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36 (25-380 mm). It was also noted by Cranney that Mullan (1975) reported a 3" (75mm) Colorado squawfish captured in the Uintah River in June of 1970 upstream of its confluence with the Duchesne (RM14.3). Cranney further noted Seethaler (1978) recorded the capture of five squawfish by Ute tribe members at the confluence of the Uinta and the Duchesne rivers in the spring of 1975. The earliest record of razorback sucker presence in the Duchesne River was M<~y 1978 in a BioWest survey (Cranney 1994). Ten fish were caught between May 1U and May 13 near the confluence of the Duchesne and Green Rivers at RM 0.1. The lower 2.5 miles of the Duchesne River was designated as critical habitat for razorback sucker in 1994 (Federal Register. Volume 59, No. 54, Monday, March 21, 1994). In recent years, razorback sucker have been collected annually at the confluence of the Duchesne and Green Rivers. Preliminary results from sampling between May and October of 1997 documents the capture of eight Colorado squawfish and two razorback sucker in the lower 33 miles of the Duchesne River (Tim Modde, USFWS, and Keith Day, UDWR, pers.comm., 1997). Use of the Duchesne River upstream of the confluence, by the endangered fish under present conditions is not yet completely understood, however, ongoing research will greatly improve that knowledge base. The legal protection and delivery of adequate flows (if necessary) for the protection of endangered fishes that reside in the Duchesne River has been identified by the RIP as necessary recovery actions (RIP RAP: Duchesne River, Items 1. thru l.c.). In the spring, Colorado squawfish and razorback sucker appear to use the mouth and some portion of the Duchesne River as a temporary residency in preparation for spawning elsewhere in the Green River system. High natural .spring flows appear to attract these native fishes which may be drawn to favorable temperatures, food supply and/or other life requirements. Cobble substrate is abundant in the Duchesne River (Keith Day, UDWR, Pers,comm., 1997) and while not yet confirmed, some spawning may be occurring. Both adult razorbacks (4) and Colorado squawfish (11) were collected in these areas in 1993 (Cranney, 1994). The overall contribution of the Duchesne River to the functioning of the Green River downstream is not yet completely understood, however, the relationship between the tributaries and their importance to the mainstem rivers is becoming clearer as studies continue on the Duchesne, Yampa, White, and Price Rivers. For example, the Price River has recently been documented as providing habitat for juvenile and adult Colorado squawfish for 88.5 river-miles upstream. Like the Duchesne River, the Price River contributes