DEMOGRAPHY AND POPULATION-DYNAMICS OF SOUTH-AMERICAN FUR SEALS

The demography and population dynamics of South American fur seals, Ar ctocephalus australis, at Isla de Lobos, Uruguay, were examined. Age-s pecific rates of survival of females were estimated during four harves t periods (1987, 1988, 1990, and 1991). The estimated continuous and f inite rate of population growth (r = 0.021 and lambda = 1.021, respect ively), obtained from an estimation of abundance of pups was about equ al to the value obtained from a matrix model (lambda = 1.014). South A merican fur seals at Isla de Lobos had the highest rates of survival o f adults between 1.5 and 2.5 years. Senescence in the age-specific rat es of reproduction was determined. The high rates of survival of young females may be the most important life-history parameter in determini ng the rates of population growth, Fur seals, as other large mammals, appear to have life histories characterized by high rates of survival of adults and low effects of reproduction on growth rates of populatio ns.