The bluefin tuna goes by different names in Japanese depending on its age. It starts out as “Meji,” grows into “Chubou” and finally is called Tuna (once it’s 50 kg or more).
Meji are less than 1 year old and weigh around 10 kg.
Chubou is an old word for relatively low-class Buddhist priests who were treated as errand boys. I guess it was meant to imply that these boys were even weaker than tuna. At this stage the fish are between 2-5 years old and weigh about 40kg.
Anything larger than that are called Maguro. The biggest is 3m long and 600kg or more. Especially large tuna are called Shibi. “Shibi” comes from the Japanese characters for “4-days”, which is how long the fish takes to mature.
Most meji and chubou are caught from May until the beginning of autumn when the tuna are thin and tasty.
Meji has its own unique scent and taste that sets it apart from full-grown tuna. The color is similar to the skipjack rather than bluefin. On the other hand, chubou has a lighter color and it isn’t as rich, but the flavor is young, refreshing tuna. That is why meji is considered to be a completely separate sushi topping and chubou is presented to be a type of tuna.
We hope this information will be helpful.
Revision date: September 14, 2018