As thousands of giant cuttlefish converge in South Australia’s Spencer Gulf, scientists are investigating emergency measures due to concerns that the state’s toxic algal bloom could be disastrous for this globally unique natural phenomenon. The annual gathering of cephalopods, known as Cuttlefest to locals, attracts thousands of tourists from Australia and around the world, taking place in a vibrant display off the coast of Whyalla from late May to August.
However, this year, scientists have raised the alarm as the event coincides with the spread of deadly algae into the Spencer Gulf. The natural spectacle is endangered by the expansion of a harmful algae species, posing a significant threat to the marine ecosystem.
Dr. Zoe Doubleday, a marine ecologist at the University of South Australia, emphasized the uniqueness of this cuttlefish population, stating that it is the only one worldwide that gathers and breeds in such extensive numbers, creating a magnificent natural wonder. The brief lifespan of the cuttlefish and the lack of overlap between generations exacerbate the vulnerability of the Spencer Gulf population to the toxic Karenia mikimotoi algae, which has already caused widespread devastation to marine life along the coast since March.
Following an emergency meeting convened by the state government, scientists and marine managers are exploring safeguards to protect the cuttlefish. Among the options considered is the feasibility of collecting an insurance population of cuttlefish eggs, an unprecedented endeavor. The urgency of the situation is underscored by fears that if the algal bloom reaches the breeding site, it could eradicate the eggs and have catastrophic consequences for the continuation of the cuttlefish population.
South Australia’s environment minister, Dr. Susan Close, acknowledged the potential threat, stating that the government will continue to monitor the situation closely but currently, there is no evidence of the algal bloom affecting the cuttlefish population. The contingeny plans are being developed, reflecting the seriousness with which authorities are viewing this possible environmental disaster.
Source: https://www.theguardian.com/environment/2025/jul/31/fears-for-south-australias-annual-cuttlefish-gathering-amid-deadly-algal-bloom
