil. The population sizes, age structure and reproduction were studied for the four most common species in the study area. The overall diversity was 1.67 and ranged between 0.8 to 1.67. The species richness was 13 considering the whole study. The most abundant species were the rodents Nectomys squamipes (n = 133, Akodon cursor (n = 74, Oligoryzomys nigripes (n = 25 and the marsupials Didelphis aurita (n = 58 and Philander frenatus (n = 50. Seven other rodents were captured once: Necromys lasiurus, Akodon montensis, Sooretamys angouya, Oecomys catherine, Oxymycterus judex, Euryzygomatomys spinosus and Trinomys iheringi. There were higher peaks for diversity and species richness during the winter (dry months, probably due to higher food availability. The marsupials had a seasonal reproduction with highest population sizes at the end of the rainy seasons. Nectomys squamipes reproduced mostly during rainy periods. Akodon cursor reproduced predominantly in the winter with the highest population peaks occurring during this season. The analysis of the population dynamics of the rodent species indicated that no species behaved as an agricultural pest, probably due to the heterogeneous landscape of high rotativity of vegetable cultivation. Rodent populations were more susceptible to the removal procedure than marsupial ones.

  18. Mechanistic insights into the effects of climate change on larval cod.

    Science.gov (United States)

    Kristiansen, Trond; Stock, Charles; Drinkwater, Kenneth F; Curchitser, Enrique N

    2014-05-01

    Understanding the biophysical mechanisms that shape variability in fisheries recruitment is critical for estimating the effects of climate change on fisheries. In this study, we used an Earth System Model (ESM) and a mechanistic individual-based model (IBM) for larval fish to analyze how climate change may impact the growth and survival of larval cod in the North Atlantic. We focused our analysis on five regions that span the current geographical range of cod and are known to contain important spawning populations. Under the SRES A2 (high emissions) scenario, the ESM-projected surface ocean temperatures are expected to increase by >1 °C for 3 of the 5 regions, and stratification is expected to increase at all sites between 1950-1999 and 2050-2099. This enhanced stratification is projected to decrease large (>5 μm ESD) phytoplankton productivity and mesozooplankton biomass at all 5 sites. Higher temperatures are projected to increase larval metabolic costs, which combined with decreased food resources will reduce larval weight, increase the probability of larvae dying from starvation and increase larval exposure to visual and invertebrate predators at most sites. If current concentrations of piscivore and invertebrate predators are maintained, larval survival is projected to decrease at all five sites by 2050-2099. In contrast to past observed responses to climate variability in which warm anomalies led to better recruitment in cold-water stocks, our simulations indicated that reduced prey availability under climate change may cause a reduction in larval survival despite higher temperatures in these regions. In the lower prey environment projected under climate change, higher metabolic costs due to higher temperatures outweigh the advantages of higher growth potential, leading to negative effects on northern cod stocks. Our results provide an important first large-scale assessment of the impacts of climate change on larval cod in the North Atlantic. © 2013 John

  19. Towards sustainable fisheries of the Öresund cod (Gadus morhua) through sub-stock-specific assessment and management recommendations

    DEFF Research Database (Denmark)

    Lindegren, Martin; Waldo, Staffan; Nilsson, P. Anders

    2013-01-01

    elements. Atlantic cod (Gadus morhua) frequently occurs in spatially segregated populations, some of which exhibit fine-scaled stock structuring within current management boundaries. Here we use the locally spawning cod stock in the Sound (“Öresund”) as a case study, and perform a sub......Fisheries management traditionally relies on stock assessments assuming discrete populations within large administrational areas. However, failing to account for sub-stock structuring may result in overestimation of the stocks' true harvest potential and unsustainable exploitation of small stock......-term net benefits to the local gill-net fishery. Furthermore, our study emphasizes the need for developing sub-stock-specific management recommendations in order to ensure the maintenance of fisheries resources in general, and the persistence of sub-stock structuring in particular....

  20. Puberty in male atlantic cod (Gadus morhua)

    OpenAIRE

    ALMEIDA, F. F. L. de

    2009-01-01

    Puberty is the process by which a juvenile acquires for the first time the capacity to reproduce sexually, a critical basis for the conservation of a species. In general, the biological processes constituting the first gonadal maturation and the mechanisms involved in this process are similar among vertebrates. Internal and/or external signals trigger the secretion of gonadotropin-releasing hormone (Gnrh) by neurosecretory neurons in the ventral forebrain, and Gnrh stimulates the synthesis an...

  1. Hazard Analysis and identification of Critical Control Points of collagen extraction from cod by-products

    NARCIS (Netherlands)

    Aalberts, C.H.J.

    2004-01-01

    The aim of the European research project “UTILISATION AND STABILISATION OF BY-PRODUCTS FROM COD SPECIES” (QLK1-CT-2000-01017 QLRT-2001-02829) is to investigate whether collagen from fish by-products could serve as an important raw material in high quality food. Since Atlantic cod is a major

  2. Geologic history of Cape Cod, Massachusetts

    Science.gov (United States)

    ,

    1976-01-01

    Cape Cod, a sandy peninsula built mostly during the Ice Age, juts into the Atlantic Ocean like a crooked arm. Because of its exposed location, Cape Cod was visited by many early explorers. Although clear-cut evidence is lacking, the Vikings may have sighted this land about 1,000 years ago. It was visited by Samuel de Champlain in 1605, and his detailed descriptions and charts have helped present-day scientists to determine the rate of growth of Nauset Beach marsh and Nauset spit. Bartholomew Gosnold, a lesser known explorer, settled for a short time on the Elizabeth Islands to the southwest and gave Cape Cod its name in 1602. The Pilgrims first landed in America on the tip of Lower Cape Cod after they were turned back from their more southerly destination by shoals between Cape Cod and Nantucket Island. On Cape Cod they found potable water and food and had their first fight with the natives. The Pilgrims, however, decided that this land was too isolated, too exposed, and too sandy to support them, and they sailed across Cape Cod Bay to establish Plymouth. These features remain today. Small villages are separated by large areas of forest, dune, beach, and marsh. This unspoiled natural beauty makes Cape Cod one of the most favored vacation areas for the people living in the thickly settled Northeastern States. Cape Cod is of particular interest to geologists because it was formed by glaciers very recently in terms of geologic time. During the Great Ice Age, (the Pleistocene Epoch which began 2 to 3 million years ago), glaciers advanced from the north into the temperate regions of the Earth. Glacial ice covered the land at least four times. Each advance was accompanied by a worldwide lowering of sea level because the source of the ice was water from the seas. When the glaciers melted, the climate and sea level were probably much like they are today. In fact, some scientists believe that the Earth is presently between glacial episodes and that ice once again will

  3. Feeding opportunities of larval and juvenile cod (Gadus morhua) in a Greenlandic fjord: temporal and spatial linkages between cod and their preferred prey

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus; Kjellerup, Sanne; Malanski, Evandro

    2014-01-01

    preferences of the early-life stages of Atlantic cod (Gadus morhua) to quantify the availability of prey during a spring-summer season in a West Greenlandic fjord. We hypothesized that abundances of larval and juvenile cod at size were synchronized to optimal availability of preferred prey in space and time....... The present analysis is based on nine cruises each covering 5 stations visited between 24 May and 5 August 2010 comparing zooplankton abundance, cod gut content and distribution patterns. Cod 4–25 mm in length preferred prey of about 5 % of their own length. During ontogeny, their preferences changed from...

  4. First record of intestinal parasites in a wild population of jaguar in the Brazilian Atlantic Forest

    Directory of Open Access Journals (Sweden)

    Ana Carolina Srbek-Araujo

    Full Text Available Small and isolated wildlife populations may be more susceptible to disease, which makes illness an important issue to investigate regarding the conservation of large carnivores. Here, we present the results of the first investigation of intestinal parasites in one of the last remaining populations of jaguars in the Brazilian Atlantic Forest. We studied parasites from fecal samples using three different techniques for parasitological examination: floatation in saturated sodium chloride solution, sedimentation and formalin-ether centrifugation. Intestinal parasites were detected in 70% of the analyzed samples, and seven taxa (mean = 3.7 taxa/sample were identified. All the groups of parasites that were identified have been recorded in previous jaguar studies. However, the records of Class Trematoda and nematodes Trichuridae are the first evidence of these groups of worms in free-ranging jaguars in Brazil. Although our results do not provide conclusive evidence on the health of this jaguar population, given its very small size (approximately 20 animals we stress the need to properly understand the dynamics of disease in this wild population and to evaluate the risk of contracting new diseases from domestic species inhabiting the neighboring areas. These represent imperative actions for the successful conservation of this threatened population of jaguar.

  5. Pre-hospital ticagrelor in ST-segment elevation myocardial infarction in the French ATLANTIC population.

    Science.gov (United States)

    Cayla, Guillaume; Lapostolle, Frédéric; Ecollan, Patrick; Stibbe, Olivier; Benezet, Jean Francois; Henry, Patrick; Hammett, Christopher J; Lassen, Jens Flensted; Storey, Robert F; Ten Berg, Jur M; Hamm, Christian W; Van't Hof, Arnoud W; Montalescot, Gilles

    2017-10-01

    ATLANTIC was a randomized study comparing pre- and in-hospital treatment with a ticagrelor loading dose (LD) in ongoing ST-segment elevation myocardial infarction (STEMI). We sought to compare patient characteristics and clinical outcomes in France with other countries participating in ATLANTIC. The population comprised 1862 patients, 660 (35.4%) from France and 1202 from 12 other countries. The main endpoints were reperfusion (≥70% ST-segment elevation resolution) and TIMI flow grade 3 before (co-primary endpoints) and after percutaneous coronary intervention (PCI). Other endpoints included a composite ischaemic endpoint (death/myocardial infarction/stroke/urgent revascularization/definite stent thrombosis) and bleeding events at 30days. In France, median times from first LD to angiography and between first and second LDs were 49 and 35min, respectively, and were similar to other countries. French patients were younger (mean 58.7 vs 61.9years, pmanagement characteristics. ClinicalTrials.gov (NCT01347580). Copyright © 2017 Elsevier B.V. All rights reserved.

  6. The between-population genetic architecture of growth, maturation, and plasticity in Atlantic salmon.

    Science.gov (United States)

    Debes, Paul Vincent; Fraser, Dylan John; Yates, Matthew; Hutchings, Jeffrey A

    2014-04-01

    The between-population genetic architecture for growth and maturation has not been examined in detail for many animal species despite its central importance in understanding hybrid fitness. We studied the genetic architecture of population divergence in: (i) maturation probabilities at the same age; (ii) size at age and growth, while accounting for maturity status and sex; and (iii) growth plasticity in response to environmental factors, using divergent wild and domesticated Atlantic salmon (Salmo salar). Our work examined two populations and their multigenerational hybrids in a common experimental arrangement in which salinity and quantity of suspended sediments were manipulated to mimic naturally occurring environmental variation. Average specific growth rates across environments differed among crosses, maturity groups, and cross-by-maturity groups, but a growth-rate reduction in the presence of suspended sediments was equal for all groups. Our results revealed both additive and nonadditive outbreeding effects for size at age and for growth rates that differed with life stage, as well as the presence of different sex- and size-specific maturation probabilities between populations. The major implication of our work is that estimates of the genetic architecture of growth and maturation can be biased if one does not simultaneously account for temporal changes in growth and for different maturation probabilities between populations. Namely, these correlated traits interact differently within each population and between sexes and among generations, due to nonadditive effects and a level of independence in the genetic control for traits. Our results emphasize the challenges to investigating and predicting phenotypic changes resulting from between-population outbreeding.

  7. Modelling approaches for relating effects of change in river flow to populations of Atlantic salmon and brown trout

    Science.gov (United States)

    John D. Armstrong; Keith H. Nislow

    2012-01-01

    Modelling approaches for relating discharge to the biology of Atlantic salmon, Salmo salar L., and brown trout, Salmo trutta L., growing in rivers are reviewed. Process-based and empirical models are set within a common framework of input of water flow and output of characteristics of fish, such as growth and survival, which relate directly to population dynamics. A...

  8. Could seals prevent cod recovery in the Baltic Sea?

    Directory of Open Access Journals (Sweden)

    Brian R MacKenzie

    Full Text Available Fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. As a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which they were formerly productive and supported sustainable fisheries. Here we investigate how a cod (Gadus morhua population in the Baltic Sea whose biomass was reduced due to a combination of high exploitation and deteriorating environmental conditions might recover and develop in the 21st century in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows that the cod population could reach high levels well above the long-term average. Scenarios with similar seal and fishing levels but with 15% lower salinity suggest that the Baltic will still be able to support a cod population which can sustain a fishery, but biomass and yields will be lower. At present knowledge of cod and seal interactions, seal predation was found to have much lower impact on cod recovery, compared to the effects of exploitation and salinity. These results suggest that dual management objectives (recovery of both seal and cod populations are realistic but success in achieving these goals will also depend on how climate change affects cod recruitment.

  9. 1H NMR metabolic profiling of cod (Gadus morhua) larvae: potential effects of temperature and diet composition during early developmental stages.

    Science.gov (United States)

    Chauton, Matilde Skogen; Galloway, Trina Falck; Kjørsvik, Elin; Størseth, Trond Røvik; Puvanendran, Velmurugu; van der Meeren, Terje; Karlsen, Ørjan; Rønnestad, Ivar; Hamre, Kristin

    2015-11-06

    Marine aquaculture offers a great source of protein for the increasing human population, and farming of, for example, Atlantic salmon is a global industry. Atlantic cod farming however, is an example of a promising industry where the potential is not yet realized. Research has revealed that a major bottleneck to successful farming of cod is poor quality of the larvae and juveniles. A large research program was designed to increase our understanding of how environmental factors such as temperature and nutrition affects cod larvae development. Data on larvae growth and development were used together with nuclear magnetic resonance. The NMR data indicated that the temperature influenced the metabolome of the larvae; differences were related to osmolytes such as betaine/TMAO, the amino acid taurine, and creatine and lactate which reflect muscle activity. The larvae were fed Artemia from stage 2, and this was probably reflected in a high taurine content of older larvae. Larvae fed with copepods in the nutrition experiment also displayed a high taurine content, together with higher creatine and betaine/TMAO content. Data on the cod larvae metabolome should be coupled to data on gene expression, in order to identify events which are regulated on the genetic level versus regulation resulting from temperature or nutrition during development, to fully understand how the environment affects larval development. © 2015. Published by The Company of Biologists Ltd.

  10. 1H NMR metabolic profiling of cod (Gadus morhua larvae: potential effects of temperature and diet composition during early developmental stages

    Directory of Open Access Journals (Sweden)

    Matilde Skogen Chauton

    2015-12-01

    Full Text Available Marine aquaculture offers a great source of protein for the increasing human population, and farming of, for example, Atlantic salmon is a global industry. Atlantic cod farming however, is an example of a promising industry where the potential is not yet realized. Research has revealed that a major bottleneck to successful farming of cod is poor quality of the larvae and juveniles. A large research program was designed to increase our understanding of how environmental factors such as temperature and nutrition affects cod larvae development. Data on larvae growth and development were used together with nuclear magnetic resonance. The NMR data indicated that the temperature influenced the metabolome of the larvae; differences were related to osmolytes such as betaine/TMAO, the amino acid taurine, and creatine and lactate which reflect muscle activity. The larvae were fed Artemia from stage 2, and this was probably reflected in a high taurine content of older larvae. Larvae fed with copepods in the nutrition experiment also displayed a high taurine content, together with higher creatine and betaine/TMAO content. Data on the cod larvae metabolome should be coupled to data on gene expression, in order to identify events which are regulated on the genetic level versus regulation resulting from temperature or nutrition during development, to fully understand how the environment affects larval development.

  11. Effects of climate change on the survival of larval cod

    Science.gov (United States)

    Kristiansen, T.; Stock, C. A.; Drinkwater, K. F.; Curchitser, E. N.

    2011-12-01

    Understanding how climate change may impact important commercial fisheries is critical for developing sustainable fisheries management strategies. In this study, we used simulations from an Earth System Model (NOAA GFDL ESM2.1) coupled with an individual-based model (IBM) for larval fish to provide a first assessment of the potential importance of climate-change driven changes in primary productivity and temperature on cod recruitment in the North Atlantic to the year 2100. ESM model output was averaged for 5 regions, each with an area of 5x5 on a latitude-longitude grid, and representing the geographic boundaries of the current cod range. The physical and environmental data were incorporated into a mechanistic IBM used to simulate the critical early phases in the life of larval fish (e.g. cod) in a changing environment. Large phytoplankton production was predicted to decrease in most regions, thereby lowering the number of meso-zooplankton in the water column. Meso-zooplankton is the most important prey item for larval cod and a reduction in their numbers have strong impacts on larval cod survival. The combination of lowered prey abundance with increased energy requirement for growth and metabolism through increased temperature had a negative impact on cod recruitment in all modeled regions of the North Atlantic. The probability of survival past the larval stages was reduced with 20-30% at all five spawning grounds by the year 2100. Together, these results suggest climate change could have significant impacts on the survival of larval cod in the North Atlantic.

  12. Influence of body condition on the population dynamics of Atlantic salmon with consideration of the potential impact of sea lice.

    Science.gov (United States)

    Susdorf, R; Salama, N K G; Lusseau, D

    2017-11-21

    Atlantic salmon Salmo salar is an iconic species of high conservation and economic importance. At sea, individuals typically are subject to sea lice infestation, which can have detrimental effects on their host. Over recent decades, the body condition and marine survival in NE Atlantic stocks have generally decreased, reflected in fewer adults returning to rivers, which is partly attributable to sea lice. We developed a deterministic stage-structured population model to assess condition-mediated population dynamics resulting in changing fecundity, age at sexual maturation and marine survival rate. The model is parameterized using data from the North Esk system, north-east Scotland. Both constant and density-dependent juvenile survival rates are considered. We show that even small sea lice-mediated changes in mean body condition of MSW can cause substantial population declines, whereas 1SW condition is less influential. Density dependence alleviates the condition-mediated population effect. The resilience of the population to demographic perturbations declines as adult condition is reduced. Indirect demographic changes in salmonid life-history traits (e.g., body condition) are often considered unimportant for population trajectory. The model shows that Atlantic salmon population dynamics can be highly responsive to sea lice-mediated effects on adult body condition, thus highlighting the importance of non-lethal parasitic long-term effects. © 2017 The Authors Journal of Fish Diseases Published by John Wiley & Sons Ltd.

  13. Testing the implications of a permanent or seasonal marine reserve on the population dynamics of Eastern Baltic cod under varying environmental conditions

    NARCIS (Netherlands)

    Roeckmann, C.; St.John, M.A.; Schneider, U.A.; Tol, R.S.J.

    2007-01-01

    A spatially disaggregated, discrete time, age-structured model for the Eastern Baltic cod (Gadus morhua callarias L.) stock was constructed, in order to test the implications of the establishment of a marine reserve in the Baltic Sea. Functional relationships for recruitment and predation mortality

  14. Testing the implications of a permanent or seasonal marine reserve on the population dynamics of eastern baltic cod under varying environmental conditions

    NARCIS (Netherlands)

    Roeckmann, C.; Schneider, U.A.; St. John, M.A.; Tol, R.S.J.

    2007-01-01

    A spatially disaggregated, discrete time, age-structured model for the Eastern Baltic cod (Gadus morhua callarias L.) stock was constructed, in order to test the implications of the establishment of a marine reserve in the Baltic Sea. Functional relationships for recruitment and predation mortality

  15. Lack of genetic structure in greylag goose (Anser anser populations along the European Atlantic flyway

    Directory of Open Access Journals (Sweden)

    Irene Pellegrino

    2015-08-01

    Full Text Available Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those from Scandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout the European Atlantic flyway, from breeding sites in Norway and the Netherlands to stopover and wintering sites in northern and south-western France. The mtDNA marker (CR1 D-Loop, 288 bp sequence, 144 ind. showed 23 different haplotypes. The genetic distances amongst individuals sampled in Norway, northern France and the Netherlands were low (range 0.012–0.013. Individuals in south-western France showed a slightly higher genetic distance compared to all other sampling areas (ranges 0.018–0.022. The NJ tree does not show evidence of any single clades grouping together all individuals from the same geographic area. Besides, individuals from each site are found in different branches. Bayesian clustering procedures on 14 microsatellites (169 individuals did not detect any geographically distinct cluster, and a high genetic admixture was recorded in all studied areas except for the individuals from the breeding sites in Norway, which were genetically very close. Estimation of migration rates through Bayesian inference confirms the scenario for the current mixing of goose populations.

  16. Population genetic structure of Guiana dolphin (Sotalia guianensis from the southwestern Atlantic coast of Brazil.

    Directory of Open Access Journals (Sweden)

    Juliana Ywasaki Lima

    Full Text Available Sotalia guianensis is a small dolphin that is vulnerable to anthropogenic impacts. Along the Brazilian Atlantic coast, this species is threatened with extinction. A prioritized action plan for conservation strategies relies on increased knowledge of the population. The scarcity of studies about genetic diversity and assessments of population structure for this animal have precluded effective action in the region. Here, we assessed, for the first time, the genetic differentiation at 14 microsatellite loci in 90 S. guianensis specimens stranded on the southeastern Atlantic coast of the State of Espírito Santo, Brazil. We estimated population parameters and structure, measured the significance of global gametic disequilibrium and the intensity of non-random multiallelic interallelic associations and constructed a provisional synteny map using Bos taurus, the closest terrestrial mammal with a reference genome available. All microsatellite loci were polymorphic, with at least three and a maximum of ten alleles each. Allele frequencies ranged from 0.01 to 0.97. Observed heterozygosity ranged from 0.061 to 0.701. The mean inbreeding coefficient was 0.103. Three loci were in Hardy-Weinberg disequilibrium even when missing genotypes were inferred. Although 77 of the 91 possible two-locus associations were in global gametic equilibrium, we unveiled 13 statistically significant, sign-based, non-random multiallelic interallelic associations in 10 two-locus combinations with either coupling (D' values ranging from 0.782 to 0.353 or repulsion (D' values -0.517 to -1.000 forces. Most of the interallelic associations did not involve the major alleles. Thus, for either physically or non-physically linked loci, measuring the intensity of non-random interallelic associations is