Evil-eye puffer fish washing up on Fish Hoek and Muizenberg’s beaches are caused by a change in water temperature, according to the Two Oceans Aquarium.
Aquarium curator Tinus Beukes said the puffer fish were washing up due to the sudden cooling of the water in False Bay.
They were not the only fish affected but were the more noticeable because seagulls avoided eating them as they were poisonous, he said.
The evil-eye puffer fish (Amblyrhynchotes honckenii) gets its name from the metallic green appearance of its eyes.
However, Mr Beukes said, “evil” was not a reflection of their nature as they were curious and gregarious puffers that exhibited a fairly placid nature towards one another and other fish.
Their skin, liver, intestines and reproductive glands contain a powerful toxin, tetrodotoxin, which is poisonous to humans and animals. It can cause paralysis that can lead to respiratory failure.
Fugu is a famous Japanese sushi dish prepared from puffer fish by carefully removing all the tetrodotoxin-containing parts and serving the flesh in delicate slices, but the fish should be avoided by humans and animals when found on the beach, said Mr Beukes.
Since Monday March 22, the City’s solid waste department has collected some 70 bags of fish weighing 200kg.
Marian Nieuwoudt, mayoral committee member for spatial planning and environment, said the City would continue to monitor all areas and the clean-up operations were ongoing.
“The puffer fish is not for human or animal consumption, so we advise that all beachgoers and dog walkers avoid areas where puffer fish have washed up,” she said.
The Department of Environment Forestry and Fisheries (DEFF) said the fish were not washing up due to water pollution or red-tide toxins in the water.