Use of Scale Circuli Pattern Analysis to Differentiate between Hatchery and Wild Red Drum

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Abstract
In 1983, the Texas Parks and Wildlife Department initiated a stock enhancement program that released up to 20 million red drum Sciaenops ocellatus annually. To evaluate the contribution of hatchery production to the fishery, scale pattern analysis was used to differentiate between hatchery-reared and wild fish. Scale patterns from 30–150-d-old hatchery-reared red drum fingerlings (13–35 mm total length, TL) from two hatcheries and wild red drum juveniles (<121 mm TL) were analyzed to establish a linear discriminant function. Accurate identification of 30-d-old hatchery-reared red drum ranged from 61–64%, but decreased to 35% for 60–150-d-old fish; classification rates for wild fish ranged from 63% to 70%. Correct classification of 30-d-old hatchery fish was significantly better than chance, but correct classification of wild fish was only significantly better than chance at one hatchery. Linear discriminant functions were used to evaluate variation between spring and fall hatchery-reared red drum...