Klamath River Bioenergetics Report

The results of the bioenergetics foraging model and P value model indicate that food availability is more important than water temperature as a factor in trout growth in the J.C. Boyle peaking reach for the Existing Conditions, WOP and Steady Flow scenarios. There is relatively little difference in four-year growth predictions between Existing Conditions, Steady Flow, and WOP scenarios in the J.C. Boyle peaking reach when only changes in water temperature were incorporated into the modeling. This happened because there was only a relatively small difference in daily temperatures between the three scenarios relative to the temperature-related growth requirements of trout. The biggest effect on predicted growth came from the assumption that increased invertebrate drift/ food availability would occur under the WOP and Steady Flow scenarios. The most uncertainty exists in this parameter, however. Based on the literature, food would likely increase, but the amount is uncertain. The invertebrate drift densities observed below Iron Gate dam or in the Keno reach provide a reasonable upper bound on the increase that could occur in the J.C. Boyle peaking reach. Actual drift density for the WOP and Steady Flow scenarios may be somewhere between what they are now with Existing Conditions and this upper bound.