Bird flu kills more than 75% of southern elephant seal pups on remote Australian islands

Bird flu has killed more than 75 percent of southern elephant seal pups on two remote islands belonging to Australia, according to new research published in the journal BioRxiv. Scientists estimate that 13,359 pups died from a group of 17,364 on Heard Island since last August. The mortality rate may be an underestimate because pups were still dying when the final surveys took place.

Research findings Drone surveys and ground visits conducted last October and this January collected samples from nine species across the islands. Six species tested positive for the H5N1 strain, including southern elephant seals, king and gentoo penguins, Antarctic fur seals, and South Georgia diving petrels.

In one area, 97 percent of baby seals died. Data also showed several hundred adult king penguins died, a figure above normal levels but still a low proportion of the overall population. No unusual deaths were recorded among albatrosses or two endemic species, the Heard Island shad and the black-faced sheathbill.

Spread and monitoring Researchers believe the virus reached the islands last August through migrating birds from the French-owned Crozet Islands, roughly 1,800 kilometers away. The findings mark the first detection of H5N1 in an Australian external territory.

"These observations of H5 bird flu at Heard Island and McDonald Island are the first detection in an Australian external territory and show the continued eastward movement of the virus around the sub-Antarctic," lead author wildlife biologist Dr Julie McInnes said.

Environment Minister Murray Watt described the seal deaths as "sobering" and said Australia must plan for the possibility that the strain reaches the mainland. The Australian Antarctic Program, a partnership between government and research institutions, will continue monitoring for signs of the virus in its territories.