The glass eel trade is coming under international scrutiny. ... Already, cultured eels account for more than 99% of the world's supplies. But the farming of these eels is totally reliant on elvers born in the wild. ... Although techniques to create artificial breeders to allow for the full cultivation of eels have been established, commercial production, as in the case of tuna, remains impossible. ... A big problem is that much of the glass eel trade essentially takes place in the dark. ... In the fishing season of 2015, for example, 18.3 tons of baby eels were procured domestically, while 3 tons were imported. The volume of eel caught domestically thus came to 15.3 tons. But data from prefectural governments, once tabulated, puts the total amount of domestic catches at 5.7 tons.