Avian Flu H5 Wipes Out 97% of Seal Pups on Remote Australian Islands

Mass Animal Die-Off Strikes Heard and McDonald Islands

According to НВ — Техно: A catastrophic die-off has been recorded on the remote Heard and McDonald Islands, driven by the H5 strain of avian influenza. This virus, which has killed seals, penguins, and other bird species, marks the first detection of H5 on an external territory of Australia. The hardest hit have been southern elephant seal pups, with mortality rates in some seal harems reaching as high as 97%.

Field studies conducted on the islands reveal that the animals had no prior immunity to this novel virus. Genetic testing has confirmed that the highly contagious H5 avian flu strain was responsible for the deaths of seals, penguins, and birds inhabiting these rocky outcrops. Researchers discovered the islands littered with seal carcasses during an expedition. Based on ground surveys and aerial photography, 13,300 dead elephant seal pups were counted between October 2025 and January 2026.

Viral Impact on the Ecosystem

Additionally, several hundred dead adult king penguins were observed. The virus is believed to have been introduced in August 2025 from the Crozet Islands, located roughly 1,500 kilometers northwest of Heard and McDonald Islands. These uninhabited islands sit about 4,000 kilometers southwest of mainland Australia, and access is granted only with permission from the Australian government.

Dr. Jarrod Hodgson, who participated in the research, noted: 'When we left the island, the deaths were still ongoing.'

Biologist Julie McInnes added: 'These observations of H5 avian flu on Heard Island and McDonald Island are the first detection on an external territory of Australia and demonstrate the continued eastward spread of the virus.' Heard and McDonald Islands were included in the international tariff list of President Donald Trump in April 2025.

The emergence of H5 avian flu on Heard and McDonald Islands serves as an alarming signal for Australia’s ecosystem, as it may indicate the virus is spreading to other regions. The mass mortality of animals, particularly elephant seals and penguins, underscores the vulnerability of local wildlife to new pathogens and the consequences of global changes such as climate shifts and human activity. This situation demands urgent action from scientists and conservation organizations to monitor and control further viral outbreaks in the wild.