Cage culture is one important form of aquaculture. The cage is made of polyethylene, metal, and other materials. At first, the cage culture was mainly used in large water. The main species were fishes. After decades of development, modern cage culture has improved greatly. The aquaculture has been developed from large water to small ponds. Species has developed from fishes to crabs, monopterus and others. Aquaculture yields and outputs have been greatly increased.
Cage culture is actually one form of captivity. The water inside and outside of the net can be naturally flowing. Water is constantly updated with wind, waves and flow. The water inside the box is constantly supplemented. The oxygen and plankton are continuously taken into the net as well. It can provide food for the fishes. At the same time, water can also take away the useless fish bait and faeces. It can keep the water fresh inside of the cage, which is good for the stockings. Without a doubt, the water exchange can guarantee the oxygen even for density fishery. Also, it can continuously recharge the natural bait. At the same time, it ensures water quality. It is a modern culture which combines natural environment and intensive cultivation. The cultivation can make full use of the favorable conditions in the large water surface.