scholarly journals The diet of free-ranging male Steller sea lions (Eumetopias jubatus) in the eastern Bering Sea: a retrospective analysis based on stomach contents of an endangered pinniped

2019 ◽  
Vol 97 (3) ◽  
pp. 195-202
Author(s):  
E.H. Sinclair ◽  
W.A. Walker ◽  
P.J. Gearin
Keyword(s):  
Bering Sea ◽  
Stomach Contents ◽  
Walleye Pollock ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Eastern Bering Sea ◽  
Ice Edge ◽  
Myoxocephalus Scorpius ◽  
Free Ranging

This study illuminates historical diet and foraging locations of endangered western U.S. stock Steller sea lions (Eumetopias jubatus (Schreber, 1776)). Prey were identified from stomachs of 22 males collected in the eastern Bering Sea from the ice edge in March 1985 and nearshore St. Paul Island in September–October 1985 and 1986. Percent frequency of occurrence (PFO) and percent number (PN) were highest for walleye pollock (Gadus chalcogrammus Pallas, 1814; PFO 69%, PN 15%, mean length 17 cm), Pacific herring (Clupea pallasii Valenciennes in Cuvier and Valenciennes, 1847; PFO 62%, PN 16%, mean length 26 cm), shorthorn sculpin (Myoxocephalus scorpius (Linnaeus, 1758); PFO 54%, PN 30%), and Pacific giant octopus (Enteroctopus dofleini (Wülker, 1910); PFO 39%, PN 8%, mean weight 31 kg) in spring, and northern rock sole (Lepidopsetta polyxystra Orr and Matarese, 2000; PFO 78%, PN 47%, mean length 35 cm), Pacific cod (Gadus macrocephalus Tilesius, 1810; PFO 56%, PN 12%, mean length 62 cm), walleye pollock (PFO 44%, PN 7%, mean length 49 cm), and red Irish lord (Hemilepidotus hemilepidotus (Tilesius, 1811); PFO 11%, PN 9%) in fall. Species of Cryptacanthidae, Liparidae, and Zoarcidae were highly represented and exclusive to spring collections. Predictable seasonal concentrations and movements of mature prey along frontal boundaries of the continental shelf and ice edge may be critical to male Steller sea lion fitness during the non-breeding season.

Longitudinal Health and Disease Monitoring in Juvenile Steller Sea Lions (Eumetopias jubatus) in Temporary Captivity in Alaska Compared with a Free-Ranging Cohort

2007 ◽  
Vol 33 (3) ◽  
pp. 337-348 ◽  
Author(s):  
Tracey Goldstein ◽  
Carol A. Stephens ◽  
Spencer S. Jang ◽  
Patricia A. Conrad ◽  
Cara Field ◽  
...  
Keyword(s):  
Disease Monitoring ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Health And Disease ◽  
Free Ranging

Organochlorine contaminant concentrations in multiple tissues of free-ranging Steller sea lions (Eumetopias jubatus) in Alaska

2016 ◽  
Vol 542 ◽  
pp. 441-452 ◽  
Author(s):  
Kimberlee B. Beckmen ◽  
Mandy J. Keogh ◽  
Kathleen A. Burek-Huntington ◽  
Gina M. Ylitalo ◽  
Brian S. Fadely ◽  
...  
Keyword(s):  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Organochlorine Contaminant ◽  
Free Ranging

Diet diversity of Steller sea lions (Eumetopias jubatus) and their population decline in Alaska: a potential relationship

1997 ◽  
Vol 54 (6) ◽  
pp. 1342-1348 ◽  
Author(s):  
Richard L Merrick ◽  
M Kathryn Chumbley ◽  
G Vernon Byrd
Keyword(s):  
Population Decline ◽  
Gulf Of Alaska ◽  
Walleye Pollock ◽  
Aleutian Islands ◽  
Strong Positive Correlation ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Diet Diversity ◽  
Sea Lions ◽  
Atka Mackerel

We examined the diet of Steller sea lions (Eumetopias jubatus) during June-August 1990-1993 from six areas in the Aleutian Islands and Gulf of Alaska and related these diets to sea lion population changes that occurred during the period. Seven general prey categories were identified, but either walleye pollock (Theragra chalcogramma) or Atka mackerel (Pleurogrammus monopterygius) dominated in every area. The diversity of prey consumed varied among sites. Only the eastern Aleutian Islands area had all seven categories in the diet, and there, walleye pollock and Atka mackerel each made up around 30% of the diet. The remainder was composed mostly of small schooling fish (e.g., Pacific herring (Clupea pallasi) and salmon (Oncorhynchus spp.)). The diet in the Gulf of Alaska included mostly walleye pollock whereas the central and western Aleutian diet was composed mostly of Atka mackerel. Populations in the six areas decreased up to 49% during 1990-1994. A strong positive correlation (r = 0.949, P = 0.004) was found between diet diversity and the amount of decline in an area: as diet diversity decreased, populations decreased. This suggests that sea lions need a variety of prey available, perhaps to buffer significant changes in abundance of any single prey.

Postnatal ontogeny of erythropoietin and hematology in free-ranging Steller sea lions (Eumetopias jubatus)

2005 ◽  
Vol 141 (3) ◽  
pp. 240-247 ◽  
Author(s):  
Julie P. Richmond ◽  
Jennifer M. Burns ◽  
Lorrie D. Rea ◽  
Kendall L. Mashburn
Keyword(s):  
Postnatal Ontogeny ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Free Ranging

A FIELD-BASED METHOD FOR ESTIMATING AGE IN FREE-RANGING STELLER SEA LIONS (EUMETOPIAS JUBATUS) LESS THAN TWENTY-FOUR MONTHS OF AGE

2007 ◽  
Vol 23 (2) ◽  
pp. 262-271 ◽  
Author(s):  
James C. King ◽  
Thomas S. Gelatt ◽  
Kenneth W. Pitcher ◽  
Grey W. Pendleton
Keyword(s):  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Free Ranging

Feeding Habits and Daily Ration of Walleye Pollock (Theragra chalcogramma) in the Eastern Bering Sea, with Special Reference to Cannibalism

1987 ◽  
Vol 44 (11) ◽  
pp. 1972-1984 ◽  
Author(s):  
Deborah A. Dwyer ◽  
Kevin M. Bailey ◽  
Patricia A. Livingston
Keyword(s):  
Body Weight ◽  
Bering Sea ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Walleye Pollock ◽  
Theragra Chalcogramma ◽  
Daily Ration ◽  
Eastern Bering Sea ◽  
Walleye Pollock Theragra Chalcogramma ◽  
Northwestern Region

Stomach contents of 3098 walleye pollock (Theragra chalcogramma) collected from the eastern Bering Sea during 1981–83 were examined to (1) describe the diet as influenced by area, season, and fish size, (2) estimate daily ration, and (3) examine the magnitude of cannibalism. Small pollock fed mainly on copepods and shifted to euphausiids and fish with increased size. Stomach contents (percent body weight) were highest in summer and autumn. Laboratory-derived estimates of gastric evacuation rates and age-structured estimates of abundance were used in conjunction with the field data to estimate daily ration of pollock in the eastern Bering Sea. Mean annual daily ration was calculated to be about 0.3% body weight per day. Daily ration was lowest in spring and lower in the northwestern region of the eastern Bering Sea than in the southeastern region. Cannibalism occurred in all seasons, but consumption was highest on age 0 pollock in the southeastern area during autumn. It is estimated that about 400 billion age 0 pollock were consumed annually by larger pollock in the eastern Bering Sea.

Diet composition of Steller sea lions (Eumetopias jubatus) in Frederick Sound, southeast Alaska: a comparison of quantification methods using scats to describe temporal and spatial variabilities

2015 ◽  
Vol 93 (5) ◽  
pp. 361-376 ◽  
Author(s):  
D.J. Tollit ◽  
M.A. Wong ◽  
A.W. Trites
Keyword(s):  
Pacific Salmon ◽  
Biomass Energy ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Southeast Alaska ◽  
Merluccius Productus ◽  
Sea Lions ◽  
Sampling Protocols ◽  
Dietary Indices

We compared eight dietary indices used to describe the diet of Steller sea lions (Eumetopias jubatus (Schreber, 1776)) from 2001 to 2004 in Frederick Sound, southeast Alaska. Remains (n = 9666 items) from 59+ species categories were identified from 1684 fecal samples (scats) from 14 collection periods. The most frequently occurring prey were walleye pollock (Theragra chalcogramma (Pallas, 1814) = Gadus chalcogrammus Pallas, 1814; 95%), Pacific herring (Clupea pallasii Valenciennes in Cuvier and Valenciennes, 1847; 30%), Pacific hake (Merluccius productus (Ayres, 1855); 29%), and arrowtooth flounder (Atheresthes stomias (Jordan and Gilbert, 1880) = Reinhardtius stomias (Jordan and Gilbert, 1880); 21%). These species, along with Pacific salmon (genus Oncorhynchus Suckley, 1861) and skate (genus Raja L., 1758), accounted for 80%–90% of the reconstructed biomass and energy contribution, with pollock contributing 37%–60%. Overall, 80% of fish were 14–42 cm long and mainly pelagic, though 40% of scats contained benthic-associated prey. Steller sea lions switched from adult pollock to strong cohorts of juvenile pollock, and took advantage of spawning concentrations of salmon in autumn and herring in late spring and summer, as well as a climate-driven increase in hake availability. Observed temporal and site differences in diet confirm the need for robust long-term scat sampling protocols. All major indices similarly tracked key temporal changes, despite differences in occurrence and biomass-energy-based diet estimates linked to prey size and energy-density effects and the application of correction factors.

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