Influence of Physico-Chemical Factors on Habitat Selection by Red Shiners, Notropis lutrensis (Pisces: Cyprinidae)

Field studies were combined with single and multifactor laboratory preference tests to determine the relative influence of several physico-chemical factors on red shiner habitat selection. Temperature, pH, and total dissolved solids were the water quality factors that had the greatest potential influence, while dissolved oxygen and turbidity were of limited importance in habitat selection by the species. Red shiners avoided temperature extremes during winter and summer in both the field and the laboratory. Values of pH encountered in the field ranged from 7.5 to 9.6, of which the shiners avoided highly alkaline conditions. Their response to pH was strong in the laboratory, usually characterized by preference for pH of 7.1 to 7.4, and an avoidance of values below neutral. The response of the species to total dissolved solids was strong in the laboratory, and they apparently responded to this factor in the field when the range exceeded 500 ppm.