Juvenile survival and population regulation in southern elephant seals at Marion Island

<strong><span style="font-size: xx-small; font-family: CharterBT-Bold;"><span style="font-size: xx-small; font-family: CharterBT-Bold;"><span style="font-size: xx-small; font-family: CharterBT-Bold;"><p>We examined annual juvenile survival in southern elephant seals (</p></span></span></span><em><span style="font-size: xx-small; font-family: CharterBT-BoldItalic;"><em><span style="font-size: xx-small; font-family: CharterBT-BoldItalic;">Mirounga leonina) </span></em></span></em><span style="font-size: xx-small; font-family: CharterBT-Bold;"><strong><span style="font-size: xx-small; font-family: CharterBT-Bold;">at Marion Island for the period 1994–1999 during which time the population was stable. Using mark–recapture models, we tested for age- and sex-specific differences in survival rates over </span></strong></span><strong><span style="font-size: xx-small; font-family: CharterBT-Bold;"><strong><span style="font-size: xx-small; font-family: CharterBT-Bold;">the first three years of life. We found that survival was age- but not sex-related and compared our estimates to similar estimates from a previous study on the same population while in a state of decline. This was done to determine whether changes in juvenile survival were instrumental in terminating the population decline at Marion Island. On average, the probability of <strong><span style="font-size: xx-small; font-family: CharterBT-Bold;"><strong><span style="font-size: xx-small; font-family: CharterBT-Bold;">survival was 59.5 %, 81.4 % and 78.1 % for the first, second and third year respectively. These estimates were remarkably similar to those previously calculated for the population while in a state of decline, and we dismiss juvenile survival as a major population regulating component in southern elephant seals at Marion Island.</span></strong></span></strong></span></strong></span></strong></strong>