Modeling growth of different developmental stages in bivalves
The five most common growth models (Gompertz, Special von Bertalanffy, Richards, Logistic and Generalized von Bertalanffy) were fitted to growth data comprising different developmental stages (i.e. free-swimming larvae, plantigrades, post-larvae and juveniles/adults) of the Caribbean pearl oyster Pinctada imbricata. As criteria for determining the most suitable model, the mean deviation of the data from the estimated growth curve (= mean square error, MSE), the deviation of the estimated asymptotic length of the observed maximum length obtained from a natural population, and the plot of the residuals against estimates were used.The Special von Bertalanffy and Richards models produce pure asymptotic curves and are therefore unable to simulate the exponential growth of the first two developmental stages (free-swimming larvae and plantigrades), furthermore they tend to overestimate the asymptotic length. Gompertz, Logistic and the Generalized von Bertalanffy model, on the other hand produce sigmoid curves and thus are much better capable of modeling growth of the combined developmental stages, thereby underestimating asymptotic length. From all models the Generalized von Bertalanffy model yields the best fit which is explained and discussed as a special mathematical property of its surface factor D.