Blue-ringed octopus

The small, highly venomous, but usually inoffensive, blue-ringed octopus lives in pools on the rock platforms all around the Australian coastline. Any swimming beach with rock rubble could have hundreds of these animals. The smaller golf-ball sized Hapalochlaena maculosa is more common along the NSW coast, while a larger species Hapalochaena lunata is found in northern Australia.

Both species are shy rather than aggressive.  They are less active during daylight than at night when they move around search for potential mates. They flash blue and are at their most dangerous only when mating, attempting to warn off predators or angered by being disturbed, frightened and injured. The few reported cases of blue-ringed octopus injuring humans involved an octopus that had been picked out of its pool and provoked or stepped on.

A bite from a blue-ringed octopus can kill an adult human, as the venom contains the same toxin that puffer fish produce.  The only treatment is heart massage and resuscitation. While death can occur within 30 minutes of a bite,  a bitten human given urgent resuscitation should recover. Only four human deaths have been attributed to the blue-ringed octopus toxin.

In the 1960s, Sutherland Shire set up warning signs about blue-ringed octopus at North Cronulla, Cronulla, Shelly and Oak Park beaches, although no-one could recall any bites. Signs at ocean pools in Sydney's Eastern suburbs including the Malabar Pool and Maroubra's Mahon Pool also warn about blue-ringed octopus, though these shy animals usually pose little danger to swimmers.

While ocean pools with pumps could unwittingly pump in octopus along with the sea water, over a 20-year period only one blue-ringed octopus has been found in Wollongong's Continental Baths.

Further Information

Back Top