A Synthesis of Existing Data for Resident Fishes in the Snoqualmie River Above Snoqualmie Falls
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A SYNTHESIS OF EXISTING DATA FOR RESIDENT FISHES IN THE SNOQUALMIE RIVER ABOVE SNOQUALMIE FALLS PREPARED FOR PUGET SOUND ENERGY AS PARTIAL FULFILLMENT OF THE SNOQUALMIE RIVER GAME FISH ENHANCEMENT PLAN LICENSE ARTICLE 413 Prepared by Nathanael C. Overman Washington Department of Fish and Wildlife Region 4, Mill Creek, Washington June 2008 TABLE OF CONTENTS LIST OF TABLES ............................................................................................................ ii LIST OF FIGURES ......................................................................................................... iv EXECUTIVE SUMMARY .............................................................................................. 1 INTRODUCTION........................................................................................................... ..4 STUDY AREA................................................................................................................... 7 Snoqualmie River Basin ................................................................................................. 7 North Fork Snoqualmie River......................................................................................... 7 Middle Fork Snoqualmie River ...................................................................................... 8 South Fork Snoqualmie River......................................................................................... 8 Mainstem Snoqualmie River above Snoqualmie Falls ................................................... 9 Mainstem Snoqualmie River below Snoqualmie Falls................................................... 9 FISH RESOURCES.......................................................................................................... 9 Above Snoqualmie Falls................................................................................................. 9 Below Snoqualmie Falls ............................................................................................... 11 Current Management .................................................................................................... 12 FISHERIES DATA AND STUDIES ............................................................................. 12 Relative Trout Abundance ............................................................................................ 12 Trout Distribution ......................................................................................................... 15 Trout Movement ........................................................................................................... 19 Trout Reproductive Life History .................................................................................. 19 Age and Growth Studies ............................................................................................... 20 Creel Census ................................................................................................................. 22 Background Environmental Data Monitoring .............................................................. 23 Habitat Surveys and Mapping....................................................................................... 24 Habitat Enhancement.................................................................................................... 27 Public Education ........................................................................................................... 29 Trophic Interactions...................................................................................................... 29 CONCLUSIONS ............................................................................................................. 30 REFERENCES................................................................................................................ 33 APPENDIX..................................................................................................................... .68 i LIST OF TABLES 1. Density, biomass, fork length, weight, and species composition of trout in the North Fork Snoqualmie River estimated in early September 1979 from electrofishing seven block netted stations......................................................................................................... .38 2. Densities of trout and mountain whitefish estimated from snorkeling twelve reaches along the North Fork Snoqualmie River during July 24-October 4, 1979....................... .39 3. Summary of electrofishing surveys in the North Fork and mainstem of the Snoqualmie River in 1983.................................................................................................................... .40 4. Snorkel survey results in the North Fork Snoqualmie River, 1983-1984.................... .41 5. Summary of electrofishing and snorkel surveys in the North Fork Snoqualmie River, 1979-1984. ....................................................................................................................... .42 6. Summary electrofishing surveys in Calligan Creek and Deep Creek.......................... .43 7. Species composition and length frequency distribution for fish collected by R.W. Beck and Associates (August 1985) and Ott Water Engineers (Fall 1984) in the Black Canyon reach of the North Fork Snoqualmie River...................................................................... .44 8. Densities of trout estimated from snorkel surveys and electrofishing surveys at four sites in the vicinity of the Twin Falls hydroelectric project............................................. .45 9. Densities of trout estimated from snorkel surveys in the three forks of the Snoqualmie River, August 1992 .......................................................................................................... .46 10. Fish observed during USFS stream habitat snorkel surveys in the North Fork (1993), the Middle Fork (1996 and 1990) and the South Fork (1998, 1991, 1990)..................... .48 11. Fish observed during USFS stream habitat snorkel and electrofishing surveys in Lennox Creek (1990), the Taylor River (1992), the Pratt River (1992), Carter Creek (1991) and Quartz Creek (1991)...................................................................................... .50 12. Snorkel observations made in July 1990 from the mainstem above Snoqualmie Falls to the lower reaches of the three forks............................................................................. .51 13. Season-long effort and catch success from creel surveys conducted on the North, Middle, and South Forks of the Snoqualmie River.......................................................... .52 14. Snoqulmie River creel data from the 1940s............................................................... .53 ii 15. Water quality data from the U.S. Army Corps of Engineers North Fork Snoqualmie River sampling program (1979-1980) ............................................................................. .54 16. Habitat measurements for snorkel survey sites in the three forks of the Snoqualmie River, August 1992 .......................................................................................................... .56 17. Stomach contents of trout caught in the North Fork Snoqualmie River and in beaver pond 6 (July-August 1979) .............................................................................................. .58 18. Densities of aquatic invertebrates collected in North Fork Snoqualmie River (June 1979). ............................................................................................................................... .59 iii LIST OF FIGURES 1. Map of the Snohomish River Basin including the Snohomish, Skykomish, and Snoqualmie rivers and associated forks........................................................................... .60 2. Map of the North Fork Snoqualmie River including, tributaries, lakes, impassible migration barriers, and river miles................................................................................... .61 3. Map of the Middle Fork Snoqualmie River including tributaries, lakes, impassible migration barriers, and river miles................................................................................... .62 4. Map of the South Fork Snoqualmie River including tributaries, lakes, impassible migration barriers, and river miles................................................................................... .63 5. Length frequencies by age for cutthroat trout collected by angling in the Middle Fork, 1981-1984. ....................................................................................................................... .64 6. Length frequencies for cutthroat trout collected by angling in the Middle Fork and by electrofishing surveys in the South Fork. ........................................................................ .65 7. Length frequencies for trout collected by elctrofishing in the North Fork and by angling in the Middle Fork and South Fork..................................................................... .66 8. Average total lengths at age for trout collected by electrofishing the North Fork and its tributaries and from angling in the Middle and South Forks........................................... .67 iv EXECUTIVE SUMMARY This synthesis is a summary of the fisheries research conducted on trout and mountain whitefish Prosopium williamsoni in the Snoqualmie River, with emphasis on resident cutthroat trout Oncorhynchus clarki, rainbow trout Oncorhynchus mykiss, and eastern