Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey
Food availability is a key concern for the conservation of marine top predators, particularly during a time when they face a rapidly changing environment and continued pressure from commercial fishing activities. Northern fur seals ( Callorhinus ursinus ) breeding on the Pribilof Islands in the east...
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Online Access: | http://dx.doi.org/10.3389/fmars.2020.597973 https://www.frontiersin.org/articles/10.3389/fmars.2020.597973/full |
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crfrontiers:10.3389/fmars.2020.597973 2024-09-15T17:59:40+00:00 Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey McHuron, Elizabeth A. Luxa, Katie Pelland, Noel A. Holsman, Kirstin Ream, Rolf Zeppelin, Tonya Sterling, Jeremy T. 2020 http://dx.doi.org/10.3389/fmars.2020.597973 https://www.frontiersin.org/articles/10.3389/fmars.2020.597973/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Marine Science volume 7 ISSN 2296-7745 journal-article 2020 crfrontiers https://doi.org/10.3389/fmars.2020.597973 2024-07-30T04:03:13Z Food availability is a key concern for the conservation of marine top predators, particularly during a time when they face a rapidly changing environment and continued pressure from commercial fishing activities. Northern fur seals ( Callorhinus ursinus ) breeding on the Pribilof Islands in the eastern Bering Sea have experienced an unexplained population decline since the late-1990s. Dietary overlap with a large U.S. fishery for walleye pollock ( Gadus chalcogrammus ) in combination with changes in maternal foraging behavior and pup growth has led to the hypothesis that food limitation may be contributing to the population decline. We developed age- and sex-specific bioenergetic models to estimate fur seal energy intake from May–December in six target years, which were combined with diet data to quantify prey consumption. There was considerable sex- and age-specific variation in energy intake because of differences in body size, energetic costs, and behavior; net energy intake was lowest for juveniles (18.9 MJ sea-day –1 , 1,409.4 MJ season –1 ) and highest for adult males (66.0 MJ sea-day –1 , 7,651.7 MJ season –1 ). Population-level prey consumption ranged from 255,232 t (222,159 – 350,755 t, 95% CI) in 2006 to 500,039 t (453,720 – 555,205 t) in 1996, with pollock comprising between 41.4 and 76.5% of this biomass. Interannual variation in size-specific pollock consumption appeared largely driven by the availability of juvenile fish, with up to 81.6% of pollock biomass coming from mature pollock in years of poor age-1 recruitment. Relationships among metabolic rates, trip durations, pup growth rates, and energy intake of lactating females suggest the most feasible mechanism to increase pup growth rates is by increasing foraging efficiency through reductions in maternal foraging effort, which is unlikely to occur without increases in localized prey density. By quantifying year-specific fur seal consumption of pollock, our study provides a pathway to incorporate fur seals into multispecies pollock stock ... Article in Journal/Newspaper Bering Sea Callorhinus ursinus Frontiers (Publisher) Frontiers in Marine Science 7 |
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Food availability is a key concern for the conservation of marine top predators, particularly during a time when they face a rapidly changing environment and continued pressure from commercial fishing activities. Northern fur seals ( Callorhinus ursinus ) breeding on the Pribilof Islands in the eastern Bering Sea have experienced an unexplained population decline since the late-1990s. Dietary overlap with a large U.S. fishery for walleye pollock ( Gadus chalcogrammus ) in combination with changes in maternal foraging behavior and pup growth has led to the hypothesis that food limitation may be contributing to the population decline. We developed age- and sex-specific bioenergetic models to estimate fur seal energy intake from May–December in six target years, which were combined with diet data to quantify prey consumption. There was considerable sex- and age-specific variation in energy intake because of differences in body size, energetic costs, and behavior; net energy intake was lowest for juveniles (18.9 MJ sea-day –1 , 1,409.4 MJ season –1 ) and highest for adult males (66.0 MJ sea-day –1 , 7,651.7 MJ season –1 ). Population-level prey consumption ranged from 255,232 t (222,159 – 350,755 t, 95% CI) in 2006 to 500,039 t (453,720 – 555,205 t) in 1996, with pollock comprising between 41.4 and 76.5% of this biomass. Interannual variation in size-specific pollock consumption appeared largely driven by the availability of juvenile fish, with up to 81.6% of pollock biomass coming from mature pollock in years of poor age-1 recruitment. Relationships among metabolic rates, trip durations, pup growth rates, and energy intake of lactating females suggest the most feasible mechanism to increase pup growth rates is by increasing foraging efficiency through reductions in maternal foraging effort, which is unlikely to occur without increases in localized prey density. By quantifying year-specific fur seal consumption of pollock, our study provides a pathway to incorporate fur seals into multispecies pollock stock ... |
format |
Article in Journal/Newspaper |
author |
McHuron, Elizabeth A. Luxa, Katie Pelland, Noel A. Holsman, Kirstin Ream, Rolf Zeppelin, Tonya Sterling, Jeremy T. |
spellingShingle |
McHuron, Elizabeth A. Luxa, Katie Pelland, Noel A. Holsman, Kirstin Ream, Rolf Zeppelin, Tonya Sterling, Jeremy T. Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey |
author_facet |
McHuron, Elizabeth A. Luxa, Katie Pelland, Noel A. Holsman, Kirstin Ream, Rolf Zeppelin, Tonya Sterling, Jeremy T. |
author_sort |
McHuron, Elizabeth A. |
title |
Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey |
title_short |
Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey |
title_full |
Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey |
title_fullStr |
Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey |
title_full_unstemmed |
Practical Application of a Bioenergetic Model to Inform Management of a Declining Fur Seal Population and Their Commercially Important Prey |
title_sort |
practical application of a bioenergetic model to inform management of a declining fur seal population and their commercially important prey |
publisher |
Frontiers Media SA |
publishDate |
2020 |
url |
http://dx.doi.org/10.3389/fmars.2020.597973 https://www.frontiersin.org/articles/10.3389/fmars.2020.597973/full |
genre |
Bering Sea Callorhinus ursinus |
genre_facet |
Bering Sea Callorhinus ursinus |
op_source |
Frontiers in Marine Science volume 7 ISSN 2296-7745 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/fmars.2020.597973 |
container_title |
Frontiers in Marine Science |
container_volume |
7 |
_version_ |
1810436775324155904 |