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1 pike, roundtail chub and flannelmouth sucker. Radio tracking was also conducted during these trips. Trip 3 was conducted exclusively to track radiotagged fish. Mark and recapture studies and radio tracking was conducted during Trip 4. Intensive sampling below the diversion structure was also conducted during Trip 4 to determine if Colorado squawfish were aggregating below the diversion structure. Radio tracking was continued during Trip 5 in addition to electrofishing above the diversion structure for purposes of recapturing marked fish. Trips 4 and 5 were both conducted during late summer and early fall base flows to specifically evaluate fish passage during a low flow period Table 1. Sampling schedule for the City of Craig, Colorado, Yampa River Diversion Fish Passage Study conducted by BIO/WEST in 1992. Trip Dates Purpose of Trip Apri122-27 2 June 7-12 3 August 3-5 Radiotag RT, FM and NP, Radio track Mark and Recapture Radiotag RT, FM-and NP, Radio track Mark and Recapture Radio track 4 September 2428 Radio track, Mark and Recapture Determine if CS are stacking below diversion structure 5 October 19-23 Radio track, Sample for recaptures above the diversion structure Capturing the Fish Electrofishin~. Electrofishing using a 220-volt DC system was the primary sampling method used to capture fish for this investigation. Electrofishing was conducted from a 16-foot aluminum Jon boat with a Mercury XD-25 horsepower outboard. Power for the electrofishing system was provided by a 3500 watt Homelite generator. Output was controlled by a Coffelt WP-15. Normal operating levels used to capture fish for this investigation were 90-150 volts and 3-8 amperes, at 60 pulses per second and a 30% pulse width. Fish were captured by two netters using long-handled dip nets. Once netted, fish were placed in a 30 gallon live well and held until processing. Electrofishing was conducted both above and below the diversion structure during Trips 1, 2 and 4. During Trip 5 electrofishing was only conducted above the diversion structure. The standard approach for each field trip was to sample below the structure during the first two to three days of a trip and then sample above the diversion structure during the remainder of the trip. Sampling runs below the diversion structure were started in the plunge pool complex immediately below the diversion structure, then extended downstream for 1 mile. Up to two electrofishing passes were made each day over the sampling reach, with as many as Eve passes conducted over the sampling reach during a trip. A similar procedure was conducted above the diversion structure, starting from a point 4 ii J