Slug toxin test scheme to start soon

The scallop season opened yesterday but there are no concerns about the poison tetrodotoxin being associated with Hauraki Gulf specimens.

A two-year testing programme has begun to see if there is any risk to seafood gatherers from the poison found in sea slugs and puffer fish.

Tetrodotoxin or TTX has been linked to dog illnesses and deaths at beaches but scientists are uncertain about its potential to enter the food chain.

For this reason underwater traps will be placed in some areas in a $250,000 project funded by Nga Pae o te Maramatanga at Auckland University, one of eight centres of research excellence, done with help from the Cawthron Institute and Hauraki Maori Trust Board.

Ecologist David Taylor found large numbers of sea slugs among asian date mussels off Narrow Neck and Cheltenham beaches where many of the dog poisonings happened. The invasive mussels arrived in the 1970s and are not believed to carry the deadly toxin. However they are providing a habitat where the sea slugs build up and wash ashore in large numbers, chemist Paul McNabb says.

He says "tidying up" the asian mussels might reduce toxic sea slug populations to more normal numbers and help alleviate the poisoning problem.

The research could also identify whether tetrodotoxin is a new phenomenon here or a seasonal event and perhaps how the slugs get the toxin.

Toxic slugs have been found at Kohimarama beach and recent dog illnesses have been reported at Torpedo Bay, Narrow Neck and Milford.

Only half a teaspoon of the slug will kill a person.

The institute was unaware of what is thought to have been a case of TTX poisoning in a dog at Mathesons Bay at Leigh last October. Warkworth vet Roger Dunn examined the dog and has now been in touch with Mr McNabb.

The Auckland Regional Public Health Service advises people against collecting shellfish from urban beaches because of general contamination issues.

But it does not regard scallop gathering as high-risk because they are generally found in deeper water.

The New Zealand Food Safety Authority says it has no concerns with recreationally or commercially caught seafood in the Hauraki Gulf.

The Kaipara Harbour returns to normal scallop season P7

- © Fairfax NZ News