Kokanee and terrestrial insects were found to be the main food items of the Gerrard stock of rainbow trout. Mysis were not a major food item. Conspicuously absent were other typical rainbow food items such as benthic invertebrates and zooplankton. Kokanee as a diet item increased in importance in the winter and with increasing rainbow size. The construction of the Duncan Dam, which destroyed a major kokanee spawning area, had no noticeable effect on the diet of these fish.
Andrusak, Harvey, Parkinson, Eric A.. 1984. Food Habits of Gerrard Stock Rainbow Trout in Kootenay Lake British Columbia. Ministry of Environment. Fisheries Technical Circular. FTC60