An outbreak of avian influenza on a remote island near Antarctica has devastated native wildlife populations, killing an estimated 13,000 seal pups as well as penguins and seabirds, researchers say.
Drone surveys conducted by the Australian Antarctic Program in October and January revealed “somber” images of dead seal pups strewn across the greyish volcanic coasts of the Heard and McDonald Islands, the organization’s senior researcher Jarrod Hodgson said.
Located approximately 2,485 miles (4,000 kilometers) southwest of mainland Australia, these islands have long been isolated sanctuaries for breeding birds and marine mammals.
Mortality among southern elephant seal pups is estimated at 76% of the total population of 17,000 seal pups born on the island, the program said. In some areas, the mortality rate was concentrated at 97%.
“What we don’t know from the research so far is what effect this has had on the population of adult breeding southern elephant seals,” Hodgson said.
Data collected in January also revealed that hundreds of adult king penguins had died across Heard Island, with scientists noting that the mortality rate was above normal levels.
“These observations of H5 avian influenza on Heard Island and Macdonald Island are the first detections in Australian overseas territories and indicate that the virus continues to move eastward around the subantarctic region,” wildlife biologist Julie McInnes said.
“Our results show similar patterns on other sub-Antarctic islands, such as South Georgia, where elephant seals are hardest hit,” added McInnes, who is also the group’s lead author on the study.
As of February, mainland Australia and New Zealand had no cases of the H5N1 strain, which has spread to birds around the world and is affecting some mammals.
Analysis of genetic data suggests that H5 avian influenza was likely introduced to the islands via wildlife from France’s sub-Antarctic Crozet Islands, 1,800 kilometers away, and is likely to arrive around August 2025.
The findings were published in the scientific journal BioRxiv, but have not yet been peer-reviewed.
