EFFECTS OF POTENTIAL INTRODUCTIONS OF SMALLMOUTH BASS {HICROPTERUS DOLOHIEUI) INTO WATERS OF THE CLARK FORK, FLATHEAD, AND KOOTENAI DRAINAGES OF WESTERN MONTANA by David H. Bennett and Kristen M. Bennett Department of Fish i Wildife Resources College of Forestry. Wildife and Range Sciences University of Idaho Moscow, Idaho 83843 Funded by and Presented to: Montana Department of Fish. Wildife, and Parks P.O. Box 67 Kalispell. Montana 59903 AND The Confederated Salish and Kootenai Tnbes of the Flathead Reservation Box 278 Pablo. MT 59855 STATEDOCUMENTSCOLLECTION ^^^^ DEC 231991 MONTANASTATELIBRARY HELEN1A5,15MEO.N6TtAhNAAVE5.9620 TABLE OF CONTENTS Topic List of Figures List ofTables List of Appendix Tables Introduction Overview of Life History Objectives Mean Annual Catch Rates Sport Fishery Yields Seasonal Factors Affecting the Fishery Water and Air Temperatures Habitat Cover and Substrate Stream Gradient/Velocity Light Intensity Turbidity Other Habitat Attributes Standing Crops Pioneering Forage Preferences 1 Disease 21 Parasitic Diseases Fungal Disease Bacterial Disease Viral Disease Natural Mortality 2* Proportional Stock Density 25 Interspecific Interactions 27 Potential Impacts of Introductions 33 General Analysis of Bass Introduction 37 Candidate Waters Region 1 Lakes Horseshoe Lake (Lincoln County) 44 Horseshoe Lake (Lake County) ^5 Loon Lake (Lincoln County) 46 Loon Lake (Lake County) Upper Thompson Lake (Lincoln County) 47 Lake Five (Flathead County) 47 Blue Lake (Flathead County) 48 Flathead Lake Little Bitterroot Lake 53 Dog Lake Lake Blaine Rivers Lower Flathead River 56 Pleasant Valley Fisher River 57 Stillwater River 59 ii Candidate Waters Region 2 Lakes A1va Inez Seeley Placid Salmon Rivers Clearwater River below Salmon L. Clark Fork River below Missoula Bitterroot River below Florence Blackfoot River below Clearwater Summary of Systems Under Consideration Recommendations Region 1 Region 2 References Appendix iii List of Figures Pages Figure 1. Comparison of growth rates for smallmouth bass in Little Goose Reservoir, Washington, South Branch Lake, Maine, Lake Geneva, Wisconsin, and Noxon Rapids Reservoir, Montana 34 Figure 2. Surface water temperatures from Little Goose Reservoir, Snake River, Washington for 1979 and 1980. The "preferred" water temperature for smallmouth bass is indicated 36 Figure 3. Water temperatures for four flowyears for the Umpqua River, OR 38 Figure 4. Water temperatures for four flowyears for the South Umpqua, and the North Umpqua River, OR 39 Figure 5. Comparison of number of frost-free days (>32°F) from 1979-1989 for Libby and Eureka, and Poison, Whitefish, and Olney, Montana. The reported threshold for smallmouth at 100 days is indicated ''^ Figure 5. Comparison of number of frost-free days (>32*F) from 1979-1989 for Missoula and St, Regis, and Thompson Falls and Trout Creek, Montana. The reported threshold for smallmouth at 100 days is indicated '^3 Figure 7. Surface water temperatures for Fisher River, Montana for 1976, 1980, and 1985. The "preferred" water temperature for smallmouth bass is indicated 58 Figure 8. Surface water temperatures for Lake Alva, Lake Inez, and Seeley Lake, Montana. The "preferred" water temperature for smallmouth bass is indicated 62 Figure 9. Surface water temperatures for Placid Lake and Salmon Lake, Montana. The "preferred" water temperature for smallmouth bass is indicated 65 iv List of Figures Cont. Pages Figure 10. Surface water temperatures for Clark Fork River, Montana from the Plains and Superior monitoring stations for 1976 and 1985. The "preferred" water temperature for smallmouth bass is indicated 69 Figure 11. Surface water temperatures for Bitterroot River, Darby, and Hamilton, Montana for 1984, 1985 and 1986. The "preferred" water temperature for smallmouth bass is indicated 71 Figure 12. Surface water temperatures for Blackfoot River, Montana for 1988. The "preferred" water temperature for smallmouth bass is indicated 74 List of Tables Pages Table 1. Back-calculated length at age data for various populations of smallmouth bass 35 List ofAppendixTables Pages Appendix Table 1. Suitability index (SI) graphs for smallmouth bass model variables (Edwards et al. 1983) 92 vi INTRODUCTION The smallmouth bass Micropterus dolomieui was originally restricted to fresh waters of eastern central North America. The original range was limited to the Great Lakes-St. Lawrence system and the systems of the Ohio, Tennessee, and upper Mississippi rivers (Scott and Grossman 1973). The species has been widely introduced and self- sustaining populations established across the continental United States and Canada, and in Hawaii, Asia, and Africa (Coble 1975). Introductions of smallmouths have also been made into South America and Europe (Robbins and MacCrimmon 1974). Introductions into the far-western United States were first made by the U.S. Fish Commission into California in 1874 (Lampman 1946). Introductions into the Northwest, however, were made considerably later around the 1920's. State game protectors made extensive introductions in Oregon in 1921 to 1925. Robbins and MacCrimmon (1974) reported that according to fish stocking records introductions of smallmouth bass were made into Church, Emmert, and Horseshoe lakes in Montana in 1913 by the U.S. Bureau of Fisheries. An estimated 15,800 fish were stocked at this time. They also reported self-sustaining populations were found in Helena Valley Reservoir and the Tongue River in southeastern Montana although these probably died-out. Bass stocks throughout the Northwest generally received light fishing pressure before World War II (Henderson and Foster 1956). Early fishing pressure on smallmouth came from immigrants from eastern and midwestern areas who were familiar with the species.