Southern Ocean sentinels: demographic insights into the declining population of Southern elephant seals at Macquarie Island

A long-term decline in the Southern elephant seal population at Macquarie Island, unique among stable or growing populations globally, is driven by extreme reproductive costs that significantly reduce survival rates for both first-time and experienced breeders. This study, using an 18-year capture-recapture dataset of over 6,000 individually marked females, revealed that environmental conditions during the post-moult foraging trip—critical to pregnancy initiation—play a pivotal role in whether seals skip reproduction. Incorporating this finding into matrix population models confirmed and re-evaluated the population's decline, offering potential clues to its causes. The research highlights how evolutionary and ecological processes shape life histories in long-lived species, contributing to broader understanding of predator dynamics in the Southern Ocean.

Desprez, M. (2020). Southern Ocean sentinels: demographic insights into the declining population of Southern elephant seals at Macquarie Island [Macquarie University]. https://doi.org/10.25949/19428572