Abstract:
Most developed aquacultural models are designed for foreign species and environments and hence the need to develop a model for African farmed fish. This paper describes the development of an Aquacultural System Management Tool (AQUASMAT) for predicting tank systems for culturing African catfish (Clarias gariepinus). The model development involved formulation of theoretical relationships for intensive tankbased fish culture from existing models and development of program code with Microsoft® Visual C# (C-sharp). The model was designed to predict the effect of different management operations on fish yield, identify and quantify the cause, effect and relationships between water quality parameters, and suggest remedial actions for impaired systems. It also predicts economic viability of the production system based on cost input used in the system and track the fate of many water quality parameters which are not readily measured. The developed model was calibrated, validated and applied to ascertain its suitability. The model calibration results showed a close trend between the predicted and observed data, indicating a reasonable performance and adequacy of system representation. Regression analysis on the validated results indicated a strong correlation between predicted and observed data for TAN, temperature, NO3 and fish weight. Model adequacy results were within the recommended range, with relative bias (rB) of 0.014, −0.159, 0.039,−0.104 and F-test of 0.740, 0.877, 0.887 and 0.736 for temperature, DO, TAN and fish weight, respectively. Model sensitivity analysis showed that the model was very sensitive to parameters such as temperature, pond size, feed and stocking density, hence accurate estimation of these parameters is recommended for optimal performance of the model. Model experimentation results showed DO and TAN were within tolerable water quality limits only for stocking densities of 7 fish/m2, 14 fish/m2 and 21 fish/m2 and predicted profit in Nigerian currency, Naira ( ) of 1100:00, 1681:00, 1575:00, 820:00 for 7 fish/m2, 14 fish/m2, 21 fish/m2 and 28 fish/m2, respectively, and a loss of 1501:00 for 35 fish/m2 for the model scenarios.
