ABSTRACT
Since about 1960 the grass carp has been disseminated throughout the world from its original biotopes in the main rivers of China. The reason for both the wide dissemination and the publicity is the fact that the grass carp is an herbivorous species, allowing it to be used in fish polyculture, as a plant-waste converter and as a biological weed control agent. Most of the technical problems in relation to grass carp production and management have been solved and the results can be used generally. This does not mean, however, that new introductions of grass carp can be made without any research. Mass breeding stands at the basis of the production process of grass carp culture. The age of sexual maturity in grass carp differs greatly with climatological region and rearing history. As is the case with most members of the cyprinid family, the fecundity of grass carp is very high.
