Toxic slugs found on east Auckland beach

Toxic sea slugs have been found on Kohimarama Beach for the first time. Photos / Brett Phibbs, Supplied

The public is being advised to supervise dogs and children on an eastern Auckland beach after toxic sea slugs were discovered there for the first time.

Warning signs will be put up this afternoon on Kohimarama Beach after a slug containing tetrodotoxin was found by a woman walking with her dog.

The poison is the same as that found in the vomit of two dogs that died last winter after visiting North Shore beaches.

Auckland City Council environmental health and licensing manager Chris Dee said beachgoers should not handle the side-gilled sea slug (Pleurobranchaea maculata), and warned people to take care with young children and animals.

"The slugs have varying levels of toxicity but handling them could result in illness. They should never be touched. Dogs should be on leashes and should not be allowed to eat anything on the sand."

He was concerned with the spread of toxic slugs to an eastern beach, and said the surrounding beaches would be thoroughly combed for more specimens.

Last winter the council suspected that dogs poisoned at Kohimarama had come into contact with sea slugs, but no slugs had been found on the beach until last night.

The toxic slugs were mottled grey or sand-coloured, usually 2 to 2.5cm in length and found near the low-tide mark. They could grow up to 10cm.

Any member of the public who found a slug was advised to mark the spot and contact the council.

A survey in June found 94 sea slugs in subtidal water around seven beaches, five of them on the North Shore.