Behavioral and life history responses of an endangered sea lion (Otariidae) following a severe marine heatwave
Year: 2026
Type: article
Abstract: Introduction: The northeast Pacific marine heatwave (PMH) of 2014–2016 had strong impacts on many species across a vast region. Impacts on upper trophic species, such as reduced survival and reproduction, were a clear consequence of reduced food availability. Materials and methods: We conducted a long-term individual-based study of behavior and vital rates in endangered Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska. Vital rates were estimated using robust design multi-state mark–recapture statistical methods. Results: After parturition, the duration of maternal attendance declined significantly during 2015–2018 and again in 2021 compared to earlier years of this study. Prior to the PMH, adult female survival rates for sea lions were approximately 93%, irrespective of parturition status. Beginning in 2016, and the years following the PMH, survival dropped to 77% for females giving birth and 85% for females that were barren, demonstrating an important cost of reproduction in terms of future survival. Females born in 2016 delayed their age at first reproduction by 1 year compared to females born in earlier years, while adult female reproductive rates declined from >70% prior to 2016, to around 60% during the years 2016–2018, as a greater proportion of mature females skipped a year of giving birth. Following the PMH years, there was also an increased lactation interval as a greater proportion of juveniles suckled beyond one year of age. Extended lactation buffered against a reduction in juvenile survival, but had a negative impact on adult female survival. Conclusions: Changes in animal behavior and vital rates can be expected during periods of reduced resource availability, but adult survival should be favored over juvenile survival and reproduction in slow-living K-selected species such as the Steller sea lion. We found that adult females will bear a cost of reproduction in terms of future survival and reproductive potential during these periods. Furthermore, a preference to nurse offspring for additional years represented a type of selfless behavior that also reduced maternal survival probabilities and may ultimately compromise population stability.
Source: Academia Biology
Institutions: Alaska SeaLife Center, Kenai Fjords National Park
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life below water
Open Access status: diamond
OpenAlex ID: W7162067792