A Study Of The Temperature Selection And Upper Lethal Temperature Responses For Two Species Of Sculpin,Cottus Cognatus And Cottus Confusus, In The Flathead River Basin Of Northwestern Montana

Abstract

The temperature selection and upper lethal temperature for two species of sculpin in the Flathead River Basin of northwestern Montana were investigated. Comparisons were made between Cottus cognatus and Cottus confusus concerning these thermal parameters to examine the possible relationship between altered thermal discharges below Hungry Horse Dam and reported hybridization between the two species. The data suggests that C. confusus has a higher preferred temperature and upper lethal temperature tolerance.