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I ~ award competitive contracts, and develop needed purchase orders or contracts for assistance" from identified experts. -Initiate spawning basket experiments. -Perform data analyses, integrate findings -Develop FY 92 scope of work dependent on results of above stud~es. Genetic assessments would determine if distinct populations exist ~mong fish from different spawning sites, reaches, and those that exhibit t differential rheotactic responses. Distinct populations would mean si e 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 ove1 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 19,5) suggests that olfactory cues indicating an acceptable site, rather t an a specific site, may operate in the latter case. In populations of Colorado squawfish studied to date, certain rivlr sections are used heavily for spawning, and there is a fidelity for hese sites over several years. Certain genetic and environmental componen s may be involved in this site selection, and the genetic assessment will be elpful in evaluating which one of these components may be operating. In any event, the development of recovery plans may require imprinting or conditio ing fish to certain sites, and fish will be needed for this work. Fertilized 9gs must be obtained, subjected to environmental conditions, and the larvae s ould be reared in the hatchery. In this manner, fish will be available for n cessary experiments to evaluate different spawning strategies. This can be b st accomplished by obtaining gametes from fish on-site. I I so~e source t . "~ ~ . ~ . ~ ~~ ACKNOWLEDGEMENTS 4 ~ 1 This paper was prepared with funds provided by the Recovery Implemen ation Program and U.S. Fish and Wildlife Service. P. B. Johnsen, J. H. Wil iamson, C. A. Karp, and others improved an earlier draft of the manuscript. F. Abarca rendered a spanish translation of the abstract. :--~ . --, ~ ~ LITERATURE CITED Baker, R. R. 1982. Migration paths through time and space. Holmes a Publishers, New York. Breder, C. M., and D. E. Rosen. 1966. Modes of reproduction in fish Natural History Press, Garden City, New York. 18