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Westwater Canyon; areas with high YOY Colorado squawfish abundance were correlated with earlier high relative abundance of larval fish (Figures 14 and 15). YOY Colorado squawfish catch per effort for the Green River is shown in Figure 16. In the Green River catch per effort of YOY Colorado squawfish was reduced to about one-half the average obtained in previous years. This reduction no doubt reflects the very high water levels in 1982 and does not indicate a poor spawning year. Shallow backwater habitats were virtually non-existent during the YOY collections on the Green River. Indeed, it is surprising that our collections produced 637 YOY fish in the Green River and we interpret these data to mean that reproduction was as high as in previous years. However, it is possible that YOY survival may be decreased due to the unfavorable water conditions. Backwater and Gravel Pit Investigations_ Adult Colorado squawfish and razorback sucker were collected from nearly all of the gravel pits investigated (Table 3). When river runoff subsided and gravel pits became isolated from the river, Colorado squawfish were no longer found in the pits; however, razorback sucker continued to be collected from four gravel pits (numbers 1,2,4, and 7 in Table 3). Colorado squawfish evidently moved out of the gravel pits before the pits became isolated. Fyke nets set in the entrance of WWWA caught 12 Colorado squawfish leaving WWWA in late June, when the river began receding. Another Colorado squawfish was caught leaving WWWA in early July. Fyke nets collected two adult Colorado squawfish leaving and one entering Labor Camp pit during that same period. Post-runoff sampling resulted in the collection of two larval Colorado squawfish in Island Backwater pit (Table 3) on August 11. No larval Colorado squawfish were collected from the remaining gravel pits. Largemouth bass (Micropterus salmoides and green sunfish Le omis c anellus were the dominant predators in both Fish Pond (Figure 17 and Labor Camp (Figure 18). However, Fish Pond also had large numbers of bluegill.(L. machrochirus) and black crappie Pomoxis nigromaculatus). Before Colorado squawfish were stocked, 155 largemouth bass, 247 green sunfish, 881 bluegill and 1483 black crappie were removed from Fish Pond. Population estimates made after small squawfish were stocked showed appreciably larger opulations of largemouth bass in Labor Camp than in Fish Pond (Table 4?. In spite of our removal effort, green sunfish remained common in Fish Pond. Largemouth bass less than 350 mm in length were the predators that most frequently contained stocked Colorado squawfish. The frequency of largemouth bass containing stocked Colorado squawfish was high early in the study, and diminished over time (Table 5). This decrease is probably a result of decreased numbers of available Colorado squawfish and a decline in water temperature (Figure 19) with an attendant decline in largemouth bass feeding rate. -25-