Southern Ocean heatwave triggers whale decline and rare seabird influx
In late June, observers in southwest Western Australia recorded a 60% drop in humpback whale sightings during their usual migration from the Southern Ocean. A week later, birdwatchers on Australia’s east coast reported unusually large numbers of albatrosses and petrels far from their normal foraging zones, many in poor condition. These events followed the confirmation of Australia’s first highly pathogenic H5N1 bird‑flu case in a migratory seabird.
Scientists attribute the anomalies to a persistent marine heatwave that has warmed waters around Heard Island and the McDonald Islands since February and extended into the southern Tasman Sea from at least April. The heatwave is among the fastest‑warming regions on the planet and may disrupt prey availability and ocean currents.
Separate research by Brazilian scientists identified atmospheric rivers—large corridors of water vapor transporting heat from the tropics—as a key factor behind recent Antarctic heatwaves, linking them to roughly 80 % of interior Antarctic warming events.
Entities: Albatross · Albatrosses and petrels · Atmospheric rivers · Heard Island and McDonald Islands · Heitor Evangelista da Silva · Humpback whale · Humpback whales · Marine heatwave · Southern Ocean
Claims
What the coverage asserts, and how well corroborated each claim is across sources.
- [● 3 SOURCES] A persistent marine heatwave has affected waters around Heard Island and the McDonald Islands since February, extending to the edge of Antarctic sea ice. (climate monitoring data)
- [● 3 SOURCES] Large numbers of rarely seen albatrosses and petrels appeared off Australia’s east coast, many in poor condition. (birdwatcher reports)
- [● 3 SOURCES] Australia’s first case of highly pathogenic H5N1 bird flu was confirmed in a migratory seabird weeks before the whale and bird sightings. (official health reports)
- [● 3 SOURCES] Humpback whale sightings off southwest Western Australia in late June were about 60% below normal. (observations of whale watchers)
- [○ 1 SOURCE] Atmospheric rivers transport heat and moisture from tropical regions to Antarctica, increasing the frequency and intensity of Antarctic heatwaves. (climatology study)
- [○ 1 SOURCE] Brazilian scientists identified atmospheric rivers as a major driver of Antarctic warming, linked to about 80 % of interior heatwaves. (research presented by Heitor Evangelista da Silva)
- [● 3 SOURCES] The southern Tasman Sea has experienced a marine heatwave since at least April, likely linked to successive La Niña events. (ocean temperature records)
- [● 3 SOURCES] The regions affected by the heatwave are among the fastest‑warming ocean areas on the planet. (global ocean warming analyses)