1
|
Lander ME, Fadely BS, Gelatt TS, Sterling JT, Johnson DS, Pelland NA. Mixing it up in Alaska: Habitat use of adult female Steller sea lions reveals a variety of foraging strategies. Ecosphere 2020. [DOI: 10.1002/ecs2.3021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Michelle E. Lander
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Brian S. Fadely
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Thomas S. Gelatt
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Jeremy T. Sterling
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Devin S. Johnson
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| | - Noel A. Pelland
- Marine Mammal Laboratory Alaska Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration Seattle Washington 98115 USA
| |
Collapse
|
2
|
Keogh MJ, Taras B, Beckmen KB, Burek-Huntington KA, Ylitalo GM, Fadely BS, Rea LD, Pitcher KW. Organochlorine contaminant concentrations in blubber of young Steller sea lion (Eumetopias jubatus) are influenced by region, age, sex, and lipid stores. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 698:134183. [PMID: 31494417 DOI: 10.1016/j.scitotenv.2019.134183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 06/10/2023]
Abstract
Contaminant exposure is particularly important for species and populations of conservation concern, such as the Steller sea lion (Eumetopias jubatus). We used blubber samples (n = 120) to determine organochlorine concentrations, including polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDTs), and blood samples (n = 107) to estimate total body lipids based on the hydrogen isotope dilution method. We assessed the influence of age, sex, condition, and geographic area on contaminant concentrations in blubber and contaminant body load. The concentration of ΣPCBs was highest in pups (<6 months) from the Aleutian Islands, and the concentrations in males were higher than females in all regions. The ΣPCBs and ΣDDTs concentrations and loads decreased with increasing mass in pups, however, there were no regional or sex differences in contaminant load. Within each of the five age classes, the concentrations of ΣPCBs and ΣDDTs decreased with increasing mass, but overall these OCs increased with age. Further, accounting for the lipid content, a potential proxy for energy balance, in the animal load reduced or removed the regional and sex effects present in age models for contaminants. We propose, that adjusting OCs concentration by the lipid content of the blubber sample alone may not fully account for the variability in OC concentrations associated with differences in condition or energy states between young Steller sea lions.
Collapse
Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024, Douglas, AK 99811-0024, United States of America.
| | - Brian Taras
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, United States of America
| | - Kimberlee B Beckmen
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, United States of America
| | - Kathleen A Burek-Huntington
- Alaska Veterinary Pathology Services, 23834 The Clearing Drive, Eagle River, AK 99577, United States of America
| | - Gina M Ylitalo
- Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 2725 Montlake Blvd. East, Seattle, WA 98112, United States of America
| | - Brian S Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, United States of America
| | - Lorrie D Rea
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, United States of America; Institute of Northern Engineering, University of Alaska Fairbanks, 1764 Tanana Loop, ELIF Suite 240, Fairbanks, AK 99775, United States of America
| | - Kenneth W Pitcher
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, United States of America
| |
Collapse
|
3
|
Valdivia A, Wolf S, Suckling K. Marine mammals and sea turtles listed under the U.S. Endangered Species Act are recovering. PLoS One 2019; 14:e0210164. [PMID: 30650125 PMCID: PMC6334928 DOI: 10.1371/journal.pone.0210164] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 12/18/2018] [Indexed: 11/24/2022] Open
Abstract
The U.S. Endangered Species Act (ESA) is a powerful environmental law protecting imperiled plants and animals, and a growing number of marine species have been protected under this law as extinction risk in the oceans has increased. Marine mammals and sea turtles comprise 38% of the 163 ESA-listed marine "species", which includes subspecies and distinct population segments, yet analyses of recovery trends after listing are lacking. Here we gathered the best available annual abundance estimates for geographically delimited populations of all 62 marine mammal and sea turtle species listed under the ESA. Of these, we chose representative populations of species that were listed before 2012, occur and reproduce in U.S. waters, and have data of sufficient quality and timespan for trend analyses. Thus, we quantitatively analyzed population trends, magnitude of population change, and recovery status for 23 and 8 representative populations of 14 marine mammal and 5 sea turtle species, respectively. Using generalized linear and non-linear models, we found that 18 marine mammal (78%) and 6 sea turtle (75%) populations significantly increased after listing; 3 marine mammal (13%) and 2 sea turtle (25%) populations showed non-significant changes; while 2 marine mammal (9%), but no sea turtle populations declined after ESA protection. Overall, the 24 populations that increased in abundance were from species listed for 20 years or more (e.g., large whales, manatees, and sea turtles). Conservation measures triggered by ESA listing such as ending exploitation, tailored species management, and fishery regulations, and other national and international measures, appear to have been largely successful in promoting species recovery, leading to the delisting of some species and to increases in most populations. These findings underscore the capacity of marine mammal and sea turtle species to recover from substantial geographical population declines when conservation actions are implemented in a timely and effective manner.
Collapse
Affiliation(s)
- Abel Valdivia
- Center for Biological Diversity, Oakland, California, United States of America
| | - Shaye Wolf
- Center for Biological Diversity, Oakland, California, United States of America
| | - Kieran Suckling
- Center for Biological Diversity, Tucson, Arizona, United States of America
| |
Collapse
|
4
|
Cronin M, Gerritsen H, Reid D, Jessopp M. Spatial Overlap of Grey Seals and Fisheries in Irish Waters, Some New Insights Using Telemetry Technology and VMS. PLoS One 2016; 11:e0160564. [PMID: 27682443 PMCID: PMC5040441 DOI: 10.1371/journal.pone.0160564] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/21/2016] [Indexed: 11/19/2022] Open
Abstract
Seals and humans often target the same food resource, leading to competition. This is of mounting concern with fish stocks in global decline. Grey seals were tracked from southeast Ireland, an area of mixed demersal and pelagic fisheries, and overlap with fisheries on the Celtic Shelf and Irish Sea was assessed. Overall, there was low overlap between the tagged seals and fisheries. However, when we separate active (e.g. trawls) and passive gear (e.g. nets, lines) fisheries, a different picture emerged. Overlap with active fisheries was no different from that expected under a random distribution, but overlap with passive fisheries was significantly higher. This suggests that grey seals may be targeting the same areas as passive fisheries and/or specifically targeting passive gear. There was variation in foraging areas between individual seals suggesting habitat partitioning to reduce intra-specific competition or potential individual specialisation in foraging behaviour. Our findings support other recent assertions that seal/fisheries interactions in Irish waters are an issue in inshore passive fisheries, most likely at the operational and individual level. This suggests that seal population management measures would be unjustifiable, and mitigation is best focused on minimizing interactions at nets.
Collapse
Affiliation(s)
- M. Cronin
- MaREI Centre, Beaufort Building, Environmental Research Institute, University College Cork, Ringaskiddy, Co. Cork, Ireland
- * E-mail:
| | | | - D. Reid
- Marine Institute, Oranmore, Co. Galway, Ireland
| | - M. Jessopp
- MaREI Centre, Beaufort Building, Environmental Research Institute, University College Cork, Ringaskiddy, Co. Cork, Ireland
| |
Collapse
|
5
|
Correction: Assessment of Competition between Fisheries and Steller Sea Lions in Alaska Based on Estimated Prey Biomass, Fisheries Removals and Predator Foraging Behaviour. PLoS One 2015; 10:e0135431. [PMID: 26244864 PMCID: PMC4526339 DOI: 10.1371/journal.pone.0135431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|