A chain of conditions has led to warnings for people not to collect shellfish anywhere inside the Bay of Islands due to a potentially deadly toxin.
Higher than usual levels of paralytic shellfish toxins (PST) in shellfish has seen the Ministry for Primary Industries issue a health warning for the area from the outer heads between Cape Wiwiki on the north to Cape Brett on the south. The warning includes all inlets and estuaries. Similar warnings are in place in Hawke's Bay and parts of Marlborough Sounds.
But the ban is not expected to affect the Bay's multi-million dollar oyster industry.
The latest weekly sample testing has shown PST at levels above the safe limit of 0.8 mg/kg set by MPI. The toxins develop in filter feeding shellfish that have fed on blooms of microscopic dinoflagellate algae. The chain reaction can lead to paralytic shellfish poisoning (PSP) in people.
The shellfish look and taste normal, despite their poisonous cargo. Mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, cat's eyes, kina (sea urchin) and all other bivalve shellfish should not be eaten. Pāua, crab and crayfish can be eaten if the gut has been completely removed before cooking.