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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />OD1233 <br /> <br />Adult/Juvenile Fish Community Monitoring <br />Fiscal Year 2005 Project Proposal <br />14 December 2004 <br /> <br />Principal Investigators: Dale Ryden and Chuck McAda <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.govandchuck_mcada@fws.gov <br /> <br />Background: <br /> <br />Studies performed before 1991 documented a native San Juan River fish fauna of eight species, <br />including Colorado pikeminnow (previously known as Colorado squawfish), razorback sucker, <br />and roundtail chub and provided baseline information on distribution and abundance of native <br />and introduced fish species in the San Juan River. Main channel fish community monitoring <br />studies (known as "adult monitoring") performed from 1991 to 2003 has greatly refined our <br />understanding of the San Juan River fish community and provided data on specific habitat usage <br />by rare fish species. Adult monitoring proved to be a highly effective tool for monitoring <br />populations of stocked razorback sucker and Colorado pikeminnow. Information gathered during <br />adult monitoring also aided in the selection of specific sites for detailed hydrologic measurements <br />and larval drift sampling. Integration of adult monitoring data with data from Colorado <br />pikeminnow macrohabitat studies, razorback sucker experimental stocking studies, tributary and <br />secondary channel studies, fish health studies, contaminants studies, habitat mapping studies, and <br />non-native species interaction studies, helped provide data to make flow recommendations for <br />reoperation of Navajo Reservoir. <br /> <br /> <br />As stated above, intensive electro fishing surveys conducted from 1991 to 2003 greatly expanded <br />our knowledge on the distribution and abundance of the San Juan River fish community, <br />especially the endangered fish species. As of October 2003, nineteen wild Colorado pikeminnow <br />(two juveniles and 17 adults) have been collected and PIT-tagged; 13 of the 19 Colorado <br />pikeminnow were radio-tagged. In addition, 45 adult and over 300 juvenile stocked Colorado <br />pikeminnow have been recaptured (95 of these fish were captured on the October 1998 adult <br />monitoring trip). Thirty-seven roundtail chub were collected, 26 of which were PIT -tagged. No <br />wild razorback sucker were collected, however 137 recapture events (including multiple <br />recaptures of individual fish) have occurred with stocked razorback sucker during adult <br />monitoring trips. The 2004 adult monitoring trip is scheduled for late September through early <br />October 2004. <br /> <br />The need for a long-term, standardized monitoring program, such as the adult monitoring study, <br />is addressed in objective 5.7.1, a Milestone in the San Juan River Long Range Plan. <br />Additionally, future monitoring will help determine fish community response to reoperation flows <br />from Navajo Dam (objective 5.2.10), as well as monitoring both wild and augmented populations <br />of Colorado pikeminnow and razorback sucker (objective 5.3.9). <br /> <br />Adult monitoring will continue with one trip in fall 2005, to measure fish community response to <br />reoperation flows from Navajo Dam, monitor populations of stocked Colorado pikeminnow and <br />razorback sucker, and assess the impacts of management actions (e.g., nonnative fish removal <br />efforts) on native fish species. In support of objective #3 below, nonnative fish removal will <br /> <br />I <br />