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<br />APPENDIX 1 - Habitat Utilization Curves <br />Utilization Curves for spawning squawfish, both deposition/ <br />fertilization and staging/resting phases were constructed for <br />depth, velocity and substrate, from observation data collected in <br />the lower Yampa by the Colorado River Fishery Project tCRFP), <br />1981 and 1983. They were developed for both phases with the <br />following restraints; also provided by CRFP. <br />Staging/Resting ..................Habitat - <br />Depth = > <br />Velocity <br />Substrate <br />Deposition/Fertilization.........Habitat = <br />Depth = < <br />Velocity <br />Substrate <br />Pools or eddies <br />5.5' <br />= No restraints <br />= No restraints <br />Riffles or runs <br />5.5' <br />= < 4 fgs <br />= Gravel, cobble or <br />rubble <br />It should be pointed out that data used to develop these <br />utilization curves were collected for Colorado squawfish observed <br />in the lower 20 miles of the Yampa River. As such they are <br />related to spawning activities of Colorado squawfish within the <br />lower Yampa River only and have no bearing whatsoever on other <br />Life stage requirements, or other river reaches. <br />Utilization Curves were not developed for other life stages tie. <br />adults, juveniles and young of the year) because there are <br />presently no existing biological data for such purpose. <br />For all curves, the vertical axis represents a habitat <br />suitability index from 0-1.00. The horizontal axis represents a <br />range of. values for depth and velocity; for substrate the <br />following code was utilized: <br />6 = Bedrock <br />5 = Boulde r <br />4 = Cobble <br />3 = Gravel <br />2 = Sand <br />1 = Silt & Clay <br />P-----Dominant bed material <br />e.g. 42 secondary bed material <br />9 <br />