Adult Steller sea lion mortality on rookeries in the Russian Far East, 2002–2010

Altukhov, Alexey; Permyakov, Peter A.; Andrews, Russel D.; Burkanov, Vladimir N.; Calkins, Donald G.; Трухин, А. М.; Gelatt, Tom

doi:10.1134/s106307401206003x

Cited by 6 publications

(6 citation statements)

References 8 publications

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“…In the current study, conspecific trauma was a direct cause of 27 deaths, and a contributing (indirect) cause in six. In contrast to the above studies, none of the affected animals in our study were adult males, which may reflect the more ritualised inter-male territorial behaviour of NZSLs in comparison to the aggressive interactions seen in other otariids ( Altukhov et al., 2012 , Marlow, 1975 ). Lesions in NZSLs were consistent with crushing (e.g.…”

Section: Discussioncontrasting

confidence: 99%

“…Similarly, Baker and McCann (1989) found that infected wounds were the main COD in 102 adult male Antarctic fur seals ( Arctocephalus gazella ) at South Georgia Island. Altukhov et al. (2012) , observed Steller sea lion ( Eumetopias jubatus ) colonies over three years, and attributed almost all observed adult deaths directly to traumatic interactions with mature males, including both mating injuries and fight wounds.…”

Section: Discussionmentioning

confidence: 99%

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Causes of adult mortality in two populations of New Zealand sea lions (Phocarctos hookeri)

Lenting

Gartrell

Kokosinska

et al. 2019

Veterinary and Animal Science

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Causes of adult mortality in two populations of New Zealand sea lions (Phocarctos hookeri)

Lenting

Gartrell

Kokosinska

et al. 2019

Veterinary and Animal Science

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“…Sex differences in survival are usually attributed to male-male competition, higher nutritional requirements linked to larger body size and to mating strategies [ 34 , 35 ]. Survival may be affected in several ways: direct injures caused by male-male aggression [ 36 ] and the cumulative effect of physical deterioration related to fasting, vigilance and breeding, reducing survival ability in late fall. According to our estimates, male survivorship by age 17 is virtually zero, suggesting that most males attempt to hold territories until the end of their lives.…”

Section: Discussionmentioning

confidence: 99%

“…Lower adult survival may suggest that these sea lions experience predation, disease or food limitation during the winter time, as there is no evidence of nutritional stress during summer [ 13 , 59 ]. We have not observed any overt sign of unusual disease mortality [ 36 ], and predation seems an unlikely explanation given that killer whales have never been observed to prey upon Steller sea lions during summer on Medny Island, despite frequent observations of predation upon juvenile male northern fur seals there. The fur seals dramatically out-number Steller sea lions on Medny Island, even in winter when most fur seals have migrated south [ 11 , 60 ].…”

Section: Discussionmentioning

confidence: 99%

Age Specific Survival Rates of Steller Sea Lions at Rookeries with Divergent Population Trends in the Russian Far East

Altukhov

Andrews

Calkins³

et al. 2015

PLoS ONE

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After a dramatic population decline, Steller sea lions have begun to recover throughout most of their range. However, Steller sea lions in the Western Aleutians and Commander Islands are continuing to decline. Comparing survival rates between regions with different population trends may provide insights into the factors driving the dynamics, but published data on vital rates have been extremely scarce, especially in regions where the populations are still declining. Fortunately, an unprecedented dataset of marked Steller sea lions at rookeries in the Russian Far East is available, allowing us to determine age and sex specific survival in sea lions up to 22 years old. We focused on survival rates in three areas in the Russian range with differing population trends: the Commander Islands (Medny Island rookery), Eastern Kamchatka (Kozlov Cape rookery) and the Kuril Islands (four rookeries). Survival rates differed between these three regions, though not necessarily as predicted by population trends. Pup survival was higher where the populations were declining (Medny Island) or not recovering (Kozlov Cape) than in all Kuril Island rookeries. The lowest adult (> 3 years old) female survival was found on Medny Island and this may be responsible for the continued population decline there. However, the highest adult survival was found at Kozlov Cape, not in the Kuril Islands where the population is increasing, so we suggest that differences in birth rates might be an important driver of these divergent population trends. High pup survival on the Commander Islands and Kamchatka Coast may be a consequence of less frequent (e.g. biennial) reproduction there, which may permit females that skip birth years to invest more in their offspring, leading to higher pup survival, but this hypothesis awaits measurement of birth rates in these areas.

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“…Therefore, negative covariation of survival and breeding success may be observed as earlier or greater breeding success associated with earlier onset or faster rate of senescence [ 15 ]. Although rarely observed, some adult males are killed in territorial conflicts [ 38 ]. Survival of non-territorial males that attempt to gain territories may also be compromised by aggressive interactions.…”

Section: Introductionmentioning

confidence: 99%

Survival of adult Steller sea lions in Alaska: senescence, annual variation and covariation with male reproductive success

Hastings¹,

Jemison²,

Pendleton³

2018

R. Soc. open sci.

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Population dynamics of long-lived vertebrates depend critically on adult survival, yet factors affecting survival and covariation between survival and other vital rates in adults remain poorly examined for many taxonomic groups of long-lived mammals (e.g. actuarial senescence has been examined for only 9 of 34 extant pinniped species using longitudinal data). We used mark–recapture models and data from 2795 Steller sea lion (Eumetopias jubatus) pups individually marked at four of five rookeries in southeastern Alaska (SEAK) and resighted for 21 years to examine senescence, annual variability and covariation among life-history traits in this long-lived, sexually dimorphic pinniped. Sexes differed in age of onset (approx. 16–17 and approx. 8–9 years for females and males, respectively), but not rate (−0.047 and −0.046/year of age for females and males) of senescence. Survival of adult males from northern SEAK had greatest annual variability (approx. ±0.30 among years), whereas survival of adult females ranged approximately ±0.10 annually. Positive covariation between male survival and reproductive success was observed. Survival of territorial males was 0.20 higher than that of non-territorial males, resulting in the majority of males alive at oldest ages being territorial.

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Adult Steller sea lion mortality on rookeries in the Russian Far East, 2002–2010

Cited by 6 publications

References 8 publications

Causes of adult mortality in two populations of New Zealand sea lions (Phocarctos hookeri)

Causes of adult mortality in two populations of New Zealand sea lions (Phocarctos hookeri)

Age Specific Survival Rates of Steller Sea Lions at Rookeries with Divergent Population Trends in the Russian Far East

Survival of adult Steller sea lions in Alaska: senescence, annual variation and covariation with male reproductive success

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