Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require?
The effects of seasonal and regional differences in diet composition on the food requirements of Steller sea lions (Eumetopias jubatus) were estimated by using a bioenergetic model. The model considered differences in the energy density of the prey, and differences in digestive efficiency and the he...
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ftaquaticcommons:oai:generic.eprints.org:15112 2023-05-15T18:48:25+02:00 Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? Winship, Arliss J. Trites, Andrew W. 2003 application/pdf http://aquaticcommons.org/15112/ http://fishbull.noaa.gov/1011/12winshi.pdf http://aquaticcommons.org/15112/1/12winshi.pdf en eng http://aquaticcommons.org/15112/1/12winshi.pdf Winship, Arliss J. and Trites, Andrew W. (2003) Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? Fishery Bulletin, 101(1), pp. 147-167. Ecology Fisheries Article PeerReviewed 2003 ftaquaticcommons 2020-02-27T09:26:50Z The effects of seasonal and regional differences in diet composition on the food requirements of Steller sea lions (Eumetopias jubatus) were estimated by using a bioenergetic model. The model considered differences in the energy density of the prey, and differences in digestive efficiency and the heat increment of feeding of different diets. The model predicted that Steller sea lions in southeast Alaska required 45–60% more food per day in early spring (March) than after the breeding season in late summer (August) because of seasonal changes in the energy density of the diets (along with seasonal changes in energy requirements). The southeast Alaska population, at 23,000 (±1660 SD) animals (all ages), consumed an estimated 140,000 (±27,800) t of prey in 1998. In contrast, we estimated that the 51,000 (±3680) animals making up the western Alaska population in the Gulf of Alaska and Aleutian Islands consumed just over twice this amount (303,000 [±57,500] t). In terms of biomass removed in 1998 from Alaskan waters, we estimated that Steller sea lions accounted for about 5% of the natural mortality of gadids (pollock and cod) and up to 75% of the natural mortality of hexagrammids (adult Atka mackerel). These two groups of species were consumed in higher amounts than any other. The predicted average daily food requirement per individual ranged from 16 (±2.8) to 20 (±3.6) kg (all ages combined). Per capita food requirements differed by as much as 24% between regions of Alaska depending on the relative amounts of low–energy-density prey (e.g. gadids) versus high–energy-density prey (e.g. forage fish and salmon) consumed. Estimated requirements were highest in regions where Steller sea lions consumed higher proportions of low–energy-density prey and experienced the highest rates of population decline Article in Journal/Newspaper Alaska Aleutian Islands International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons Atka ENVELOPE(151.789,151.789,60.835,60.835) Gulf of Alaska |
institution |
Open Polar |
collection |
International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons |
op_collection_id |
ftaquaticcommons |
language |
English |
topic |
Ecology Fisheries |
spellingShingle |
Ecology Fisheries Winship, Arliss J. Trites, Andrew W. Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? |
topic_facet |
Ecology Fisheries |
description |
The effects of seasonal and regional differences in diet composition on the food requirements of Steller sea lions (Eumetopias jubatus) were estimated by using a bioenergetic model. The model considered differences in the energy density of the prey, and differences in digestive efficiency and the heat increment of feeding of different diets. The model predicted that Steller sea lions in southeast Alaska required 45–60% more food per day in early spring (March) than after the breeding season in late summer (August) because of seasonal changes in the energy density of the diets (along with seasonal changes in energy requirements). The southeast Alaska population, at 23,000 (±1660 SD) animals (all ages), consumed an estimated 140,000 (±27,800) t of prey in 1998. In contrast, we estimated that the 51,000 (±3680) animals making up the western Alaska population in the Gulf of Alaska and Aleutian Islands consumed just over twice this amount (303,000 [±57,500] t). In terms of biomass removed in 1998 from Alaskan waters, we estimated that Steller sea lions accounted for about 5% of the natural mortality of gadids (pollock and cod) and up to 75% of the natural mortality of hexagrammids (adult Atka mackerel). These two groups of species were consumed in higher amounts than any other. The predicted average daily food requirement per individual ranged from 16 (±2.8) to 20 (±3.6) kg (all ages combined). Per capita food requirements differed by as much as 24% between regions of Alaska depending on the relative amounts of low–energy-density prey (e.g. gadids) versus high–energy-density prey (e.g. forage fish and salmon) consumed. Estimated requirements were highest in regions where Steller sea lions consumed higher proportions of low–energy-density prey and experienced the highest rates of population decline |
format |
Article in Journal/Newspaper |
author |
Winship, Arliss J. Trites, Andrew W. |
author_facet |
Winship, Arliss J. Trites, Andrew W. |
author_sort |
Winship, Arliss J. |
title |
Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? |
title_short |
Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? |
title_full |
Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? |
title_fullStr |
Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? |
title_full_unstemmed |
Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? |
title_sort |
prey consumption of steller sea lions (eumetopias jubatus) off alaska: how much prey do they require? |
publishDate |
2003 |
url |
http://aquaticcommons.org/15112/ http://fishbull.noaa.gov/1011/12winshi.pdf http://aquaticcommons.org/15112/1/12winshi.pdf |
long_lat |
ENVELOPE(151.789,151.789,60.835,60.835) |
geographic |
Atka Gulf of Alaska |
geographic_facet |
Atka Gulf of Alaska |
genre |
Alaska Aleutian Islands |
genre_facet |
Alaska Aleutian Islands |
op_relation |
http://aquaticcommons.org/15112/1/12winshi.pdf Winship, Arliss J. and Trites, Andrew W. (2003) Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? Fishery Bulletin, 101(1), pp. 147-167. |
_version_ |
1766241327837609984 |