【Reading】わたりがに

【English Name】Swimming Crab

The watari-gani, a group of swimming crabs belonging to the order Decapoda, is classified as a member of the family Portunidae that possesses swimming legs. In the English-speaking world too it is treated as a symbolic representative of swimming-type crabs, and in Japan "watari-gani" customarily refers to the gazami (Portunus trituberculatus).

What characterizes this crab is the presence of swimming legs whose rearmost limbs have evolved into an oar shape. From the way it skillfully uses these legs to swim freely about in the sea and even makes long-distance migrations, it is said to have been named "watari-gani" (migrating crab). It is a large species with a carapace width exceeding 15cm, and from the outline of its nearly rhombic carapace it is also affectionately known by the alternative name "hishi-gani" (diamond crab).

Its habitat spans the entire Japanese coast from southern Hokkaido to Kyushu, and it is also confirmed in Korea, China, and Taiwan. Major domestic production areas include Aichi, Fukuoka, and Ehime prefectures, and it makes its main home on the sandy-muddy bottoms of inner bays. Its season differs between males and females: males are at their best from summer to autumn, and females from late autumn to spring. Females from winter to spring are especially prized as their inner roe (uchiko, ovaries) develops.

The meat in the legs is only a small amount, and the body meat and crab miso (tomalley) are considered the highlights. Salt-boiling, steaming, miso soup, and takikomi gohan (mixed rice) are representative ways of eating it, and it is also widely used as an ingredient for the Korean dish gejang. It is said that in Edo-period Tokyo, "kani" meant the gazami, and it is also a presence deeply tied to the food culture of Edomae.