The Waikato District Health Board today issued a public health warning advising the public not to collect or consume shellfish harvested from Mohakatino, north to (but not including) Manukau Harbour.
The warning includes Kawhia, Aotea and Raglan harbours.
Routine tests on shellfish samples taken from Kawhia and Raglan have shown levels of Paralytic Shellfish Poisoning (PSP) at 0.83 and 1.10 milligrams of toxin per kilogram of flesh.
This is above the Ministry for Primary Industry safe limit of 0.8 milligrams per kilogram of flesh.
Anyone eating these toxic shellfish is potentially at risk of illness.
The levels of PSP at Manukau Harbour are below the safe limit and hence the warning does not include Manukau Harbour.
Kina, mussels, toheroa, pipis, tuatua, oysters, cockles and scallops in the affected area should not be eaten.
Cooking shellfish does not remove the toxin.
Paua, crab and crayfish may still be eaten if the gut has been completely removed prior to cooking as toxins accumulate in the gut.
If the gut is not removed its contents could contaminate the meat during the cooking process.
Symptoms of PSP usually occur within 12 hours of consuming shellfish and include numbness and tingling around the mouth, face or extremities, difficulties in swallowing or breathing, dizziness and double vision.
In severe case people may suffer from paralysis and respiratory failure.
If anyone becomes ill after eating shellfish from an area where a public health warning has been issued they should contact a doctor immediately, advise their local Health Protection Unit and keep any left over shellfish.