KEY POINTS:
Holidaymakers were today warned against eating shellfish from the Bay of Islands after routine monitoring discovered an increased level of marine biotoxin.
Paralytic shellfish poisoning (PSP) affects the central nervous system, and its symptom include weakness, clumsiness, dizziness, double vision, slurred speech, difficulty swallowing or breathing, and paralysis.
The area in question encompasses the whole of Bay of Islands, from Cape Wikiwiki north of Kerikeri on the east coast down as far as Cape Brett.
Northland District Health Board shellfish programme co-ordinator Elizabeth Watt said a test site had returned a reading of 150 micrograms per 100 grams, well above the limit of 80.
"We don't want to alarm people, as the regulatory levels are very low and give plenty of safety margin.
"But if people eat large quantities of shellfish, which at this time of the year they may do, they could experience symptoms," she told NZPA.
There have been no deaths reported from PSP in New Zealand.
Dr Watts said the problem was a common one, both in New Zealand and overseas.
"We don't think it's to do with sewage - it's an environmental thing which affects most countries from time to time, and seems to be due to tide, weather and temperatures."
- NZPA
