Sankei News reported that in 1957 approximately 207 tons of small eel were caught, but by 2008 that number had dropped to just nine tons. Beyond that, attempts at farm breeding the animal have not been successful worldwide.

In response, scientists at the Fisheries Research Agency began studying artificial breeding methods.

By 2002 the Agency had accomplished artificially fertilizing and incubating eel eggs. The Agency has also had success in raising eel larvae to maturity.