Estimation of the Length-at-Age Relationship of Mississippi's Spotted Seatrout

We estimated the length-at-age relationship of Mississippi’s Spotted Seatrout using tag-recapture records and otolith-derived age estimates. Three length-at-age models were fit to sex-aggregated tag-recapture data and four length-at-age models were fit to sex-specific otolith-derived age estimates. The Francis 1988 “GROTAG” method had 100% support of the models fit to the tag-recapture data and the resulting parameter estimate of L_∞ was 550.8 mm (95% CI = 499.6 to 633.5). The three-parameter logistic model had the most support of the models fit to the otolith-derived age estimates for both female and male Spotted Seatrout. The resulting parameter estimates of L_∞ were 604.3 mm (95% CI = 565.8 to 657.1) for females and 588.2 mm (95% CI = 529.0 to 688.3) for males. The results of this study indicate that the “GROTAG” model was the preferred method for the determination of the von Bertalanffy growth function parameters from tag-recapture information, but that the von Bertalanffy growth function may not be the best model to describe the length-at-age relationship of Spotted Seatrout. Also, there was no significant sex-specific differences in the length-at-age relationship. This work highlights the utility of fitting multiple models to multiple sources of length and age information.