Studies on the southern elephant seal, Mirounga leonina (L.). V. Population dynamics and utilization

Abstract

The breeding population of Mirounga leonina (L.) at Macquarie Island is stable at about 36,000 cows and 3500–4000 bulls, with an annual maximum of the order of 110,000. Survival of branded weaned pups to the fourth year of life is over 40% in both sexes: 20% of females survive to the eighth year of life, but few may live more than 12 years: 16% of males survive to the eighth year of life, but the small number of breeding males may contain individuals 20 years old. Important factors limiting the world population are the number of possible breeding places in the zone of maximum food supply near the Antarctic Convergence, and the amount of food immediately around them. The logistic and biological merits of harvesting large bulls and fat weaned pups are compared: the latter merits experimental investigation, which should always precede commercial operations.