[01] Judith W. Muya, Department of Fisheries and Aquatic Sciences, School of Natural Resources, University of Eldoret, Eldoret, Kenya. [02] Julius O. Manyala, Department of Fisheries and Aquatic Sciences, School of Natural Resources, University of Eldoret, Eldoret, Kenya.

The importance of aquaculture has become more apparent at present, with higher demanding pressure from an ever-increasing world population. However, the industry is facing copious challenges the major one being the need to obtain a perfect balance between precipitous fish growth and optimum use of the stocked feed. In any aquaculture system, the cost of feeds accounts for approximately 40 - 60% of the operating costs in intensive culture systems. These costs highly affect the output since the economic viability of any culture operation depends on the feed and feeding frequency. The relevance of fish farming in the aquaculture context lies in the urgent need for income generation. The economic viability of any specie lies in its ability to consume less and produce more. This study therefore sought to determine the growth performance in relation to economic viability of four fish species (rabbit fish (Siganusvermiculatus), red snapper (Lutjanusargentimaculatus), milk fish (Chanoschanos) and groupers (Epinephelusfuscoguttatus)) under cage culture. The experiment consisted of 16 floating cages, four cages for each species and each cage holding a total of 50 juvenile fish of weight between 50-70 gm, reared for six months. Monthly variations of mean weight for each species in each of the cages show that groupers had the highest final body weight (242 ± 10.2 g). The groupers had the highest Percent Weight Gain (PWG) (290.3%) followed by milk fish (168.6%). The Specific Growth Rate (SGR) was also highest for the grouper (0.89%) as compared to milkfish (0.65%), rabbit fish (0.53%) and red snapper (0.33%). Groupers had the highest length – weight relationship value (R2) of 96.6%. The milk fish recorded the highest Feed Conversion Ratio (FCR) (38.9 ± 2.68). As for the economic value, milk fish also had the highest value of 4,050 for the catch of 162. Based on the results it is concluded that groupers is the best candidate for culture as compared to the other three test species. It is recommended that intensive pilot culture of groupers be undertaken in cages to develop an enterprise budget and business plan for commercial investment to improve livelihoods of the coastal community and at the same time, open up the opportunities for further research on nutrition, husbandry and further research on growth requirement of groupers.

Growth Performance, Economic Viability, Cage Culture, Fish Species

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