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Overall, there were no differences in mean size of backwater habitats sampled in the San Juan River between 1991 and 1992. However, mean backwater size in the reach between Chinle Creek and Grand Gulch was smaller than in the remainder of the study area during both years. Lower San Juan River Fish Community Survey - Fish community surveys were conducted in 1991 and. 1992 in the extreme lower portion of the San Juan River and the upper San Juan arm of Lake Powell, Utah. During this period, both riverine and reservoir habitats were sampled from RM 4.0 to RM - 10.0. These surveys were primarily conducted to collect rare fish of the Colorado River Basin. In all, 41,116 fish were collected, 20,910 in 1991 and 20,206 in 1992. Over the course of the two-year study period, only one Federally protected fish was collected, a young-of-year Colorado squawfish. Sampling for adult fish was conducted by electrofishing and entanglement netting during the spring when it was hypothesized that adult rare fish would more likely be present. Sampling efficiency was low due to high flows, including high water velocities and high turbidity. No adult rare fish were seen or collected during this period. In 1991 and 1992, 3,619 and 1,361 fish were collected by electrofishing. In 1992, an additional 229 fish were collected by trammel netting. During both years, common carp and channel catfish were the most common fish collected by all methods. Flannelmouth sucker was the most common native fish collected in both years. However, this species was infrequently collected and comprised less than S~ (1991) and 5~ (1992) of total fish sampled. San Juan River low velocity habitats were sampled. with seines each year during late September. In 1991 and 1992, 17,310 and 18,616 fish were respectively collected including one young-of-year Colorado squawfish. This single specimen was seined from a bacckwater in 1992 approximately 6 RM downstream from a 8-10 m high waterfall and within 2 RM of Lake Powell. Overall, red shiner was th'e most abundant fish collected, comprising 86~ of the total fish sampled. The most common native fishes collected were flannelmouth sucker and speckled dace. Collectively, native fish comprised less than 1~ of all fish sampled from low velocity habitats. The results of this survey confirmed successful spawning by Colorado squawfish in the upper reaches of the San Juan River in 1992. Within the same study area, three adult razorback sucker were sampled from Lake Powell in April 1992 during a separate study in the extreme upper San Juan River arm. The occurrence of Colorado River Basin native fishes within the area studies was low. Nonnative fish populations, particularly common carp and channel catfish, are flourishing. Adult sampling within the San Juan River downstream of RM 0 will be 10