A Compendium of Trout Stream Habitat Improvement Projects Done by the Wyoming Game and Fish Department, 1953-1998. By N. Allen Binns, Aquatic Habitat Supervisor Fish Division Wyoming Game & Fish Department Cheyenne, Wyoming 82006 April, 1999 TABLE OF CONTENTS TABLE OF CONTENTS ..................................................................................................................... i ABSTRACT ..................................................................................................................................... xiii LIST OF ACRONYMS.................................................................................................................... xiv INTRODUCTION................................................................................................................................1 Figure 1. The WGF Aquatic Habitat Construction Crew did the installation of stream habitat improvement structures for most projects. Here they are building a timber plunge in Big Willow Creek (top photo) and the completed plunge, with its plunge pool and a cover tree along one side, is shown in the bottom photo............................................................................................................4 Figure 2. Installation of tree jams on the upper Green River was done with the aid of heavy equipment rented from private contractors. A work crew installed cables after the trees and rocks were placed by the tracked hoe. .......................................................................................................5 Figure 3. Fish population response to stream habitat improvement was regularly monitored with electrofishing gear at many WGF projects. This scene is at a diagonal rock weir on South Cottonwood Creek............................................................................................................................6 Table 1. Characteristics of streams where WGF trout habitat improvement projects were located, 1953-1998. Constr. Year is the year primary construction occurred; area is drainage area upstream from the project; class is WGF stream class; width is mean wetted width......................8 Figure 4. Success rates at Level 1 (percent change > 25%) for four trout population indices, summarized over all projects. The mixed trout category summarizes all projects combined and includes both those containing only wild trout and those where fish of hatchery origin were present. Interpretation example: the percent change gain of wild trout/mile between RZ and TZ was at least 25% at 80% of the projects. .......................................................................................10 Figure 5. Success rates at Level 2 (percent change > 50%) for four trout population indices, summarized over all projects. The mixed trout category summarizes all projects combined and includes both those containing only wild trout and those where fish of hatchery origin were present. Interpretation example: the percent change gain of wild trout/mile between RZ and TZ was at least 50% at 73% of the projects. .......................................................................................10 Figure 6. Success rates by stream order for wild trout subjected to habitat improvement. Level 1 requires a percent change gain in trout/mile of at least 25%, and level 2 requires a gain of at least 50%. Interpretation example: 73% of the projects done at second order streams achieved a percent gain of at least 50%...........................................................................................................11 Table 2. Lowest percent success rates for wild trout by habitat characteristic. Success level 1 is percent change of 25%, or greater, in the population indices (total trout/mile, lbs/acre, trout/mile 6 inches, or greater, or lbs/acre 6 inches, or greater). Level 2 is a change of 50%, or greater. ..11 Figure 7. Mean empirical abundance of wild trout in treatment zones (TZ) and reference zones (RZ) at WGF habitat improvement projects done statewide from 1953 to 1997. ..........................12 i Figure 8. Mean empirical biomass of wild trout in treatment zones (TZ) and reference zones (RZ) at WGF habitat improvement projects done statewide from 1953 to 1997....................................13 Table 3. Mean empirical values for four trout population variables averaged over all habitat improvement projects done statewide from 1953-1997. No. Meas. is number of projects with measurements; % chg. is mean percent change averaged over all projects; RZ is reference zone; TZ is treated zone. The mixed trout category summarizes all projects combined and includes both those containing only wild trout and those where fish of hatchery origin were present. ..............14 Figure 9. Mean percent change in posttreatment abundance of wild trout at streams sorted by stream order. ..................................................................................................................................15 Figure 10. Mean percent change in posttreatment biomass of wild trout at streams sorted by stream order. ..................................................................................................................................16 Figure 11. Mean abundance of wild trout at different elevations after habitat improvement.......17 Figure 12. Mean biomass of wild trout at different elevations after habitat improvement............17 Figure 13. Mean abundance of wild trout at streams of different gradient after habitat improvement. ..................................................................................................................................18 Figure 14. Mean biomass of wild trout at streams of different gradient after habitat improvement. No data is available for streams with gradients 2-3%...................................................................19 Figure 15. Mean posttreatment abundance of wild trout at streams of different WGF stream class. No projects were done on Class 1 streams.....................................................................................20 Figure 16. Mean posttreatment biomass of wild trout at streams of different WGF stream class. No projects were done on Class 1 streams.....................................................................................20 Figure 17. Mean posttreatment abundance of wild trout at streams with different Rosgen Classification. No data were available for catchable sized trout in stream type A. ......................21 Figure 18. Mean posttreatment biomass of wild trout at streams with different Rosgen Classifications. No data were available for catchable size trout in stream type A........................22 Figure 19. Posttreatment response of wild trout to plunge and bank revetment structures. Plunges include log, timber, and rock plunges, while bank stabilization devices include rock riprap, tree/rock revetments, and tree revetments. Population indices summarize all projects where these two structure types were the primary structure type affecting fish response.................................23 Figure 20. Posttreatment response to plunge and bank revetment structures in trout populations where both wild trout and trout of hatchery origin may be present. Plunges include log, timber, and rock plunges, while bank stabilization devices include rock riprap, tree/rock revetments, and tree revetments. Population indices summarize all projects where these two structure types were the primary structure type affecting fish response. ........................................................................23 Figure 21. Posttreatment response to tree jams and rock weirs in trout populations where both wild trout and trout of hatchery origin may be present. Population indices summarize all projects where these two structure types were the primary structure type affecting fish response.............24 Figure 22. Mean HU for trout at 20 HQI stations located in reference (RZ) and treated zones (TZ) at habitat improvement projects.....................................................................................................25 ii Figure 23. Mean cover for trout at 23 HQI stations located in reference (RZ) and treated zones (TZ) at habitat improvement projects.............................................................................................25 Figure 24. Mean posttreatment residual pool depth (RPD) in plunge pools at 79 rock plunges, 264 timber plunges, and 47 log plunges at habitat improvement projects in Wyoming. ......................26 Figure 25. Mean amount of cover present posttreatment in plunge pools at 79 rock plunges, 264 timber plunges, and 47 log plunges at habitat improvement projects in Wyoming. ......................27 Figure 26. Posttreatment cover for trout in streams of different orders. Cover was measured at HQI stations located in RZ and TZ at habitat improvement projects and values shown are mean percent change between RZ and TZ over all observations. ...........................................................28 Figure 27. Change in HU at streams of different order following habitat improvement. HU was measured at HQI stations located in RZ and TZ at habitat improvement projects and values shown are mean percent change between RZ and TZ over all observations. ...........................................29 Figure 28. Cost of trout habitat improvement for 52 projects at Wyoming streams of different orders. Project cost was adjusted for inflation to 1995 US dollars...............................................29