Also called Fish Farming, Fish Culture, or Mariculture, an approximate equivalent in fishing to agriculture—that is, the rearing of fish, shellfish, and some aquatic plants to supplement the natural supply. Fish are reared under controlled conditions all over the world. Fish may be confined in earth ponds, concrete pools, barricaded coastal waters, or cages suspended in open water. In these enclosures, the fish can be supplied with adequate food and protected from many natural predators. While most fish farming is devoted to the commercial food market, many governmental agencies engage in it to stock lakes and rivers for sport fishing; there is, in addition, a steady commercial market for goldfish and other decorative fish for home aquariums. Aquaculturists also raise bait fish for both sport and commercial fishing. Ocean ranching by governments is intended to restock lakes and oceans. The young fish are bred in the controlled environment and when sufficiently mature are released into the open sea. Oysters (as a source of both food and pearls), scallops, and mussels are raised throughout most of the world. Carp, trout, catfish, and tilapia are also widely raised. Experiments with ocean ranching in the late 20th century led to the economically successful aquaculture of lobsters.
Source: Encyclopaedia Britannica 2002