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METHODS 1 I 11 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 USF!WS. 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 biweekly 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 conditions, water and ambient air temperature, time monitored, sketch of the surrounding habitat including fish locations, and any notes on movement during the observation,' period. Other physical habitat data that were collected whenever possible at each fish location included total water depth, water velocity (mean column and bottom), substrate type, proximity to cover, description of cover at the location, general description of! the site; measurements of the habitat type including length, width, bank features, shoreline vegetation, dominant substrate and cover for the habitat type. Discharge was obtained from the USGS gaging station near Maybell, Colorado. The 24-hour observations began during week 5 (the first week after all Colorado squawfish had been captured and implanted) and continued weekly until the end of the study. One Colorado squawfish was chosen for a 24-hour continuous observation curing each observation week. The fish chosen for the 24 hour observation was located and observed for movement approximately every hour except for some short periods when weather interfered. All observed activity and movement by fish during this time was recorded. Yampa River Radio Telemetry Report Miller Ecological Consultants, Inc. Page 2 January ?3, 1997