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San Juan-Colorado: Investigations in the upper Colorado River in 1985 (Valdez et al. 1985) added substantially to the knowledge about Colorado squawfish in Cataract Canyon and upper lake Powell. Four adults, three juveniles, and 152 YOY were captured within the 16.5-mile reach of Cataract Canyon. The presence of these YOY in the canyon and additional YOY in upper lake Powell indicates the possibility of spawn- ing by the species in these areas. Adult Colorado squawfish have been captured for several years by Bureau of Reclamation biologists and others. Fish have been monitored in movements from the upper Colorado and lower Green Rivers into the Cataract Canyon area (Archer, et al. 1985) and between the upper end of Lake Powell and the Dirty Deyil River. These observations suggest that the adults, found in the upper lake since 1980 (Person et al. 1982), spawn in the vicinity of Cataract Canyon. bution of these young fishes from river mile (Rm) 110.4 upstream to RM 175. Highest densities of the young of the year varied by river region for the three years (1982-84), but generally, catch rates were highest in the 100 mjles between Professor Valley and the Green River confluence. Investigations of larval fish drift in 1983 (Carter and Valdez 1983) near Parachute, CO, in 1984 (Valdez 1984) near Palisade, CO, and in 1984 in Plateau Creek, CO (Carlson and Platania 1985) con- firmed the current upstream distribution of the four rare species. These investigations, which extended as far downstream as RM 188.2 failed to yield any of the four rare fishes. The upstream-most dis- tribution of the Colorado squawfish remains at the Grand Valley Canal at RM 185.0 (Valdez et al. 1982). Remarks: The Colorado squawfish continues to be an imperiled species and is most appropriately classified as endangered. Although some recent information has added to our knowledge of this fish, there is no indication that its recruitment is secure, and no spawning areas have been confirmed outside the Green River sub-basin. Further water resources development continues to reduce its range. Humpback Chub Green: Little additional knowledge has been obtained for the humpback chub since 1981, although specimens are incidentals in lower Yampa Canyon and the Desolation-Gray Canyons. No basin-wide compre- hensive survey for this species has been undertaken in recent years, so its relative abundance remains a mystery. Recent observations on the Gila species in the Green River suggests the existence of a single polymorphic complex. -24-