Comparison of the Performance of Growth Models for Farmed Tilapia

A number of models exist for describing fish growth. The von Bertalamffy model, being the most popular, has been used by numerous studies to model the growth of different fish species under various growth conditions. Economic analysis of size-at-age in aquaculture systems requires models with minimum uncertainty. Aquaculture presents a different challenge when modeling fish growth because farming involves control of feeding and improvement of the environment aimed at achieving large fish sizes in a relatively short time. This accelerated growth diverges from the pattern expected of the same species in the wild. In this study, we compared the performance of the von Bertalamffy model with the Gompertz, Chapman-Richard, and other models hypothesized to better describe fast growth during a 6-8 month growout of Nile tilapia Oreochromis niloticus. We obtained length and weight data measured at approximately 2-week intervals from 24 experimental ponds in Ghana, where mostly male tilapia were managed under four combinations of feeding and water quality management regimen.  On the basis of minimized small-sample corrected Akaike Information Criterion (AICc), initial comparison between the von Bertalamffy and Gompertz models suggests that the Gompertz is a better fit to the early growth pattern of tilapia in pond systems.