Overview
- Thousands of recently dead fish were reported at Port Noarlunga this week, with residents hauling away buckets in ad hoc cleanups as conditions shift from day to day.
- The months-long bloom has affected roughly 30% of South Australia’s coastline and is linked to more than 87,000 animal deaths across 390-plus species logged to iNaturalist.
- Genetic work reported in a pre-print identifies multiple Karenia species, with brevetoxin-producing K. cristata emerging as dominant since July and raising health concerns pending peer review.
- State monitoring shows K. cristata cell counts reaching several million cells per liter in Gulf St Vincent, with some metropolitan declines recent weeks but unpredictable rebounds, including near Victor Harbor.
- Researchers caution that seasonal flares are possible and cite a marine heatwave, nutrient enrichment and calm seas as drivers, with locals reporting ongoing beach odors, safety hazards and tourism worries.