Aquaculture is the captive rearing and production of fish and other aquatic animal and plant species under controlled conditions. Many aquatic species have been cultured, especially fish, crustaceans and molluscs and aquatic plants and algae. Aquaculture production methods have been developed in various regions of the world, and have thus been adapted to the specific environmental and climatic conditions in those regions.
The four major categories of aquaculture include open water systems (e.g. cages, longlines), pond culture, flow-through raceways and recirculating aquaculture systems (RAS).
In a RAS operation water is reused for the fish after a cleaning and a filtering process. Although a RAS is not the cheapest production system owing to its higher investment, energy and management costs, it can considerably increase productivity per unit of land and is the most efficient water-saving technology in fish farming.
A RAS is the most applicable method for the development of integrated aquaculture agriculture systems because of the possible use of by-products and the higher water nutrient concentrations for vegetable crop production.