A national whale census along Western Australia’s south coast has recorded a 60 per cent decline in humpback sightings compared to the previous two years, a drop that marine scientists describe as far beyond normal variability. At Cape Naturaliste, observers counted just 22 whales, down from 69 in 2025 and 62 in 2024. Charter operators in Flinders Bay reported similarly stark figures, with one describing the season as the worst in 17 years. The cause remains unexplained, though researchers are examining whether the H5N1 avian influenza strain, already confirmed in migratory seabirds in the region, may have jumped to cetaceans.

The hypothesis draws on the virus’s known impact on marine mammals: the same clade caused mass mortality among southern elephant seal pups on Heard Island, 4,000 kilometres south-west of the Australian mainland. Four H5N1 cases have been detected in wild birds along Western Australia’s coast and one in South Australia, but authorities report no evidence of spillover into resident bird populations or domestic poultry. In Nepal, however, the outbreak has intensified sharply. More than 600,000 birds have been culled in the Kathmandu Valley, and the capital’s only zoo has closed. Veterinary officials there say crows are acting as vectors, spreading the pathogen between farms, heightening fears of a mutation that could increase human exposure.

Tourism operators and rangers on Australia’s frontline say they have received little practical guidance on identifying sick wildlife. In Port Lincoln, a shark-cage-diving operator reported seeing ailing giant petrels six weeks before the first confirmed case, but did not know to alert authorities. The state government says it targets messaging to high-risk periods. Meanwhile, KFC’s largest Australian franchisee, Collins Foods, told investors it has contingency plans to manage any supply disruption, though its European operations are already absorbing higher poultry prices linked to bird flu. In Argentina, a separate zoonotic alert emerged after the Malbrán Institute confirmed the first-ever detection of hantavirus in rodents in Ushuaia. Five of 144 captured mice carried antibodies to a variant related to the Andes virus, but genetically distinct from the strain that caused a fatal cruise-ship outbreak earlier this year. The finding forces Tierra del Fuego to intensify environmental surveillance where none previously existed.

Australian authorities are now under pressure to test whale carcasses for H5N1, with scientists noting disoriented behaviour in a southern right whale off Dawesville as a potential warning sign. In Argentina, genome sequencing continues to characterise the novel hantavirus variant. The next factual milestones are the results of any cetacean pathology, the completion of the hantavirus genome, and the outcome of Australian government talks on lifting remaining chicken export restrictions to Papua New Guinea.