Pollution-linked fur loss drives steep decline in Australian seal pups on Deen Maar

Australian fur seals on Deen Maar Island are losing fur due to pollution, leading to a drop of more than 40 % in pup numbers over the past nine years.

Deen Maar (also known as Lady Julia Percy Island) off south-west Victoria, previously the nation’s biggest fur-seal breeding ground, now shows a sharp decline in pup counts—more than 40 % fewer since 2017 and over 65 % fewer since 2007, with roughly 700 pups counted in February. Sea-country coordinators Dave Williams and Mandy Watson attribute the extensive fur loss, identified as alopecia, to pollution that impairs the seals’ ability to stay warm and feed.

Marine researcher Rebecca McIntosh notes that such pervasive hair loss is unprecedented in Australian fur-seal colonies and may stem from heavy metals and persistent organic pollutants linked to nearby industrial sources. The weakened seals could be more vulnerable to the H5N1 bird-flu strain recently detected near Portland. Genetic analyses indicate Deen Maar’s population holds distinct diversity crucial for the species’ long-term resilience, raising concerns that its collapse would affect the entire fur-seal gene pool. Collaborative research is underway to trace pollutant origins and safeguard the broader ecosystem.