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<br />Adult/Juvenile Fish Community Monitoring <br />Fiscal Year 2001 Project Proposal <br /> <br />Principal Investigators: Dale Ryden and Frank Pfeifer <br />. U. S. Fish and Wildlife Service, Colorado River Fishery Project <br />764 Horizon Drive, Building B <br />Grand Junction, Colorado 81506-3946 <br />(970) 245-9319 <br />dale _ ryden@fws.gov frankyfeifer@fws.gov <br /> <br />Back~round: <br /> <br />Studies performed before 1991 documented a native San Juan River fish fauna of eight species, including <br />Colorado pikeminnow (previously known as Colorado squawfish), razorback sucker, and round tail chub and <br />provided baseline information on distribution and abundance of native and introduced fish species in the San <br />Juan River. Main channel fish community monitoring studies (known as "adult monitoring") performed from <br />1991 to 1998 refined this baseline data and provided data on specific habitat usage by rare fish species. Adult <br />monitoring has proven to be the most effective t601 for monitoring populations of stocked razorback sucker and <br />recently stocked adult Colorado pikeminnow. In addition adult monitoring has recently captured numerous <br />stocked, early life stage Colorado pikeminnow. Information gathered during adult monitoring also aided in the <br />selection of specific sites for detailed hydrologic measurements and larval drift sampling. Integration of adult <br />monitoring data with data from Colorado pikeminnow macrohabitat studies, razorback sucker experimental <br />stocking studies, tributary and secondary channel studies, fish health studies, contaminants studies, habitat <br />mapping studies, and non-native species interaction studies, helped provide data to make flow <br />recommendatioqs for reoperation of Navajo Reservoir. <br /> <br />Thirty-two intensive electro fishing surveys conducted from 1991 to 1999 expanded our knowledge on the <br />distribution and abundance of the San Juan River fish community, As of October 1999, nineteen wild juvenile <br />and adult Colorado pikeminnow have been collected and PIT-tagged; 13 of the 19 Colorado pikeminnow were <br />radio-tagged. In addition, 10 adult and 188 juvenile, experimentally-stocked Colorado pikeminnow have been <br />recaptured. Ninety-five of these fish were captured on the October 1998 adult monitoring trip. Twenty-four <br />roundtail chub were collected, 19 of these were PIT -tagged. No wild razorback sucker were collected, however <br />73 stocked razorback sucker have been recaptured during adult monitoring trips, <br /> <br />The need for a long-term, standardized monitoring program, such as the adult monitoring study is addressed in <br />objective 5.7.1, a Milestone in the San Juan River Long Range Plan. Additionally, future monitoring will help <br />determine fIsh community response to reoperation flows from Navajo Dam (objective 5.2.10), as well as <br />monitoring both wild and augmented populations of Colorado squawfish and razorback sucker (objective <br />5.3.9). <br /> <br />Adult monitoring will continue with one trip in fall 2001, to measure fish community response to reoperation <br />flows from Navajo Dam, monitor populations of experimentally-stocked Colorado pikeminnow and razorback <br />sucker, and assess impacts of instream diversion structures to native fish species. In support of objective #4 <br /> <br />2 <br />