Status of Bull Trout in the Kakwa River, Alberta, 2006
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Status of Bull Trout in the Kakwa River, Alberta, 2006 CONSERVATION REPORT SERIES The Alberta Conservation Association is a Delegated Administrative Organization under Alberta’s Wildlife Act. CONSERVATION REPORT SERIES 25% Post Consumer Fibre When separated, both the binding and paper in this document are recyclable Status of Bull Trout in the Kakwa River, Alberta, 2006 Tyler Johns Alberta Conservation Association 9621‐96 Avenue Peace River, Alberta, Canada T8S 1T4 Report Series Editor PETER AKU KELLEY KISSNER Alberta Conservation Association 59 Hidden Green NW #101, 9 Chippewa Rd Calgary, AB T3A 5K6 Sherwood Park, AB T8A 6J7 Conservation Report Series Type Data, Technical ISBN printed: 978‐0‐7785‐7050‐9 ISBN online: 978‐0‐7785‐7051‐6 Publication No.: T/183 Disclaimer: This document is an independent report prepared by the Alberta Conservation Association. The authors are solely responsible for the interpretations of data and statements made within this report. Reproduction and Availability: This report and its contents may be reproduced in whole, or in part, provided that this title page is included with such reproduction and/or appropriate acknowledgements are provided to the authors and sponsors of this project. Suggested Citation: Authors please provide citation for your reports here. Johns, T. 2006. Status of bull trout in the Kakwa River, Alberta, 2006. Data Report, D‐ 2006‐013, produced by the Alberta Conservation Association, Peace River, Alberta, Canada. 12 pp + App. Cover photo credit: David Fairless Digital copies of conservation reports can be obtained from: Alberta Conservation Association #101, 9 Chippewa Rd Sherwood Park, AB T8A 6J7 Toll Free: 1‐877‐969‐9091 Tel: (780) 410‐1998 Fax: (780) 464‐0990 Email: info@ab‐conservation.com Website: www.ab‐conservation.com i EXECUTIVE SUMMARY The bull trout, a native sport fish in Alberta, has declined in abundance and distribution across the province as a result of increased angling pressure, habitat alteration and non‐native species introductions. In the present study, a mark‐recapture survey was conducted to generate data on distribution and abundance of bull trout in the Kakwa River. I compared the abundance and distribution of this species in 2006 with historical data from 1997 and 2000. This information will update the current status of this species and should aid in formulating management guidelines for this species in the Kakwa River. Overall, estimated bull trout abundance appears to have changed little between 1997 and 2006. Based on the mark‐recapture survey, the estimated population size of bull trout in the 32‐km reach was 421 (95% CI = 299 – 544) or 13 fish/km in 2006 compared to 278 (95% CI = 137 – 418) or 9 fish/km in 1997 and 330 (95% CI = 233 – 427) or 10 fish/km in 2000. Size of bull trout captured in 2006 ranged from 103 to 646 mm FL compared to 151 to 629 mm FL in 1997 and 155 to 584 mm FL in 2000. Overall, the mean size did not differ significantly among years (ANOVA, F = 4.02, df = 2, p = 0.02), ranging from 397 mm in 1997 to 422 in 2006. Key words: bull trout, Salvelinus confluentus, mark‐recapture survey, catch‐per‐unit‐ effort, abundance, electrofishing, angling, size composition, Kakwa River, Alberta ii ACKNOWLEDGEMENTS I thank Paul Hvenegaard, Greg Fortier, Nathan Carruthers, Ryan Hermanutz, Mike Rodtka, Kevin Gardiner, John Hallett, Dave Fairless (Alberta Conservation Association) and Craig Johnson (Alberta Sustainable Resource Development) for their help with data collection. Weyerhaeuser Canada, Talisman Energy and Devon Energy Corporation provided financial contributions toward this project. iii TABLE OF CONTENTS EXECUTIVE SUMMARY.......................................................................................................... ii ACKNOWLEDGEMENTS....................................................................................................... iii TABLE OF CONTENTS ........................................................................................................... iv LIST OF FIGURES...................................................................................................................... v LIST OF TABLES....................................................................................................................... vi LIST OF APPENDICES ........................................................................................................... vii 1.0 INTRODUCTION ..........................................................................................................1 2.0 STUDY AREA.................................................................................................................2 2.1 Description........................................................................................................ 2 2.2 Fish communities .............................................................................................. 2 3.0 MATERIALS AND METHODS ...................................................................................4 3.1 General sampling design................................................................................... 4 3.2 Data management and analysis......................................................................... 6 4.0 RESULTS .........................................................................................................................7 4.1 Bull trout abundance in the 32-km reach .......................................................... 7 4.2 Size composition in the 32-km reach................................................................ 7 4.3 Relative abundance and distribution in the 146-km study area ........................ 9 4.4 Summary ......................................................................................................... 10 5.0 LITERATURE CITED ..................................................................................................11 6.0 APPENDICES...............................................................................................................13 iv LIST OF FIGURES Figure 1. Kakwa River study area in west‐central Alberta in 2006.................................. 3 Figure 2. Length distribution of bull trout captured by raft electrofishing and angling in a 32‐km reach of the Kakwa River, Alberta in 1997, 2000 and 2006. .......... 8 Figure 3. Catch‐per‐unit‐effort for bull trout captured by raft electrofishing in the Kakwa River, Alberta in 1997, 2000 and 2006..................................................... 9 v LIST OF TABLES Table 1. Fish species present in the Kakwa River watershed. ........................................ 2 vi LIST OF APPENDICES Appendix 1. Bull trout mark‐recapture data from 1997, 2000 and 2006 in the Kakwa River, Alberta.............................................................................................. 13 Appendix 2. Summary of other sport fish species captured using raft electrofishing in the Kakwa River, 2006........................................................................... 13 Appendix 3. Universal Traverse Mercator (UTM zone 11, NAD 83) coordinates of reaches sampled in the Kakwa River, 2006 ............................................ 14 vii 1.0 INTRODUCTION Declines in the abundance and distribution of bull trout, Salvelinus confluentus, have been widely documented throughout Alberta (Brewin and Brewin 1997; Post and Johnson 2002), and currently this species is listed in The General Status of Alberta Wild Species, 2005 as ‘sensitive’ (Alberta Sustainable Resource Development (ASRD) 2005) presumably as a result of their vulnerability to angling pressure, habitat alteration and stocking of non‐native species. In 1994, the provincial (Alberta) Bull Trout Management and Recovery Plan (BTMRP) was developed to address issues related to the decline of the species. The plan identifies that adequate knowledge of the species’ life history, including movements and critical habitat requirements, is essential to its recovery (Berry 1994). In 1995, the Kakwa River bull trout population was considered to be one of the last pristine, unexploited bull trout populations in the province (Hvenegaard, Alberta Conservation Association (ACA), pers. comm.). As such, this population provides an excellent opportunity to gather information on abundance, distribution, seasonal movement patterns, spawning frequency and site fidelity. In 1997, a 32‐km reach was selected as an index monitoring site for future measurements of bull trout status in the river. This reach was used for abundance estimates in 1997 (Hvenegaard and Fairless 1998) and 2000 (Tchir 2000). In this study (2006), this reach was surveyed again to replicate previous work and to allow for temporal comparisons with these earlier surveys. In addition, the 2006 study area extended an additional 114 km downstream of the 32‐km reach to cover a total of 146 km. During a telemetry survey in 1998, this 146‐km reach was identified as the area of occupancy for bull trout in the Kakwa River (Hvenegaard and Fairless 1998). The purpose of the present study was to update the status of bull trout in the Kakwa River. Specifically, the objectives of this study were to: 1. Determine the abundance of bull trout in the 32‐km reach using a mark‐ recapture survey. 2. Describe size structure of bull trout within the 32‐km reach. 3. Determine relative abundance and distribution of bull trout within the 146‐km study area. 1 4. Compare the abundance and distribution of bull trout in 2006 with data from 1997 and 2000. 2.0 STUDY AREA 2.1