New Zealand Food Safety today issued an extension to the public health warning advising the public not to collect or consume shellfish harvested from the Western Firth of Thames.

The area now includes the entire Firth of Thames up to a line from Raukura Point across to Deadmans Point.

Routine tests on shellfish samples taken from this region have shown levels of Paralytic Shellfish Poisoning - PSP - toxins above the safe limit of 0.8mg/kg set by New Zealand Food Safety. Anyone eating shellfish from this area is potentially at risk of illness.

Mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, catseyes, kina (sea urchin) and all other bivalve shellfish should not be eaten.

Note that cooking shellfish does not remove the toxin.

Pāua, 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 typically appear between 10 minutes and three hours after ingestion and may include:

• numbness and a tingling (prickly feeling) around the mouth, face, and extremities (hands and feet)
• difficulty swallowing or breathing
• dizziness
• headache
• nausea
• vomiting
• diarrhoea
• paralysis and respiratory failure and in severe cases, death.

If anyone becomes ill after eating shellfish from an area where a public health warning has been issued, phone Healthline for advice on 0800 61 11 16, or seek medical attention immediately.

You are also advised to contact your nearest public health unit and keep any leftover shellfish in case it can be tested.

Monitoring of toxin levels will continue and any changes will be communicated accordingly. Commercially harvested shellfish – sold in shops and supermarkets, or exported – is subject to strict water and flesh monitoring programmes by MPI to ensure they are safe to eat.

Find out more:

Shellfish biotoxin alerts

Subscribe to shellfish biotoxins to receive email alerts

Collecting shellfish and keeping them safe

Causes and symptoms of toxic shellfish poisoning

About toxic algal blooms

Food safety for seafood gatherers booklet