Freshwater crayfish
Crayfish are farmed from northern Scandinavia to Australia, and in the Americas, in Asia (notably China) and in Africa. Unlike most aquaculture species the female crayfish incubates her eggs, conveniently avoiding the need for, and cost of, hatcheries. Once a pond has been stocked the crayfish ensure their own survival, disease permitting, without the need for restocking after harvest.
Crayfish are frequently combined with crop production, especially rice, and the crayfish, which escape the harvest, survive during the period while crops are growing by burrowing into the levees or pond banks. They form the brood stock for the next season, feeding on the residue of the crop and its associated food web.
Harvesting is the most costly element in crayfish production because baited traps must be used to attract the catch. Pond draining and seines are far less effective. There are some 400 species of freshwater crayfish but fewer than 15 species are cultivated on a regular basis. As with any other form of farming, correct choice of species for local conditions is essential.
