Dolphin deaths in South Australia spike after algal bloom decimates food sources

Many of the dolphins found in Gulf St Vincent, which was impacted by South Australia’s algal bloom, were severely emaciated, scientists say. Photograph: Dr Mike Bossley

The number of dead dolphins washing up on South Australian beaches spiked in 2025, according to long-term data that reveals mortalities during the state’s devastating algal bloom were the highest in 12 years.

Last year, at least 70 carcasses of common and bottlenose dolphins were found across SA, with a further 20 reported in 2026, including the recent death of a popular Port River dolphin known as Zoom.