A marine expert has warned swimmers and fishermen to be aware of highly-poisonous, blue-ringed octopi in local waters after a woman was bitten off the coast of Rockingham last month.
Picture by Yolanda Zaw: Rockingham Volunteer Sea Rescue commander Peter Edwards with his rescue crew Les Bignell, Brian Cole, Jim Roche, Rod Smith and Peter Ewens.
The woman and her husband were recreational cray-fishing in waters off Garden Island when the incident occurred.
A baby blue-ringed octopus had found its way into the couple’s cray pot and bit the woman’s hand as she tried to pull the pot from the water.
She was rushed to Peron Point boat rampwhere she was helped by Rockingham Volunteer Sea Rescue and driven to Rockingham District Hospital.
Aaron Cosgrove-Wilkie, a marine molluscs expert at WA Museum’s Department of Aquatic Zoology, said while the blue-ringed octopus preferred to live in rocky substrates they did have a presence at beach sites around Rockingham and Mandurah.
‘‘They are rather common in the entire south coast of Australia but they usually prefer to live in rocky areas or in sea grass where they can hide and feed. They can also be prevalent under jetties,’’ he said.
‘‘It’s important people are aware though because they are definitely around, they just tend to avoid people.
‘‘People don’t usually get bitten in the water, octopi crawl into shells that then wash up on shore and when someone tries to pick up the shell, they bite as a defence mechanism.’’
Mr Cosgrove-Wilkie said the sea creature’s venom contained a neurotoxin which could paralyse victims in minutes and cause respiratory arrest.
‘‘Your motor function is the first to go, you’re paralysed. The venom then attacks your respiratory system so you can’t breathe,’’ he said.
‘‘The lack of oxygen can lead to cardiac arrest and death if medical assistance is not given.
‘‘This can happen within minutes so it’s important for anyone who has been bitten to remain as still as possible and call an ambulance immediately.’’
Blue-ringed octopus venom is regarded as 10,000 times more toxic than cyanide and no anti-venom exists.
MrCosgrove-Wilkie said the octopi bred in winter with the first offspring being born in early summer.
‘‘December and January are probably the most dangerous months because that’s when all the baby octopi are born and in the water,’’ he said.
‘‘They are venomous from birth and fully develop in size very quickly.’’