Mysterious sea foam on South Australian beaches reportedly leaves more than 100 surfers ill

Waitpinga Beach, pictured, and Parsons Beach were closed amid a ‘fish mortality event’ following foam washing up in South Australia, a state environment department spokesperson said. Photograph: Anthony Rowland

A mysterious foam on a South Australian beach is being blamed for more than 100 surfers becoming ill, and for the deaths of leafy seadragons, fish, and octopuses.

Health authorities have closed Waitpinga and Parsons Beach, about 80km south of Adelaide, and say the foam could be due to a microalgal bloom driven by hot temperatures, still water, and an ongoing marine heatwave.