Sharp drop in humpback sightings and weakened albatrosses signal possible Southern Ocean shift

Whale watchers in southwest Western Australia reported a 60% decline in humpback sightings, and days later rare, weak albatrosses and petrels were spotted far east on Australia’s coast, hinting at changing ocean conditions.

Whale observers in southwest Western Australia noted a sharp 60% drop in humpback sightings in late June, a period when the species normally migrates northward to breed and feed. A week later, birdwatchers along Australia’s east coast reported the appearance of rare albatrosses and petrels thousands of kilometres from their usual Southern Ocean feeding grounds, many appearing weak or malnourished. Researchers attribute both phenomena to a lingering marine heat wave that has warmed waters around Heard and McDonald Islands and the southern Tasman Sea, two of the fastest-warming ocean regions on Earth.

Warmer water can alter currents and prey distribution, forcing marine mammals and seabirds to stray from established routes. The timing is concerning, as Australia recently confirmed its first highly pathogenic H5N1 case in a dying migratory seabird, adding disease pressure to already stressed populations. Limited monitoring of the Southern Ocean hampers understanding of how such temperature spikes affect krill, fish and higher predators. Scientists call for coordinated, long-term observation programs to distinguish short-term fluctuations from a possible systemic shift in the Southern Ocean ecosystem.