Habitat selection by Forster's Terns (Sterna forsteri) at multiple spatial scales in an urbanized estuary: The importance of salt ponds

Science.gov (United States)

Bluso-Demers, Jill; Ackerman, Joshua T.; Takekawa, John Y.; Peterson, Sarah

2016-01-01

The highly urbanized San Francisco Bay Estuary, California, USA, is currently undergoing large-scale habitat restoration, and several thousand hectares of former salt evaporation ponds are being converted to tidal marsh. To identify potential effects of this habitat restoration on breeding waterbirds, habitat selection of radiotagged Forster's Terns (Sterna forsteri) was examined at multiple spatial scales during the pre-breeding and breeding seasons of 2005 and 2006. At each spatial scale, habitat selection ratios were calculated by season, year, and sex. Forster's Terns selected salt pond habitats at most spatial scales and demonstrated the importance of salt ponds for foraging and roosting. Salinity influenced the types of salt pond habitats that were selected. Specifically, Forster's Terns strongly selected lower salinity salt ponds (0.5–30 g/L) and generally avoided higher salinity salt ponds (≥31 g/L). Forster's Terns typically used tidal marsh and managed marsh habitats in proportion to their availability, avoided upland and tidal flat habitats, and strongly avoided open bay habitats. Salt ponds provide important habitat for breeding waterbirds, and restoration efforts to convert former salt ponds to tidal marsh may reduce the availability of preferred breeding and foraging areas.

Low Spatial Genetic Differentiation Associated with Rapid Recolonization in the New Zealand Fur Seal Arctocephalus forsteri.

Science.gov (United States)

Dussex, Nicolas; Robertson, Bruce C; Salis, Alexander T; Kalinin, Aleksandr; Best, Hugh; Gemmell, Neil J

2016-01-01

Population declines resulting from anthropogenic activities are of major consequence for the long-term survival of species because the resulting loss of genetic diversity can lead to extinction via the effects of inbreeding depression, fixation of deleterious mutations, and loss of adaptive potential. Otariid pinnipeds have been exploited commercially to near extinction with some species showing higher demographic resilience and recolonization potential than others. The New Zealand fur seal (NZFS) was heavily impacted by commercial sealing between the late 18th and early 19th centuries, but has recolonized its former range in southern Australia. The species has also recolonized its former range in New Zealand, yet little is known about the pattern of recolonization. Here, we first used 11 microsatellite markers (n = 383) to investigate the contemporary population structure and dispersal patterns in the NZFS (Arctocephalus forsteri). Secondly, we model postsealing recolonization with 1 additional mtDNA cytochrome b (n = 261) marker. Our data identified 3 genetic clusters: an Australian, a subantarctic, and a New Zealand one, with a weak and probably transient subdivision within the latter cluster. Demographic history scenarios supported a recolonization of the New Zealand coastline from remote west coast colonies, which is consistent with contemporary gene flow and with the species' high resilience. The present data suggest the management of distinct genetic units in the North and South of New Zealand along a genetic gradient. Assignment of individuals to their colony of origin was limited (32%) with the present data indicating the current microsatellite markers are unlikely sufficient to assign fisheries bycatch of NZFSs to colonies. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxidative stress response of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia) to mercury and selenium bioaccumulation in liver, kidney, and brain

Science.gov (United States)

Hoffman, David J.; Eagles-Smith, Collin A.; Ackerman, Joshua T.; Adelsbach, Terrence L.; Stebbins, Katherine R.

2011-01-01

Bioindicators of oxidative stress were examined in prebreeding and breeding adult and chick Forster's terns (Sterna forsteri) and in prebreeding adult Caspian terns (Hydroprogne caspia) in San Francisco Bay, California. Highest total mercury (THg) concentrations (mean±standard error;μg/g dry wt) in liver (17.7±1.7), kidney (20.5±1.9), and brain (3.0±0.3) occurred in breeding adult Forster's terns. The THg concentrations in liver were significantly correlated with hepatic depletion of reduced glutathione (GSH), increased oxidized glutathione (GSSG):GSH ratio, and decreased hepatic gamma-glutamyl transferase (GGT) activity in adults of both tern species. Prefledging Forster's tern chicks with one-fourth the hepatic THg concentration of breeding adults exhibited effects similar to adults. Total mercury-related renal GSSG increased in adults and chicks. In brains of prebreeding adults, THg was correlated with a small increase in glucose-6-phosphate dehydrogenase (G-6-PDH) activity, suggestive of a compensatory response. Brain THg concentrations were highest in breeding adult Forster's terns and brain tissue exhibited increased lipid peroxidation as thiobarbituric acid-reactive substances, loss of protein bound thiols (PBSH), and decreased activity of antioxidant enzymes, GSSG reductase (GSSGrd), and G-6-PDH. In brains of Forster's tern chicks there was a decrease in total reduced thiols and PBSH. Multiple indicator responses also pointed to greater oxidative stress in breeding Forster's terns relative to prebreeding terns, attributable to the physiological stress of reproduction. Some biondicators also were related to age and species, including thiol concentrations. Enzymes GGT, G-6-PDH, and GSSGred activities were related to species. Our results indicate that THg concentrations induced oxidative stress in terns, and suggest that histopathological, immunological, and behavioral effects may occur in terns as reported in other species.

Trematodes of fishes of the Indo-west Pacific: told and untold richness

Czech Academy of Sciences Publication Activity Database

Cribb, T.H.; Bray, R. A.; Diaz, P.E.; Huston, D.C.; Kudlai, Olena; Martin, S.B.; Yong, R.Q.-Y.; Cutmore, S.C.

2016-01-01

Roč. 93, č. 3 (2016), s. 237-247 ISSN 0165-5752 Institutional support: RVO:60077344 Keywords : Great Barrier reef * French Polynesia * Cardicola forsteri Subject RIV: EH - Ecology, Behaviour Impact factor: 1.181, year: 2016

Distribution of the species of Dipturus Rafinesque (Rajidae, Rajinae, Rajini off Brazil and first record of the Caribbean skate D. teevani (Bigelow & Schroeder, in the Western South Atlantic

Directory of Open Access Journals (Sweden)

Ulisses Leite Gomes

2001-03-01

Full Text Available The Caribbean skate Dipturus teevani (Bigelow & Schroeder, 1951 is recorded for the first time from Brazilian waters. The specimen was collected in the continental slope off Bahia State. With this record, four species of Dipturus Rafinesque, 1810 are known from Brazil: D. chilensis (Guichenot, 1848, D. leptocauda (Kreft & Stehmann, 1975, D. trachyderma (Krefft & Stehmann, 1975 and D. teevani (Bigelow & Schroeder, 1951. They are typical inhabitants of deep waters between the outer shelf edge (195-200m and the slope (more than 500m. Although morphologically conservative, the species of Dipturus can be distinguished from each other by the number of dorsal and nuchal thorns, the number of caudal thorns, dorsal and ventral spinulation and specific total length. An identification key for the species of Dipturus recorded from Brazil is presented.

Projected continent-wide declines of the emperor penguin under climate change

NARCIS (Netherlands)

Jenouvrier, S.; Holland, M.; Stroeve, J.; Serreze, M.; Barbraud, C.; Weimerskirch, H.; Caswell, H.

2014-01-01

Climate change has been projected to affect species distribution1 and future trends of local populations2, 3, but projections of global population trends are rare. We analyse global population trends of the emperor penguin (Aptenodytes forsteri), an iconic Antarctic top predator, under the influence

76 FR 9681 - Endangered and Threatened Wildlife and Plants; Determination of Threatened Status for the New...

Science.gov (United States)

2011-02-22

... species under the Act: emperor penguin (Aptenodytes forsteri), southern rockhopper penguin (Eudyptes... emperor penguin (73 FR 77264). We finalized the actions listed in (1) and (2) above on September 28, 2010... little as 6 miles (mi) (10 kilometers (km)) of the colony (as at the Crozet Archipelago in the Indian...

Evaluation of social attraction measures to establish Forster’s tern (Sterna forsteri) nesting colonies for the South Bay Salt Pond Restoration Project, San Francisco Bay, California—2017 Annual Report

Science.gov (United States)

Hartman, C. Alex; Ackerman, Joshua T.; Herzog, Mark P.; Wang, Yiwei; Strong, Cheryl

2018-05-31

Forster’s terns (Sterna forsteri), historically one of the most numerous colonial-breeding waterbirds in South San Francisco Bay, California, have had recent decreases in the number of nesting colonies and overall breeding population size. The South Bay Salt Pond (SBSP) Restoration Project aims to restore 50–90 percent of former salt evaporation ponds to tidal marsh habitat in South San Francisco Bay. This restoration will remove much of the historical island nesting habitat used by Forster’s terns, American avocets (Recurvirostra americana), and other waterbirds. To address this issue, the SBSP Restoration Project organized the construction of new nesting islands in managed ponds that will not be restored to tidal marsh, thereby providing enduring island nesting habitat for waterbirds. In 2012, 16 new islands were constructed in Pond A16 in the Alviso complex of the Don Edwards San Francisco Bay National Wildlife Refuge, increasing the number of islands in this pond from 4 to 20. However, despite a history of nesting on the four historical islands in Pond A16 before 2012, no Forster’s terns have nested in Pond A16 since the new islands were constructed.In 2017, we used social attraction measures (decoys and electronic call systems) to attract Forster’s terns to islands within Pond A16 to re-establish nesting colonies. We maintained these systems from March through August 2017. To evaluate the effect of these social attraction measures, we also completed waterbird surveys between April and August, where we recorded the number and location of all Forster’s terns and other waterbirds using Pond A16, and monitored waterbird nests. We compared bird survey and nest monitoring data collected in 2017 to data collected in 2015 and 2016, prior to the implementation of social attraction measures, allowing for direct evaluation of social attraction efforts on Forster’s terns.To increase the visibility and stakeholder involvement of this project, we engaged in

Deep-Diving California Sea Lions: Are They Pushing Their Physiological Limit

Science.gov (United States)

2015-09-30

highly variable. Venous oxygen content can actually increase during short duration dives. This suggests very little muscle blood flow and evven the use...the sea lion, the emperor penguin (Aptenodytes forsteri), another animal that dives on inspiration with a large respiratory O2 store, also can...in deep-diving emperor penguins (Wright et al. 2014), and in deep-diving bottlenose dolphins (Tursiops truncatus), which also dive on inspiration

Morphological description of Dipturus mennii (Chondrichthyes: Elasmobranchii: Rajidae and its differentiation from Dipturus trachyderma

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Renan A Moreira

2011-02-01

Full Text Available Squamation patterns and skeletal anatomy (neurocranium, visceral arches, synarcual cartilage, scapulocoracoid, puboischiadic bar, and mixopterigium of Dipturus mennii Gomes & Paragó, 2001 are described as a contribution to our limited knowledge of the anatomy of species of Dipturus Rafinesque, 1810. The hyoid and branchial arches, as well as the synarcual cartilage, are described for the first time in this species. We provide morphological comparisons of this species with Dipturus trachyderma (Krefft & Stehmann, 1975, a species that may be confused with D. mennii; we further corroborate, through anatomical features, that these species warrant separate taxonomic recognition. The main differences between D. mennii and D. trachyderma were found in squamation of the nuchal and middisc region, neurocranium, pectoral girdle, and principally the clasper skeleton. The morphology of the pelvic girdle is similar in both species. Dipturus is characterized by having the ventral terminal cartilage J-shaped (as opposed to the Z-shaped ventral terminal cartilage in Zearaja, whose species were, until recently, placed in Dipturus. Additional characters that may be derived for Dipturus include the anterior rostral groove and elevated rostral proportions

Are environmental factors responsible for changed breeding behaviour in emperor penguins?

OpenAIRE

Zitterbart, Daniel; Richter, Sebastian; Spiekermann, Georg; Behrens, Lisa Katharina; Regnery, Julia; Fontes, René Pascal; Hänssler, Thedda; König-Langlo, Gert; Weller, Rolf; Fabry, Ben

2014-01-01

Emperor penguins (Aptenodytes forsteri Gray) are the only vertebrate species that breed during the Antarctic winter. From the beginning of the breeding season in April until fledging of the chicks in January, emperor penguins rely on the stability of sea (fast) ice. The International Union for Conservation of Nature (IUCN) has recently listed the species as ‘near threatened’ because the habitat of emperor penguins may deteriorate significantly over the coming years with the anticipated change...

Habitat Selectivity and Reliance on Live Corals for Indo-Pacific Hawkfishes (Family: Cirrhitidae)

KAUST Repository

Coker, Darren James; Hoey, Andrew S.; Wilson, Shaun K.; Depczynski, Martial; Graham, Nicholas A. J.; Hobbs, Jean-Paul A.; Holmes, Thomas H.; Pratchett, Morgan S.

2015-01-01

Hawkfishes (family: Cirrhitidae) are small conspicuous reef predators that commonly perch on, or shelter within, the branches of coral colonies. This study examined habitat associations of hawkfishes, and explicitly tested whether hawkfishes associate with specific types of live coral. Live coral use and habitat selectivity of hawkfishes was explored at six locations from Chagos in the central Indian Ocean extending east to Fiji in the Pacific Ocean. A total of 529 hawkfishes from seven species were recorded across all locations with 63% of individuals observed perching on, or sheltering within, live coral colonies. Five species (all except Cirrhitus pinnulatus and Cirrhitichthys oxycephalus) associated with live coral habitats. Cirrhitichthys falco selected for species of Pocillopora while Paracirrhites arcatus and P. forsteri selected for both Pocillopora and Acropora, revealing that these habitats are used disproportionately more than expected based on the local cover of these coral genera. Habitat selection was consistent across geographic locations, and species of Pocillopora were the most frequently used and most consistently selected even though this coral genus never comprised more than 6% of the total coral cover at any of the locations. Across locations, Paracirrhites arcatus and P. forsteri were the most abundant species and variation in their abundance corresponded with local patterns of live coral cover and abundance of Pocilloporid corals, respectively. These findings demonstrate the link between small predatory fishes and live coral habitats adding to the growing body of literature highlighting that live corals (especially erect branching corals) are critically important for sustaining high abundance and diversity of fishes on coral reefs.

Habitat Selectivity and Reliance on Live Corals for Indo-Pacific Hawkfishes (Family: Cirrhitidae.

Directory of Open Access Journals (Sweden)

Darren J Coker

Full Text Available Hawkfishes (family: Cirrhitidae are small conspicuous reef predators that commonly perch on, or shelter within, the branches of coral colonies. This study examined habitat associations of hawkfishes, and explicitly tested whether hawkfishes associate with specific types of live coral. Live coral use and habitat selectivity of hawkfishes was explored at six locations from Chagos in the central Indian Ocean extending east to Fiji in the Pacific Ocean. A total of 529 hawkfishes from seven species were recorded across all locations with 63% of individuals observed perching on, or sheltering within, live coral colonies. Five species (all except Cirrhitus pinnulatus and Cirrhitichthys oxycephalus associated with live coral habitats. Cirrhitichthys falco selected for species of Pocillopora while Paracirrhites arcatus and P. forsteri selected for both Pocillopora and Acropora, revealing that these habitats are used disproportionately more than expected based on the local cover of these coral genera. Habitat selection was consistent across geographic locations, and species of Pocillopora were the most frequently used and most consistently selected even though this coral genus never comprised more than 6% of the total coral cover at any of the locations. Across locations, Paracirrhites arcatus and P. forsteri were the most abundant species and variation in their abundance corresponded with local patterns of live coral cover and abundance of Pocilloporid corals, respectively. These findings demonstrate the link between small predatory fishes and live coral habitats adding to the growing body of literature highlighting that live corals (especially erect branching corals are critically important for sustaining high abundance and diversity of fishes on coral reefs.

Habitat Selectivity and Reliance on Live Corals for Indo-Pacific Hawkfishes (Family: Cirrhitidae).

Science.gov (United States)

Coker, Darren J; Hoey, Andrew S; Wilson, Shaun K; Depczynski, Martial; Graham, Nicholas A J; Hobbs, Jean-Paul A; Holmes, Thomas H; Pratchett, Morgan S

2015-01-01

Hawkfishes (family: Cirrhitidae) are small conspicuous reef predators that commonly perch on, or shelter within, the branches of coral colonies. This study examined habitat associations of hawkfishes, and explicitly tested whether hawkfishes associate with specific types of live coral. Live coral use and habitat selectivity of hawkfishes was explored at six locations from Chagos in the central Indian Ocean extending east to Fiji in the Pacific Ocean. A total of 529 hawkfishes from seven species were recorded across all locations with 63% of individuals observed perching on, or sheltering within, live coral colonies. Five species (all except Cirrhitus pinnulatus and Cirrhitichthys oxycephalus) associated with live coral habitats. Cirrhitichthys falco selected for species of Pocillopora while Paracirrhites arcatus and P. forsteri selected for both Pocillopora and Acropora, revealing that these habitats are used disproportionately more than expected based on the local cover of these coral genera. Habitat selection was consistent across geographic locations, and species of Pocillopora were the most frequently used and most consistently selected even though this coral genus never comprised more than 6% of the total coral cover at any of the locations. Across locations, Paracirrhites arcatus and P. forsteri were the most abundant species and variation in their abundance corresponded with local patterns of live coral cover and abundance of Pocilloporid corals, respectively. These findings demonstrate the link between small predatory fishes and live coral habitats adding to the growing body of literature highlighting that live corals (especially erect branching corals) are critically important for sustaining high abundance and diversity of fishes on coral reefs.

Habitat Selectivity and Reliance on Live Corals for Indo-Pacific Hawkfishes (Family: Cirrhitidae)

KAUST Repository

Coker, Darren James

2015-11-03

Hawkfishes (family: Cirrhitidae) are small conspicuous reef predators that commonly perch on, or shelter within, the branches of coral colonies. This study examined habitat associations of hawkfishes, and explicitly tested whether hawkfishes associate with specific types of live coral. Live coral use and habitat selectivity of hawkfishes was explored at six locations from Chagos in the central Indian Ocean extending east to Fiji in the Pacific Ocean. A total of 529 hawkfishes from seven species were recorded across all locations with 63% of individuals observed perching on, or sheltering within, live coral colonies. Five species (all except Cirrhitus pinnulatus and Cirrhitichthys oxycephalus) associated with live coral habitats. Cirrhitichthys falco selected for species of Pocillopora while Paracirrhites arcatus and P. forsteri selected for both Pocillopora and Acropora, revealing that these habitats are used disproportionately more than expected based on the local cover of these coral genera. Habitat selection was consistent across geographic locations, and species of Pocillopora were the most frequently used and most consistently selected even though this coral genus never comprised more than 6% of the total coral cover at any of the locations. Across locations, Paracirrhites arcatus and P. forsteri were the most abundant species and variation in their abundance corresponded with local patterns of live coral cover and abundance of Pocilloporid corals, respectively. These findings demonstrate the link between small predatory fishes and live coral habitats adding to the growing body of literature highlighting that live corals (especially erect branching corals) are critically important for sustaining high abundance and diversity of fishes on coral reefs.

Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968 (Rajiformes: Rajidae, with notes on its biology.

Directory of Open Access Journals (Sweden)

Carlos Bustamante

Full Text Available Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries.

Morphological Characters of the Thickbody Skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with Notes on Its Biology

Science.gov (United States)

Bustamante, Carlos; Lamilla, Julio; Concha, Francisco; Ebert, David A.; Bennett, Michael B.

2012-01-01

Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries. PMID:22768186

Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with notes on its biology.

Science.gov (United States)

Bustamante, Carlos; Lamilla, Julio; Concha, Francisco; Ebert, David A; Bennett, Michael B

2012-01-01

Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries.

Musculoskeletal anatomy of the pelvic fin of Polypterus: implications for phylogenetic distribution and homology of pre- and postaxial pelvic appendicular muscles.

Science.gov (United States)

Molnar, Julia L; Johnston, Peter S; Esteve-Altava, Borja; Diogo, Rui

2017-04-01

As a member of the most basal clade of extant ray-finned fishes (actinopterygians) and of one of the most basal clades of osteichthyans (bony fishes + tetrapods), Polypterus can provide insights into the ancestral anatomy of both ray-finned and lobe-finned fishes, including those that gave rise to tetrapods. The pectoral fin of Polypterus has been well described but, surprisingly, neither the bones nor the muscles of the pelvic fin are well known. We stained and dissected the pelvic fin of Polypterus senegalus and Polypterus delhezi to offer a detailed description of its musculoskeletal anatomy. In addition to the previously described adductor and abductor muscles, we found preaxial and postaxial muscles similar to those in the pectoral fin of members of this genus. The presence of pre- and postaxial muscles in both the pectoral and pelvic fins of Polypterus, combined with recent descriptions of similar muscles in the lobe-finned fishes Latimeria and Neoceratodus, suggests that they were present in the most recent common ancestor of bony fishes. These results have crucial implications for the evolution of appendicular muscles in both fish and tetrapods. © 2016 Anatomical Society.

[Use of energy reserves during the breeding fast of the emperor penguin, Aptenodvtes forsteri].

Science.gov (United States)

Groscolas, R; Clément, C

1976-01-19

During the breeding fasting of the emperor penguin, the lipid and protein stores are steadily used to meet the metabolic needs; they represent respectively 93 and 7% of the energy production in the animal. The role of the glucid stores are quantitively negligible. Loss of tissue water represents 35,3% of body weight loss. Increased weight loss below 20 kg a "critical weight", is associated with a conversion to protein catabolism when lipid supplies are exhausted. These results allow the estimation of the metabolism when the body weight loss is considered in this antartic penguin.

The phylogenetic position of the roughskin skate Dipturus trachyderma (Krefft & Stehmann, 1975) (Rajiformes, Rajidae) inferred from the mitochondrial genome.

Science.gov (United States)

Vargas-Caro, Carolina; Bustamante, Carlos; Lamilla, Julio; Bennett, Michael B; Ovenden, Jennifer R

2016-07-01

The complete mitochondrial genome of the roughskin skate Dipturus trachyderma is described from 1 455 724 sequences obtained using Illumina NGS technology. Total length of the mitogenome was 16 909 base pairs, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Phylogenetic analysis based on mtDNA revealed low genetic divergence among longnose skates, in particular, those dwelling the continental shelf and slope off the coasts of Chile and Argentina.

Habitat Use and Spatial Variability of Hawkfishes with a Focus on Colour Polymorphism in Paracirrhites forsteri

KAUST Repository

Coker, Darren James; Chaidez, Veronica; Berumen, Michael L.

2017-01-01

continuing to face environmental pressures, insight into abundance and distribution patterns along with resource use of fish communities will aid in advancing our ecological understanding and management processes. Based on ecological surveys of hawkfish

Mercury in birds of San Francisco Bay-Delta, California: trophic pathways, bioaccumulation, and ecotoxicological risk to avian reproduction

Science.gov (United States)

Ackerman, Joshua T.; Eagles-Smith, Collin A.; Heinz, Gary; De La Cruz, Susan E. W.; Takekawa, John Y.; Miles, A. Keith; Adelsbach, Terrence L.; Herzog, Mark P.; Bluso-Demers, Jill D.; Demers, Scott A.; Herring, Garth; Hoffman, David J.; Hartman, Christopher A.; Willacker, James J.; Suchanek, Thomas H.; Schwarzbach, Steven E.; Maurer, Thomas C.

2014-01-01

San Francisco Bay Estuary in northern California has a legacy of mercury contamination, which could reduce the health and reproductive success of waterbirds in the estuary. The goal of this study was to use an integrated field and laboratory approach to evaluate the risks of mercury exposure to birds in the estuary. We examined mercury bioaccumulation, and other contaminants of concern, in five waterbird species that depend heavily on San Francisco Bay Estuary for foraging and breeding habitat: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster’s terns (Sterna forsteri), Caspian terns (Hydroprogne caspia), and surf scoters (Melanitta perspicillata). These species have different foraging habitats and diets that represent three distinct foraging guilds within the estuary’s food web. In this report, we provide an integrated synthesis of the primary findings from this study and results are synthesized from 54 peer-reviewed publications generated to date with other unpublished results.

Waterbirds (other than Laridae nesting in the middle section of Laguna Cuyutlán, Colima, México

Directory of Open Access Journals (Sweden)

Eric Mellink

2008-03-01

Full Text Available Laguna de Cuyutlán, in the state of Colima, Mexico, is the only large coastal wetland in a span of roughly 1150 km. Despite this, the study of its birds has been largely neglected. Between 2003 and 2006 we assessed the waterbirds nesting in the middle portion of Laguna Cuyutlán, a large tropical coastal lagoon, through field visits. We documented the nesting of 15 species of non-Laridae waterbirds: Neotropic Cormorant (Phalacrocorax brasilianus, Tricolored Egret (Egretta tricolor, Snowy Egret (Egretta thula, Little Blue Heron (Egretta caerulea, Great Egret (Ardea alba, Cattle Egret (Bubulcus ibis, Black-crowned Nightheron (Nycticorax nycticorax, Yellow-crowned Night-heron (Nyctanassa violacea, Green Heron (Butorides virescens, Roseate Spoonbill (Platalea ajaja, White Ibis (Eudocimus albus, Black-bellied Whistling-duck (Dendrocygna autumnalis, Clapper Rail (Rallus longirostris, Snowy Plover (Charadrius alexandrinus, and Black-necked Stilt (Himantopus mexicanus. These add to six species of Laridae known to nest in that area: Laughing Gulls (Larus atricilla, Royal Terns (Thalasseus maximus, Gull-billed Terns (Gelochelidon nilotica, Forster’s Terns (S. forsteri, Least Terns (Sternula antillarum, and Black Skimmer (Rynchops niger, and to at least 57 species using it during the non-breeding season. With such bird assemblages, Laguna Cuyutlán is an important site for waterbirds, which should be given conservation status. Rev. Biol. Trop. 56 (1: 391-397. Epub 2008 March 31.Durante la prospección de la parte media de la Laguna Cuyutlán, una gran laguna costera en Colima, México, entre 2003 y 2006, documentamos la anidación de 15 especies de aves acuáticas que no pertenecer a la familia Laridae: Phalacrocorax brasilianus, Egretta tricolor, Egretta thula, Egretta caerulea, Ardea alba, Bubulcus ibis, Nycticorax nycticorax, Nyctanassa violacea, Butorides virescens, Platalea ajaja, Eudocimus albus, Dendrocygna autumnalis, Rallus longirostris

Mercury and selenium contamination in waterbird eggs and risk to avian reproduction at Great Salt Lake, Utah

Science.gov (United States)

Ackerman, Joshua T.; Herzog, Mark P.; Hartman, Christopher A.; Isanhart, John P.; Herring, Garth; Vaughn, Sharon; Cavitt, John F.; Eagles-Smith, Collin A.; Browers, Howard; Cline, Chris; Vest, Josh

2015-01-01

The wetlands of the Great Salt Lake ecosystem are recognized regionally, nationally, and hemispherically for their importance as breeding, wintering, and migratory habitat for diverse groups of waterbirds. Bear River Migratory Bird Refuge is the largest freshwater component of the Great Salt Lake ecosystem and provides critical breeding habitat for more than 60 bird species. However, the Great Salt Lake ecosystem also has a history of both mercury and selenium contamination, and this pollution could reduce the health and reproductive success of waterbirds. The overall objective of this study was to evaluate the risk of mercury and selenium contamination to birds breeding within Great Salt Lake, especially at Bear River Migratory Bird Refuge, and to identify the waterbird species and areas at greatest risk to contamination. We sampled eggs from 33 species of birds breeding within wetlands of Great Salt Lake during 2010 ̶ 2012 and focused on American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster’s terns (Sterna forsteri), white-faced ibis (Plegadis chihi), and marsh wrens (Cistothorus palustris) for additional studies of the effects of contaminants on reproduction.

Mercury exposure may influence fluctuating asymmetry in waterbirds

Science.gov (United States)

Herring, Garth; Eagles-Smith, Collin A.; Ackerman, Joshua T.

2017-01-01

Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds.

Egg turning behavior and incubation temperature in Forster’s terns in relation to mercury contamination

Science.gov (United States)

Taylor, Gregory T.; Ackerman, Joshua T.; Shaffer, Scott A.

2018-01-01

Egg turning behavior is an important determinant of egg hatchability, but it remains relatively understudied. Here, we examined egg turning rates and egg temperatures in Forster’s terns (Sterna forsteri). We used artificial eggs containing a data logger with a 3-D accelerometer, a magnetometer, and a temperature thermistor to monitor parental incubation behavior of 131 tern nests. Overall, adults turned their eggs an average (±SD) of 3.8 ± 0.8 turns h-1, which is nearly two times higher than that of other seabirds. Egg turning rates increased with nest initiation date. We also examined egg turning rates and egg temperatures in relation to egg mercury contamination. Mercury contamination has been shown to be associated with reduced egg hatchability, and we hypothesized that mercury may decrease egg hatchability via altered egg turning behavior by parents. Despite the high variability in egg turning rates among individuals, the rate of egg turning was not related to mercury concentrations in sibling eggs. These findings highlight the need for further study concerning the potential determinants of egg turning behavior.

Ultraviolet reflecting photonic microstructures in the King Penguin beak.

Science.gov (United States)

Dresp, Birgitta; Jouventin, Pierre; Langley, Keith

2005-09-22

King and emperor penguins (Aptenodytes patagonicus and Aptenodytes forsteri) are the only species of marine birds so far known to reflect ultraviolet (UV) light from their beaks. Unlike humans, most birds perceive UV light and several species communicate using the near UV spectrum. Indeed, UV reflectance in addition to the colour of songbird feathers has been recognized as an important signal when choosing a mate. The king penguin is endowed with several highly coloured ornaments, notably its beak horn and breast and auricular plumage, but only its beak reflects UV, a property considered to influence its sexual attraction. Because no avian UV-reflecting pigments have yet been identified, the origin of such reflections is probably structural. In an attempt to identify the structures that give rise to UV reflectance, we combined reflectance spectrophotometry and morphological analysis by both light and electron microscopy, after experimental removal of surface layers of the beak horn. Here, we characterize for the first time a multilayer reflector photonic microstructure that produces the UV reflections in the king penguin beak.

Kidnapping of chicks in emperor penguins: a hormonal by-product?

Science.gov (United States)

Angelier, Frédéric; Barbraud, Christophe; Lormée, Hervé; Prud'homme, François; Chastel, Olivier

2006-04-01

The function and causes of kidnapping juveniles are little understood because individuals sustain some breeding costs to rear an unrelated offspring. Here we focus on the proximal causes of this behaviour in emperor penguins (Aptenodytes forsteri), whose failed breeders often kidnap chicks. We experimentally tested the hypothesis that kidnapping behaviour was the result of high residual levels of prolactin (PRL), a hormone involved in parental behaviour. Penguins with artificially decreased PRL levels by bromocriptine administration kidnapped chicks less often than control penguins. Within the bromocriptine treated group, kidnapping behaviour was not totally suppressed and the probability of kidnapping a chick was positively correlated to PRL levels measured before treatment. During breeding, emperor penguins have to forage in remote ice-free areas. In these birds, PRL secretion is poorly influenced by chick stimuli and has probably evolved to maintain a willingness to return to the colony after a long absence at sea. Therefore, penguins that have lost their chick during a foraging trip still maintain high residual PRL levels and this, combined with colonial breeding, probably facilitates kidnapping. We suggest that kidnapping in non-cooperative systems may result from a hormonal byproduct of a reproductive adaptation to extreme conditions.

The effects of vessel approaches on the New Zealand fur seal (Arctocepahlus forsteri) in the Bay of Plenty, New Zealand

NARCIS (Netherlands)

Cowling, M.; Kirkwood, R.J.; Boren, L.; Sutherland, D.; Scarpaci, C.

2015-01-01

Animals that establish new sites near the edge of the species' range may be vulnerable to disturbance as they are low in numbers and are not tied to the sites. Pinniped distributions world-wide are changing as many species are recolonizing areas of their former ranges and establishing new colonies.

Rapid changes in small fish mercury concentrations in estuarine wetlands: Implications for wildlife risk and monitoring programs

Science.gov (United States)

Eagles-Smith, Collin A.; Ackerman, Joshua T.

2009-01-01

Small fish are commonly used to assess mercury (Hg) risk to wildlife and monitor Hg in wetlands. However, limited research has evaluated short-term Hg variability in small fish, which can have important implications for monitoring programs and risk assessment. We conducted a time-series study of Hg concentrations in two small fish species representing benthic (longjaw mudsuckers [Gillichthys mirabilis]) and pelagic (threespine sticklebacks [Gasterosteus aculeatus]) food-webs within three wetland habitats in San Francisco Bay Estuary. We simultaneously monitored prey deliveries, nest initiation, and chick hatching dates of breeding Forster's terns (Sterna forsteri), the most abundant nesting piscivore in the region. Mudsuckers and sticklebacks were the predominant prey fish, comprising 36% and 25% of tern diet, and Hg concentrations averaged (geometric mean ?? SE, ??g/g dw) 0.44 ?? 0.01 and 0.68 ?? 0.03, respectively. Fish Hg concentrations varied substantially over time following a quadratic form in both species, increasing 40% between March and May then decreasing 40% between May and July. Importantly, Forster's terns initiated 68% of nests and 31% of chicks hatched during the period of peak Hg concentrations in prey fish. These results illustrate the importance of short-term temporal variation in small fish Hg concentrations for both Hg monitoring programs and assessing wildlife risk.

Adaptation to extreme environments: structure-function relationships in Emperor penguin haemoglobin.

Science.gov (United States)

Tamburrini, M; Condò, S G; di Prisco, G; Giardina, B

1994-04-15

The functional properties of the single haemoglobin (Hb) of Emperor penguin (Aptenodytes forsteri) have been investigated at different temperatures as a function of proton and organic phosphate concentration. The complete amino acid sequence has been established. Comparison with that of human HbA shows 12 substitutions in the contact regions of alpha beta dimers. In addition to overall similarities shared with most of the avian Hbs previously described, this Hb shows significant differences, which could be related to the peculiar behaviour of this penguin. In particular we may consider that: (1) the shape of the Bohr effect curve seems well adapted for gas exchange during very prolonged dives, preserving penguin Hb from a sudden and not controlled stripping of oxygen; (2) the very minor enthalpy change observed at lower pH could be an example of molecular adaptation, through which oxygen delivery becomes essentially insensitive to exposure to the extremely low temperatures of the environment. Moreover, the small alkaline Bohr effect has been found to be only chloride-linked, since the pH dependence of the oxygen affinity is totally abolished in the absence of this ion. These functional characteristics are discussed on the basis of the primary structure of alpha and beta-chains.

Geochemical record of high emperor penguin populations during the Little Ice Age at Amanda Bay, Antarctica

Energy Technology Data Exchange (ETDEWEB)

Huang, Tao, E-mail: huangt@ahu.edu.cn [School of Resources and Environmental Engineering, Anhui University, Hefei 230601 (China); School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Yang, Lianjiao; Chu, Zhuding [School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Sun, Liguang, E-mail: slg@ustc.edu.cn [School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Yin, Xijie [Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005 (China)

2016-09-15

Emperor penguins (Aptenodytes forsteri) are sensitive to the Antarctic climate change because they breed on the fast sea ice. Studies of paleohistory for the emperor penguin are rare, due to the lack of archives on land. In this study, we obtained an emperor penguin ornithogenic sediment profile (PI) and performed geochronological, geochemical and stable isotope analyses on the sediments and feather remains. Two radiocarbon dates of penguin feathers in PI indicate that emperor penguins colonized Amanda Bay as early as CE 1540. By using the bio-elements (P, Se, Hg, Zn and Cd) in sediments and stable isotope values (δ{sup 15}N and δ{sup 13}C) in feathers, we inferred relative population size and dietary change of emperor penguins during the period of CE 1540–2008, respectively. An increase in population size with depleted N isotope ratios for emperor penguins on N island at Amanda Bay during the Little Ice Age (CE 1540–1866) was observed, suggesting that cold climate affected the penguin's breeding habitat, prey availability and thus their population and dietary composition. - Highlights: • Emperor penguin colonized at Amanda Bay, East Antarctic as early as AD 1540. • Populations of emperor penguin at Amanda Bay increase during the little ice age. • Depleted N isotope ratios of Emperor penguins during the LIA were observed.

Geochemical record of high emperor penguin populations during the Little Ice Age at Amanda Bay, Antarctica

International Nuclear Information System (INIS)

Huang, Tao; Yang, Lianjiao; Chu, Zhuding; Sun, Liguang; Yin, Xijie

2016-01-01

Emperor penguins (Aptenodytes forsteri) are sensitive to the Antarctic climate change because they breed on the fast sea ice. Studies of paleohistory for the emperor penguin are rare, due to the lack of archives on land. In this study, we obtained an emperor penguin ornithogenic sediment profile (PI) and performed geochronological, geochemical and stable isotope analyses on the sediments and feather remains. Two radiocarbon dates of penguin feathers in PI indicate that emperor penguins colonized Amanda Bay as early as CE 1540. By using the bio-elements (P, Se, Hg, Zn and Cd) in sediments and stable isotope values (δ"1"5N and δ"1"3C) in feathers, we inferred relative population size and dietary change of emperor penguins during the period of CE 1540–2008, respectively. An increase in population size with depleted N isotope ratios for emperor penguins on N island at Amanda Bay during the Little Ice Age (CE 1540–1866) was observed, suggesting that cold climate affected the penguin's breeding habitat, prey availability and thus their population and dietary composition. - Highlights: • Emperor penguin colonized at Amanda Bay, East Antarctic as early as AD 1540. • Populations of emperor penguin at Amanda Bay increase during the little ice age. • Depleted N isotope ratios of Emperor penguins during the LIA were observed.

Vocal activity as a low cost and scalable index of seabird colony size.

Science.gov (United States)

Borker, Abraham L; McKown, Matthew W; Ackerman, Joshua T; Eagles-Smith, Collin A; Tershy, Bernie R; Croll, Donald A

2014-08-01

Although wildlife conservation actions have increased globally in number and complexity, the lack of scalable, cost-effective monitoring methods limits adaptive management and the evaluation of conservation efficacy. Automated sensors and computer-aided analyses provide a scalable and increasingly cost-effective tool for conservation monitoring. A key assumption of automated acoustic monitoring of birds is that measures of acoustic activity at colony sites are correlated with the relative abundance of nesting birds. We tested this assumption for nesting Forster's terns (Sterna forsteri) in San Francisco Bay for 2 breeding seasons. Sensors recorded ambient sound at 7 colonies that had 15-111 nests in 2009 and 2010. Colonies were spaced at least 250 m apart and ranged from 36 to 2,571 m(2) . We used spectrogram cross-correlation to automate the detection of tern calls from recordings. We calculated mean seasonal call rate and compared it with mean active nest count at each colony. Acoustic activity explained 71% of the variation in nest abundance between breeding sites and 88% of the change in colony size between years. These results validate a primary assumption of acoustic indices; that is, for terns, acoustic activity is correlated to relative abundance, a fundamental step toward designing rigorous and scalable acoustic monitoring programs to measure the effectiveness of conservation actions for colonial birds and other acoustically active wildlife. © 2014 Society for Conservation Biology.

Two Antarctic penguin genomes reveal insights into their evolutionary history and molecular changes related to the Antarctic environment.

Science.gov (United States)

Li, Cai; Zhang, Yong; Li, Jianwen; Kong, Lesheng; Hu, Haofu; Pan, Hailin; Xu, Luohao; Deng, Yuan; Li, Qiye; Jin, Lijun; Yu, Hao; Chen, Yan; Liu, Binghang; Yang, Linfeng; Liu, Shiping; Zhang, Yan; Lang, Yongshan; Xia, Jinquan; He, Weiming; Shi, Qiong; Subramanian, Sankar; Millar, Craig D; Meader, Stephen; Rands, Chris M; Fujita, Matthew K; Greenwold, Matthew J; Castoe, Todd A; Pollock, David D; Gu, Wanjun; Nam, Kiwoong; Ellegren, Hans; Ho, Simon Yw; Burt, David W; Ponting, Chris P; Jarvis, Erich D; Gilbert, M Thomas P; Yang, Huanming; Wang, Jian; Lambert, David M; Wang, Jun; Zhang, Guojie

2014-01-01

Penguins are flightless aquatic birds widely distributed in the Southern Hemisphere. The distinctive morphological and physiological features of penguins allow them to live an aquatic life, and some of them have successfully adapted to the hostile environments in Antarctica. To study the phylogenetic and population history of penguins and the molecular basis of their adaptations to Antarctica, we sequenced the genomes of the two Antarctic dwelling penguin species, the Adélie penguin [Pygoscelis adeliae] and emperor penguin [Aptenodytes forsteri]. Phylogenetic dating suggests that early penguins arose ~60 million years ago, coinciding with a period of global warming. Analysis of effective population sizes reveals that the two penguin species experienced population expansions from ~1 million years ago to ~100 thousand years ago, but responded differently to the climatic cooling of the last glacial period. Comparative genomic analyses with other available avian genomes identified molecular changes in genes related to epidermal structure, phototransduction, lipid metabolism, and forelimb morphology. Our sequencing and initial analyses of the first two penguin genomes provide insights into the timing of penguin origin, fluctuations in effective population sizes of the two penguin species over the past 10 million years, and the potential associations between these biological patterns and global climate change. The molecular changes compared with other avian genomes reflect both shared and diverse adaptations of the two penguin species to the Antarctic environment.

Maternal transfer of contaminants in birds: Mercury and selenium concentrations in parents and their eggs

Science.gov (United States)

Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark P.; Hartman, C. Alex

2016-01-01

We conducted a detailed assessment of the maternal transfer of mercury and selenium to eggs in three bird species (n = 107 parents and n = 339 eggs), and developed predictive equations linking contaminant concentrations in eggs to those in six tissues of the mother (blood, muscle, liver, kidney, breast feathers, and head feathers). Mercury concentrations in eggs were positively correlated with mercury concentrations in each of the mother's internal tissues (R2 ≥ 0.95), but generally not with feathers. For each species, the proportion of mercury transferred to eggs decreased as mercury concentrations in the mother increased. At the same maternal mercury concentration, the proportion of mercury transferred to eggs differed among species, such that Forster's tern (Sterna forsteri) and black-necked stilt (Himantopus mexicanus) females transferred more methylmercury to their eggs than American avocet (Recurvirostra americana) females. Selenium concentrations in eggs also were correlated with selenium concentrations in the mother's liver (R2 = 0.87). Furthermore, mercury and selenium concentrations in tern eggs were positively correlated with those in the father (R2 = 0.84). Incubating male terns had 21% higher mercury concentrations in blood compared to incubating females at the same egg mercury concentration. We provide equations to predict contaminant concentrations in eggs from each of the commonly sampled bird tissues.

Survival of postfledging Forster's terns in relation to mercury exposure in San Francisco Bay

Science.gov (United States)

Ackerman, Joshua T.; Eagles-Smith, Collin A.; Takekawa, John Y.; Iverson, S.A.

2008-01-01

We examined factors influencing mercury concentrations in 90 fledgling Forster's terns (Sterna forsteri) and evaluated whether mercury influenced postfledging survival in San Francisco Bay, California. Mercury concentrations (??SE) in chicks 21-29 days old (just before fledging) were 0.33 ?? 0.01 ??g g-1 ww for blood and 6.44 ?? 0.28 ??g g -1 fw for breast feathers. Colony site had an overriding influence on fledgling contamination, however hatching date and age also affected blood, but not feather, mercury concentrations. Blood mercury concentrations decreased by 28% during the 50-day hatching period and increased with chick age by 30% during the last week prior to fledging. Using radio-telemetry, we calculated that cumulative survival during the 35-day postfledging time period was 0.81 ?? 0.09 (SE). Postfledging survival rates increased with size-adjusted mass, and cumulative survival probability was 61% lower for terns with the lowest, compared to the highest, observed masses. Conversely, survival was not influenced by blood mercury concentration, time since fledging, sex, or hatch date. Mercury concentrations in breast feathers of fledglings found dead at nesting colonies also were no different than those in live chicks. Our results indicate that colony site, hatching date, and age influenced mercury concentrations in fledgling Forster's terns, but that mercury did not influence postfledging survival. ?? 2008 Springer Science+Business Media, LLC.

Effects of the presence of official-looking volunteers on harassment of New Zealand fur seals.

Science.gov (United States)

Acevedo-Gutiérrez, Alejandro; Acevedo, Lisa; Boren, Laura

2011-06-01

An increased number of tourists viewing animals in the wild have increased stress on these animals (hereafter wildlife). Many wildlife-viewing locations rely on voluntary compliance with posted regulations to protect animals from tourists because of the expense of employing on-site enforcement personnel. Voluntary compliance, however, is ineffective. The presence of official-looking volunteers may decrease the incidence of wildlife harassment by tourists. To test this possibility, we observed tourists interacting with 5- to 12-month-old New Zealand fur seals (Arctocephalus forsteri) at the popular Ohau Stream waterfall while in the absence or presence of a young woman in plain sight wearing a neon vest (i.e., observer) and when an observer was not present. We observed 254 tourist groups at the waterfall when young seals were present. The percentage of groups in which at least one person harassed (approached, touched, or threw objects) a young seal was two-thirds lower when the official-looking observer was present. Frequency of harassment was inversely related to observer presence. Programs in which volunteers work at tourist sites are popular in countries with high tourism rates, such as New Zealand. Our results show that a relatively inexpensive and effective tourism-management strategy may be to post such volunteers as observers at sites where tourists view wildlife. ©2010 Society for Conservation Biology.

Embryo malposition as a potential mechanism for mercury-induced hatching failure in bird eggs

Science.gov (United States)

Herring, G.; Ackerman, Joshua T.; Eagles-Smith, Collin A.

2010-01-01

We examined the prevalence of embryo malpositions and deformities in relation to total mercury (THg) and selenium (Se) concentrations in American avocet (Recurvirostra americana), black-necked stilt (Himantopus mexicanus), and Forster's tern (Sterna forsteri) eggs in San Francisco Bay (CA, USA) during 2005 to 2007. Overall, 11% of embryos were malpositioned in eggs ???18 d of age (n=282) and 2% of embryos were deformed in eggs ???13 d of age (n=470). Considering only those eggs that failed to hatch (n=62), malpositions occurred in 24% of eggs ???18 d of age and deformities occurred in 7% of eggs ???13 d of age. The probability of an embryo being malpositioned increased with egg THg concentrations in Forster's terns, but not in avocets or stilts. The probability of embryo deformity was not related to egg THg concentrations in any species. Using a reduced dataset with both Se and THg concentrations measured in eggs (n=87), we found no interaction between Se and THg on the probability of an embryo being malpositioned or deformed. Results of the present study indicate that embryo malpositions were prevalent in waterbird eggs that failed to hatch and the likelihood of an embryo being malpositioned increased with egg THg concentrations in Forster's terns. We hypothesize that malpositioning of avian embryos may be one reason for mercury-related hatching failure that occurs late in incubation, but further research is needed to elucidate this potential mechanism. ?? 2010 SETAC.

Mercury exposure may influence fluctuating asymmetry in waterbirds.

Science.gov (United States)

Herring, Garth; Eagles-Smith, Collin A; Ackerman, Joshua T

2017-06-01

Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Demographic models and IPCC climate projections predict the decline of an emperor penguin population

Science.gov (United States)

Jenouvrier, Stéphanie; Caswell, Hal; Barbraud, Christophe; Holland, Marika; Strœve, Julienne; Weimerskirch, Henri

2009-01-01

Studies have reported important effects of recent climate change on Antarctic species, but there has been to our knowledge no attempt to explicitly link those results to forecasted population responses to climate change. Antarctic sea ice extent (SIE) is projected to shrink as concentrations of atmospheric greenhouse gases (GHGs) increase, and emperor penguins (Aptenodytes forsteri) are extremely sensitive to these changes because they use sea ice as a breeding, foraging and molting habitat. We project emperor penguin population responses to future sea ice changes, using a stochastic population model that combines a unique long-term demographic dataset (1962–2005) from a colony in Terre Adélie, Antarctica and projections of SIE from General Circulation Models (GCM) of Earth's climate included in the most recent Intergovernmental Panel on Climate Change (IPCC) assessment report. We show that the increased frequency of warm events associated with projected decreases in SIE will reduce the population viability. The probability of quasi-extinction (a decline of 95% or more) is at least 36% by 2100. The median population size is projected to decline from ≈6,000 to ≈400 breeding pairs over this period. To avoid extinction, emperor penguins will have to adapt, migrate or change the timing of their growth stages. However, given the future projected increases in GHGs and its effect on Antarctic climate, evolution or migration seem unlikely for such long lived species at the remote southern end of the Earth. PMID:19171908

OCCURRENCE OF PHYTOPHAGOUS SCARABAEIDAE (INSECTA: COLEOPTERA LARVAE IN DIFFERENT SUCCESSION CROP SYSTEMS OCORRÊNCIA DE LARVAS DE SCARABAEIDAE FITÓFAGOS (INSECTA: COLEOPTERA EM DIFERENTES SISTEMAS DE SUCESSÃO DE CULTURAS

Directory of Open Access Journals (Sweden)

Elison Floriano Tiago

2011-01-01

Full Text Available Information about Scarabaeidae phytophagous are still rare for the Center-West Region of Brazil. Thus, in the experimental area of the Universidade Estadual do Mato Grosso do Sul, in Aquidauana, Mato Grosso do Sul State, Brazil, the succession of soybean, maize, and forage turnip was sowed from February 2004 to October 2005, when the larvae population dynamics was evaluated. From October 2006 to May 2008, nine succession systems were sowed, the larval density evaluated, and the identification of the current species was carried out. When the larvae were sampled for soybean, in January 2005 and 2006, the highest densities were found in the field (3.44 larvae m-2 and 4.19 larvae m-2, respectively. The forage turnip, sampled in October 2004 and 2005, showed the lowest densities (0.03 larvae m-2 and 0.02 larvae m-2, respectively. In the crop succession systems, the following species were found: Liogenys fuscus Blanchard (highest amount, Liogenys bidenticeps Moser, Anomala testaceipennis Blanchard, Paranomala inconstans (Burmeister, Geniates borelli Camerano, Cyclocephala forsteri Endrodi, Cyclocephala verticalis Burmeister, and Phyllophaga sp. For the succession systems with maize sowed at the traditional season, the highest larval densities were found, specially favoring the development of L. fuscus, while the succession systems with soybean, maize, and under fallow, and soybean, crotalaria, and forage turnip, as well as the three systems with cotton-plant, did not favor it.

KEY-WORDS: Zea mays; Glycine max; Raphanus sativus; soil pests; larvae density.Informações sobre Scarabaeidae fitófagos são ainda escassas para a região Centro-Oeste do Brasil. Por esta razão, na área experimental da Universidade Estadual do Mato Grosso do Sul, em Aquidauana (MS, foi semeada, de fevereiro de 2004 a outubro de 2005, a sucessão de culturas soja, milho e nabo forrageiro, onde se avaliou a dinâmica da densidade larval. De outubro de 2006 a maio

Accuracy of egg flotation throughout incubation to determine embryo age and incubation day in waterbird nests

Science.gov (United States)

Ackerman, Joshua T.; Eagles-Smith, Collin A.

2010-01-01

Floating bird eggs to estimate their age is a widely used technique, but few studies have examined its accuracy throughout incubation. We assessed egg flotation for estimating hatch date, day of incubation, and the embryo's developmental age in eggs of the American Avocet (Recurvirostra americana), Black-necked Stilt (Himantopus mexicanus), and Forster's Tern (Sterna forsteri). Predicted hatch dates based on egg flotation during our first visit to a nest were highly correlated with actual hatch dates (r = 0.99) and accurate within 2.3 ± 1.7 (SD) days. Age estimates based on flotation were correlated with both day of incubation (r = 0.96) and the embryo's developmental age (r = 0.86) and accurate within 1.3 ± 1.6 days and 1.9 ± 1.6 days, respectively. However, the technique's accuracy varied substantially throughout incubation. Flotation overestimated the embryo's developmental age between 3 and 9 days, underestimated age between 12 and 21 days, and was most accurate between 0 and 3 days and 9 and 12 days. Age estimates based on egg flotation were generally accurate within 3 days until day 15 but later in incubation were biased progressively lower. Egg flotation was inaccurate and overestimated embryo age in abandoned nests (mean error: 7.5 ± 6.0 days). The embryo's developmental age and day of incubation were highly correlated (r = 0.94), differed by 2.1 ± 1.6 days, and resulted in similar assessments of the egg-flotation technique. Floating every egg in the clutch and refloating eggs at subsequent visits to a nest can refine age estimates.

Diving physiology of seabirds and marine mammals: Relevance, challenges and some solutions for field studies.

Science.gov (United States)

Andrews, Russel D; Enstipp, Manfred R

2016-12-01

To fully understand how diving seabirds and marine mammals balance the potentially conflicting demands of holding their breath while living their lives underwater (and maintaining physiological homeostasis during exercise, feeding, growth, and reproduction), physiological studies must be conducted with animals in their natural environments. The purpose of this article is to review the importance of making physiological measurements on diving animals in field settings, while acknowledging the challenges and highlighting some solutions. The most extreme divers are great candidates for study, especially in a comparative and mechanistic context. However, physiological data are also required of a wide range of species for problems relating to other disciplines, in particular ecology and conservation biology. Physiological data help with understanding and predicting the outcomes of environmental change, and the direct impacts of anthropogenic activities. Methodological approaches that have facilitated the development of field-based diving physiology include the isolated diving hole protocol and the translocation paradigm, and while there are many techniques for remote observation, animal-borne biotelemetry, or "biologging", has been critical. We discuss issues related to the attachment of instruments, the retrieval of data and sensing of physiological variables, while also considering negative impacts of tagging. This is illustrated with examples from a variety of species, and an in-depth look at one of the best studied and most extreme divers, the emperor penguin (Aptenodytes forsteri). With a variety of approaches and high demand for data on the physiology of diving seabirds and marine mammals, the future of field studies is bright. Copyright © 2016 Elsevier Inc. All rights reserved.

Myoglobin production in emperor penguins.

Science.gov (United States)

Ponganis, P J; Welch, T J; Welch, L S; Stockard, T K

2010-06-01

Increased oxygen storage is essential to the diving capacities of marine mammals and seabirds. However, the molecular mechanisms underlying this adaptation are unknown. Myoglobin (Mb) and Mb mRNA concentrations were analyzed in emperor penguin (Aptenodytes forsteri) adults and chicks with spectrophotometric and RNase protection assays to evaluate production of their large Mb-bound O(2) stores. Mean pectoral Mb concentration and Mb mRNA content increased throughout the pre-fledging period and were 15-fold and 3-fold greater, respectively, in adults than in 3.5 month old chicks. Mean Mb concentration in 5.9 month old juveniles was 2.7+/-0.4 g 100 g(-1) muscle (44% that of wild adults), and in adults that had been captive all their lives it was 3.7+/-0.1 g 100 g(-1) muscle. The Mb and Mb mRNA data are consistent with regulation of Mb production at the level of transcription as in other animals. Significant Mb and Mb mRNA production occurred in chicks and young juveniles even without any diving activity. The further increase in adult Mb concentrations appears to require the exercise/hypoxia of diving because Mb concentration in captive, non-diving adults only reached 60% of that of wild adults. The much greater relative increase in Mb concentration than in Mb mRNA content between young chicks and adults suggests that there is not a simple 1:1 relationship between Mb mRNA content and Mb concentration. Nutritional limitation in young chicks and post-transcriptional regulation of Mb concentration may also be involved.

Poly-brominated diphenyl-ethers (PBDEs) and other persistent organic pollutants in blood of penguins from the Ross Sea (Antarctica)

Energy Technology Data Exchange (ETDEWEB)

Corsolini, S.; Ademollo, N.; Mariottini, M.; Focardi, S. [Universita degli Studi di Siena, Siena (Italy)

2004-09-15

Polychlorobiphenyls (PCBs), hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs) and dichlorodiphenyl-dichloro ethane (pp'-DDE) including its isomers and metabolites are known as POPs very well. POPs are particularly hazardous to wildlife not only because they are toxic but because they are persistent and distributed on global scale. Polybrominated diphenyl ethers (PBDEs) are a class of POPs used worldwide as flame retardants with an increasing trend in the market demand (67.4 ktons in 2001), but with some restrictions in their usage in Europe. PBDEs are hydrophobic, highly soluble in lipids, resistant to biodegradation and have similar behavior to polychlorinated biphenyls (PCBs) in aquatic and terrestrial ecosystems. Their bioaccumulation and biomagnification properties, as well their global increasing presence, have already been reported by many authors. PBDEs have been detected in remote Arctic regions10 that seem to be their final sink. PBDEs show acute toxicity and a prolonged exposure can affect the function of thyroid and cause neurodevelopmental disorders and estrogenic and hepatic effects. Furthermore, a synergic effect with dioxin-like compounds or other POPs cannot be excluded. The two aims of this study are: (1) to evaluate accumulation levels and patterns of PCBs, PBDEs and chlorinated pesticides in blood samples of the Adelie penguin, Pygoscelis adeliae, the Emperor penguin, Aptenodytes forsteri and the South Polar skua, Cataracta maccormicki from three sites in the Ross Sea (Antarctica); (2) to assess the suitability of blood for the detection of POP residues in supposedly low contaminated organisms that live in protected/ecologically sensitive areas.

Accuracy of egg flotation throughout incubation to determine embryo age and incubation day in water bird nests

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Ackerman, Joshua T.; Eagles-Smith, Collin A.

2010-01-01

Floating bird eggs to estimate their age is a widely used technique, but few studies have examined its accuracy throughout incubation. We assessed egg flotation for estimating hatch date, day of incubation, and the embryo's developmental age in eggs of the American Avocet (Recurvirostra americana), Black-necked Stilt (Himantopus mexicanus), and Forster's Tern (Sterna forsteri). Predicted hatch dates based on egg flotation during our first visit to a nest were highly correlated with actual hatch dates (r = 0.99) and accurate within 2.3 ?? 1.7 (SD) days. Age estimates based on flotation were correlated with both day of incubation (r = 0.96) and the embryo's developmental age (r = 0.86) and accurate within 1.3 ?? 1.6 days and 1.9 ?? 1.6 days, respectively. However, the technique's accuracy varied substantially throughout incubation. Flotation overestimated the embryo's developmental age between 3 and 9 days, underestimated age between 12 and 21 days, and was most accurate between 0 and 3 days and 9 and 12 days. Age estimates based on egg flotation were generally accurate within 3 days until day 15 but later in incubation were biased progressively lower. Egg flotation was inaccurate and overestimated embryo age in abandoned nests (mean error: 7.5 ?? 6.0 days). The embryo's developmental age and day of incubation were highly correlated (r = 0.94), differed by 2.1 ?? 1.6 days, and resulted in similar assessments of the egg-flotation technique. Floating every egg in the clutch and refloating eggs at subsequent visits to a nest can refine age estimates. ?? The Cooper Ornithological Society 2010.

First recorded loss of an emperor penguin colony in the recent period of Antarctic regional warming: implications for other colonies.

Directory of Open Access Journals (Sweden)

Philip N Trathan

Full Text Available In 1948, a small colony of emperor penguins Aptenodytes forsteri was discovered breeding on Emperor Island (67° 51' 52″ S, 68° 42' 20″ W, in the Dion Islands, close to the West Antarctic Peninsula (Stonehouse 1952. When discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time the colony showed a continuous decline. By 1999 there were fewer than 20 pairs, and in 2009 high-resolution aerial photography revealed no remaining trace of the colony. Here we relate the decline and loss of the Emperor Island colony to a well-documented rise in local mean annual air temperature and coincident decline in seasonal sea ice duration. The loss of this colony provides empirical support for recent studies (Barbraud & Weimerskirch 2001; Jenouvrier et al 2005, 2009; Ainley et al 2010; Barber-Meyer et al 2005 that have highlighted the vulnerability of emperor penguins to changes in sea ice duration and distribution. These studies suggest that continued climate change is likely to impact upon future breeding success and colony viability for this species. Furthermore, a recent circumpolar study by Fretwell & Trathan (2009 highlighted those Antarctic coastal regions where colonies appear most vulnerable to such changes. Here we examine which other colonies might be at risk, discussing various ecological factors, some previously unexplored, that may also contribute to future declines. The implications of this are important for future modelling work and for understanding which colonies actually are most vulnerable.

Enamel ultrastructure of fossil and modern pinnipeds: evaluating hypotheses of feeding adaptations in the extinct walrus Pelagiarctos

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Loch, Carolina; Boessenecker, Robert W.; Churchill, Morgan; Kieser, Jules

2016-06-01

This study aimed to assess the enamel ultrastructure in modern otariid pinnipeds and in the extinct walrus Pelagiarctos. Teeth of the New Zealand fur seal ( Arctocephalus forsteri), sea lion ( Phocarctos hookeri), and fossil walrus Pelagiarctos thomasi were embedded, sectioned, etched, and analyzed via scanning electron microscopy. The enamel of NZ otariids and Pelagiarctos was prismatic and moderately thick, measuring 150-450 μm on average. It consisted of transversely oriented Hunter-Schreger bands (HSBs) from the enamel-dentine junction (EDJ) to near the outer surface, where it faded into prismless enamel less than 10 μm thick. The width of HSB was variable and averaged between 6 and 10 prisms, and they presented an undulating course both in longitudinal and cross sections. The overall organization of the enamel was similar in all teeth sampled; however, the enamel was thicker in canines and postcanines than in incisors. The crowns of all teeth sampled were uniformly covered by enamel; however, the grooved incisors lacked an enamel cover on the posterior side of the buccal face. Large tubules and tuft-like structures were seen at the EDJ. HSB enamel as well as tubules and tufts at the EDJ suggest increased occlusal loads during feeding, a biomechanical adaptation to avoid enamel cracking and failure. Despite overall simplification in tooth morphology and reduced mastication, the fossil and modern pinnipeds analyzed here retained the complex undulating HSB structure of other fossils and living Carnivora, while other marine mammals such as cetaceans developed simplified radial enamel.

Uptake of planar polychlorinated biphenyls and 2,3,7,8-substituted polychlorinated dibenzofurans and dibenzo-p-dioxins by birds nesting in the lower Fox River and Green Bay, Wisconsin, USA

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Ankley, Gerald T.; Niemi, Gerald J.; Lodge, Keith B.; Harris, Hallett J.; Beaver, Donald L.; Tillitt, Donald E.; Schwartz, Ted R.; Giesy, John P.; Jones, Paul D.; Hagley, Cynthia

1993-01-01

The uptake of persistent polychlorinated hydrocarbons (PCHs) by four avian species was investigated at upper trophic levels of two aquatic food chains of the lower Fox River and Green Bay, Wisconsin. Accumulation of total and specific planar polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxin (PCDDs), and H411E rat hepatoma cell bioassay-derived 2,37,8-tetrachlorodibenzop-dioxin equivalents (TCDD-EQ) was evaluated in Forster's tern (Sterna forsteri) and common tern (Sterna hirundo) chicks, and in tree swallow (Tachycineta bicolor) and red-winged blackbird (Agelaius phoeniceus) nestlings from colonies nesting in several locations within the watershed. Concentrations of the PCHs were greatest in eggs and chicks of the two tern species, less in the tree swallows and least in the red-winged blackbirds. Young of all four species accumulated total PCBs, PCB congeners 77, 105, 126, and 169, and TCDD-EQ. The young birds also accumulated small concentrations of several 2,3,7,8-sbustituted PCDF and PCDD congeners. Uptake rates for certain of the PCHs for the Forster's tern chicks were: 15 μg/day for total PCBs, 70, 200, 6.5, and 0.14 ng/day for PCB congeners 77, 105, 126, and 169, respectively, and 270 μg/day for TCDD-EQ. Principal components analysis revealed that the patterns of PCH concentrations in the samples were influenced by species of bird, their age (or length of exposure) and nesting location. Collectively, our findings demonstrate that exposure of avian species to contaminants derived from aquatic food chains can be characterized and quantified for the purposes of ecological risk assessment.

High-affinity hemoglobin and blood oxygen saturation in diving emperor penguins.

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Meir, Jessica U; Ponganis, Paul J

2009-10-01

The emperor penguin (Aptenodytes forsteri) thrives in the Antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. To examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (O2) transport and depletion while diving, we characterized the O2-hemoglobin (Hb) dissociation curve of the emperor penguin in whole blood. This allowed us to (1) investigate the biochemical adaptation of Hb in this species, and (2) address blood O2 depletion during diving, by applying the dissociation curve to previously collected partial pressure of O2 (PO2) profiles to estimate in vivo Hb saturation (SO2) changes during dives. This investigation revealed enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species. This allows for increased O2 at low blood PO2 levels during diving and more complete depletion of the respiratory O2 store. SO2 profiles during diving demonstrated that arterial SO2 levels are maintained near 100% throughout much of the dive, not decreasing significantly until the final ascent phase. End-of-dive venous SO2 values were widely distributed and optimization of the venous blood O2 store resulted from arterialization and near complete depletion of venous blood O2 during longer dives. The estimated contribution of the blood O2 store to diving metabolic rate was low and highly variable. This pattern is due, in part, to the influx of O2 from the lungs into the blood during diving, and variable rates of tissue O2 uptake.

Phase transitions in huddling emperor penguins

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Richter, S.; Gerum, R.; Winterl, A.; Houstin, A.; Seifert, M.; Peschel, J.; Fabry, B.; Le Bohec, C.; Zitterbart, D. P.

2018-05-01

Emperor penguins (Aptenodytes forsteri) are highly adapted to the harsh conditions of the Antarctic winter: they are able to fast for up to 134 days during breeding. To conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. The effect of different meteorological factors on the huddling behaviour, however, is not well understood. Using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase transition from a fluid to a solid state. We use the colony density as order parameter, and an apparent temperature that is perceived by the penguins as the thermodynamic variable. We approximate the apparent temperature as a linear combination of four meteorological parameters: ambient temperature, wind speed, global radiation and relative humidity. We find a wind chill factor of  ‑2.9 , a humidity chill factor of  ‑0.5 rel. humidity, and a solar radiation heating factor of 0.3 . In the absence of wind, humidity and solar radiation, the phase transition temperature (50% huddling probability) is  ‑48.2 °C for the investigated time period (May 2014). We propose that higher phase transition temperatures indicate a shrinking thermal insulation and thus can serve as a proxy for lower energy reserves of the colony, integrating pre-breeding foraging success at sea and energy expenditure at land due to environmental conditions. As current global change is predicted to have strong detrimental effects on emperor penguins within the next decades, our approach may thus contribute towards an urgently needed long-term monitoring system for assessing colony health.

Comparative embryotoxicity of a pentabrominated diphenyl ether mixture to common terns (Sterna hirundo) and American kestrels (Falco sparverius)

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Rattner, Barnett A.; Lazarus, Rebecca S.; Heinz, Gary H.; Karouna-Reiner, Natalie K.; Schultz, Sandra L.; Hale, Robert C.

2013-01-01

Concentrations of polybrominated diphenyl ethers (PBDEs) in Forster’s tern (Sterna forsteri) eggs from San Francisco Bay have been reported to range up to 63 μg g−1 lipid weight. This value exceeds the lowest-observed-adverse-effect level (1.8 μg g−1 egg wet weight; ∼32 μg−1 lipid weight) reported in an embryotoxicity study with American kestrels (Falco sparverius). As a surrogate for Forster’s terns, common tern (Sterna hirundo) eggs were treated by air cell injection with corn oil vehicle (control) or a commercial penta-BDE formulation (DE-71) at nominal concentrations of 0.2, 2, and 20 μg g−1 egg. As a positive control, kestrel eggs received vehicle or 20 μg DE-71 g−1 egg. In terns, there were no effects of DE-71 on embryonic survival, and pipping or hatching success; however, treated eggs hatched later (0.44 d) than controls. Organ weights, organ-to-body weight ratios, and bone lengths did not differ, and histopathological observations were unremarkable. Several measures of hepatic oxidative stress in hatchling terns were not affected by DE-71, although there was some evidence of oxidative DNA damage (8-hydroxy-deoxyguanosine; 8-OH-dG). Although DE-71 did not impair pipping and hatching of kestrels, it did result in a delay in hatch, shorter humerus length, and reduced total thyroid weight. Concentrations of oxidized glutathione, reduced glutathione, thiobarbituric acid reactive substances, and 8-OH-dG in liver were greater in DE-71-treated kestrels compared to controls. Our findings suggest common tern embryos, and perhaps other tern species, are less sensitive to PBDEs than kestrel embryos.

Prey fish returned to Forster's tern colonies suggest spatial and temporal differences in fish composition and availability.

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Peterson, Sarah H; Ackerman, Joshua T; Eagles-Smith, Collin A; Herzog, Mark P; Hartman, C Alex

2018-01-01

Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster's tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay, California. We compared the species composition among repeatedly-sampled colonies (≥ 4 years), using both relative species abundance and the composition of total dry mass by species. Overall, the relative abundances of prey species at seven repeatedly-sampled tern colonies were more different than would be expected by chance, with the most notable differences in relative abundance observed between geographically distant colonies. In general, Mississippi silverside (Menidia audens) and topsmelt silverside (Atherinops affinis) comprised 42% of individuals and 40% of dry fish mass over the study period. Three-spined stickleback (Gasterosteus aculeatus) comprised the next largest proportion of prey species by individuals (19%) but not by dry mass (6%). Five additional species each contributed ≥ 4% of total individuals collected over the study period: yellowfin goby (Acanthogobius flavimanus; 10%), longjaw mudsucker (Gillichthys mirabilis; 8%), Pacific herring (Clupea pallasii; 6%), northern anchovy (Engraulis mordax; 4%), and staghorn sculpin (Leptocottus armatus; 4%). At some colonies, the relative abundance and biomass of specific prey species changed over time. In general, the abundance and dry mass of silversides increased, whereas the abundance and dry mass of three-spined stickleback and longjaw mudsucker decreased. As central place foragers, Forster's terns are limited in the distance they forage; thus, changes in the prey species returned to Forster's tern colonies suggest that the relative availability of some fish species in the environment has changed, possibly in response to alteration of the available habitat.

Prey fish returned to Forster’s tern colonies suggest spatial and temporal differences in fish composition and availability

Science.gov (United States)

Peterson, Sarah; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark; Hartman, C. Alex

2018-01-01

Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster’s tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay, California. We compared the species composition among repeatedly-sampled colonies (≥ 4 years), using both relative species abundance and the composition of total dry mass by species. Overall, the relative abundances of prey species at seven repeatedly-sampled tern colonies were more different than would be expected by chance, with the most notable differences in relative abundance observed between geographically distant colonies. In general, Mississippi silverside (Menidia audens) and topsmelt silverside (Atherinops affinis) comprised 42% of individuals and 40% of dry fish mass over the study period. Three-spined stickleback (Gasterosteus aculeatus) comprised the next largest proportion of prey species by individuals (19%) but not by dry mass (6%). Five additional species each contributed ≥ 4% of total individuals collected over the study period: yellowfin goby (Acanthogobius flavimanus; 10%), longjaw mudsucker (Gillichthys mirabilis; 8%), Pacific herring (Clupea pallasii; 6%), northern anchovy (Engraulis mordax; 4%), and staghorn sculpin (Leptocottus armatus; 4%). At some colonies, the relative abundance and biomass of specific prey species changed over time. In general, the abundance and dry mass of silversides increased, whereas the abundance and dry mass of three-spined stickleback and longjaw mudsucker decreased. As central place foragers, Forster’s terns are limited in the distance they forage; thus, changes in the prey species returned to Forster’s tern colonies suggest that the relative availability of some fish species in the environment has changed, possibly in response to alteration of the available

Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions.

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Takekawa, John Y; Ackerman, Joshua T; Brand, L Arriana; Graham, Tanya R; Eagles-Smith, Collin A; Herzog, Mark P; Topping, Brent R; Shellenbarger, Gregory G; Kuwabara, James S; Mruz, Eric; Piotter, Sara L; Athearn, Nicole D

2015-01-01

Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

VORICONAZOLE TOXICITY IN MULTIPLE PENGUIN SPECIES.

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Hyatt, Michael W; Georoff, Timothy A; Nollens, Hendrik H; Wells, Rebecca L; Clauss, Tonya M; Ialeggio, Donna M; Harms, Craig A; Wack, Allison N

2015-12-01

Aspergillosis is a common respiratory fungal disease in penguins managed under human care. Triazole antifungal drugs, including itraconazole, are most commonly used for treatment; however, itraconazole treatment failures from drug resistance are becoming more common, requiring newer treatment options. Voriconazole, a newer triazole, is being used more often. Until recently, no voriconazole pharmacokinetic studies had been performed in penguins, leading to empiric dosing based on other avian studies. This has led to increased anecdotal reporting of apparent voriconazole toxicity in penguins. This report describes 18 probable and 6 suspected cases of voriconazole toxicity in six penguin species from nine institutions: 12 African penguins (Spheniscus demersus), 5 Humboldt penguins (Spheniscus humboldti), 3 Magellanic penguins (Spheniscus magellanicus), 2 gentoo penguins (Pygoscelis papua papua), 1 macaroni penguin (Eudyptes chrysolophus), and 1 emperor penguin (Aptenodytes forsteri). Observed clinical signs of toxicity included anorexia, lethargy, weakness, ataxia, paresis, apparent vision changes, seizure-like activity, and generalized seizures. Similar signs of toxicity have also been reported in humans, in whom voriconazole therapeutic plasma concentration for Aspergillus spp. infections is 2-6 μg/ml. Plasma voriconazole concentrations were measured in 18 samples from penguins showing clinical signs suggestive of voriconazole toxicity. The concentrations ranged from 8.12 to 64.17 μg/ml, with penguins having plasma concentrations above 30 μg/ml exhibiting moderate to severe neurologic signs, including ataxia, paresis, and seizures. These concentrations were well above those known to result in central nervous system toxicity, including encephalopathy, in humans. This case series highlights the importance of species-specific dosing of voriconazole in penguins and plasma therapeutic drug monitoring. Further investigation, including pharmacokinetic studies, is

Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions.

Directory of Open Access Journals (Sweden)

John Y Takekawa

Full Text Available Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus, and chick survival of Forster's Tern (Sterna forsteri. Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction

Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions

Science.gov (United States)

Takekawa, John Y.; Ackerman, Joshua T.; Brand, Arriana; Graham, Tanya R.; Eagles-Smith, Collin A.; Herzog, Mark; Topping, Brent R.; Shellenbarger, Gregory; Kuwabara, James S.; Mruz, Eric; Piotter, Sara L.; Athearn, Nicole D.

2015-01-01

Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

Fish diets in a freshwater-deprived semiarid estuary (The Coorong, Australia) as inferred by stable isotope analysis

Science.gov (United States)

Lamontagne, S.; Deegan, B. M.; Aldridge, K. T.; Brookes, J. D.; Geddes, M. C.

2016-09-01

In 2007, high rates of water extraction combined with a regional drought stopped freshwater discharge to the Coorong, a ∼120 km estuarine and coastal lagoon system at the outlet of the River Murray (Australia). The sources of organic matter sustaining the Coorong food web in the absence of river-borne organic matter and nutrient inputs were evaluated by measuring δ13C, δ15N and δ34S in large-bodied fish and their prey. In general, the δ34S of the food web (mean = 11.3‰; range = 4.32-18.9‰) suggested a comparable contribution from autochthonous pelagic (∼21‰) and benthic (<5‰) primary production. A relatively high δ13C in all organisms (-20 to -9.2‰) was also consistent with a dominant contribution from autochtonous sources to the food web. A Bayesian mixing model framework (SIMMR) was used to estimate the diet of large-bodied fish for statistically-determined prey groups based on their similarity in isotopic composition. Argyrosomus japonicus preyed primarily on Fish Group 1 (small pelagic fish like galaxiids and Hyperlophus vittatus), Rhombosolea tapirina on Invertebrate Group 2 (polychaetes like Capitella spp.) but Acanthopagrus butcheri fed on a wide variety of fish and invertebrate groups. A partial switch in diet to other prey groups suggested larger Ar. japonicus fed on larger prey, such as crabs and adult Aldrichetta forsteri. Despite being numerically abundant at the time, Fish Group 2 (benthic species) was a relatively low proportion of large-bodied fish diets. This probably reflected the tendency of some salt-tolerant members of this group (such as Atherinosoma microstoma) to prefer hypersaline habitats, which the large-bodied fish avoided. As the heavily preyed-on Fish Group 1 included species with a marine component to their life-cycle, marine productivity may also help to maintain this estuarine ecosystem in the absence of river-borne organic matter inputs.

Maternal transfer of contaminants in birds: Mercury and selenium concentrations in parents and their eggs

International Nuclear Information System (INIS)

Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark P.; Hartman, C. Alex

2016-01-01

We conducted a detailed assessment of the maternal transfer of mercury and selenium to eggs in three bird species (n = 107 parents and n = 339 eggs), and developed predictive equations linking contaminant concentrations in eggs to those in six tissues of the mother (blood, muscle, liver, kidney, breast feathers, and head feathers). Mercury concentrations in eggs were positively correlated with mercury concentrations in each of the mother's internal tissues (R"2 ≥ 0.95), but generally not with feathers. For each species, the proportion of mercury transferred to eggs decreased as mercury concentrations in the mother increased. At the same maternal mercury concentration, the proportion of mercury transferred to eggs differed among species, such that Forster's tern (Sterna forsteri) and black-necked stilt (Himantopus mexicanus) females transferred more methylmercury to their eggs than American avocet (Recurvirostra americana) females. Selenium concentrations in eggs also were correlated with selenium concentrations in the mother's liver (R"2 = 0.87). Furthermore, mercury and selenium concentrations in tern eggs were positively correlated with those in the father (R"2 = 0.84). Incubating male terns had 21% higher mercury concentrations in blood compared to incubating females at the same egg mercury concentration. We provide equations to predict contaminant concentrations in eggs from each of the commonly sampled bird tissues. - Highlights: • We developed predictive equations linking contaminant concentrations in eggs to those in the mother. • Mercury concentrations in eggs were positively correlated with those in the mother. • The proportion of mercury transferred to eggs decreased as mercury in the mother increased. • The proportion of mercury transferred to eggs differed among species. • Selenium concentrations in eggs also were correlated with those in the mother's liver. - We examined the maternal transfer of mercury and selenium to eggs in

Chlorinated biphenyls and pesticides in migrating and resident seabirds from East and West Antarctica.

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Corsolini, Simonetta; Borghesi, Nicoletta; Ademollo, Nicoletta; Focardi, Silvano

2011-11-01

The unhatched eggs of the following seabirds were analyzed to quantify PCBs, hexachlorobenzene (HCB), α-, β-, γ-, δ-hexachlorocyclohexanes (HCHs), o,p' and p,p' isomers of DDT, DDD and DDE: resident Adèlie (Pygoscelis adèliae, ADPE) and Emperor (Aptenodytes forsteri, EMPE) penguins, migrating snow petrel (Pagodroma nivea, SNPT) and South Polar skua (Catharacta maccormicki, SPSK) from the Ross Sea (East Antarctica); and migrating Brown skua (Catharacta antartica, BRSK) and resident ADPE from the Brainsfield Strait (West Antarctica). The general aims were to evaluate the contaminant accumulation in eggs of migrating and resident species in the two study areas, and to compare levels in penguins and skuas nesting in East and West Antarctica. PCB congener and HCH and DDT isomer profiles were also assessed. Comparisons were evaluated using seven PCB congeners (IUPAC nos. 28, 52, 101, 118+149, 138, 153, and 180), p,p'-DDE, ΣDDTs, and ΣHCHs. Higher contaminant concentrations were detected in migrating seabirds (South polar skua and brown skua)>sub-Antarctic species (snow petrel)>Antarctic species (penguins) from both the sampling sites, suggesting contamination events at lower latitudes for those birds migrating northward. HCHs showed the lowest concentrations in all species (from 0.03±0.03 ng/g wet wt in SPSK to 1.81±1.23 ng/g wet wt in ADPE from West Antarctica), and PCBs were the most abundant contaminants (from 4.34±2.15 ng/g wet wt. in EMPE to 53.41±19.61 ng/g wet wt. in brown skua). Among pesticides, it is relevant the detection of p,p'-DDT in Adèlie penguin from West Antarctica and in both species of skua; the detection of this pesticide can confirm its actual use in certain malaria-endemic countries from where it is transferred through the long range transport to the polar regions. Contaminants did not show any significant temporal trend during a ten year time span, from 1994/95 to 2004/05, in organisms collected in East Antarctica and they did not

It's what's inside that counts: egg contaminant concentrations are influenced by estimates of egg density, egg volume, and fresh egg mass.

Science.gov (United States)

Herzog, Mark P; Ackerman, Joshua T; Eagles-Smith, Collin A; Hartman, C Alex

2016-05-01

In egg contaminant studies, it is necessary to calculate egg contaminant concentrations on a fresh wet weight basis and this requires accurate estimates of egg density and egg volume. We show that the inclusion or exclusion of the eggshell can influence egg contaminant concentrations, and we provide estimates of egg density (both with and without the eggshell) and egg-shape coefficients (used to estimate egg volume from egg morphometrics) for American avocet (Recurvirostra americana), black-necked stilt (Himantopus mexicanus), and Forster's tern (Sterna forsteri). Egg densities (g/cm(3)) estimated for whole eggs (1.056 ± 0.003) were higher than egg densities estimated for egg contents (1.024 ± 0.001), and were 1.059 ± 0.001 and 1.025 ± 0.001 for avocets, 1.056 ± 0.001 and 1.023 ± 0.001 for stilts, and 1.053 ± 0.002 and 1.025 ± 0.002 for terns. The egg-shape coefficients for egg volume (K v ) and egg mass (K w ) also differed depending on whether the eggshell was included (K v  = 0.491 ± 0.001; K w  = 0.518 ± 0.001) or excluded (K v  = 0.493 ± 0.001; K w  = 0.505 ± 0.001), and varied among species. Although egg contaminant concentrations are rarely meant to include the eggshell, we show that the typical inclusion of the eggshell in egg density and egg volume estimates results in egg contaminant concentrations being underestimated by 6-13 %. Our results demonstrate that the inclusion of the eggshell significantly influences estimates of egg density, egg volume, and fresh egg mass, which leads to egg contaminant concentrations that are biased low. We suggest that egg contaminant concentrations be calculated on a fresh wet weight basis using only internal egg-content densities, volumes, and masses appropriate for the species. For the three waterbirds in our study, these corrected coefficients are 1.024 ± 0.001 for egg density, 0.493 ± 0.001 for K v , and 0.505 ± 0.001 for K w .

[Morphologic-functional study of the locomotor system of penguins as a general model of movement in under-water flight. I].

Science.gov (United States)

Bannasch, R

1986-01-01

Regarding several theories of the evolution of the Sphenisciformes the specific morpho-physiological alterations for the changeover from aerial to underwater life are discussed. The peculiarities in the Penguin's "construction" become comprehensible as strong adjustments to the subaquatic locomotion. Surely they took their origin from the equipment of flying birds. The present data of the kinematics of the underwater locomotion show, that propulsion is produced in the same principal way by the flapping wings as in aerial flight. Therefore the short term "underwater flight" for the Penguin's style of locomotion is justified. Known data of swimming performance suggest that its essential adaptation is not that to top achievements but more to an economical use of energy budget. The favourable hydrodynamic characteristics of the Penguin body may be well interpreted from this point of view. The peculiarity of underwater flight is the absence of the necessity to produce a weight-compensating force. In order to create thrust forces in an appropriate magnitude during up- and downstroke of the beating cycle the upstroke must be powered. The anatomical architecture and the mode of operation of the parts of the muscle system must be adjusted to this demand. Based on these statements, the anatomy of active and passive apparatus of movement was studied by dissection of 26 individuals of Pygoscelis papua, P. antarctica, P. adeliae, Eudyptes chrysolophus, and Aptenodytes forsteri. Besides the functional explanation of the Articulatio sternocoracoidea (diverging considerably from the usual type in birds), a new interpretation is given for the structures of the Articulatio humeri. In this context, the role of the Ligamentum acrocoracohumerale as an important element for coordination of the motion processes in the shoulder joint is elucidated. The essential curvature of the Caput humeri is found to be satisfactorily approximated by a logarithmic spiral. The understanding of the

Surface elevation dynamics in vegetated Spartina marshes versus unvegetated tidal ponds along the mid-Atlantic coast, USA, with implications to waterbirds

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Erwin, R. Michael; Cahoon, Donald R.; Prosser, Diann J.; Sanders, Geoffrey; Hensel, Philippe

2006-01-01

-dependent seaside sparrows Ammodramus maritimus, saltmarsh sharp-tailed sparrows A. caudacutus, black rails Laterallus jamaicensis, clapper rails Rallus longirostris, Forster's terns Sterna forsteri, common terns Sterna hirundo, and gull-billed terns Sterna nilotica. Although short-term inundation of many lagoonal marshes may benefit some open-water feeding ducks, geese, and swans during winter, the long-term ecosystem effects may be detrimental, as wildlife resources will be lost or displaced. With the reduction in area of emergent marsh, estuarine secondary productivity and biotic diversity will also be reduced.

Collision and displacement vulnerability among marine birds of the California Current System associated with offshore wind energy infrastructure

Science.gov (United States)

Adams, Josh; Kelsey, Emily C.; Felis, Jonathan J.; Pereksta, David M.

2016-10-27

With growing climate change concerns and energy constraints, there is an increasing need for renewable energy sources within the United States and globally. Looking forward, offshore wind-energy infrastructure (OWEI) has the potential to produce a significant proportion of the power needed to reach our Nation’s renewable energy goal. Offshore wind-energy sites can capitalize open areas within Federal waters that have persistent, high winds with large energy production potential. Although there are few locations in the California Current System (CCS) where it would be acceptable to build pile-mounted wind turbines in waters less than 50 m deep, the development of technology able to support deep-water OWEI (>200 m depth) could enable wind-energy production in the CCS. As with all human-use of the marine environment, understanding the potential impacts of wind-energy infrastructure on the marine ecosystem is an integral part of offshore wind-energy research and planning. Herein, we present a comprehensive database to quantify marine bird vulnerability to potential OWEI in the CCS (see https://doi.org/10.5066/F79C6VJ0). These data were used to quantify marine bird vulnerabilities at the population level. For 81 marine bird species present in the CCS, we created three vulnerability indices: Population Vulnerability, Collision Vulnerability, and Displacement Vulnerability. Population Vulnerability was used as a scaling factor to generate two comprehensive indicies: Population Collision Vulnerability (PCV) and Population Displacement Vulnerability (PDV). Within the CCS, pelicans, terns (Forster’s [Sterna forsteri], Caspian [Hydroprogne caspia], Elegant [Thalasseus elegans], and Least Tern [Sternula antillarum]), gulls (Western [Larus occidentalis] and Bonaparte’s Gull [Chroicocephalus philadelphia]), South Polar Skua (Stercorarius maccormicki), and Brandt’s Cormorant (Phalacrocorax penicillatus) had the greatest PCV scores. Brown Pelican (Pelicanus occidentalis

Waterbird nest monitoring program in San Francisco Bay (2005-10)

Science.gov (United States)

Ackerman, Joshua T.; Herzog, Mark P.

2012-01-01

Historically, Forster’s Terns (Sterna forsteri), American Avocets (Recurvirostra americana), and Black-necked Stilts (Himantopus mexicanus) were uncommon residents of San Francisco Bay, California (Grinnell and others, 1918; Grinnell and Wythe, 1927; Sibley, 1952). Presently, however, avocets and stilts are the two most abundant breeding shorebirds in San Francisco Bay (Stenzel and others, 2002; Rintoul and others, 2003). More than 4,000 avocets and 1,000 stilts, roughly 20 percent of their San Francisco Bay wintering populations, breed within the estuary, making San Francisco Bay the largest breeding area for these species on the Pacific Coast (Stenzel and others, 2002; Rintoul and others, 2003). Forster’s Terns were first observed breeding in the San Francisco Bay in 1948 (110 nests); they had increased to over 4000 individuals by the 1980s (Sibley, 1952; Gill, 1977; Harvey and others, 1992; Carter and others, 1990) and were estimated at 2000–3000 for 1998–2002; (Strong and others, 2004).It is hypothesized that the relatively large size of the current waterbird breeding populations is a result of the creation of artificial salt evaporation ponds from the 1930s through the 1950s (Gill, 1977; Goals Project, 1999). Until recently, these salt ponds and associated islands used by waterbirds for nesting have been managed relatively similarly and have supported large breeding waterbird populations. Recently, the South Bay Salt Pond Restoration Project has implemented plans to convert 50–90 percent of the 15,000 acres of salt ponds in the South San Francisco Bay back to tidal marsh habitat. Therefore, there is concern that the Restoration Project, while benefiting other native species, could negatively influence local breeding populations of waterbirds that are reliant on salt pond habitats for both breeding and foraging. A primary goal of the South Bay Salt Pond Restoration Project is to maintain current breeding waterbird populations (South Bay Salt Pond Long

Penguin lungs and air sacs: implications for baroprotection, oxygen stores and buoyancy.

Science.gov (United States)

Ponganis, P J; St Leger, J; Scadeng, M

2015-03-01

The anatomy and volume of the penguin respiratory system contribute significantly to pulmonary baroprotection, the body O2 store, buoyancy and hence the overall diving physiology of penguins. Therefore, three-dimensional reconstructions from computerized tomographic (CT) scans of live penguins were utilized to measure lung volumes, air sac volumes, tracheobronchial volumes and total body volumes at different inflation pressures in three species with different dive capacities [Adélie (Pygoscelis adeliae), king (Aptenodytes patagonicus) and emperor (A. forsteri) penguins]. Lung volumes scaled to body mass according to published avian allometrics. Air sac volumes at 30 cm H2O (2.94 kPa) inflation pressure, the assumed maximum volume possible prior to deep dives, were two to three times allometric air sac predictions and also two to three times previously determined end-of-dive total air volumes. Although it is unknown whether penguins inhale to such high volumes prior to dives, these values were supported by (a) body density/buoyancy calculations, (b) prior air volume measurements in free-diving ducks and (c) previous suggestions that penguins may exhale air prior to the final portions of deep dives. Based upon air capillary volumes, parabronchial volumes and tracheobronchial volumes estimated from the measured lung/airway volumes and the only available morphometry study of a penguin lung, the presumed maximum air sac volumes resulted in air sac volume to air capillary/parabronchial/tracheobronchial volume ratios that were not large enough to prevent barotrauma to the non-collapsing, rigid air capillaries during the deepest dives of all three species, and during many routine dives of king and emperor penguins. We conclude that volume reduction of airways and lung air spaces, via compression, constriction or blood engorgement, must occur to provide pulmonary baroprotection at depth. It is also possible that relative air capillary and parabronchial volumes are

Evaluation of Caspian tern (Hydroprogne caspia) and snowy plover (Charadrius alexandrinus nivosus) nesting on modified islands at the Don Edwards San Francisco Bay National Wildlife Refuge, California—2016 Annual Report

Science.gov (United States)

Hartman, C. Alex; Ackerman, Joshua T.; Herzog, Mark P.; Strong, Cheryl; Trachtenbarg, David; Shore, Crystal A.

2017-05-08

attraction measures were successful in establishing Caspian tern breeding colonies at Ponds A16 and SF2 of DENWR. The success of 2015 continued in 2016, the second year of the study. In 2016, Caspian terns nested on two of the five islands modified for Caspian terns (one island in Pond A16 and one island in Pond SF2). Caspian terns initiated at least 317 nests, fledged at least 158 chicks, and had a breeding success rate of 0.50 fledged chicks per breeding pair. This represents a 42 percent increase in nests initiated, a 9 percent decrease in the number of fledged chicks, and a 36 percent decrease in the number of chicks fledged per breeding pair in 2016 compared to 2015. Although overall productivity decreased from 2015, these results indicate that the Caspian tern breeding population on modified islands of the DENWR is increasing relative to 2015, the first year of the effort, and relative to years prior to 2015 when no breeding colonies of Caspian terns existed in Ponds A16 or SF2. These results indicate the effectiveness of social attraction measures in helping to establish tern nesting colonies in San Francisco Bay. Conversely, for the second year in a row, snowy plovers did not attempt to nest on any island in Ponds A16 and SF2. Social attraction measures similar to those used in this study, but targeting other colonial species such as Forster’s terns (Sterna forsteri) and American avocets (Recurvirostra americana), may help to establish waterbird breeding colonies at wetlands enhanced as part of the SBSP Restoration Project.