Researchers at a marine science institute believe they have found 'strong evidence' that incidents of sickness and death in dogs after eating fish on the north Norfolk coastline were caused by a neurotoxin found in shellfish.

Eastern Daily Press: Starfish washed up on the beach at Holme on New Year's Eve. Photo: Lisa BromleyStarfish washed up on the beach at Holme on New Year's Eve. Photo: Lisa Bromley (Image: Archant)

Scientists at the centre for environment, fisheries and aquaculture science (Cefas), in Weymouth, have analysed samples of fish and starfish from Cley beach where Hattie, a golden retriever died on New Year's Eve.

They reported finding 'paralytic shellfish poisoning (PSP) toxins in the starfish samples' from Cley, and added that this shows 'a potential route of intoxication'.

Cefas say they will be testing samples of crab claw, starfish and dog vomit from Chris Poole, the owner of a Siberian husky who died in Felixstowe on January 13 for PSP 'in the next few days.'

The seven-year-old husky was sick multiple times, before he became paralysed and died on the way to the vets, 90 minutes after eating crab on a beach walk.

Map key - Red pin: Confirmed death, Yellow pin: Reported sickness

Commenting on the death of the husky, Doctor Andrew Turner, principal chemist at Cefas, said: 'I have not seen any reports on the death of this dog.

'However, Chris' description includes facts such as rapid death - within 90 minutes - and included paralysis of the legs.

'Both aspects show similarities to some symptoms of PSP.'

The scientists are not currently able to determine exactly how the PSP toxins got into the dogs' systems and caused their deaths.

They said while they: 'do not know for sure that it was PSP intoxication, there is strong circumstantial evidence to suggest this as a possibility.'

They added that it is 'extremely unexpected to find PSP toxins in UK waters at this time of year.'

Cefas is responsible for conducting routine monitoring of shellfish for marine toxins.

Dr Turner said: 'We are offering to analyse more samples, but understand recent high spring tides have washed away the mass strandings which affected the area in question.'

Several dog owners reported their pets becoming sick or dying after ingesting washed up fish on the coastline in north Norfolk in early January.

Julie Thomas' dog, Hattie, died within an hour of eating a fish on Cley beach on December 31.

And Doug Thompson and Zelda Eady's labradors became seriously ill after eating fish on the beach near Holkham on January 1.

Mike Hamilton, whose dog Bramble was sick after a walk at Cley on New Year's Eve, said: 'Cefas looked at samples early on and shared the findings with us.'

He added that the experience had made him more careful when walking his dogs on the beach, and said: 'It's really important that vets know the signs [of PSP] to look out for and that people are aware of the risks.'

What is paralytic shellfish poisoning?

Paralytic shellfish poisoning (PSP) toxins are produced naturally at certain times of the year by some species of plankton.

The best-known PSP toxin is saxitoxin, a powerful neurotoxin - meaning it is poisonous to the nervous system and destructive to nerve tissue.

PSP toxins make their way into the food chain after being consumed by shellfish such as mussels, oysters and clams.

These toxins are dangerous to humans if consumed, and regulated levels are stipulated in EU law.

Shellfish production areas are not allowed to harvest when PSP levels rise above 800 micrograms of PSP toxins per kilo of shellfish until they have two negative samples taken in a row.

However, Cefas said there is no risk from the presence of these toxins in the seawater.

They added that they would not generally expect to find the toxin-producing plankton or the PSP toxins in UK waters during the winter.

Recent routine testing of shellfish taken from production areas in Norfolk and Suffolk has shown no presence whatsoever of PSP toxins.