COLUMBIA LAKE BURBOT POPULATION COLUMBIA BASIN ESTIMATE PROGRAM, CANAL FLATS, BC FISH & WILDLIFE COMPENSATION PROGRAM PREPARED BY J.E. Bisset, S.K.A. Arndt, R.S. Cope FOR Columbia-Kootenay Fisheries Renewal Partnership In Partnership with June 2002 www.cbfishwildlife.org Columbia Lake Burbot Population Estimate Program, Canal Flats, B.C. Prepared for: Columbia-Kootenay Fisheries Renewal Partnership 7468 Mission Road Cranbrook, BC V1C 7E5 June 2002 Prepared by: Westslope Fisheries 517 13th Avenue South Cranbrook, B.C. V1C 2W5 (250) 426-8381 AND Columbia Basin Fish & Wildlife Compensation Program 103-333 Victoria Street Nelson, BC V1L 4K3 (250) 352-6178 Columbia Lake Burbot Monitoring Program Westslope Fisheries Executive Summary Columbia Lake burbot have been the subject of a number of investigations since 1996. These have included six years of spawner enumeration at a tributary, tracking of post-spawning movement, surveys of juvenile abundance and habitat use, and estimates of angler harvest. This study was designed to provide a population estimate of adult burbot in the lake to complement the earlier studies. In addition, information was obtained on the size distribution of lake-captured fish, and the depth and habitats used. The study took advantage of the fact that 995 burbot had been tagged as part of spawner enumeration early in 2001; these fish were used as the first phase of a mark-recapture population estimate. Sixteen cod traps were deployed at locations across Columbia Lake and the upper Columbia River from May 30 to June 7, and October 2 to October 11, 2001. The sites for the location of cod traps were chosen based on previous radiotelemetry surveys and suspected concentrations of prey in the autumn. These traps have been used very successfully to capture burbot in other lakes of the Kootenay Region. A total of 266 trap-days of effort were expended during the spring and autumn capture periods, resulting in a catch of 57 burbot of which three had been tagged in previous studies. There were zero recaptures for tags applied during this study. These catch rates were approximately one tenth of that expected based on other lakes, and resulted in a population estimate with wide 95% confidence limits (11,194 ± 9,557) that restrict its application to research and management questions. However, new information was obtained on aspects of life history and habitat use. Size distribution of burbot in the lake changed substantially between the spring and autumn periods, suggesting that a large number of adult burbot may have been absent from the lake during spring sampling. This contradicts an earlier radiotelemetry study and may indicate that post-spawning movement patterns differ from year to year. Also, when spring and fall size distributions in the lake are combined, it appears that the 1997 cohort was more abundant than the 1999 cohort. This contrasts with the relative abundance of these two cohorts in the tributary spawners of 2001. Depths occupied by lake-captured burbot were different from those determined in an earlier study that suggested a length of 39 cm as the size at which burbot moved from shoreline to deeper habitats. In this study, burbot less than 30 cm were captured at depths up to 6 m, and burbot over 50 cm were captured as shallow as 1 m. June 2002 •ii Columbia Lake Burbot Monitoring Program Westslope Fisheries If future population estimates are contemplated, consideration should be given to the following recommendations: • Assume relatively low catch rates and plan for a longer, intensive collection period; • Consider that autumn sampling coinciding with kokanee spawning migration (and spawning locations) may be more productive than spring sampling; • Use fresh kokanee bait to improve capture rates if available; and • Consider expanding the study area beyond Columbia Lake (e.g., Windermere Lake, Moyie Lake). June 2002 •iii Columbia Lake Burbot Monitoring Program Westslope Fisheries Acknowledgements Funding for the “Columbia Lake Burbot Population Estimate” was provided by Columbia- Kootenay Fisheries Renewal Partnership, Fisheries Renewal British Columbia (FsRBC) and Columbia Basin Trust (CBT), and administered by the Columbia Basin Fish and Wildlife Compensation Program (CBFWCP). CBFWCP also provided in kind support of the project for planning and design of the study, aspects of fieldwork, and reporting. The CBFWCP is a joint initiative between BC Hydro and the Government of British Columbia to conserve and enhance fish and wildlife populations in the Canadian portion of the Columbia River basin. The authors wish to acknowledge all the individuals that have contributed to bringing this project to a successful conclusion. Their contributions and on-going efforts are greatly appreciated. Marty Williams, Pat Nicholas (St. Mary’s Band), Glen Smith, (Westslope Fisheries), Kenton Andreashuk, Chris Beers (CKFRP), Harald Manson, Beth Woodbridge (CBFWCP), and Colin Spence (Ministry of Water, Land, and Air Protection) provided technical support. Dr. Carl Schwarz (Cooperative Resource Management Institute, Simon Fraser University) provided advice on the sampling design. Cod traps were loaned by the Ministry of Water, Land, and Air Protection. Suggested citation for this report: Bisset, J.E., Arndt, S.K.A. and R.S. Cope 2002. Columbia Lake Burbot Population Estimate Program, Canal Flats B.C. Report prepared for Columbia-Kootenay Fisheries Renewal Partnership, Cranbrook, B.C. Prepared by Westslope Fisheries, Cranbrook, B.C. and Columbia Basin Fish and Wildlife Compensation Program, Nelson, B.C. 21 pp. + 2 app. June 2002 •iv Columbia Lake Burbot Monitoring Program Westslope Fisheries Table of Contents EXECUTIVE SUMMARY ........................................................................................................... II ACKNOWLEDGEMENTS......................................................................................................... IV TABLE OF CONTENTS............................................................................................................. V LIST OF TABLES ..................................................................................................................... VI LIST OF FIGURES.................................................................................................................... VI 1 INTRODUCTION............................................................................................................... 1 1.1 Background .................................................................................................................... 1 1.2 Project Rationale ............................................................................................................ 2 1.3 Study Area...................................................................................................................... 3 2 METHODS ........................................................................................................................ 5 2.1 Sampling Design ............................................................................................................ 5 2.2 Spring Sampling ............................................................................................................. 7 2.3 Autumn Sampling ......................................................................................................... 11 3 RESULTS .......................................................................................................................14 3.1 Water Temperature....................................................................................................... 14 3.2 Fishing Effort and Catch ............................................................................................... 15 June 2002 •v Columbia Lake Burbot Monitoring Program Westslope Fisheries 3.3 Burbot Size, Abundance, and In-lake Distribution ......................................................... 19 4 DISCUSSION.................................................................................................................. 22 5 LITERATURE CITED ...................................................................................................... 26 APPENDIX A FIELD DATA FORMS - COD TRAP SET SUMMARIES FROM THE COLUMBIA LAKE BURBOT POPULATION ASSESSMENT, 2002 APPENDIX B FIELD DATA FORMS – INDIVIDUAL FISH CAPTURE DATA FROM THE COLUMBIA LAKE BURBOT POPULATION ASSESSMENT, 2002 List of Tables Table 1. Summary of geographic information for Columbia Lake.............................................. 3 Table 2. Known species composition in Columbia Lake. .......................................................... 5 Table 3. Summary of data on previously tagged burbot captured during trapping in Columbia Lake and River in 2001. ........................................................................................... 19 List of Figures Figure 1. Location of Columbia Lake in relation to communities of Canal Flats and Fairmont Hot Springs, BC. Source: BC Ministry of Forests, Forest Service Recreation Map, Invermere Forest District........................................................................................... 4 Figure 2. Typical baited cod trap used in Columbia Lake burbot population study being deployed. .................................................................................................................. 8 Figure 3. Autumn sampling locations on the south end of Columbia Lake near Canal Flats, BC. ............................................................................................................................