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Blue-ringed Octopus
Hapalochlaena maculosa, H. lunulata and H. fasciata (Blue-lined Octopus)
What do they look like?
Small in size (up to 8cm) they are the colour of ‘rock’ (mottled brown). They have an incredible ability to camouflage, being able to disappear into the background, with the identifying blue-rings only becoming visible only when aggravated.
Where are they found?
They live in shallow rock pools amongst algae, seaweed often hiding in crevices or the empty shells of other coastal marine animals. They have been seen on numerous occasions on rock platforms around Pittwater’s beaches and headlands.
The Danger
Although small, the blue-ringed octopus has venom powerful enough to kill humans (tetrodotoxin, also found in Puffer Fish). There is no anti-venom available. The toxin, once injected, causes weakness, nausea, numbness, blindness, loss of speech, touch and the ability to swallow, motor paralysis, fixed dilated pupils and respiratory arrest within minutes of exposure, leading to full cardiac arrest due to lack of oxygen. As bites are tiny and often painless, many victims don’t realise they have been bitten until breathing problems and start to set in.
The Treatment
Call an ambulance. First aid response number one is to put on a pressure immobilisation bandage over the wound. Keep the patient still as mobility will only spread the venom through the body quicker. Commence artificial respiration once paralysis has disabled the victim’s respiratory muscles, which often occurs within minutes of being bitten. The victim will remain conscious and with rescue breathing the body will metabolise the toxin within 24 hours. It’s important that negative comments and panic are minimised as the patient, although unable to respond, is completely conscious and alert. Once the patient has processed the toxin there are no known after-effects.
Since there is no anti-venom available, the best treatment is avoidance. Always keep an eye on your children when exploring our beautiful rock platforms and beaches and remember: Never put your hands into deep crevices or areas where you cannot see. If exploring under rocks, tilt the rock so that any animal underneath must move away from you. Always replace the rock as you found it. And finally, look but don’t touch!
Updated: 23 Jan 2012
More Information
- Australian Venom Research Unit
- Blue-ringed Octopus Project - Museum Victoria