Queen Charlotte Sound Algal Bloom – shellfish dangerous to eat
Monday 11 April 2011, 8:46AM
By Marlborough District Council
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Nelson Marlborough Medical Officer of Health Dr Jill Sherwood today advised that levels of toxin had continued to increase and had reached dangerous levels in shellfish. This meant that eating even
small amounts of shellfish could cause severe illness. There have been cases overseas of death from eating shellfish contaminated with this same toxin.
The area affected remains all of inner Queen Charlotte Sound, including Tory Channel.
Dr Sherwood said, “Continued testing of shellfish in Queen Charlotte Sound and Tory Channel has shown increasing levels of the toxins that can cause Paralytic Shellfish Poisoning (PSP).”
She said symptoms of contamination 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 eating shellfish”. She advised people not to eat kina, mussels, pipi, tuatua, oysters, cockles and scallops harvested from affected areas since March 22, 2011.
“Paua, crab, and crayfish may still be eaten if the gut was completely removed prior to cooking. If the gut was not removed its contents could contaminate the meat during the cooking process,” she said.
“Cooking affected shellfish does not remove the toxin.” Fish, such as snapper, cod, gurnard, and terakihi
were not affected by the toxin algae and are still safe to eat.
PSP group toxins are produced by a variety of phytoplankton species, mainly of the Alexandrium genus.
The affected area (shown on the attached map) remains all of inner 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.
The shellfish ban in Port Underwood, caused by a different toxin, is still also in place.
People who want more information about the safety of shellfish in their possession should contact the On Call Health Protection Officer on (03) 520 9999 Blenheim or (03) 546 1800 Nelson. People who become ill after eating shellfish should seek medical attention.