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YOUNG-OF-THE-YEAR MONITORING .. Total numbers of age-0 squawfish captured in fall sampling, and corresponding mean CPUE, varied considerably between years (Table 5). Mean CPUE was highest in 1991 (12.2 fish/100 mZ) and lowest in 1994 (0.5 fish/100 m2); the third highest and lowest yet reported, respectively. Mean lengths of YOY squawfish captured from 1990 to 1993 were not highly variable (Table 5). These mean lengths, between 36 and 45 mm, were comparable to those reported by Cranney (1990). In 1994, however, mean lengths increased by approximately 50% to 67 mm. Distribution around means did vary between years (Figure 9). Ranges of lengths were narrower in 1991 and 1993 than in 1990 and 1992. Numbers and sizes of age-0 fish are likely influenced by flow events. In 1991 and 1993, run-off flows lasted approximately 6 weeks and were relatively stable throughout that period (Figure 10). This may have restricted spawning to the true descending arm of the hydrograph, thus accounting for the narrow range of lengths. These flows also represent anear-normal hydrograph which would have provided greater opportunity far spawning and, thus, higher numbers of fish produced. Flows in 1990 and 1992 were of much shorter duration and showed less uniformity, possibly allowing a prolonged spawning season. However, these conditions may not have been optimal for spawning, thus the lower CPUE values in these years. The significant decrease in numbers and increase in mean length of fish sampled in 1994 may also be a result of the hydrograph. An 8000 cfs peak occurred in late April 1994. This was followed by a sharp drop in flows in early May. This may have allowed squawfish to spawn in April, thus providing greater opportunity for growth. In 1994 the Green kiver appeared to have very low sediment load. In addition, weather conditions in northeastern Utah was very hot, dry and sunny. These condition may have contributed to rapid growth in YOY squawfish which, in turn, allowed squawfish to Ieave backwaters earlier than in previous years, thereby accounting for the low catch of that year. The true peak which followed may have eliminated any additional spawning. Alternately, if spawning occurred on the true descending limb of the hydrograph, growth was probably enhanced by weather and water conditions. Sampling in nursery habitats throughout the summer, however, seems to support the former scenario. .. Distribution of YOY squawfish by river mile indicated 2 peaks of occurrence and a region of consistent low numbers (Figure 11). Very few fish were caught above the Highway 40 bridge at Jensen (RM 301.8), as reported by Cranney (1990). The highest incidence of captures occurred in a 10 mile stretch above Ouray NWR (Rm 270 to RM 260). Another small peak of occurrence was noted between Stewart Lake (RM 300) and the Utah State Highway 45 bridge (Bonanza bridge) {RM 289.8). Distribution throughout the remainder of the river was fairly uniform. 20