Imports of adult eels from China and Taiwan between September and May came to 2,549 tons, a decline of around 35 percent from a year earlier, according to recent government trade data.
Imports of processed eels, such as those that have been broiled, also declined, down 41 percent to 5,482 tons, Finance Ministry data showed.
The figures indicate a decline of eel resources not only in Japan but in the rest of East Asia as well, including China and Taiwan, requiring economies in the region to better manage eel resources, experts said.
The sales volume of domestic and imported eels is expected to decrease 30 to 40 percent this year from a year earlier.
Meanwhile, imports of young eels for cultivation in Japan increased slightly, but domestic catches of young eels were poor, according to the Fisheries Agency.
The volume of young eels to be raised in domestic cultivation pools is expected to drop 20 percent from a year earlier.
Prices of imported eels at one point plunged to ¥3,000 per kilogram due to weak consumer demand but recently shot up to more than ¥3,500 owing largely to an expected seasonal increase in consumption.
Government data show that two-thirds of the roughly 40,000 tons of eels consumed in Japan in 2012 was imported in the form of adult eels and processed ones.