Preliminary Evaluation of the Scale Method for Describing Age and Growth of Spotted Seatrout (Cynoscion nebulosus) in the Matagorda Bay System, Texas


Inconsistent literature and inadequate methods validation data prompted a pilot study to evaluate the use of scales to estimate age and growth of spotted seatrout (Cynoscion nebulosus) in Matagorda Bay, Texas. Scale impressions were read with 80 percent agreement between examiners on the first reading. Time of annulus formation appeared prolonged, but too few data were available to conclude whether this was characteristic or the result of marginal increment variability and small sample sizes. Preliminary growth estimates indicated females were significantly larger than males through age IV. Comparison of Matagorda Bay back calculated lengths with averaged values obtained in Florida investigations indicated age I males and females through age IV were 16 to 20 percent longer, although < 10 percent differential growth was evident for remaining age groups. The scale method has the potential to reliably estimate spotted seatrout age and growth, but conclusive demonstration that annuli are formed once per year is necessary before it can be incorporated into Texas management plans.


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spotted seatrout, Cynoscion nebulosus, Matagorda Bay, Texas, age determination