The Ministry for Primary Industries (MPI) is worried that there may be holidaymakers headed to the Bay of Plenty area hoping for a feed of shellfish who are not aware of the high risk of getting paralytic shellfish poisoning.
A health warning is in place advising against the gathering of shellfish from much of the Bay of Plenty coastline.
MPI collects and tests weekly water and shellfish samples from around the coastline of New Zealand to monitor shellfish toxicity so public health units can issue warnings when toxins are present.
MPI also warns holidaymakers in the Marlborough area to keep an eye out for shellfish warnings in that area. A warning is in place for Tory Channel due to an Alexandrium catenella bloom. This bloom has recurred every year for the past few years and may well spill out into Queen Charlotte Sound to contaminate shellfish as it has done in past years.
Monitoring in the Bay of Plenty area shows toxin levels are very high (in some places more than 20 times the level at which warnings are issued) and they may still be rising.
MPI Principal Adviser Animal Products, Jim Sim, says the last time levels this high occurred people ended up in intensive care.
Two years ago 30 people were poisoned and some ended up in intensive care. To date, there has been 13 cases of toxic shellfish poisoning notified to the Medical Officer of Health this year, with several admitted to hospital. Each person affected had eaten shellfish collected from the Bay of Plenty coastline. It appears some members of the public are continuing to collect shellfish in the affected area, despite the risk.
The area now subject to warning was extended last week, and now includes the entire coastline from Whakatane Heads in the Eastern Bay of Plenty, all the way along the coast to Waihi Beach, and up the eastern side of the Coromandel Peninsula to the river at the southern end of Whangamata Beach. All harbours, estuaries and islands along this coastline are included in the warning.
Mr Sim says the toxic algae species causing the problem is Alexandrium minutum, which produces the most toxic compounds of the various toxic algal species in New Zealand waters.
“Alexandrium minutum causes toxicity regularly in this area. It’s not known exactly what causes toxic algae to bloom but some species such as Alexandrium minutum have a resting cysts stage which remain in an area after a bloom and, when conditions are right it, reappears. This is why it occurs time and again in the Bay of Plenty area.”
Mr Sim says toxic algal blooms occur naturally and have been monitored routinely in New Zealand since outbreaks of poisonings occurred in 1993.
In the absence of rapid medical help, fatalities may occur and frequently do in other countries where medical help may not be available fast enough. Even with medical help, fatalities sometimes occur.
The public can obtain up to date information at www.ttophs.govt.nz/health_warnings MPI monitoring programme information at: http://www.foodsmart.govt.nz/food-safety/hunting-collecting-fishing/seafood-gatherers/