Saturday, February 06, 2010

"Baby boom" for deadly irukandji jellyfish

From the Sydney Morning Herald:

Potentially deadly marine stingers may be blooming in unprecedented numbers off the Queensland coast, as far south as Moreton Bay.

But a request by a world-leading expert to study the jellyfish phenomenon has been denied by the Australian Research Council, despite mounting evidence overseas and a series of recent stingings involving the species, including the feared irukandji.

A ship worker on board a bulk carrier became the latest victim, when he was stung 25 metres above sea level on Sunday.

The man had been fishing off the deck of the bulk carrier while waiting to collect coal off Abbott Point, north of Bowen, when it is believed he was splashed with water carrying the irukandji jellyfish.

In December, the notorious box jellyfish stung a 10-year-old girl swimming in a river 23 kilometres inland, north of Gladstone, while Brisbane holidaymaker Clinton Scott dived face first into the tenticles of an irukandji in the Whitsundays.

The winner of Tourism Queensland's "Best Job in the World" contest, Ben Southall, was also stung by a fingernail-size irukandji jellyfish while jetskiing off Hamilton Island on December 30.

Dr Lisa Gershwin, touted as the world's only jellyfish taxonomist, or species classifier, said the prevalence of marine stingers was the result of an expected cyclical jellyfish bloom.

However, she said there was no quantitative data in Australia to confirm long-held suspicions that jellyfish - known as the cockroaches of the sea - were breeding in exceptional numbers in Queensland waters.

"We're definitely having an irukandji bloom right now, there's no question. We've had at least 15 irukandji stings this season so far, starting December," Dr Gershwin, the director of the Australian Marine Stinger Advisory Services, said.

"Whether they are actually on the increase in Australia, we don't know."

"Overseas there is a lot of data that demonstrates that jellyfish are on the increase globally. Overseas ecosystems, one by one, are flipping to jellyfish dominated ecosystems...

She said there was no doubt the number of irukandji stings had increased off the Queensland coast in the last decade, although that could be attributed to better reporting methods.

However, the Australian Research Council rejected Dr Gershwin's request for a grant to research the trend.

"They said I had failed to demonstrate that there was any link; that just because it was happening overseas they (did not) see any reason why it might happen here."...

Dr Gershwin said an increase in jellyfish numbers in Queensland waters was not unlikely, as the translucent sea creatures - usually no more than 2.5 centimetres in diameter - are capable of thriving off their neighbours' misfortunes.

She has referred to the phenomenon as the "jellyfish joyride".

"Jellyfish can survive any perturbation, which can unbalance the (ecosystem)," she said.

Chemical imbalances in the water from urban run-off, thermal water changes, pollution, over-fishing or the introduction of new aquatic species, which could drive other species to extinction, do not bother the jellyfish.

"Jellyfish are basically the last man left standing. You see a very bad situation - like a domino effect - where you get a little bit of a wobble in the system, and jellyfish get a bit of a toe-hold, and they can out-compete other species for food and they can actually prey on other species, or the larvae of other species."...

Irukandji stings cause severe abdominal, limb and joint pain, nausea, vomiting, sweating and agitation, although their effects may not be felt until 30 minutes after a victim is first stung.

Dr Gershwin said vinegar remained the best treatment for marine stings, as it neutralised the venom.

1 comment:

Anonymous said...

It should be noted that vinegar does not "neutralize" the venom per se-it does temporarily inactivate the venom enzymes and buy time and allow the clearance of adherent tentacles from the skin.
As a biochemist studying the venoms of cubozoans including the Irukanji causing species, I find that the venom is a complex mixture of potent enzymes and lysins as well as small molecules. The low pH of vinegar temporarily _inactivates_ the venom enzymes and stills the discharge of nondischarged stinging cells or nematocysts from adherent tentacles. It is therefore an excellent emergency wash step.
Heat will however _inactivate_ these cold water enzymes. The best emergency treatment after washing the sting site with salt water or vinegar is hot water immersion up to 45oC for 20-40 min.
Dr. Angel Yanagihara
Assistant Research Professor,
University of Hawaii at Manoa