The true spread of a deadly bird flu strain on a sub-Antarctic Australian island is yet to be understood as scientists await further test results.
H5 avian influenza was confirmed for the first time on World Heritage-listed Heard Island, which sits 4100km southwest of Perth in the Southern Ocean, in November.
In February, there were preliminary positive test results from Antarctic fur seals and gentoo penguins.
The devastating strain reached Antarctica from South America in 2023 and has caused mass sea bird deaths and killed seals.
The detection of H5 on Heard Island wasn't unexpected, given it exists on nearby French islands.
Researchers who travelled to Heard Island aboard Australian icebreaker Nuyina initially noticed an increase in dead elephant seals, before testing confirmed the presence of H5.
"It was pretty striking and a pretty hard thing for people to watch," Australian Antarctic Division chief investigator Aleks Terauds told AAP.
"We’re expecting to get the last of the results back over the coming weeks to confirm if there is any spread in other species.
"We’ll also get an understanding of the extent of its spread around the island.
"Some of the molecular work will help ... give clues as to where it came from."
The Heard Island detection does not substantially increase risks to mainland Australia, which is free of the disease, the federal government has said.
The island, an Australian external territory, is home to a vast array of wildlife and is an important breeding ground for various penguin species.
Scientists from voyages to Heard Island and McDonald Islands in recent months, the first of their kind in decades, are poring over data to better understand how the region is faring.
They also removed 800kg of waste from Heard Island including marine debris and 300kg of asbestos from an old station site.
It was a significant start on asbestos removal, Dr Terauds said, with more mapping and samples to determine future clean-up efforts.
An autonomous environment-monitoring system has been set up to send real-time data to Australia, while the spread of a non-native grass is being investigated.
