Aquaculture, the farming of aquatic organisms including fish, mulluscs, crustacean and aquatic plant is necessary to meet the protein need of Nigerians. Overtime, there has been increase in fish production in Nigeria. Despite this increase in fish production, the desired result has not been attained. Quantitatively, details of fish production as at 2005 stood at 490,600 tons (FAO, 2003) from the artisan fishery, 56,300 tons from industry fishery through the use of trawlers, while fish importation stood at 61,150 tons. In meeting up with the growing need for fish production, aquaculture practice has been identified as a possible alternative, the reasons being that the activities of artisans and industrial fishery in our natural waters have led to over exploitation and degradation due to human activities in our coastal water. To fully bring aquaculture to its desired level, four production challenges have been identified. These are the challenges of feeding the fish stock in the pond, management of pond water supply, fish seeds provision and pond construction/establishment. The first two challenges: fish feeding and water quality management affect each other. The level of feeding of the stocks affects the water quality and the level of water quality affect the feeding performance of fish in the pond (George, 2001).
Fish like other animals need food to be able to carry out their metabolic activities. In aquaculture, fish feeding is either supplemental or complete (total supply). Supplemental feeding is when feeds are given to the animal at a minimal level to add to the natural food available for the fish in the pond water. These natural foods are in the form of phytoplankton and zooplanktons. The complete feeding is when the source of food fed to the fish is solely supplied by the farmer. In whichever case, the type of feeding practiced depends on the nature of the pond and the type of production the farmer is involved with (Michael, 1987; Michael et al., 2005).
The most popular cultured fish in Nigeria is the Catfish. It is naturally carnivorous, a bottom pond dweller, nocturnally very active and belongs to the family of Claridae (Willian, 1967; Idoho-Umeh, 2003). However, with the fish domestication, its modes of feeding and activities have been destabilized and modified. To this end, the feeding regime has become diverse but the thumb rule of feeding stock at optimum level should be very economical so as to have savings in feed cost and the overall economic justification. Webster et al., (1992) reported that catfish can be fed once or twice daily and rainbow trout at three times a day. In whichever case, the type of feeding practiced depends on the nature of the pond and the type of production; climatic condition and economic status of the farmer dictate the feeding requirement.
Various studies have been done in fish feeding (Collins and Delmendo, 1979; Sena and Brain, 1992) but much is still to be done in the area of the best time of the day and frequency to feed catfish so as to have good growth performance that will justify the high cost of feeding provided by the farmer. Determining the best frequency of feeding the catfish is therefore expected to help to maximize performance, discourage waste, and ensure the success of the enterprise. This will help to discourage the deterioration of water quality which may arise from the decomposition of feeds fed to the fish due to feeding at inappropriate time and frequency. This in turn is expected to help to minimize fish mortality due to pond water quality deterioration. The Overall production of the stock will also be enhanced (Norm, 2000). Hence, the need to study the growth performance of Clarias gariepinus fed at a frequency of once and twice daily for an enhanced yield derived from better and faster growth for production of the catfish.
1.1 AIM AND OBJECTIVES
The aim of this research is to feed Clarias gariepinus at different frequencies of once and twice daily with the following specific objective:
This study is useful to fish farmers as it is expected to create awareness on the appropriate feeding frequency that can yield better growth in Clarias gariepinus culture. It is also expected to enable aqua culturists to be aware of the best economical method that yields better growth in different feeding frequencies within a short production period. Finally, the results are expected to be useful to commercial fish farmers in making managerial decisions in the production of Clarias gariepinus.