South Fork Flathead Watershed Westslope Cutthroat Trout Conservation Program
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South Fork Flathead Watershed Westslope Cutthroat Trout Conservation Program Annual Report 2002 DOE/BP-00005043-1 June 2003 Field37: This Document should be cited as follows: Grisak, Grant, Brian Marotz, ''South Fork Flathead Watershed Westslope Cutthroat Trout Conservation Program'', Project No. 1991-01903, 143 electronic pages, (BPA Report DOE/BP-00005043-1) Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208 This report was funded by the Bonneville Power Administration (BPA), U.S. Department of Energy, as part of BPA's program to protect, mitigate, and enhance fish and wildlife affected by the development and operation of hydroelectric facilities on the Columbia River and its tributaries. The views in this report are the author's and do not necessarily represent the views of BPA. South Fork Flathead Watershed Westslope Cutthroat Trout Conservation Program Bonneville Power Administration Hungry Horse Dam Mitigation U.S. Department of Energy Bonneville Power Administration Project Number 199101903 Montana Fish, Wildlife & Parks State Project 31002/31042 January 2003 Annual Report 2002 South Fork Flathead Watershed Westslope Cutthroat Trout Conservation Program Annual Report 2002 Prepared by Grant Grisak, Project biologist Montana Fish, Wildlife & Parks 490 North Meridian Road Kalispell, Mt. 59901 Prepared for Ron Morinaka, Project Manager U.S. Department of Energy Bonneville Power Administration Division of Fish and Wildlife P.O. Box 3621 Portland, OR 97208 ii Table of contents Page Introduction……………………………………………………………………………………………... 1 Project rationale…………………………………………………………………………………………. 2 Project area……………………………………………………………………………………………… 4 Background and present legal status of westslope cutthroat trout……………………………………… 9 Decisions to be made……………………………………………………………………………………. 11 Methods of fish removal………………………………………………………………………………… 12 Angling………………………………………………………………………………………. 12 Downstream barriers…………………………………………………………………………. 12 Explosives……………………………………………………………………………………. 13 Genetic swamping…………………………………………………………………………… 13 Gill netting…………………………………………………………………………………… 14 Seining……………………………………………………………………………………….. 16 Trap nets……………………………………………………………………………………... 16 Electrofishing………………………………………………………………………………… 17 Tiger muskellunge…………………………………………………………………………… 19 Chemical removal……………………………………………………………………………. 20 Antimycin………………………………………………………………………….. 20 Rotenone……………………………………………………………………………. 24 Potassium permanganate…………………………………………………………… 34 Applications……………………………………………………………. 36 Summary and conclusions…………………………………………………………………… 38 Methods of transportation……………………………………………………………………………... 44 Backpacking…………………………………………………………………………………. 44 Livestock……………………………………………………………………………………... 44 Truck…………………………………………………………………………………………. 44 Helicopter……………………………………………………………………………………. 44 SEAT aircraft………………………………………………………………………………… 45 Summary and conclusions…………………………………………………………………… 48 Wilderness lakes being treated with antimycin and transported with livestock……. 49 Non-wilderness lakes being treated with Prenfish and transported with aircraft…... 50 Both wilderness and non-wilderness lakes being treated with antimycin and transported with aircraft or truck…………………………………………… 50 Amphibians……………………………………………………………………………………………. 51 Monitoring………………………………………….………………………………………... 52 Fish stocking…………………………………………………………………………………………... 53 Partial restocking…………………………………………………………………………….. 53 Deferred restocking…………………………………………………………………………... 53 No restocking………………………………………………………………………………… 54 Fishless lakes………………………………………………………………………………… 56 Summary and conclusions…………………………………………………………………… 57 Development and use of new strains of westslope cutthroat trout…………………………………….. 58 iii Table of contents (cont’d) Page Lake descriptions and management. ………………………………………………………………….. 63 Wildcat………………………………………………………………………………………. 63 Clayton………………………………………………………………………………………. 64 Blackfoot…………………………………………………………………………………….. 65 Black…………………………………………………………………………………………. 66 Handkerchief……………………………………………………………………………….… 68 Upper Three Eagles………………………………………………………………………….. 69 Lower Three Eagles…………………..……………………………………………………… 70 Pilgrim……………………………………………………………………………………….. 71 Lower Bighawk……………………………………………………………………………… 73 Margaret……………………………………………………………………………………… 74 Sunburst……………………………………………………………………………………… 75 Woodward……………………………………………………………………………………. 76 Necklace ……………………………………………………………………………………... 78 Lena………………………………………………………………………………………….. 79 Lick…………………………………………………………………………………………... 80 Koessler……………………………………………………………………………………… 82 George……………………………………………………………………………………….. 83 Pyramid………………………………………………………………………………………. 84 Summary and timing of lake treatments……………………………………………………... 85 References……………………………………………………………………………………………... 88 Appendix A – Amphibian survey results and food habits of westslope cutthroat trout from lakes in the Flathead basin……………………………………………………………………… 98 Appendix B – Bathymetric maps of project lakes in the South Fork Flathead River drainage……….. 103 iv List of Tables Table Page 1 Fish population status of natural lakes in the South Fork Flathead drainage……………….. 4 2 National Forest and Hiking Area lakes that harbor exotic trout in the South Fork Flathead River drainage……………………………………………………………………………….. 5 3 Bob Marshall Wilderness lakes that harbor exotic trout in the South Fork Flathead River drainage…………………………………………………………………………………….... 5 4 Summary of fish removal methods evaluated for South Fork Flathead westslope cutthroat trout conservation program………………………………………………………………….. 38 5 Elevation differential, distance to bull trout populations and values for natural detoxification using antimycin in lakes with downstream bull trout populations…………... 41 6 Size and volume of lakes in which antimycin will be used, amount required for trout removal, and lake pH………………………………………………………………………... 42 7 Size and volume of non-wilderness lakes, and Prenfish required for trout removal………... 43 8 Summary of transport methods evaluated to implement the South Fork Flathead westslope cutthroat trout conservation program………………………………………………………... 48 9 Wilderness lakes that will require livestock to transport antimycin, amount of material, number of animals needed, and trail distance……………………………………………….. 49 10 Non-wilderness lakes that will require aircraft to transport Prenfish, amount of Prenfish needed, and number of flights……………………………………………………………….. 50 11 Wilderness and non-wilderness lakes that will require aircraft and automobile to transport antimycin, amount of antimycin needed, and number of flights or loads needed…………... 50 12 Angler use estimates for select lakes in the South Fork Flathead River drainage, 1989-2001 and statewide rank based on 1,529 fisheries in the state………………………….….……… 55 13 Summary of fish removal methods recommended for each lake and associated stream, transport method(s), number of fish restocked to establish a population, and amphibian status…………………………………………………………………………………………. 86 14 Tentative sequence of lake treatments………………………………………………………. 87 A1 Presence, species composition and/or nearest population of amphibians in lakes proposed for hybrid trout removal, South Fork Flathead River drainage, 1999-2001………………… 99 A2 Temporal status of amphibian populations in 21 waters treated with rotenone in the Kalispell area, 2002…………………………………………………………………...……... 100 A3 Observations of amphibians during electrofishing surveys in South Fork Flathead streams. Data collected incidental to fish population surveys and is not considered qualitative or quantitative.………………………………………………………………………………….. 101 A4 Stomach contents of westslope cutthroat trout (n=89) sampled during periods of high amphibian tadpole abundance in four lakes in the Flathead basin, Montana, 2002……….... 102 v List of Figures Figure Page 1 Map of non-wilderness lakes that contain hybrid trout populations, South Fork Flathead River drainage……………………………………………………………….. 6 2 Map of wilderness lakes that contain hybrid trout populations, South Fork Flathead River drainage……………………………………………….………………………… 7 3 Map of Sunburst Lake, which contains a hybrid trout population, Bob Marshall Wilderness, South Fork Flathead River drainage……………………………………... 8 4 Map of Pyramid Lake, which contains a hybrid trout population, Bob Marshall Wilderness, South Fork Flathead River drainage……………………………………... 8 5 Inflection point of mean daily surface and benthic temperatures ( oF) of Black Lake, South Fork Flathead River drainage, 2002……………………………………………. 31 6 Inflection point of mean daily surface and benthic temperatures ( oF) of Wildcat Lake, South Fork Flathead River drainage, 2002……………………………………... 31 7 Regression plot of linear coverage and gallons of water released from a Dromader M18B flown at 80 knots and a mean altitude of 32 feet, Fort Benton, Montana……... 47 B1 Bathymetric map of Wildcat Lake…………………………………………………... 104 B2 Bathymetric map of Clayton Lake……………………………………………………. 105 B3 Bathymetric map of Blackfoot Lake……………………………………………….….. 106 B4 Bathymetric map of Black Lake…………………………………………………….… 107 B5 Bathymetric map of Handkerchief Lake………..……………………………………... 108 B6 Bathymetric map of Upper Three Eagles Lake……………………………………….. 109 B7 Bathymetric map of Lower Three Eagles Lake……………………………………….. 110 B8 Bathymetric map of Pilgrim Lake……………………………………………………... 111 B9 Bathymetric map of Lower Bighawk Lake……………………………………………. 112 B10 Bathymetric map of Margaret Lake…………………………………………………… 113 B11 Bathymetric map of Sunburst Lake…………………….…………………………….. 114 B12 Bathymetric map of Woodward Lake………………………………………………… 115 B13 Index