News release 22 April 2004 4.00pm

Puffer fish on Wellington's beaches a mystery

The reason why hundreds of dead puffer fish washed up on Wellington beaches today remains a mystery. Greater Wellington's pollution control team found the dead fish washed up with the mid-morning tide from Fort Dorset to Karaka Bay.

An estimated 250-350 New Zealand porcupinefish (scientific name Allomycterus jaculiferus) were found along a 2km stretch of Seatoun coastline. Greater Wellington pollution control officer Chris Keenan says staff dispatched to check for fish on other beaches around the harbour reported no other incidents.

He says the regional council issued a warning to the public not to go near or touch the fish. "As a precaution we asked that members of the public didn't go near the potentially toxic fish, and we also suggested that dogs be kept away from the affected beaches. By midday the Wellington City Council had removed the fish and cleared the beaches."

Mr Keenan says investigations will focus on the fish and water samples to determine the possible cause. Greater Wellington is working with NIWA and the Regional Health Authority, with results from laboratory testing expected a in a few days. "We've had confirmation from NIWA that the fish are commonly known as porcupinefish. These fish can be toxic and potentially lethal and should not be eaten. NIWA have said that even handling the skin might transfer a toxic mucus."

The spiky fish which puffs up in defence occurs naturally around Wellington and is found in New Zealand and Australian waters, according to NIWA. Though the spikes aren't poisonous, the internal organs and mucus can be toxic.

Mr Keenan says the cause is a mystery. "The appearance of a large number of one species suggests it could be the result of an unwanted catch being dumped by a fishing boat. Otherwise the death could be from a disease, virus or bloom of toxic algae or plankton."

NIWA is aware of similar instances of large numbers of fish washing up on beaches in 1998 and 2000, attributed to toxic algal or plankton blooms.

Weekly monitoring by the Regional Public Health on Monday revealed the presence of a phyto-plankton harmful to fish in low levels around the Day's Bay monitoring site, suggesting there could be higher levels offshore. The phyto-plankton could release a toxin or be eaten by the porcupinefish.

Large numbers of dead fish on beaches in the Wellington region should be reported to Greater Wellington on 0800 496 734. ENDS

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