This summer, the death of several dogs after exercising on Auckland’s beaches has caused us all great concern. After all, the daily promenade on the beach is one of New Zealand’s most popular pastimes, for both man and dog. Is this much loved activity about to be threatened?. Well fortunately it seems not.
The toxin involved, tetrodotoxin, a neurotoxin, is carried by puffer fish (those spiky bloated fish occasionally seen washed up ), as a defensive biotoxin to ward off predators. The toxin itself is produced by bacteria and is also found in sun fish, and porcupine fish to name a few. Unusually, it seems that sea slugs had ingested the toxin, and were then poisonous to the dogs that ate them. Puffer fish themselves will rarely be eaten, because of their spines and their unpalatability, and the external part of the fish is far less toxic than the internal organs which are generally decomposed by the time the fish reaches the beach.
Interestingly, tetrodotoxin poisoning of people is common in Japan, where puffer fish is a traditional delicacy. Only specially trained chefs are allowed to prepare the fish. Symptoms of poisoning occur within minutes to hours and include tremors and paralysis and often death. There is no specific treatment.
After extensive testing, only two beaches in Auckland and Coromandel had affected sea slugs and so it’s been concluded that this was a localised and transient issue.
So, keep enjoying those beach excursions, but if you go to Japan watch out for the fish and chips!