What are the aquatic foods?

Animals and plants produced by marine and freshwater fisheries and their processed products are collectively referred to. Fresh aquatic products are divided into four categories: fish, shrimp, crab and shellfish. Fish include bass, salmon, soft-shelled turtle, eel, grouper, yellow pomfret, left-handed fish, red snapper and three fish. Shrimp includes Australian and New Zealand lobsters, Taiwan Province grass shrimp, bamboo shrimp, giant shrimp and river shrimp; Crabs include Eriocheir sinensis, American rare crabs, king crabs, cream crabs and clean crabs. Shellfish include Canadian mussels, clams, oysters and clams. Aquatic products must be frozen if they are to be stored for a long time. There are many freezing methods, mainly air freezing, salt water immersion freezing and plate freezing. In China, air freezing method is widely used. In recent years, the plate freezing method has developed rapidly. When the freezing chamber temperature is below -25℃, and the central temperature of the fish body is reduced to-15℃, it is moved to the cold storage room with the storage temperature below-18℃ for cold storage, and the storage time is 6-9 months. The changes of aquatic products in cold storage are basically the same as those in cold storage, mainly the color, tissue structure and weight of fish, but all changes in cold storage are extremely slow.