Abstract
Resistance times to high temperatures were determined for fingerling and juvenile rainbow trout (Salmo gairdneri) from the Firehole River, Yellowstone National Park, and from the Ennis and Winthrop hatchery strains, after acclimation to 5, 9, 13, 17, 21, and 24.5°C. Firehole and hatchery trout acclimated to 21 and 24.5°C had similar median resistance times and upper incipient lethal temperatures. After acclimation to the lower temperatures of 5, 9, 13, and 17°C, Firehole trout had longer median resistance times and slightly higher upper incipient lethal temperatures than did the hatchery trout. The ultimate upper incipient lethal temperature for the Firehole trout and for both hatchery strains was about 26.2°C. Rainbow trout inhabiting and reproducing in the heated waters of the lower Firehole River do not appear to have developed the ability to acclimate to higher temperatures.

This publication has 2 references indexed in Scilit: