Four sea lions, including a pup, have tested positive for bird flu at a major breeding ground for the endangered species in South Australia, raising fears of a wider outbreak.
The infected animals were among 14 sea lions found dead on North Page, South Page and nearby Liguanea Island. All four positive cases were recorded on the Pages islands, which are among South Australia’s most significant sea lion breeding sites.
The deaths were identified through aerial surveillance, with 12 carcasses found on the Pages islands and two on Liguanea Island. Ten were tested, while the remaining four were too badly decomposed for samples to be taken.
The islands have also recently been the site of a mass mortality event involving crested terns, with about 900 birds found dead.
South Australian Environment Minister Emily Bourke said the discovery was significant, although similar cases had been recorded previously.
“This isn’t new in the sense of a new species or a new event, but it is an event of significance to be highlighting today,” she told reporters.
The detections bring the number of confirmed bird flu cases in sea lions to five, after an earlier case was identified on Kangaroo Island on September 13.
Conservationists have warned that H5N1 bird flu could severely affect Australian sea lions, which are classified as endangered in Australia and internationally. The species was reclassified from vulnerable to endangered in 2021 after its local population fell by a reported 60 per cent over four decades.
Jack Gough, chief executive of the Invasive Species Council, said the deaths could signal a much larger threat.
“Multiple deaths in a single location could indicate that devastation is just around the corner,” he said. “This is just one population in one location, but the threat we are facing is continental in scale.”
Plans for an experimental sea lion vaccine
Ms Bourke said the South Australian Government was working with the federal government to secure Australian approval for an experimental vaccine for mammals.
A separate vaccination programme for birds has begun at Cleland Wildlife Park, south-east of Adelaide city centre, where more than 150 birds have been vaccinated.
“A lot has been achieved in two months,” Ms Bourke said, adding that preparedness and resilience programmes were also part of the wider response.
There have been 583 confirmed bird flu events across Australia since the disease was first detected in June, including 303 in South Australia. Under national protocols, H5 bird flu detections are recorded as events rather than individual animal cases.
