H5N1 bird flu has taken thousands of baby southern elephant seals on Heard Island, a remote Australian territory, according to a study published in the journal BioRxiv.
Massive loss in a fragile ecosystem
The team used winter drone surveys and a handful of ground visits to track the seals between October last year and January this year. Researchers estimated that 13,359 baby seals—over 75% of the 17,364 pups that were present at the start of the survey—had died from the H5N1 strain of bird flu. In some nesting areas, the death toll was as high as 97%.
Other species affected too
While the seal population suffered the heaviest blow, scientists also found mortalities among king and gentoo penguins. The H5N1 virus was positive in six of nine species sampled—including the Antarctic fur seal and South Georgia diving petrel—but the study reported no unusual deaths among albatrosses or the island’s two endemic birds.
How did the virus arrive?
Bird flu is not yet present on the Australian mainland. The researchers believe the virus arrived last August aboard migration routes from the French‑owned Crozet Islands, roughly 1,800 kilometres away. This marks the first detection of H5N1 in an Australian external territory and signals the virus’s eastward spread across the sub‑Antarctic.
Implications for mainland Australia
Environment Minister Murray Watt called the seal deaths “sobering” and urged a realistic assessment of the probability of bird flu invading Australia’s mainland. “We must be realistic about the likelihood of an incursion here, and plan accordingly,” he said.
Ongoing monitoring
The Australian Antarctic Program will continue to watch for signs of the virus in these remote territories through regular surveys and sample collections. Though the study is yet to go through peer review, it provides a stark warning of the vulnerability of sub‑Antarctic wildlife to global viral pandemics.
For more details, the researchers published their initial findings on BioRxiv, where the raw data and methodology are available to the scientific community. The study underscores the need for rapid information exchange between nations and a proactive approach to wildlife disease surveillance.
Image source: Getty Images.
