How common are Irukandji jellyfish and what are the risks?

Australia Broadcast Center

13 hours ago

They may be tiny, but Irukandji jellyfish can pack a fatal punch.
Residents in Western Australia's far north know to be wary of jellyfish stings, especially during the wet season from November to April.
But an "unusual" sting at Broome's tourist hot spot Cable Beach in late July has sparked the interest of overseas academics at the University of Hawaii, who will do further research into the species.
WA Country Health Service would not release information on the latest patient's condition.
While incidents of Irukandji stings are rare, they can be life-threatening and cause other side effects like feeling an impending sense of doom.
The local shire website warns Irukandji jellyfish are typically present during the wet season, but former CSIRO marine biologist and jellyfish expert, Lisa-ann Gershwin, said they frequented Broome waters year-round.
"There is a kind of safer season where they are less common … but there's always a chance."
When a swimmer is stung at Cable Beach, lifeguards close the beach to swimming and conduct stinger drags, which involves sampling sections of water close to the shore for the presence of jellyfish.
Lifeguards identify the jellyfish, and if needed, researchers conduct further studies.
But lifeguards don't only conduct stinger drags when an incident occurs.
It's a routine precautionary measure done twice daily to ensure safety, according to Shire of Broome manager of environmental health, emergency and rangers Aaron Ahtong.
"The lifeguards are constantly monitoring conditions," he said.
"So, including the drone patrols, they are doing everything they can to make sure the community is protected."
While the Irukandji species is not rare in tropical environments, being stung is uncommon.
Mr Ahtong said there were six recorded stings in the past five years.
This marks a significant decrease from the findings detailed in the Medical Journal of Australia, Irukandji syndrome in northern Western Australia: an emerging health problem, 20 years ago.
The report found 88 people were treated for Irukandji syndrome in Broome between 2001 and 2003.
"[Stings] are out of the ordinary, but definitely not rare," Mr Ahtong said.
There are 16 known species of Irukandji globally.
Dr Gershwin has named and classified 14, including all six found in WA.
There are two known types in Broome, including Malo maxima and Carukia shinju.
"The body is about the size of a thimble and it's got four super-fine tentacles, as fine as cobwebs, and that one I named Carukia shinju," she said.
"Of course, shinju is the Japanese word for pearl."
Dr Gershwin said she was surprised to hear about the timing of the latest sting, but not shocked.
"They don't read the signs and say, 'No, no, it's not the right season yet.'"
Dr Gershwin said a strong onshore wind or a "cracking good storm" would heighten the stinging risk, regardless of the time of year.
"The atmospheric and oceanic conditions bring them into the beaches, where tragedy occurs when they make [contact] with people," she said.
Short answer — no, but it's worth staying informed.
Local rangers and scientists agree that Cable Beach is one of the safest beaches because of the precautionary measures taken.
Dr Gershwin echoed the Shire of Broome's sentiment, agreeing the most important detail was that people remained aware.
"I think scaring people to say there's always a risk is not as effective as saying, 'There's always a risk, but here's what you can do about it.'"
Dr Gershwin advised beachgoers to wear protective beachwear, such as full-length lycra suits or wetsuits, and swim in patrolled areas.