Why is puffer fish so poisonous

License to kill puffer fish

Fugu, in English puffer fish, is valued as an expensive delicacy in Japan. The fishing season lasts from September to March, and lovers of this specialty can look forward to a variety of different fugu dishes during this time of year.

The consumption of this fish also has a special attraction because it contains a poison called tetrotodoxin, so that special care must be taken when removing the liver and ovaries. If even a drop of the poison it contains came into contact with the rest of the fish when you gutted the liver, it could easily be your last meal.
Before 1969, around 200 people fell victim to fugu annually in Japan. Since then, there has been a tightening of training for fugu chefs, which has led to a drastic decrease in deaths. In earlier times there were restaurants that served the liver anyway, as the body can tolerate small amounts of this poison. However, after the death of a famous kabuki actor in 1975, the law was tightened even further.

There are around 40 species of Fugu on the Japanese coasts, which vary considerably in size, shape and color. The Torah fugu, which has the "classic" puffer fish appearance, is considered a good food fish. It occurs in the waters from Hokkaido to southern Japan and is up to 70 cm long. It is particularly poisonous during the spawning season in May and June and is therefore only caught in winter.

A license is required to prepare puffer fish in a restaurant. The budding fugu cook must learn to differentiate between the different types and learn for several years under the guidance of a state-certified fugu cook. So poisoning only occurs with improper preparation, in restaurants today the risk is zero. Although the Japanese are well aware of the dangers of the puffer fish, incidents occur from time to time, e.g. when six men caught the delicacy on a fishing trip and then prepared it themselves in the kitchen of a gas station. Two of them were rushed to hospital with severe poisoning but were saved.

Source: Geo Japan, Kodansha Encyclopedia of Japan