Minute jellyfish get sting blame

By KATHERINE HOBY

Stinging jellyfish are lurking off Auckland beaches.

They are only a few millimetres in diameter but have up to 100 tentacles that can inflict a nasty sting.

Sealice are getting the blame for stinging swimmers on east coast beaches of the North Island but the culprit is "sea bather's eruption", a tiny stinging jellyfish known as hydromedusae.

The sting is also known as the Caribbean itch, depending on where you don your swimming togs.

Dr Anita Freudenthal, a visiting American research scientist based at Leigh, north of Auckland, first encountered the creature more than 20 years ago in New York.

On an annual visit to New Zealand in 1996 she heard about swimmers suffering itchy red bites.

"I thought, 'They have a seabather's eruption on their hands and they don't know it'," she says.

"I wasn't going around the world looking for it. It had followed me." Dr Freudenthal, who has become known by some as "the itch lady", said that while the tiny pest looked like a dewdrop under the microscope, or a small pearly drop, it was almost impossible to see unmagnified.

The tiny jellyfish often get trapped in togs or tangled in body hair and as a natural defence release a sting when faced with pressure, friction or a change from salt to fresh water.

"Often when it starts hurting people rush to get under fresh water," Dr Freudenthal said.

"That's the last thing they should do as the change in water salinity might cause some of the stingers to detonate if they haven't already."

She said lifeguards are particularly prone to being stung because they are often in and out of the water several times a day in the same togs.

Dr Freudenthal has been told of suspected cases in the waters off Sydney, Fiji, Spain, and parts of the United States.

Here they have been reported from Bucklands Beach to Orewa, from Coromandel to Whangaparaoa.