Pup growth and maternal attendance patterns in Subantarctic fur seals

Abstract

Samples of pups from the expanding populations of Subantarctic fur seals  (Arctocephalus tropicalis) at Marion and Gough islands were weighed at specific ages between birth and weaning in the period 1993-2000. Growth was estimated and compared between years, sexes, sites of different density, and populations. Pups of comparable age were consistently heavier at Marion Island than at Gough Island, probably reflecting relative prey resource abundance. No changes in pup growth rates were apparent over the study period, nor was there any evidence that growth was affected by ENSO events. Measures of pup growth at Marion Island were complemented by measures of maternal attendance behaviour during three summer and winter  seasons. More years of data are required to determine patterns between attendance, growth, resource conditions and population abundance trends.

Key words: Subantarctic fur seal, Marion Island, Gough Island, pup growth, maternal attendance behaviour.