DESIGN, CONSTRUCTION AND USE OF A MODEL WATER RECIRCULATING SYSTEM FOR INCUBATION AND REARING OF Cyprinus carpio

This study was designed to design and construct a model Water Recirculatory System and use same to carryout induced breeding and larvae rearing of Cyprinus carpio using hormonal techniques. A simple 660 litres capacity Water Recirculation System (WRS) technology was developed, built and evaluated for this study. The WRS was designed and constructed in relation to waste production and waste removal kinetics. The system rearing troughs were made of black and white rectangular plastic containers. Efficiency of the design method and the effect of color of rearing unit were tested on growth performance and survival of Cyprinus carpio hatchlings, to assess the technical functionality of the system. The experiment was divided into two phases; artificial propagation of each Fish species using synthetic hormone and rearing the Fry for 14 days; and rearing the 14 days old fry for 42 days. In the first phase of the experiment, hatchability was estimated, while in the second phase, growth performance and nutrient utilization were investigated. Daily water replacement was maintained at 10 % of total volume of water in the WRS throughout the experimental period. Results of breeding/rearing trial gave high survival rate and fast growth rate of hatchlings. Hatchability results indicated that Black troughs had higher hatchability rate of 69.80±0.55 than white troughs 67.45±0.99. There was no significant difference (p>0.05) between the Treatments in Mean Weight Gain (MWG), Specific Growth Rate (SGR), Food Conversion Ratio (FCR), Food Conversion Efficiency (FCE) and Protein Efficiency Ratio (PER). High % Shooters was recorded in Black troughs than in white troughs for the specie studied. % Survival rate was high (71.33 %) in Black troughs than in white troughs (53.33 %). Based on the results of the water quality parameter analysis, the system was technically able to deliver optimum water quality for Fish growth and survival of Cyprinus carpio incubated and reared within system facility. This study revealed that the designed system can be used to incubate and culture hatchlings of Cyprinus carpio. Keyword: Water Recirculatory System, Cyprinus carpio.