1.1 INTRODUCTIONAquaculture according to FAO (1997) is defined as the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants up to final commercial production in selected or controlled environment. The rapid growth in the culture fisheries sector contrasts with the decline or near stagnation in the growth of supplies from capture fisheries. There are inherent hazard and risks associated with aquaculture production. (Erondu and Anyanwu, 2005).In developed countries there have been heated debates among stakeholders as to the risk and hazards of the system. This does not in any way preclude the importance or significance of aquaculture in the food sector; rather it is a means of resolving issues related to the undesirable effects of the system. Unfortunately, the awareness has not been created in developing countries that produce a major proportion of the product. This is predicted on the fact that majority of the producers belong to the informal sector of the economy. The production system also present risk to public health, change landscape of aquatic system resulting in habitat destruction and loss of biodiversity. Chemical used in culture fisheries can become disruptive and when they: Find their way into natural aquatic system, they can cause irreparable damage to the ecosystem. Effluents from culture fisheries which consist largely of fish and feed wastes contain large quantities of nutrients that damage the water quality and also generate unwanted algae. The situation is exacerbated by the fact that these farms operate outside the institutional regulatory framework and with minimal supervision from regulatory bodies.
1.2 AQUACULTURE PRODUCTION SYSTEMS AND ANCILLARY INDUSTRIESThe associated processes in aquaculture are:(a) Processing: fish product are processed and packaged for local consumption and export. The processes are carried out at the local and industrial level. Theses include smoking, chilling, freezing, canning, filleting and production of other value-added products.(b) Laboratories: These are established in research station, large hi-tech farms and processing plants for environmental/facility water quality monitoring and quantity control. (c) Feed mill plants: These are established to produce on farm or commercial feeds. The scale operation is varied.(d) Association industries: These are industries that are involved in manufacturing equipment used in culture fisheries, these include nets, fertilizer plants, bio filter, drugs, fibre glass tanks etc. Finfish, shell fish and other farmed aquatic organisms are produced in fresh water, brackish water and marine environment.
The receptacles for cultivation of these organisms include earthen ponds, pens, cages, rice fields, race ways, open water bodies etc. based on the level of operation the system is classified as:.