A common dolphin found dead near Goolwa on South Australia’s Fleurieu Peninsula has tested positive for H5N1 bird flu, making it the second native mammal species in Australia known to have contracted the virus. State tests confirmed the infection, with samples sent to the Australian Centre for Disease Preparedness for further analysis.
Dolphin detection follows seal and fox cases
The dolphin’s death follows two earlier detections of H5N1 in long-nosed fur seals in South Australia at Beachport and the Pages Islands, as well as a case in a red fox near Port Adelaide. The federal government’s risk assessment had rated common dolphins at high risk from bird flu, indicating they could face severe population declines where the virus takes hold.
“While the detection in the common dolphin is a new development in Australia, there is evidence of dolphins and porpoises catching H5 bird flu overseas,” a spokesperson for South Australia’s Department of Primary Industries and Regions said. “Dolphins would not commonly eat birds but it is not unusual for them to sometimes interact.”
Researchers withdrawn from Macquarie Island
On Friday, the federal government announced it would withdraw 24 expeditioners based at the research station on Macquarie Island, located in the Southern Ocean about 1,500km south-east of Tasmania. While bird flu had not yet been detected on the island, it is home to large elephant seal populations close to station buildings. Expert assessments predicted “a high likelihood of a significant mortality event during the upcoming breeding season.”
“While the risk to humans remains low, a significant mortality event during the upcoming seal breeding season could expose expeditioners to prolonged psychological stress and other workplace impacts,” the department said.
Psychosocial risk and operational decision
Department deputy secretary Sean Sullivan explained the reasoning behind the unusual measure. “This is an unusual measure, but is the most appropriate course of action, based on our assessments of risk, and operational realities,” Sullivan said. “Our first priority is the health and safety of our expeditioners. While the risk to humans of H5 bird flu is considered low, we can’t ignore the psychosocial risks of living near potentially large numbers of affected animals.”
Sullivan noted that researchers live and work in one of the world’s most remote and challenging environments. “We’ve seen what this disease can do, based on our experience at Heard Island and McDonald Islands,” he said. Drone surveys detected more than 13,000 dead southern elephant seal pups on Australia’s Heard Island in 2025 and 2026.
Macquarie Island’s unique risk profile
Sullivan said the decision was made to minimise risks to researchers and “across the whole Antarctic program” in advance of any mass mortality event. He highlighted Macquarie Island’s uniqueness: thousands of elephant seal pups are born close to the station every spring. “No other Australian Antarctic station is in this position, and there are no elephant seal colonies on mainland Australia,” he said.
The government is exploring options for monitoring the situation on Macquarie Island, with a view to “returning expeditioners to the station in coming seasons.”
Testing improvements and vaccination plans
South Australia’s government announced on Friday it would move to confirming H5 bird flu cases in the state through local laboratories. Until now, state-based test results required verification by the CSIRO’s Australian Centre for Disease Preparedness in Geelong. The state government said improvements to its testing processes meant confirmation of H5N1 cases could now be done locally.
Meanwhile, the New South Wales government announced plans to vaccinate wild populations of little penguins at Manly and Barunguba Montague Island. The government also said “trial cohorts” of some captive bird populations, including little penguins, Carnaby’s black cockatoos and red-tailed black cockatoos, had received their first vaccinations at Taronga Zoo this week.
