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became relatively abundant in electrofishing samples in 1994. Bluehead YOY catch rates declined steadily from 1992 through 1996 as did the native speckled dace. Channel catfish were the most abundant species collected from main channel habitats. with nets and electrofishing every year of study. Throughout the course of eight years offish community monitoring channel catfish have been nearly twice as abundant as Gila spp. As with chubs and flannelmouth suckers, channel catfish average annual net catch rates were greatest in 1989 (0.918) and were lowest in 1994 (0.149)(Report C; Appendix Figure 2). The highest channel catfish catch rate (1.21) was recorded in 1990 at Cedar Ridge (RK 295.7).. A length frequency analysis reveals a dynamic population with Age 1 catfish (TL range 100-200 mm) present every year with the exception of 1994 (Report C; Appendix Figure 5). In 1993, channel catfish apparently failed to successfully reproduce or overwinter, however, successful recruitment was documented during this project's. highest flow year (1995). CONCLUSIONS Geomorphology arzd Habitat The character of eddy habitats was strongly influenced by discharge, whereas the total eddy area was not. Eddies increase in frequency and decrease in size as discharge increases from baseflow to about 7,000 cfs. Above 7,000 cfs eddies became larger but less frequent, resulting in essentially no net change. In Deso/Gray, the area occupied by the active channel has decreased on average 19 percent since the beginning of this century. Two episodes of channel narrowing were identified, evidenced by two new and distinct surfaces that have formed this century. The cottonwood terrace is an abandoned floodplain that began to stabilize between 1922 and 1936 as a result ofnaturally-occurring climate change. After the closure of Flaming Gorge Dam a second lower surface, the modern floodplain, has become densely colonized by riparian vegetation and is accumulating sediment. Increasing discharge now submerges bare sand and cobble bars and substantially increases the amount of inundated vegetation along shorelines. Green River fish habitat is complex and dependent on surrounding geology and variable flow regimes (Schmidt 1996). The following geomorphological tendencies were apparent. Eddy formed backwaters are the dominant backwater habitat available to YOY fish in these canyon reaches. The shoreline features that create eddy habitats are generally stable structures and usually persist through a runoff event. As result low velocity habitats during the baseflow period formed in basically the same places from year to year. ~` -~; xviii