A shellfish ban is in place for Queen Charlotte Sound which could be infected with potentially fatal toxins.
Nelson Marlborough Medical Officer of Health Dr Jill Sherwood has told the public not to take or eat shellfish from Queen Charlotte Sound.
All of Queen Charlotte Sound is affected, including Tory Channel.
Dr Sherwood said routine testing of shellfish in Tory Channel had shown higher than acceptable levels of the toxins that can cause paralytic shellfish poisoning (PSP).
Testing also showed increased numbers of the phytoplankton that produced the toxin in Queen Charlotte Sound. Previous experience indicates toxin levels are likely to be unsafe there as well.
She said symptoms of poisoning were numbness and tingling around the mouth, face or extremities; difficulty swallowing or breathing; dizziness; double vision. In severe cases, paralysis and respiratory failure can occur.
"Acute symptoms usually occur within 12 hours of consuming shellfish," Dr Sherwood said. She advised people not to eat kina, mussels, pipi, tuatua, oysters and cockles harvested from the affected areas since February 19.
"Scallops, paua, crab, and crayfish may still be eaten if the gut [and skirt of scallops] was completely removed prior to cooking. If the gut was not removed, its contents could contaminate the meat during the cooking process.
"Cooking affected shellfish does not remove the toxin," she said.
Fish, such as snapper, cod, gurnard, and tarakihi were not affected by the toxin and are still safe to eat, she said.
The affected area is all of Queen Charlotte Sound from a line drawn between Cape Jackson, across to Cape Koamaru, including Tory Channel out to East Head and West Head.
"Continued monitoring of the situation is planned but, in the meantime, people should not take shellfish from this area
"Any shellfish that has been harvested since February 19, but not yet eaten, should not be consumed. Freezing the shellfish does not kill or remove the toxin," Dr Sherwood said.
People who want more information about the safety of shellfish in their possession should contact the on call health protection officer, ph 03 546 1800. People who become ill after eating shellfish should seek medical attention.
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