Age and growth parameters of the panamic stingray (Urotrygon aspidura)

The aim of this study was to estimate the age and growth parameters of the Panamic stingray (Urotrygon aspidura) of the Pacific coast of Colombia. Vertebral centra were removed from 309 individuals and used for estimation of age. The results of edge type and marginal increment analysis indicate an annual formation of band pairs. The maximum ages estimated were 7.5 and 5.5 years for female and male Panamic stingrays, respectively. Individual growth was described through a multi-model approach and inference, by using von Bertalanffy, Gompertz, and logistic models with 2 and 3 parameters each and a two-phase growth model with 4 and 5 parameters. A two-phase growth function of 5 parameters with adjusted age provided the best description of growth for females (asymptotic disc width [DW_∞]=24.71 cm, growth coef­ficient [k]=0.47 cm/year, disc width at birth [DW₀]=8.18 cm, age at transition between 2 phases [t_h or inflection point of the curve]=2.32 years, and maximum difference in disc width at age between von Bertalanffy and two-phase models [h]=0.36) and males (DW_∞=15.96 cm, k=1.63 cm/year, DW₀=8.07 cm, t_h= 2.22 years, h=0.54). The growth curves were dissimilar between sexes mainly after the inflection point, and differences were found for all parameters, except for t_h. The Panamic stingray is a fast-growing and short-lived elasmobranch, similar to other species of the Urotrygonidae.