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3-7 located in Salt Lake City from 1978 to 1984, has been discontinued, and CRFMP is now administered directly by the Regional Office. Proposed work plans for FWS in the subject reach include: 1. Equip adult Colorado squawfish with radiotags to determine movement in the region, and to attempt to locate spawning areas, 2. Seine for larvae and YOY Colorado squawfish and razorback sucker during August and September, and 3. Conduct physical habitat measurements for PHABSIM (Physical Habitat Simulation Model) by establishing cross sections at or near the possible squawfish spawning sites at RM 178.3 or 176.0, or both. Work elements 1 and 2 will be performed by the Grand Junction Field Station, while element 2 will be conducted by a special team from the Habitat Resources Staff of the FWS, Region 6. 3.4 Significance Of Reach The IS-mile reach of the Colorado River between the Grand Valley Canal and the mouth of the Gunnison River currently supports at least two species of endangered fishes; Colorado squawfish and razorback sucker. These mayor may not occupy the reach year around, but they have been found nearly every year since 1974, between May and October; sampling has rarely been conducted at other times of the year. Reproduction by Colorado squawfish within the reach may have occurred in 1982, as is indicated by an aggregation of ripe males and females at RM 178.3 and 176.0. The capture of larval squawfish (<1% of the catch) during two sample efforts in August 1982, between RM 170.0 and 180.0, indicates that the species did reproduce succeSSfully somewhere in that region of the river; larval squawfish usually drift downstream shortly after hatching, and their capture location does not necessarily reflect the spawning site. Al though the razorback sucker has been found in spawni ng condition in that reach of the river, there is no evidence of successful reproduction by the species. Only one humpback chub is reported from the IS-mile reach; a fish taken in 1977 by George Kidd. No bony tail chub have ever been reported from this reach of the Colorado River. This IS-mile reach of the Colorado probably holds no significance to either of these two species. From this brief analysis, it ap,.ars that the significance of the 15- mile reach lies in the possible use of the area by spawning Colorado squawfish and razorback sucker. Larval squawfish collected in August 1982 suggest success by the species somewhere in the region, but no evidence of successful reproduction is available for the razorback. Significance of this reach of river to the population of Colorado squawfish in the upper basincannot be assessed on the basis of suspected spawning sites. The contribution of young squawfish to the system is a more readily attainable statistic for assessing this significance.