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Information on entrainment of larval fish in the raceway, irrigation canals, and power- generation facilities is also quite limited. Data collected in 1996 (Utah Division of Wildlife Resources, unpublished) showed that larvae of speckled dace (Rhinichthys osculus), unidentified suckers (Catostomus spp.), red shiner (Cyprinella lutrensis), and channel catfish (Ictalurus punctatus) were entrained in the canal system. The same species assemblage was captured in the Green River during the same time period. Objectives Since Tusher Wash Diversion Dam spans the entire width of the Green River and the raceway diverts a significant portion of the river, it was hypothesized that these structures were limiting the movement and survival of larval and juvenile native fish. However, given the sparse data that were available, it was not possible to determine what impact these structures were having on the native fish community. Therefore, this study was designed to collect more data on the impacts of the diversion dam and its associated features. This information was needed to make decisions as to whether the diversion system needed any modifications to protect native fish species. The objectives of this research were: 1. To determine if Tusher Wash Diversion Dam prevents upstream movement of subadult native fishes (particularly during low-flow periods). 2. To determine if the raceway or Green River Canal entrains native fish, and 3. To determine if Tusher Wash Diversion Dam needs to be modified to better accommodate native fishes. The study was designed to include two years of field research. However, the Recovery Implementation Program decided not to fund the second year of field work. Unfortunately, during the year of the study, flows observed during the low-flow period were approximately twice as high as normal (Figure 3); therefore, objectives 1 and 3 were not fully addressed. In addition, the total catch of Colorado pikeminnow larvae in drift nets was much lower than the catch noted during past years, so conclusions drawn from work designed to address Objective 2 were also limited. METHODS Evaluation of Fish Entrainment in the Green River Canal Larval Entrainment Fine-mesh drift nets (12" X 18") were set from May 5 through May 26, 1998, and from June 29 through August 22, 1998. The first period was selected to target razorback sucker larvae, while the second period was selected to target Colorado pikeminnow larvae. Water temperature in the Green River was monitored during these periods with an electronic thermograph (Onset Computer Corporation). Two nets were set in the Green River and two nets were set in the Green River Canal (Figure 2) during the month of May. An additional net was set 2