Types of fish culture systems according to the different feeding management practices.

  In terms of land requirements, for a given prospected fish production, ponds need much more area of land (or water surface) than more intensive fish culture systems which, on the other hand, need higher water flow rates provided by natural currents in lakes or rivers (in the case of cages or pens) or by water supply by gravity or artificial pumping (tanks, raceways).

 Ponds used for fish culture have generally a low level of negative impact on the environment. Moreover, they can be used for recycling various types of wastes.

For example, ponds can recycle wastes such as night soil directly as sewage-loaded ponds where fish are cultured or indirectly within an aquaculture excreta rinse system with stabilization and maturation ponds, the fish being farmed in the latter.

 Capital for investment needed for building ponds can be provided in the form of labor, which is not the case for cage, pens, tanks that require material to be purchased, or even imported.

Supply of high quality feed used for exogenous feeding fish farming systems requires a high level of cash flow, which is not the case of semi-intensive fish farming systems using lo w cost inputs such as agricultural by-products and wastes from livestock and crops.

 Expressed in man-days per unit of harvested fish, higher level of labor is required for fishpond system management (mainly for pond maintenance and cleaning, manuring, and harvesting) than for cages or other intensive fish production system.

 For a long time, it was admitted that endogenous feeding based fish farming systems were requiring only a low level of technical know-how from the fish farmers compared with exogenous feeding systems.

 The reality is far from so simple: the former system is developed in countries with an old tradition of fish culture practice and where a strong know-how has been accumulated even if mainly empirical.

 The many attempts to transfer these fish culture models into countries where there was no fish culture tradition failed because on the other hand, high feed input aquaculture models are based on technologies that are easier to transfer because their main components (fish stocking density, feeding rate, and composition of feed,) are well defined and are carried out within a culture environment where the environment components either interfere only few (cage culture in lakes or rivers) or are under control (raceways, tanks).

 Level of risks, in terms of fish diseases, is considerably reduced in extensive culture systems than in intensive ones. Similarly, production costs and yields are higher in intensive systems than in extensive, and semi-intensive culture systems.

 Ponds are multipurpose fish culture systems: they can be used for brood stock stocking and maturation, breeding according various methods (natural, semi-natural, artificial), fry nursing and fish growing out. Moreover, in pond structures such as hapas used for tilapia, fry production for example can be implemented. Intensive structures usually specialized for growing out purposes from fingerlings to market size fish.



 Lionel Dabbadie and Jerome Lazard