Water-quality-induced stress upon striped bass populations in three East Tennessee reservoirs

The reduction in suitable striped bass habitat reductions was most prevalent during the month of August (1985-1986) in both Cherokee and Watts Bar reservoirs. The percentage of available habitat within Cherokee decreased from 25% in 1985 to 8% in 1986. Within Watts Bar Reservoir system, only the Piney River was unsuitable in 1985 whereas all habitat except the Clinch River was unfavorable in 1986. Severe water quality conditions affected morphometric measurements in striped bass populations from three East Tennessee reservoirs. The liver-somatic and visceral somatic indices, condition factor (K) as well as the total liver lipid concentration provided little statistical variability among the three stocks. The visceral fat and gonadosomatic indexes were, however, highly significant among all three populations. Cherokee striped bass had the lowest fat index (mean) value of 0.78 while Norris had the highest, with 3.07. Both in summer and spring, Cherokee females had the highest gonadosomatic index (1.2 and 15.6, respectively) whereas females from Watts Bar had significantly lower GSI values of 0.5 and 5.5, respectively for the same two periods. Observations on the condition of the digestive tract revealed pronounced differences among the striped bass from all three reservoirs. Intestinal wall thinning was also observed in 28% of the Cherokee fish, 50% in Norris, and 71% of the Watts Bar striped bass. Discriminant analysis, from summer data of 1986, correctly classified 94.4% of the striped bass into its respective reservoirs. Only 44.7% were correctly classified into the appropriate reservoirs from the data collected the following spring (1987).