The government plans to impose regulations on eel farmers because the Japanese variety was internationally designated as a species at risk of extinction last month, government sources said.

Since eel farming in Japan relies mostly on catches of wild young eel, which are on the decline, the government wants to prevent excessive production and catches from developing in the world's biggest consumer of the fish.

Japan plans to work out a decree by the end of the year requiring eel farmers to file reports to help it determine actual conditions, such as the number being produced on fish farms, the sources said Wednesday.

In the future, the government plans to start a permit system for eel farmers, they said.

Two groups of domestic eel farmers — the All Japan Eel Culture Association and the Union of Eel Farmers Corporation of Japan — also plan to launch a joint organization to manage production and call on nonmembers to participate, the sources said.

There are around 420 eel farmers in Japan, according to the Fisheries Agency.

A new law enacted in June allows the government to regulate inland fisheries when necessary to ensure sustainable use of resources.

In June, the International Union for Conservation of Nature and Natural Resources put the Japanese eel on its red list of species at risk of extinction, citing overfishing, destruction of habitats and other factors.

In 2013, the Environment Ministry designated the variety as at risk of extinction, but subsequent efforts to improve the situation have yet to bear fruit.