Abstract
The only large mainland colony of southern elephant seals ( Mirounga leonina ) is on Península Valdés, at 42°S, in Argentine Patagonia. Censuses of pups have been carried out regularly there since 1970, and the population grew five‐fold by 2010. Here we use Bayesian modeling tools to make rigorous estimates of the rate of population growth, r , and to estimate survival and recruitment parameters that could account for the growth, incorporating observation error across different census methods. In the 1970s, r = 8%/yr, but has slowed to