As part of the FERC relicensing of the Don Pedro Project described above, FISHBIO conducted a predatory fish acoustic tracking study in the lower Tuolumne River, California, for the Turlock and Modesto Irrigation Districts. We captured and attached external acoustic transmitters to piscivorous fishes capable of consuming juvenile salmonids, including Sacramento pikeminnow and striped, smallmouth, and largemouth bass. We subsequently tracked their movements in riffle and pool habitats to evaluate the predation risk of juvenile salmonids in those areas. Additionally, we acoustically tagged and released juvenile Chinook salmon during three different flow ranges. We deployed two-dimensional acoustic arrays at select locations to study the habitat use of predators and outmigrating juvenile Chinook salmon in relation to river flow and water temperature.