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🇦🇺 Australia /Environment & Climate

Fears for sea lions as suspected bird flu spreads to breeding ground

From ABC Australia · () English

Summarized and contextualized by DistantNews.

At a glance

News Named sources Ongoing story
  • Endangered Australian sea lions are at risk from bird flu, with mass bird deaths reported at key breeding sites.
  • While the disease hasn't been detected in sea lions yet, H5 bird flu has affected marine mammals in South America and Antarctica.
  • Increased pup deaths in the 2025 breeding season, possibly due to algal blooms and lack of food, add to existing concerns for the species' survival.

Concerns are mounting for the endangered Australian sea lion as suspected bird flu outbreaks lead to mass deaths among seabirds at critical breeding grounds. Although the disease has not yet been detected in Australian sea lions, the H5 strain of bird flu has previously jumped species, impacting pinnipeds, including seals and sea lions, in South America and Antarctica.

It was really saddening

— Rachael GrayDescribing the impact of bird flu on marine mammals in the sub-Antarctic region.

Associate Professor Rachael Gray, a veterinarian at the University of Sydney and an expert on the Australian sea lion, described the situation in the sub-Antarctic region as "really saddening" and potentially "catastrophic." She noted not only immediate mortalities but also reduced breeding numbers in subsequent years, a "sobering and very upsetting" observation.

It just really made you think, 'Wow, this has hit here, it's going to be really catastrophic'

— Rachael GrayExpressing concern about the potential impact of bird flu on the Australian sea lion population.

The Australian sea lion population, estimated at fewer than 10,000, is primarily located in South Australia (85%) and Western Australia (15%). One of its largest breeding colonies is on the remote Pages Islands. Two of the three recent mass bird deaths reported by the South Australian government, involving about 1,000 birds mostly greater crested terns, occurred at The Pages. Authorities are awaiting test results to confirm if the birds had H5N1.

Not only were there mortalities at the time, but we're now seeing papers coming out talking about reduced numbers coming back to breed in subsequent years, so it really was very sobering and very upsetting to see

— Rachael GrayDetailing the long-term effects of the bird flu outbreak observed in the sub-Antarctic.

These developments are particularly worrying as the Australian sea lion population was already facing challenges. The 2025 breeding season saw an alarming increase in pup deaths, with over 34% mortality recorded at The Pages, compared to the usual 5%. While algal blooms and subsequent lack of food were cited as likely causes, compounding these threats with a potential bird flu outbreak raises significant fears for the species' future. Efforts are underway, including a $1.4 million government program for worming pups and providing shelters, to bolster the sea lions' resilience.

It's very concerning when it's at Australian sea lion colonies

— Dr GrayReacting to the detection of potential bird flu at sea lion breeding sites.
DistantNews Editorial

Originally published by ABC Australia. Summarized and contextualized by our editorial team with added local perspective. Read our editorial standards.

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