Insights into fin whale movements and foraging behaviour around Elephant Island, Antarctica

Abstract

Following near‐extinction from 20th‐Century industrial whaling, fin whales are now reappearing in growing numbers in Antarctic waters. Shipboard and aerial surveys have documented their return to ancestral feeding grounds along the Western Antarctic Peninsula. Using behavioural analyses based on satellite telemetry data, this study aims to complement existing knowledge on the ecology of fin whales, with insights into movement patterns and behaviour at feeding grounds that support some of the largest aggregations of baleen whales ever observed. In the austral autumn (March and April) of 2021 and 2023, four and nine fin whales, respectively, were equipped with satellite transmitters at their foraging grounds off Elephant Island. Their movements were tracked for durations ranging from 4 to 39 days (SD = 9 days). Behavioural analyses employing a two‐state Hidden‐Markov model (HMM) were conducted to assess the whales’ activity states. The HMM revealed that fin whales dedicated almost 80% of their time to area‐restricted search, a behaviour commonly associated with foraging. Most individuals (n = 8) exhibited a notable site fidelity to the waters off the Northern coast of Elephant Island. Three whales moved away from the tagging location in different directions: south‐west into the Bransfield Strait, east towards the South Orkneys, and south towards the Weddell Sea, where they again engaged in area‐restricted search. The concentration of foraging behaviour around Elephant Island, the South Orkneys and the Northern region of the Weddell Sea highlights known and potentially novel core feeding grounds within the Western Antarctic Peninsula and Islands IMMA (Important Marine Mammal Area). The identification of these foraging areas within an IMMA strengthens the urgent need for special protection to ensure the continued recovery of this species and preserve core feeding habitats.