The present state
of the crayfish in Japan (2)
From now on in front of about 90 years, the signal crayfish was imported by Japan for the first time.
Japan of those days had little food.
Therefore, the government looked for the new foods for the Japanese.
The signal crayfish was imported from the United States by the government as one of the new foods.
The government distributed it to the fisheries experimental station, and made it study.
However, almost all institutions went wrong and the Japanese did not eat it.
The government stopped the research and the signal crayfish became remaining in Lake Mashu in Hokkaido, and Lake Tankai of Shiga Prefecture.
And the state as it is continued about 50 years.
It becomes around 1980 and a signal crayfish came to be discovered suddenly in the eastern part of Hokkaido.
Lake Mashu has neither a river flowing in nor a river flowing out.
The signal crayfish was artificially carried out by of who doing.
Then, they increased power rapidly.
Now, it is found in Fukushima Prefecture, Chiba Prefecture, Niigata Prefecture, Fukui Prefecture, etc. in addition to Hokkaido.
They have given the serious damage to the ecosystem of the introduced place.
The place extinct by them also has a peculiar crayfish.
Although the government regulated movement and breeding of them law in 2006, the situation has not improved.
We have caught this state very seriously.