Pygmy Blue Whale Sightings Decline Off Australian Coast
New data shows a significant drop in whale sightings and surface krill swarms within the Bonney Upwelling system.
Updated on Oct. 30, 2026 in Environmental
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Aerial surveys conducted between 2020 and 2024 reveal that pygmy blue whale sightings off the coast have fallen by 51 per cent compared to the 2000-2004 period. This decline coincides with a 65 per cent decrease in surface krill swarms, impacting essential feeding grounds.
Why it matters
The Bonney Upwelling current, which usually supports marine wildlife from November to May between Cape Otway and Robe, is experiencing increased variability due to climate change. This instability is leading to widespread malnourishment among Australian fur seal colonies and changing whale migration patterns.
Pygmy blue whales must now dive 200 metres to locate food sources as surface krill swarms have declined by 65 per cent over the last 28 years. This shift in availability follows the strongest recorded Bonney Upwelling event in 2024.
The players
Australian fur seal
These marine mammals inhabiting the Bonney Upwelling system are currently experiencing population decline and malnourishment.
The details
Researchers monitoring the waters between Cape Otway and Robe note that the Bonney Upwelling, which normally sweeps nutrient-rich cold water and krill to the surface, is becoming increasingly erratic. As these krill swarms fail to reach the surface, marine predators like Australian fur seals are suffering from significant food shortages.
Timeline
2000-2004: First period of aerial whale surveys.
2020-2024: Second period of aerial whale surveys.
2024: Bonney Upwelling reached strongest level on record.
November to May: Annual feeding season for marine wildlife.
1-2 November 2026: Bonney Upwelling Festival in Portland.
The Big Picture
The study of the Bonney Upwelling system highlights a critical paradigm shift in how upwelling ecosystems respond to climate change variability. By documenting the decline in krill availability, this research disproves the assumption that traditional upwelling currents will remain stable food sources.
These findings could lead to new management strategies for coastal zones to ensure the survival of marine populations. Understanding these shifts helps predict long-term changes in Australian coastal biodiversity and potential impacts on local fishing industries.
The takeaway
Marine ecosystems are showing visible signs of stress as climate change alters traditional nutrient-rich upwelling currents. Observing these changes is essential for maintaining the health of coastal waters and protecting native species like the Australian fur seal.
What happens next
The Bonney Upwelling Festival will take place in Portland on 1-2 November 2026.
Further reading
Learn more about local Environmental studies in the region.
Source note: This article includes information reported by Australian Broadcasting Corporation.
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