Estimation of juvenile survival, adult survival, and age-specific pupping probabilities for the female grey seal (Halichoerus gryprus) on Sable Island from capture-recapture data

We use a longitudinal capture-recapture study from resightings of grey seal s (Halichoerus gryprus) branded as young on Sable Island to estimate (i) th e juvenile survival rate from the time of branding to age 4, (ii) the yearl y adult survival rate from age 4 to age 9, and (iii) the age-specific puppi ng probabilities, i.e., the probability that a seal will first give birth a t each age. The estimated juvenile survival rate from branding (just after weaning) to age 4 ranged from 70 to 80%; however, the lower values are know n to be biased low because the study was terminated early. The estimated ye arly adult survival rates for ages 4-9 ranged from 0.88 to 0.92.year(-1). T he estimated probabilities of first giving birth to a young seal (pupping) at ages 4-9 are 0.28, 0.41, 0.18, 0.06, 0.05, and 0.02, respectively, and t he estimated average age of first pupping is 5.2 years.