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Spotted Seatrout Cynoscion nebulosus are a highly valued recreational inshore species in Mississippi coastal waters. The accurate description of the length-at-age relationship is critical for assessment efforts of the stock. Because Spotted Seatrout exhibit small-scale movements, the stocks in the Gulf of Mexico are managed as statespecific units. Therefore, local demographic estimates of length at age are needed for assessment. We estimated the length-at-age relationship of Spotted Seatrout in Mississippi by using tag recapture records and otolith-derived age estimates. Three nonlinear length-at-age models were fit to sex-aggregated, tag recapture data and four nonlinear length-at-age models were fit to sex-specific, otolith-derived age data. For each suite of models, model support was determined using Akaike information criteria. The Francis (1988a) GROTAG method had the greatest support of the three models fit to the tag recapture data, and the resulting parameter estimates from the model were L 1 D 550.8 mm and k D 0.45/year. The three-parameter logistic model had the greatest support of the four models fit to the otolith-derived age data for both males and females and the resulting parameter estimates of L 1 were 605.3 mm TL for females and 574.9 mm TL for males. The results of this study indicate that (1) the Francis (1988a) GROTAG model was the best-supported method for the determination of the von Bertalanffy growth function parameters from tag recapture information, and (2) the von Bertalanffy growth function may not be the best model to describe the length-at-age relationship of Mississippi's Spotted Seatrout. This work highlights the utility of using multiple sources of length-at-age information and fitting multiple models to enhance both the description of the length-at-age relationship and to determine biases that occur in both.

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Spotted seatrout, Cynoscion nebulosus, is an important recreational fishery in the coastal waters of the Gulf of Mexico and is the most sought after gamefish in coastal Mississippi. The management of C. nebulosus is state-specific, and unlike other similarly managed species, data on both population structure and movement support the existence of local sub-stocks. It is important for each state to clearly examine its own sub-stock in the context of its own state fishery in order to properly manage for local sustainability. We used an age-structured assessment model to examine the status (1993-2005) of the Mississippi C. nebulosus population and to project forward several probable management actions (i.e., length limits) while also accounting for uncertainty in both fishing mortality and annual recruitment. Model results suggest annual fishing mortality for Mississippi C. nebulosus is close to F msy , but that spawning stock biomass (SSB) is not below SSB msy. This suggests the sub-stock is currently stable, but with high fishing pressure and a high dependence on annual recruitment to the fishery. Projections suggest that when uncertainty in angler effort and annual recruitment are included in the analysis, more conservative management actions are warranted in order to achieve both higher fishery yield and stable SSB.

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