Multi-criteria approach to estimate the growth curve in the marine shrimp, Penaeus vannamei Boone, 1931 (Decapoda, Penaeidae)

The aim of the present study was to test the hypothesis that size variation among individuals of one particular age affects the precise assessment of anticipated growth curve trajectories and their parameters for the marine shrimp, Penaeus vannamei Boone, 1931. The data came from shrimp farmed in earthen ponds of an aquaculture farm located in the Gulf of California. Five asymptotic models were applied to averaged length-at-age data: specialized Von Bertalanffy, generalized Von Bertalanffy, Gompertz, Logistic and Johnson. These models were parametrized considering two criteria: (1) variability in length-at-age (σi2) decreases with age (growth compensation approach), (2) constant variance ("normal" and "fat tail"). The model parameters were computed with the maximum likelihood criterion. The corrected version of Akaike's information criterion AICc, selected the Gompertz model and the growth compensation approach as those who fitted the data best. We conclude that the growth compensation approach allows the application of a very high performance objective function to analyse individual length-at-age variability without underestimation of the parameters, and also that the best model to describe the growth trajectory of P. vannamei in a farmed environment is a sigmoid curve with an inflection point at 34% of the life period analysed (the Gompertz model).