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TL had been implanted. Movement patterns of these fish were somewhat different than those observed in the Green River in 1980 and 1981; with larger fish moving into or remaining in whitewater canyon areas after the spawning season. In addition, radio-tagged fish lead us to a previously suspected spawning site in Gray Canyon. Collections of ripe fish in Gray Canyon and subsequent young-of-the-year studies provide the first documentation of this spawning site. One 810 mm fish (No. 3001) moved about 322 miles during the study period. Colorado squawfish implanted in the Green and White rivers apparently used the lower Yampa and Gray canyons for spawning in 1982. The movement patterns of radio- telemetered Green River fish are shown in Figure 13. During the 1982 spawning season (July-August) the Vernal Station conducted sampling in Yampa Canyon, on the Yampa River and in Split Mountain and Gray canyons on the Green River. A total of seven ripe Colorado squawfish were collected in the vicinity of radio-tagged fish in Gray Canyon between July 13 and July 22. Only one collecting trip was made to the lower Yampa River where one ripe fish was collected. The reason for the comparative absence of ripe fish in the Yampa was provided by co-workers doing a Yampa River fish study (Stoneburner, 1983), which indicated that spawning occurred about 3 to 4 weeks later than our sampling in 1982 (also 3-4 weeks later than spawning in 1981). Study results indicated that spawning occurred in Gray Canyon about 3 weeks earlier than spawning in Yampa Canyon. Larval and Young-of-the-Year (YOY) Surveys Larval sampling in the Colorado River was initiated in mid-July and performed on a weekly basis between Palisade and the Westwater Ranger Station through August. Two sampling trips were made during August in the river reach between Westwater Canyon and Potash, Utah. An attempt was made to sample below Potash in late August; however, this effort was canceled because of equipment failure. Sampling was also accomplished in upper Lake Powell in July, concurrent with radio-tracking work. Larval Colorado squawfish (148 individuals) were found throughout the study area (Figure 14). Colorado squawfish larvae (107 individuals) were most frequently encountered and were in highest relative abundance in samples taken from the river reach below Westwater Canyon (Westwater Canyon itself was not sampled). Colorado squawfish larvae were first collected from the river reach above Loma, Colorado later in the season than from the downstream river reach; this might reflect marked differences in the spawning time between river reaches. Larval data for the Green River have not been completely analyzed at this time. In mid-September through October, when YOY Colorado squawfish were large enough to be identified in the field, the Colorado River and Green River were quantitatively sampled using 3x5 mm mesh seines. Colorado River YOY (30-40 mm TL) Colorado squawfish were only collected below -22-