Recent population change of the southern elephant seal at Îles Crozet and Îles Kerguelen: the end of the decrease?

Abstract

The elephant seal populations breeding on the Îles Crozet and Kerguelen were regularly surveyed over the last three decades. At Îles Kerguelen the number of breeding females decreased at an annual rate of 3.6% between 1970 and 1987, then increased at an annual rate of 1.1% to 1997. At Îles Crozet, the population was reported to decrease at a rate of 5.35% between 1970 and 1990 but no change in numbers was found between 1990 and 1997. These results indicate that the rapid decline observed both at Îles Crozet and Îles Kerguelen has ended, and these populations are now either stable or slightly increasing. We suggest that broad scale change in environmental factors affecting the food availability for elephant seals may be responsible for the change in numbers of these marine predators. The higher rate of decrease, the longer period of decline, and the absence of any significant change between 1990 and 1997 observed on the Îles Crozet may be explained by additional factors such as killer whale predation.