【Reading】めじTuna

【English Name】Young Bluefin Tuna (Meji Maguro)

A young Pacific bluefin tuna (hon-maguro) before it becomes an adult is a meji-maguro, a name that spread in the Chubu and Kanto regions. In the Kinki and Shikoku regions it is fondly called "yokowa," a name derived from the white spots and 10 to 20 horizontal stripes that appear on the flanks of the juvenile.

With the scientific name Thunnus orientalis, it is a fish of the genus Thunnus in the family Scombridae, living in a wide expanse of the Pacific Ocean from the tropics to the temperate zone. It was once grouped as a single species with the Atlantic bluefin tuna inhabiting the Atlantic, but today the accepted view regards the two as independent, separate species.

The parent Pacific bluefin tuna is a large migratory fish reaching 3 m in total length and 400 kg in weight, but the meji-maguro is immature and small in body, offering light lean flesh (akami) with modest fat. It is highly popular as sashimi and as a sushi topping.

In dietary guidelines for pregnant women published by the Ministry of Health, Labour and Welfare in 2005, an intake limit of once a week (about 80 g) was set for the adult Pacific bluefin tuna. By contrast, meji-maguro has low mercury accumulation in its body, and the view has been issued that there is no problem in eating it as part of an everyday diet.