Four Sea Lions Test Positive for H5 Bird Flu at Key Breeding Ground off Kangaroo Island
SOUTH AUSTRALIA, AUSTRALIA — September 21, 2026

Four Australian sea lions, including a pup, have tested positive for H5 bird flu after being found dead on the Pages Islands, a key breeding ground between Kangaroo Island and mainland South Australia.

The discovery is raising further concerns about the impact of the virus on Australia’s endangered Australian sea lion population.

Four Sea Lions Test Positive
South Australian Environment Minister Emily Bourke said samples from 10 deceased sea lions found on the Pages Islands were available for testing.

Results showed that three adult sea lions and one pup tested positive for H5 bird flu.

The cases bring the total number of confirmed Australian sea lions with H5 bird flu in South Australia to five, following the first confirmed case at Seal Bay on Kangaroo Island last week.

The Pages Islands are an important breeding location for Australian sea lions, making the detection particularly significant for wildlife authorities.

Hundreds of Birds Also Found Dead
The sea lion detections came amid a mass mortality event involving seabirds on the same islands.

About 900 crested terns have been found dead on the Pages Islands, with authorities investigating whether H5 bird flu was responsible for the deaths.

The concentration of infected wildlife at a major breeding site has increased concerns about transmission between birds and marine mammals.

Researchers have previously warned that H5 bird flu has caused major mortality events among seals and sea lions in other parts of the world.

Concerns for an Endangered Species
Australian sea lions are considered endangered on international threatened-species lists. South Australia is home to about 85 per cent of Australia’s Australian sea lion population, which is estimated at fewer than 12,000 animals.

Authorities are closely monitoring the situation because outbreaks among marine mammals overseas have resulted in substantial deaths, particularly among young animals.

Researchers are also conducting surveillance to determine whether the virus is spreading between marine mammals or primarily reaching them through infected birds.

Authorities Continue Monitoring
South Australian authorities have restricted access to some wildlife areas as a precaution.

At Seal Bay on Kangaroo Island, visitors can still see the sea lions through guided boardwalk tours, while beach access has been temporarily paused to reduce potential risks to the colony. The government says the risk to human health from the current H5 bird flu detections remains low.

Wildlife authorities are continuing to test sick and dead animals and encourage the public not to touch them.

The latest detections add to Australia’s growing H5 bird flu outbreak and highlight concerns about its potential impact on threatened native wildlife.

Sources: ABC News Australia; South Australian Government Bird Flu Response; PIRSA.