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Because all parts of this project will require several years (5-7) to complete, we recommend that immediate steps be taken to implement appropriate parts during the remainder of FY 90. As examples, there are several projects that will be sampling target fish during this period, including razorback sucker and Colorado squawfish spawning, Gila, and others. Some of these projects will have the capability to obtain genetic material and to preserve this for use in evaluating stocks of Colorado squawfish and razorback sucker. PIs in those projects should be encouraged to cooperate by assisting in obtaining needed material. if extra funds are available, they could be provided to assist sampling during the spawning seasons. Tasks: -Select locations for studies with input from Work Group, and the Technical Committee f -Develop Final SOW after review and comments received from Technical Committee, select cooperators and study sites. -Contact field personnel involved in on-going work, provide them with guidelines and any needed equipment to tag breeding fish and to obtain genetic material from fish they may encounter. -Begin work on RFP's for contractors, memoranda of agreement for cooperating agencies. -Develop non-lethal tissue-sampling techniques. -Capture genetrc.material from marked fish at large during monitoring programs, or other field work that may be in progress. IX. Recommendations for FY 1991-FY 1993 work: Genetic assessments would determine if distinct populations exist among fish from different spawning sites, reaches, and those that exhibit differential rheotactic responses. Distinct populations would mean site specific spawning and this would require a mechanism in the fish that would allow identifications of the home site. Previous experience in other species suggests that imprinting may be the mechanism responsible if site-specific differences exist. If no distinct populations are found, a high degree of straying and genetic mixing would be indicated, and this would suggest that the spawning site fidelity previously reported is practiced only over a few spawning seasons. However, recognition of the spawning sites, as indicated by the return to them of the fish, would suggest that some environmental cue is available to the fish. Work with lake trout (Horrall 1981, Foster 1985) suggests that olfactory cues indicating an acceptable site, rather than a specific site, may operate in the latter case. In populations of Colorado squawfish studied to date, certain river sections are used heavily for spawning, and there is a fidelity for. these sites over several years. Certain genetic and environmental components may be 10