shellfish
Refers to shellfish as a general category, including bivalves, gastropods, and other edible or collectible marine mollusks.
この海岸ではいろいろな貝類が採れます。
Various kinds of shellfish can be gathered on this beach.
conchology
bivalves
Compound of 貝 (kai, 'shellfish') and 類 (rui, 'kind, category').