TY - JOUR
T1 - Survival rates of the California sea lion, Zalophus californianus, in Mexico
AU - Hernández-Camacho, Claudia J.
AU - Aurioles-Gamboa, David
AU - Laake, Jeffrey
AU - Gerber, Leah R.
PY - 2008/8
Y1 - 2008/8
N2 - 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.
AB - 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.
KW - Demography
KW - Mark-recapture
KW - Survival probabilities
UR - http://www.scopus.com/inward/record.url?scp=44949091778&partnerID=8YFLogxK
U2 - 10.1644/07-MAMM-A-404.1
DO - 10.1644/07-MAMM-A-404.1
M3 - Artículo
SN - 0022-2372
VL - 89
SP - 1059
EP - 1066
JO - Journal of Mammalogy
JF - Journal of Mammalogy
IS - 4
ER -