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- Title
SURVIVAL RATES OF THE CALIFORNIA SEA LION, ZALOPHUS CALIFORNIANUS, IN MEXICO.
- Authors
Hernández-Camacho, Claudia J.; Aurioles-Gamboa, David; Laake, Jeffrey; Gerber, Leah R.
- Abstract
California sea lions (Zalophus californianus) in the Gulf of California have declined by 20% over the past 2 decades. The lack of data on life-history parameters for this species has limited the development of demographic models to assess the status of this population.We estimated age- and sex-specific annual survival probabilities for California sea lions using resighting data on 5 pup cohorts from 1981 to 2006. We modeled apparent survival and resighting probability using age-class, sex, and time as potential explanatory variables. Apparent survival rates varied for different age- and sex-classes. Only survival of pups varied by year (from 0.556 to 0.998). Survival was the same for immature males and females (0.90), but differed by sex for young (males=0.90, females=0.97) and old (males=0.75, females=0.91) adults. Resighting probabilities varied by time, age-class, and sex. Resighting probabilities were higher for females than for males, and lowest for juveniles. The survival estimates presented here provide practical insight into understanding age- and sex-specific survival rates for California sea lions.
- Subjects
CALIFORNIA; CALIFORNIA sea lion; ANIMAL populations; SEA lions; EARED seals; ZALOPHUS
- Publication
Journal of Mammalogy, 2008, Vol 89, Issue 4, p1059
- ISSN
0022-2372
- Publication type
Article