What are the characteristics of the black carp's living habits?
The black carp, also known as the black grass carp, green hybrid, spiral shell carp, black carp, etc., has strong adaptability and is easy to raise. It is an important fishery resource in the middle and lower reaches of the Yangtze River and along its lakes, and a main aquaculture species in various lakes and ponds. It is one of the "Four Major Chinese Carps" of freshwater aquaculture in China.
The black carp is not active in habit and usually inhabits the middle and lower layers of the water. Its food consists mainly of river snails, mussels, small clams, clams, etc., and it also preys on shrimp and insect larvae. At the fry stage, it mainly feeds on zooplankton. The black carp grows rapidly and has a relatively large body size; the largest adult individual can reach 70 kg.
Black carp mostly gather in river bends and along-lake areas rich in food to feed and fatten up, and overwinter in deep water. Its movements are powerful and it is not easy to catch. Its oxygen consumption is close to that of the grass carp; when the dissolved oxygen content in the water is below 1.6 mg/L, its respiration is inhibited, and when it drops to 0.6 mg/L, it begins to suffocate and die. It can survive within a water temperature range of 0.5-40 degrees C.
The optimum temperature for black carp reproduction and growth is 22-28 degrees C. It prefers slightly alkaline, clear and lean water quality. It mainly feeds on shellfish such as snails, small clams, and young mussels, and also eats a small amount of aquatic insects and arthropods. Its daily food intake is usually about 40% of its body weight, and can reach 60-70% when environmental conditions are suitable. When the larval fish reaches a body length of 7-9 mm, it enters a mixed nutrition period, during which it continues to use its own yolk while beginning to feed on rotifers and nauplii; at 10-12 mm, it feeds on cladocerans, copepods, and chironomid larvae; when the body length reaches about 30 mm, its feeding habits gradually differentiate, and it begins to feed on small snails.