The catch of young Japanese eel used for cultivation has dramatically decreased, according to the Fisheries Agency. From a peak of 232 tons in 1963, the annual catch fell by half in the 1970s and has remained below 10 tons since 2010. The catch of adult eels has also sunk to 4 per cent of peak levels.
Last year, the Environment Ministry designated the Japanese eel as a species at risk of extinction on its domestic Red List.
Though the catch shows chances of recovery, doubling last year's record-low haul, an official of the International Union for Conservation of Nature (IUCN) said, "The situation of the Japanese eel still shows a long-term decreasing trend."
The European eel was listed in the critically endangered category of the IUCN's Red List last year, with the same designation given once again this year.
The status of the shortfin eel (Anguilla bicolor), which is farmed in Indonesia with an increasing amount being exported to Japan, was reevaluated from the IUCN category of Least Concern to Near Threatened.
The IUCN is continuing to assess the status of American eel.