Performance of Yellowstone and Snake River Cutthroat Trout Fry Fed Seven Different Diets

Five commercial diets and two formulated feeds were fed to initial-feeding Yellowstone cutthroat trout Oncorhynchus clarkii bouvierifry and Snake River cutthroat trout O. clarkiispp. (currently being petitioned for classification as O. clarkii behnkei) fry for 18 weeks from June 16 to October 18, 2006, to evaluate fish performance. Eyed eggs from Yellowstone and Snake River cutthroat trout were received from the Yellowstone River State Fish Hatchery and Jackson National Fish Hatchery, respectively. Each diet was fed to four tanks of each subspecies of cutthroat trout (7 diets × 4 tanks/diet × 2 cutthroat trout subspecies = 56 tanks). Skretting Nutra-Plus provided optimal fish weight, total length, survival, and feed conversion for Yellowstone cutthroat trout. The weight and total length of Snake River cutthroat trout were also greatest when fish were fed Skretting Nutra-Plus. Skretting Nutra-Plus is no longer available, but Skretting/Bio-Oregon Bio-Vita is very similar; this feed and similar premium feeds from other manufacturers should be considered for future cutthroat trout propagation programs.