noun
ayu sushi; sweetfish sushi
A regional specialty where sweetfish (ayu) is salted, pickled, and served on vinegared rice. Often associated with areas like Gifu or Shiga.
岐阜の名物、鮎ずしを初めて食べた。
I tried ayu sushi, a specialty of Gifu, for the first time.
鮎ずしは、鮎の腹に塩をして漬け込み、ご飯の上にのせて作られる。
Ayu sushi is made by salting and pickling the belly of sweetfish, then placing it on rice.
Refers to the sweetfish itself, not the sushi dish.
General term for sushi; 鮎ずし is a specific type.
Compound of 鮎 (ayu, 'sweetfish') and ずし (zushi, a voiced form of すし 'sushi'). The voicing is a common rendaku phenomenon in Japanese compounds.