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_ been collected, and those from the Colorado River have been in different habitat than those from the Green River. Colorado River - collections were from gravel pits and backwaters; Green River col- ~ lections were from deep shorelines (2-8 ft) and main channel areas, mostly with sand substrates (Miller et al. 1982). This species may avoid whitewater habitats; rarely have they been found in canyon areas of the Upper Colorado River Basin (Tyus et al. 1987). Generally, razorbacks seem to be stationary in localized populations. Spawning congregations and relatively short spawning migrations have been noted ~ (Miller et al. 1982). Reproduction has appeared successful, but not recruitment to older life stages (Tyus et al. 1987). Tyus et al. (1987) felt black bullhead and green sunfish may be preying upon razorback sucker and suppressing recruitment. They also felt lower temperatures caused by Flaming Gorge Dam may negatively impact spawn- ing and hatching success. Failure to sample the irrigation pond near ~ Bluff, Utah where BLM records (BLM 1981) show razorbacks were col- lected in the past was an oversight in this study of the San Juan River. The BLM (1981) collection indicates that habitat use in the San Juan may be similar to that observed in the Colorado River. Tyus et al. (1987) determined that razorback sucker in the Upper Colorado River Basin are declining and may become extinct without identifi- ~ cation and remedy of the causes for decline. _ As discussed earlier, there appears to be little historical evidence that bonytail and humpback chub occurred in the San Juan River. This is not particularly surprising. Large, deep eddies, such _ as in Desolation Canyon, Green River and Black Rocks and Westwater ~ Canyon, Colorado River considered typical humpback chub habitat, were not observed in the canyons of the San Juan River. Although "typical chub habitat" was not visually apparent, narrow areas with relatively deep water do occur within the canyon of the San Juan River. Some effort should be made to verify the presence or absence of Gila spp. in the San Juan Canyon. The apparent lack of chub habitat in the San ~ Juan Canyon, and high flows and swift velocities, discouraged us from sampling with trammel nets in 1987. Summary and Recommendations ~ The Utah Division of Wildlife Resources (UDWR) and U.S. Bureau of Reclamation (BOR) surveyed the fishes of the San Juan River, Utah and transition zone between the river and San Juan Arm of Lake Powell. Sampling was conducted with boat electrofishing gear and seines in riverine areas and with gill and trammel nets in lentic areas during March through September, 1987. One adult Colorado squawfish was captured in the San Juan Arm of - Lake Powell in April and recaptured in September nearly 90 miles up - river in the San Juan River. Fifteen YOY Colorado squawfish were seined from backwater habitats during fall. Six of these YOY fishes were found in backwaters between 102-94 river miles above Lake Powell, ~ and nine were found in backwaters between 14-6 river miles above Lake - 43 -