ESTIMATION OF INDIVIDUAL GROWTH PARAMETERS OF THE CORTES GEODUCK PANOPEA GLOBOSA FROM THE CENTRAL GULF OF CALIFORNIA USING A MULTIMODEL APPROACH

We describe the growth of the Cortes geoduck Panopea globosa (Dall 1898) in the Central Gulf of California using a multimodel approach. Geoducks were collected from November 2008 to February 2010 as part of an experimental fishery off Guaymas, Sonora, Mexico. Their age was established using the acetate peel method. Individual growth was estimated by means of 4 models: von Bertalanffy, logistic, Gompertz, and Schnute. The parameters in each model and their confidence intervals (CIs) were computed using the maximum likelihood method. The best-fitting model was selected using Akaike's information criterion (AIC). According to the AIC, the logistic growth model best describes the growth of P. globosa in this region. We recomputed the CIs of the best model through bootstrapping the model 1,000 times. We found that the asymptotic length of the shell of P. globosa off Guaymas (located in the Central Gulf of California) was 122.2 mm (95% Cl, 116.3-128.1) by averaging the asymptotic length estimated in the 3 candidate models (Schnute was not supported). After bootstrapping, the values for the parameters and the first-order corrected 95% CI of the logistic model were L-infinity = 122.16(118.2-124.94), K = 0.497 (0.36-0.614), and t(0) = 2.26 (1.599-2.571). We concluded that using a multimodel approach and the AIC represent the most robust method for growth parameter estimation, at least in the studied species.