scholarly journals Winter movements and long-term dispersal of Steller sea lions in the Glacier Bay region of Southeast Alaska

2018 ◽  
Vol 37 ◽  
pp. 11-24 ◽  
Author(s):  
M Rehberg ◽  
L Jemison ◽  
JN Womble ◽  
G O’Corry-Crowe
Keyword(s):  
Steller Sea Lions ◽  
Southeast Alaska ◽  
Glacier Bay ◽  
Sea Lions

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.

AGE-STRUCTURED MODELING REVEALS LONG-TERM DECLINES IN THE NATALITY OF WESTERN STELLER SEA LIONS

2007 ◽  
Vol 17 (8) ◽  
pp. 2214-2232 ◽  
Author(s):  
E. E. Holmes ◽  
L. W. Fritz ◽  
A. E. York ◽  
K. Sweeney
Keyword(s):  
Steller Sea Lions ◽  
Structured Modeling ◽  
Sea Lions ◽  
Age Structured

scholarly journals Demographic consequences and characteristics of recent population mixing and colonization in Steller sea lions, Eumetopias jubatus

2019 ◽  
Vol 101 (1) ◽  
pp. 107-120
Author(s):  
Kelly K Hastings ◽  
Michael J Rehberg ◽  
Gregory M O’corry-Crowe ◽  
Grey W Pendleton ◽  
Lauri A Jemison ◽  
...  
Keyword(s):  
Genetic Material ◽  
Genetic Lineage ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Southeast Alaska ◽  
Population Mixing ◽  
Western Population ◽  
Sea Lions ◽  
Asymmetric Dispersal ◽  
Fitness Benefits

Abstract Steller sea lions (Eumetopias jubatus) are composed of two genetically distinct metapopulations (an increasing “eastern” and a reduced and endangered “western” population, or stock for management purposes in U.S. waters) that are only recently mixing at new rookeries in northern Southeast Alaska, east of the current stock boundary. We used mark-recapture models and 18 years of resighting data of over 3,500 individuals marked at the new rookeries and at neighboring long-established rookeries in both populations to examine morphology, survival, and movement patterns of pups born at new rookeries based on whether they had mitochondrial DNA haplotypes from the western or eastern population (mtW or mtE); examine survival effects of dispersal to the Eastern Stock region for animals born in the Western Stock region; and estimate minimum proportions of animals with western genetic material in regions within Southeast Alaska. Pups born at new rookeries with mtW had similar mass, but reduced body condition and first-year survival (approximately −10%) compared to pups with mtE. mtE pups ranged more widely than mtW pups, including more to the sheltered waters of Southeast Alaska’s Inside Passage. Fitness benefits for western-born females that dispersed to Southeast Alaska were observed as higher female survival (+0.127, +0.099, and +0.032 at ages 1, 2, and 3+) and higher survival of their female offspring to breeding age (+0.15) compared to females that remained west of the boundary. We estimated that a minimum of 38% and 13% of animals in the North Outer Coast–Glacier Bay and Lynn Canal–Frederick Sound regions in Southeast Alaska, respectively, carry genetic information unique to the western population. Despite fitness benefits to western females that dispersed east, asymmetric dispersal costs or other genetic or maternal effects may limit the growth of the western genetic lineage at the new rookeries, and these factors require further study.

Population growth and colonization of Steller sea lions in the Glacier Bay region of southeastern Alaska: 1970s-2009

2011 ◽  
Vol 27 (4) ◽  
pp. 852-880 ◽  
Author(s):  
Elizabeth A. Mathews ◽  
Jamie N. Womble ◽  
Grey W. Pendleton ◽  
Lauri A. Jemison ◽  
John M. Maniscalco ◽  
...  
Keyword(s):  
Population Growth ◽  
Steller Sea Lions ◽  
Glacier Bay ◽  
Sea Lions

Pupping-site fidelity among individual Steller sea lions (Eumetopias jubatus) at Chiswell Island, Alaska

2008 ◽  
Vol 86 (8) ◽  
pp. 826-833 ◽  
Author(s):  
P. Parker ◽  
J. T. Harvey ◽  
J. M. Maniscalco ◽  
S. Atkinson
Keyword(s):  
Site Fidelity ◽  
Surf Zone ◽  
Gulf Of Alaska ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Photo Identification ◽  
Pup Survival ◽  
Breeding Seasons

Pupping-site fidelity (defined as pupping within 5.8 m of a previous location in ≥2 years) in Steller sea lions ( Eumetopias jubatus (Schreber, 1776)) was investigated during the breeding seasons from 2001 to 2005 at Chiswell Island, a small rookery in the Gulf of Alaska. Density of females was minimal with 54–80 pups born. Photo-identification of individuals and GPS points, including elevation of the rookery, were used to determine locations of 297 births. Sixty-four percentage (35/55) of the females exhibited pupping-site fidelity, and mean frequency of site fidelity was greater for females that gave birth >3 times. Fifty percentage of the births occurred at 22% of the locations for all years, indicating that multiple births occurred at some locations throughout the breeding season. Competition or aggression among females for specific pupping locations before birth was not observed, and there was no temporal order of pupping locations used, indicating that the rookery was not overcrowded and that many suitable pupping locations existed. Multiparous females gave birth at significantly greater distances from the surf zone than primiparous females. Long-term monitoring of pupping-site fidelity in combination with other measures of maternal care will ultimately determine which factors have the greatest effect on pup survival.

Foraging behavior of adult female Steller sea lions during the breeding season in Southeast Alaska

2009 ◽  
Vol 25 (3) ◽  
pp. 588-604 ◽  
Author(s):  
M. J. Rehberg ◽  
R. D. Andrews ◽  
U. G. Swain ◽  
D. G. Calkins
Keyword(s):  
Foraging Behavior ◽  
Breeding Season ◽  
Adult Female ◽  
Steller Sea Lions ◽  
Southeast Alaska ◽  
Sea Lions

A long-term study reveals multiple reproductive behavior strategies among territorial adult male Steller sea lions (Eumetopias jubatus)

2014 ◽  
Vol 92 (5) ◽  
pp. 405-415 ◽  
Author(s):  
Pamela Parker ◽  
John M. Maniscalco
Keyword(s):  
Reproductive Success ◽  
Gulf Of Alaska ◽  
Lifetime Reproductive Success ◽  
First Year ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Term Study ◽  
Sea Lions ◽  
Long Term Study

We conducted a long-term study to assess how tenure and territorial behaviors influence reproductive success among male Steller sea lions (Eumetopias jubatus (Schreber, 1776)). Copulations by males (n = 44) that maintained territories on a rookery in the Gulf of Alaska from 2001 to 2009 were observed using a remote video system. Approximately half of postpartum females copulated with a male in a different territory from where they gave birth. Nearly two-thirds of territorial males with known tenure were unsuccessful in copulating during their first year. Number of copulations for territorial males increased from acquisition year to year 2 with no change in subsequent years. Cluster analysis of tenure and territorial tactic variables for 15 males with observed lifetime reproductive success was used to describe multiple reproductive strategies. Characteristics of the two most successful strategies were the following: (i) males typically copulated in their first year, retained the same territories for 3–5 years, and occupied centrally located coastal territories where the highest percentage of females gave birth and (ii) males did not copulate until at least their third year and occupied peripheral territories with fewer births for a longer tenure of 7–8 years. Results indicated that lifetime reproductive success was not achieved solely by time on the breeding area; rather, it was achieved from a combination of tenure and territorial tactics.

Sign in / Sign up

Export Citation Format

Share Document