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<br />pike, roundtail chub and f1annelmouth sucker. Radio tracking was also conducted during these trips. <br />Trip 3 was conducted exclusively to track radio tagged fISh. Mark and recapture studies and radio <br />tracking was conducted during Trip 4. Intensive sampling below the diversion structure was also <br />conducted during Trip 4 to determine if Colorado squawfish were aggregating below the diversion <br />structure. Radio tracking was continued during Trip 5 in addition to electrofishing above the <br />diversion structure for purposes of recapturing marked fish. Trips 4 and 5 were both conducted <br />during late summer and early fall base flows to specifically evaluate fish passage during a low flow <br />period. <br /> <br />Table 1. Sampling schedule for the City of Craig, Colorado, Yampa River Diversion Fish Passage <br />Study conducted by BIOIWEST in 1992. <br /> <br />Trip Dates Purpose of Trip <br /> <br />Radiotag RT, FM and NP, Radio track <br />Mark and Recapture <br /> <br />Radiotag RT, FM and NP, Radio track <br />Mark and Recapture <br /> <br />Radio track <br /> <br />Radio track, Mark and Recapture <br />Determine if CS are stacking below <br />diversion structure <br /> <br />1 April 22-27 <br />2 June 7-12 <br />3 August 3-5 <br />4 September 24-28 <br /> <br />5 <br /> <br />October 19-23 <br /> <br />Radio track, Sample for recaptures <br />above the diversion structure <br /> <br />Capturing the Fish <br /> <br />Electrofishinl!. ElectroflShing using a 220-volt DC system was the primary sampling method used <br />to capture fISh for this investigation. Electrofishing was conducted from a 16-foot aluminum Jon boat <br />with a Mercury XD-25 horsepower outboard. Power for the electrofishing system was provided by <br />a 3500 watt Homelite generator. Output was controlled by a Coffelt VVP-15. Normal operating <br />levels used to capture fish for this investigation were 90-150 volts and 3-8 amperes, at 60 pulses per <br />second and a 30% pulse width. Fish were captured by two netters using long-handled dip nets. Once <br />netted, fish were placed in a 30 gallon live well and held until processing. <br /> <br />Electrofishing was conducted both above and below the diversion structure during Trips 1, 2 and <br />4. During Trip 5 electrofishing was only conducted above the diversion structure. The standard <br />approach for each field trip was to sample below the structure during the first two to three days of <br />a trip and then sample above the diversion structure during the remainder of the trip. Sampling runs <br />below the diversion structure were started in the plunge pool complex immediately below the <br />diversion structure, then extended downstream for 1 mile. Up to two electroflShing passes were made <br />each day over the sampling reach, with as many as five passes conducted over the sampling reach <br />during a trip. A similar procedure was conducted above the diversion structure, starting from a point <br /> <br />4 <br />