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<br />541 <br /> <br />Adult Rare Fish Monitoring and Radio Telemetry Studies <br />Fiscal Year 1997 Project Proposal <br />U.S. Fish and Wildlife Setvice, Region 6 <br /> <br />Background: <br /> <br />Studies performed before 1991 documented a native San Juan River fish fauna of eight species, <br />including Colorado squawfish, razorback,sucker, and roundtail chub and provided baseline <br />information on distribution and abundance of native and introduced fish species in the San Juan <br />River, Adult monitoring studies ani designed to refine this baseline data, as well as determine <br />specific habitat usage by rare fish species, Information gathered during adult monitoring will aid <br />in the selection of specific sites for detailed hydrologic measurements and latval drift sampling. <br />Integration of adult fish community monitoring data with data from Colorado squawfish <br />macro habitat studies, razorback sucker experimental stocking studies, tributary and secondary <br />channel studies, fish health studies, contaminants studies, habitat mapping studies, and non-native <br />species interaction studies, will help to provide flow recommendations for reoperation of Navajo <br />Resetvoir as well as helping address objectives 5,1 through 5.5 in the San Juan River Long Range <br />Plan. <br /> <br />To date twenty intensive electrofishing sutveys conducted from 1991 to 1996 have expanded our <br />baseline knowledge on the distribution and abundance of the San Juan River fish community. <br />Future monitoring will help determine fish community response to test flows from Navajo Dam. <br />Nineteen Colorado squawfish were collected and PIT --tagged during these studies; 13 of the 19 <br />Colorado squawfish were radio-tagged. Eighteen roundtail chub were collected, 13 of these were <br />PIT "tagged. No wild razorback sucker were collected, however 38 experimentally stocked <br />razorback sucker have been recaptured to date. Radio telemetry efforts located the primary range <br />and probable staging, spawning, and rearing areas of Colorado squawfish and documented <br />dispersal patterns and habitat use of stocked razorback sucker, Location of probable spawning <br />aggregations of Colorado squawfish led to the placement oflatval drift stations below these sites. <br />To date only one radio-telemetered Colorado squawfish has moved above any instream water <br />diversion structure while under our obsetvation. This fish was obsetved approximately 100 yards <br />above the Cudei Diversion (RM 142.0) in the summer of 1994. After approximately a day and a <br />half contact was lost with this fish at this location. It was later contacted below the diversion <br />structure. Radio contact has not been made with it, or any other Colorado squawfish above this <br />structure since that time. FLOY-tagged native suckers have yielded preliminary data about the <br />movement of these species in relation to four instream diversion structures in the area of <br />Farmington, New Mexico. <br /> <br />Adult monitoring will continue with four trips in 1997, to measure fish community response to <br />research flows from Navajo Dam, and to monitor the dispersal oflentic predators (e.g.- <br />largemouth bass, smallmouth bass, striped bass, and walleye) and stocked razorback sucker which <br />have invaded the lower San Juan River since the June 1995 inundation of the waterfall at river <br /> <br />1 <br />