Interpopulational Differences in Chloride Tolerances Among Red Shiners, Cyprinella Lutrensis (Baird and Girard), and Sand Shiners, Notropis Ludibundus (Cope), in Central Kansas

Effects of sodium chloride on red shiners (Cyprinella lutrensis) and sand shiners (Notropis ludibundus) in central Kansas streams were investigated in September and October of 1998. Individuals were collected from four streams; one collection each from \saline\ (Rattlesnake Creek and Salt Creek) and \non-saline\ (Saline River and Walnut Creek) streams, within the Kansas and Arkansas drainage basins. Mean chloride concentration ranges in \non-saline\ streams are below 500 mg/L, while \saline\ streams were characterized by mean chloride concentrations above 1000 mg/L. Mortality rate, opercular oscillation rates, tissue water analysis, and developmental asymmetry were used to assess tolerances to chloride concentrations for individuals collected from these four streams. Three morphological and three meristic characters were used in the developmental asymmetry analysis to determine if significant developmental differences occurred among the four populations. Such differences have been used as indicators of environmental stress in aquatic organisms. Approximately 20 individuals were exposed to 10 chloride concentrations for 24 hours per concentration. Chloride concentrations were as follows: 3500, 4500, 5500, 6500, 7050, 7500, 8000, 8500, 9000, and 9500 mg/L of chloride. Complete mortality occurred at 9500 mg/L of chloride. Inter-populational differences in chloride tolerances and respiration rates indicated lower respiration rates and higher chloride tolerances in populations from “saline” streams. Results derived from developmental asymmetry analyses indicated the presence of fluctuating asymmetry in populations from saline streams interbasin differences in chloride tolerance with populations from the Kansas River basin possessing higher tolerances to chloride than populations from the Arkansas River basin. Differences in respiration rates and bilateral asymmetry among populations and between species exist among red shiners and sand shiners exposed to increasing concentrations of sodium chloride. Comparison between dry/wet weight ratios (water tissue analysis) of each population was inconclusive.