【Reading】にほんうなぎ

【English Name】Unagi (Japanese Eel)

Nihon-unagi (Japanese eel) is a fish of the family Anguillidae distributed across East Asia, deeply connected to the history of Japanese food. Adults are usually about 1 meter in body length, with large ones reaching about 1.3 meters. Its distinctive slender, cylindrical body has a surface made slimy by mucus.

After living for about 5 to 12 years in rivers and lakes, it migrates a long distance to near the Mariana Ridge in the south to spawn. This spawning ground was long unknown, but in 2006 it was pinpointed by the team of Katsumi Tsukamoto to the offing west of Guam Island. The larvae born from the eggs are carried to the East Asian coasts using ocean currents, become glass eels (shirasu-unagi), and ascend rivers.

As a sushi topping, the form of placing kabayaki (grilled glazed eel) on nigiri is common, and it is also used in oshi-zushi (pressed sushi) and maki-zushi. Its appeal is the richness of fat and soft flesh quality, and the combination with a sweet-savory sauce is standard.

In recent years resource decline has become serious, and in 2014 the IUCN classified it as an endangered species (EN). Aquaculture depends on catching natural glass eels; complete aquaculture succeeded at an experimental level in 2010, but the road to practical application and mass production has not yet opened. In 2025, there were moves such as the EU proposing the listing of all eel species in CITES Appendix II, strengthening the international momentum for conservation.