Marine biotoxin alerts.

Shellfish and seawater samples around New Zealand are tested each week to ensure they are not contaminated with biotoxin from blooms of algae. Public warnings are issued when shellfish are not safe to eat. This page contains information relating to the non-commercial (recreational and traditional) taking of shellfish only.

This page is updated as soon as new information comes to hand. All the warnings on this page are current and remain in force.

Marine biotoxin warnings currently in force

South Island

31 March 2014

Shellfish ban lifted in Queen Charlotte Sound and Tory Channel

The public has been given the all clear to collect shellfish in the Queen Charlotte Sound and Tory Channel.

Nelson Marlborough Medical Officer of Health, Dr Ed Kiddle, said that two consecutive shellfish tests taken in Queen Charlotte Sound and Tory Channel had shown the levels of Paralytic Shellfish Poisoning (PSP) toxin in shellfish had returned to a safe level.

“Although the algae bloom responsible for the toxin had been declining during March it has taken several weeks for the toxin to be flushed from the shellfish.
“This particular bloom was sufficient to contaminate shellfish in the Queen Charlotte Sound and Tory Channel area, giving rise to a closure on February 25, 2014.”

Paralytic Shellfish Poisoning (PSP) a Marine Biotoxin can cause numbness and tingling around the mouth, face or extremities; difficulty swallowing or breathing; dizziness; double vision. Symptoms usually occur within 12 hours of consuming shellfish.  In severe cases, paralysis and respiratory failure can occur. It is produced by particular types of phytoplankton found commonly around New Zealand.   Monitoring for marine biotoxins continues on a regular basis in all shellfish gathering areas around New Zealand. 

Signs put up to inform people of the closure will be removed over the next few days.  Dr Kiddle reminded people to only take shellfish from clean water and never take shellfish after rain or when the water is dirty.  He said certain areas such as estuaries near urban settlements were never suitable for taking shellfish for eating.

“Also remember to refrigerate your shellfish as soon as possible,” he said.

North Island

Bay of Plenty Contaminated Area Map

North Island contaminated areas

Toxic shellfish warning revised - 14th February 2014

Toxic Shellfish warning revised

Regular shellfish monitoring along the coast has seen Paralytic Shellfish Poisoning (PSP) levels fall along part of the Bay of Plenty coastline.

“There is now no PSP concern from Pukehina eastwards. 

However, the current warning remains in place from Waihi Beach to the northern end of Pukehina,” says Medical Officer of Health, Dr Phil Shoemack

The Medical Officer of Health continues to advise against gathering or eating shellfish from Waihi Beach, along the Bay of Plenty coast to Pukehina.  The warning includes Tauranga Harbour, Maketu and Waihi estuaries, Matakana and Motiti Islands, and all other islands along this coastline.

The health warning applies to all bi-valve shellfish including mussels, pipi, tuatua, cockles, oysters, scallops as well as cat’s eyes, snails and kina (sea urchin).    PSP is caused by natural toxins that are produced by algal blooms and accumulate in shellfish that feed on the algae. Shellfish containing toxic levels of paralytic shellfish poison don't look or taste any different from shellfish that are safe to eat. Cooking or freezing the shellfish does not remove the toxin.  Paua, crayfish and crabs can still be taken but as always, the gut should be removed before cooking or eating.

Eating shellfish affected by paralytic shellfish toxin can cause numbness and tingling around the mouth, face, hands and feet; difficulty swallowing or breathing; dizziness; double vision; and in severe cases, paralysis and respiratory failure.  These symptoms can start as soon as 1-2 hours after eating toxic shellfish and usually within 12 hours.  Anyone suffering illness after eating shellfish should seek urgent medical attention.

Monitoring of toxin levels will continue along the coast and any changes in advice will be communicated accordingly.  The public can obtain up-to-date information on the toxic shellfish health warning through these channels:

Hokianga Harbour

The Health Protection Unit of Northland District Health Board continues to advise people not to consume shellfish from the Hokianga Harbour. This public health warning has been issued due to the persistence of Microcystin Toxins above safe levels in shellfish.

Shellfish in the Hokianga Harbour were tested for Microcystins after a bloom of toxic Cyanobacteria occurred in Lake Omapere which drains into the Hokianga Harbour.High levels of microcystins are frequently associated with the death of animals consuming contaminated water. Human deaths from consumption on microcystins have not been well reported but it is acutely toxic in animal studies and they are thought to cause liver damage in humans. Human fatalities have also occurred when water used for dialysis of patients with kidney failure has become contaminated.

For further information contact: Northland District Health Board (09) 430 4100

Please note:

Warnings about unsafe areas are subject to change. The public should contact their local health protection officers at District Health Boards if they are in doubt about where they should take shellfish.

Public health unit contacts