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channel cross sections and modeled hydraulics of various water levels to determine how habitat changes with flow. Study Area The area which the radio tagged fish occupied was the reach from just downstream of Signal Butte (RM 103) down to about 2 miles below Maybell bridge (RM 77) thereby defining the area for this study. The radio telemetry observation data was acquired within this limited reach. This area was where squawfish have been located in previous years. METHODS The project consisted of radio tracking implanted fish to determine the location within a reach of river, habitat use, and movement by those fish. Five adult Colorado squawfish, five adult channel catfish, and five adult northern pike were opportunistically implanted with radio transmitters in a cooperative effort by personnel from Miller Ecological Consultants and the Colorado Division of Wildlife (Table 1). Four Colorado squawfish and three northern pike were collected by angling, all other fish were collected by electro- fishing. Radio transmitters were implanted using procedures developed by the USFWS. Fish were anesthetized with MS-222 and transmitters were surgically implanted into the gut cavity. Fish were observed in a recovery tank for a minimum of ten minutes. When fully recovered, they were released back into the habitat from which they were captured. Radio tracking was conducted on a bi-weekly basis between July 22, 1996 and October 26, 1996. Observations were made on five consecutive days each week that tracking was conducted. An attempt was made to locate each fish at least one time during each observation week. After a fish was located it was monitored for a minimum of 30 minutes (Colorado squawfish were monitored for a minimum of one hour). During this time a variety of habitat usage data were collected including; date, time of day, weather Draft Yampa River Radio Telemetry Report Page 2 Miller Ecological Consultants, Inc. December 13, 1996