Definitions of Aquaculture

Aquaculture

Aquaculture is the farming of aquatic organisms: fish, molluscs, crustaceans, aquatic plants, crocodiles, alligators, turtles, and amphibians. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated.

 

For statistical purposes, aquatic organisms which are harvested by an individual or corporate body which has owned them throughout their rearing period contribute to aquaculture, while aquatic organisms which are exploitable by the public as a common property resource, with or without appropriate licences, are the harvest of capture fisheries.

 

The main culture environments

 

  • Freshwater Culture - cultivation of aquatic organisms where the end product is raised in freshwater, such as reservoirs, rivers, lakes, canals and groundwater, in which the salinity does not normally exceed 0.5%. Earlier stages of the life cycle of these aquatic organisms may be spent in brackish or marine waters.



  • Brackish water - cultivation of aquatic organisms where the end product is raised in brackish water, such as estuaries, coves, bays, lagoons and fjords, in which the salinity may lie or generally fluctuate between 0.5% and full strength seawater. If these conditions do not exist or have no effect on cultural practices, production should be recorded under either "Freshwater culture" or "Mariculture". Earlier stages of the life cycle of these aquatic organisms may be spent in fresh or marine waters.



  • Mariculture - cultivation of the end product takes place in seawater, such as fjords, inshore and open waters and inland seas in which the salinity generally exceeds 20. Earlier stages in the life cycle of these aquatic organisms may be spent in brackish water or freshwater.

 

The main growing units


  • Tanks and ponds - artificial units of varying sizes constructed above or below ground level capable of holding and interchanging water.

 

  • Enclosures and pens - refer to water areas confined by net, mesh and other barriers allowing uncontrolled water interchange and distinguished by the fact that enclosures occupy the full water column between substrate and surface; pens and enclosures will generally enclose a relatively large volume of water.

 

  • Cages - refer to open or covered enclosed structures constructed with net, mesh or any porous material allowing natural water interchange. These structures may be floating, suspended, or fixed to the substrate but still permitting water interchange from below.



  • Raceways and silos - artificial units constructed above or below ground level capable of high rates of water interchange in excess of 20 changes per day.

  • Barrages - semi-permanent or seasonal enclosures formed by impervious man-made barriers and appropriate natural features.

 

  • Rice-cum-fish paddies - refer to paddy fields used for the culture of rice and aquatic organisms; rearing them in rice paddies to any marketable size.

 

  • Recirculating aquaculture systems (RAS) recycle water by circulating it through filters to remove fish waste and food and then recirculating it back into the tanks. This saves water and the waste gathered can be used in compost or, in some cases, could even be treated and used on land.

 

  • Rafts, ropes, stakes - refer to the culture of shellfish, notably mussels, and seaweeds usually conducted in open waters using rafts, long lines or stakes. The stakes are impaled in the seabed in inter-tidal areas and ropes are suspended in deeper waters from rafts or buoys.

 

  • Hatcheries - refer to installations for housing facilities for breeding, nursing and rearing seed of fish, invertebrates or aquatic plants to fry, fingerlings or juvenile stages.

 

  • Nurseries - refer generally to the second phase in the rearing process of aquatic organisms and refer to small, mainly outdoor ponds and tanks.