Shellfish lovers beware: Kiwis warned as deadly toxin reaches dangerous levels ahead of summer

People living in Hawke's Bay, Gisborne and Northland are being warned to avoid eating shellfish, as a potentially deadly toxin reaches dangerous levels. 

The rising toxins could be partly due to the millions of tonnes of silt washed into the ocean during Cyclone Gabrielle. 

Don't let the sparkling blue waters fool you, because underneath lives a paralytic shellfish toxin that is potentially deadly. 

"It can be more commonly associated with nausea, vomiting, headaches and the likes," Ngāti Kahungunu marine scientist Shade Smith said.   

It has the locals worried, so they are taking precautions. 

"Yeah, I won't take crayfish from now on, I'll give that a miss," Hawke's Bay fisherman Norm Fraser said. 

Fraser is also refusing to take any paua, mussels or "things like that". 

The food safety warning covers part of Northland's east coast, and a huge area of Hawke's Bay and Tairawhiti - from Cape Kidnappers right to the top of the East Cape. 

"The biggest concern is the frequency in which these events seem to be occurring over time," Smith said. 

Toxin levels have rapidly risen as algal blooms grew over spring. 

The highest levels are in Tolaga Bay, where it's 11 times over the safe limit to eat. 

"Essentially, our coastline is our pataka kai (pantry)," Uawa Tolaga Bay resident Victor Walker said. "So, it has huge implications for us". 

Although the warnings aren't putting some people off. 

"Let's be careful out there, let's be careful and proactive about listening to the messages," Walker said. 

It's believed the problem could be partly due to the millions of tonnes of silt from Cyclone Gabrielle that's washed into the ocean, due to its nutrients feeding the algae. 

However it's too soon to confirm if that's the cause. 

"That's something that we are certainly interested in," Smith said.  

So far there are no known cases of poisoning, but people are being urged to ring Healthline if they become sick after eating shellfish and to keep leftovers for testing, so authorities can keep track of the problem.