The term aquaculture was coined to embrace all the activities of man, to produce any aquatic resource of economic value through husbandry during the whole or part of its life cycle. The resources can take the form all the way from a tiny plant, the algae, to a giant seaweed or from a micro-crustacean to a big fish. It may be reared in a small aquarium, a compact re-circulating tank system to big ponds or even in the open lake or sea.
Asia is supposed to be the seat of the oldest aquaculture dating as far back as 3,500 years ago. It is often mentioned that in Southeast Asia, there existed long-established aquaculture industries (Ling and Rabanal, 1973). Such industries cover extensive areas estimated at two million hectares and producing annually over 4.5 million metric tons of fish. The investment can be equivalent to as much as US$3,000 million.
The world production of fish averages about 60 million metric tons per year of which 6 million or 10 percent come from aquaculture (Pillay, 1976). The major part of the aquaculture production or over 80 percent come from Southeast Asia (Rabanal, 1974).