Recruitment failures of stocked kokanees (lacustrine sockeye salmon Oncorhynchus nerka) in Lake Roosevelt have led to examination of various limiting factors. We evaluated the predatory impacts of piscivores on hatchery-released and net-pen-released kokanees and rainbow trout O. mykiss from the Sherman Creek Hatchery in 1999 and 2000. We used an angler tournament to mark walleyes Stizostedion vitreum for an abundance estimate, and then used gillnetting and electrofishing to collect recaptures and monitor the diet of walleyes. A bioenergetics model was used to quantify consumption, and estimates were extrapolated to walleye abundance to determine a percent loss of hatchery fish. Kokanees averaged 22-100% of the diet contents of walleyes (>300 mm total length), whereas rainbow trout averaged 0-25%, depending on location and timing following release. In 1999, we estimated that 16,610 walleyes consumed 15% of the hatchery kokanees within 41 d of release; however, our diet information did not correspond spatially with our population estimate. In 2000, we corrected our spatial bias and estimated that the population of 12,233 walleyes consumed 9.4% of the hatchery kokanees and 7.3% of the hatchery rainbow trout within 41 d of release. We conclude that the walleye population in northern Lake Roosevelt was effectively “swamped” by the biomass of salmonids released at the Sherman Creek Hatchery. However, piscivores may still limit kokanee recruitment, depending on long-term predation rates for the reservoir-wide walleye population.