scholarly journals Physiological predictors of long-term survival in juvenile Steller sea lions (Eumetopias jubatus)

2015 ◽  
Vol 3 (1) ◽  
pp. cov043 ◽  
Author(s):  
C. Shuert ◽  
J. Mellish ◽  
M. Horning
Keyword(s):  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Term Survival ◽  
Long Term Survival ◽  
Sea Lions

scholarly journals The Effect of Novel Research Activities on Long-term Survival of Temporarily Captive Steller Sea Lions (Eumetopias jubatus)

PLoS ONE ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. e0141948 ◽  
Author(s):  
Courtney Shuert ◽  
Markus Horning ◽  
Jo-Ann Mellish
Keyword(s):  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Term Survival ◽  
Long Term Survival ◽  
Sea Lions ◽  
Research Activities

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.

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.

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.

Long-term survival and reproductive success of New Zealand sea lions (Phocarctos hookeri) treated with ivermectin as pups

2015 ◽  
Vol 42 (8) ◽  
pp. 660 ◽  
Author(s):  
S. A. Michael ◽  
B. L. Chilvers ◽  
W. D. Roe ◽  
B. D. Gartrell
Keyword(s):  
New Zealand ◽  
Management Tool ◽  
Juvenile Survival ◽  
Sea Lion ◽  
Term Survival ◽  
Long Term Survival ◽  
Growth And Survival ◽  
Sea Lions ◽  
Phocarctos Hookeri

Context Hookworms (Uncinaria spp.) are a common parasite of neonatal fur seals and sea lions around the world and may contribute to decreased pup growth and survival. Removal of these parasitic burdens by administration of the anthelmintic ivermectin has been trialled in New Zealand (NZ) sea lion (Phocarctos hookeri) pups at Sandy Bay, Enderby Island, with initial benefits in growth and survival reported. Long-term effects, however, are not known. Aims To determine the impact of ivermectin treatment administered in the first month of life, on long-term survival and fecundity in a sample of NZ sea lion pups. Methods For a sample of treated and control pups born between 2002 and 2004, resighting data to 2012 was assessed with the Cox proportional hazards analysis to evaluate survival to maturity and fecundity. Key results Sample size was a limiting factor as juvenile survival was very low, but a trend of improved survival was observed in the ivermectin-treated group. Year of birth was significant due to the effects of a bacterial epizootic in the first year of the trial. Reproductive rate was not significantly different between groups. Conclusions The effect of disease and parasitism on the survival of NZ sea lions is apparent, contributing to early pup mortality, with potentially wider-ranging implications for juvenile survival and beyond. Implications Further research is warranted to investigate anthelmintic treatment of NZ sea lion pups as a safe and effective management tool to improve survival and recruitment in declining populations.

scholarly journals Steller Sea Lion (Eumetopias jubatus) Response to Non-lethal Hazing at Bonneville Dam

2021 ◽  
Vol 2 ◽  
Author(s):  
Kyle S. Tidwell ◽  
Brett A. Carrothers ◽  
Daniel T. Blumstein ◽  
Zachary A. Schakner
Keyword(s):  
Chinook Salmon ◽  
Steller Sea Lion ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lion ◽  
Sea Lions ◽  
Physical Stimuli ◽  
Multiple Species ◽  
Fisheries Interactions

Protected Steller sea lions (Eumetopias jubatus) aggregate at Bonneville Dam on the Columbia River and prey upon multiple species of endangered salmon ascending the river. Hazing is a non-lethal activity designed to repel sea lions that includes aversive auditory and physical stimuli to deter animals from an area and has been employed with sea lion—fisheries interactions for more than 40 years but sea lion responses to hazing through time is not well-documented. We observed the behavior of Steller sea lions in periods with and without hazing during two spring Chinook salmon passage seasons to evaluate: (1) what effect hazing had on the number of animals present and their foraging behavior, and (2) whether they habituated to hazing. We found that hazing temporarily reduced the number of Steller sea lions, but only when actively hazed. During hazing, Steller sea lions were more likely to move away from hazers on the dam, decreased their foraging, and increased their time investigating the environment. However, these effects were temporary; their behavior returned to initial observation levels once hazing ceased. Furthermore, their responsiveness to hazing declined throughout the season, indicating habituation and raising concern for the application and long-term efficacy of hazing in managing predation on endangered salmon.

scholarly journals Maternal and offspring effects on the timing of parturition in western Steller sea lions (Eumetopias jubatus)

2018 ◽  
Vol 96 (4) ◽  
pp. 333-339 ◽  
Author(s):  
John M. Maniscalco ◽  
Pamela Parker
Keyword(s):  
Random Effect ◽  
Theoretic Approach ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Information Theoretic ◽  
Sea Lions ◽  
Limited Support ◽  
Long Term Trends ◽  
Information Theoretic Approach

Identifying factors that affect the timing of parturition among annual breeders is important to aid our understanding of how variations may adversely affect population trends over both short and long temporal scales. We investigated the effect of several parameters on the timing of parturition among individual Steller sea lions (Eumetopias jubatus (Schreber, 1776)) over 6 years between 2005 and 2016 using an information–theoretic approach. In addition to the random effect of year, birth and care of a pup in the previous year had the largest effect on parturition, causing a 2.4 day delay. Maternal age was negatively correlated with timing of parturition and male pups were born nearly a day earlier than female pups, on average. There was limited support for effects of sex and mass, with heavier pups born marginally earlier than lighter ones. This study illustrates some of the complexity of variables that can influence the timing of birth in this species and which should be considered in models that attempt to identify long-term trends in changing marine ecosystems.

Human thymic epithelial cells maintain long-term survival of clonogenic myeloid and erythroid progenitor cells in vitro

2000 ◽  
Vol 111 (1) ◽  
pp. 363-370 ◽  
Author(s):  
Katsuto Takenaka ◽  
Mine Harada ◽  
Tomoaki Fujisaki ◽  
Koji Nagafuji ◽  
Shinichi Mizuno ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Progenitor Cells ◽  
Thymic Epithelial Cells ◽  
Erythroid Progenitor ◽  
Term Survival ◽  
Long Term Survival ◽  
Erythroid Progenitor Cells

Clinical outcome and long-term survival following radical esophagectomy in the elderly

2001 ◽  
Vol 120 (5) ◽  
pp. A747-A748
Author(s):  
S DRESNER ◽  
A IMMMANUEL ◽  
P LAMB ◽  
S GRIFFIN
Keyword(s):  
Clinical Outcome ◽  
The Elderly ◽  
Radical Esophagectomy ◽  
Term Survival ◽  
Long Term Survival

201: Determinants of Mortality in Men with Prostate Cancer: How Important are Cancer Parameters on Long Term Survival?

2006 ◽  
Vol 175 (4S) ◽  
pp. 65-65
Author(s):  
Ashutosh K. Tewari ◽  
George Divine ◽  
Mani Menon
Keyword(s):  
Prostate Cancer ◽  
Term Survival ◽  
Long Term Survival
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