BULL TROUT REDD COUNT SURVEYS IN SELECT KOOTENAY LAKE TRIBUTARIES (2011) AND RECOMMENDATIONS FOR FUTURE SURVEYS February 2012 BULL TROUT REDD COUNT SURVEYS IN SELECT KOOTENAY LAKE TRIBUTARIES (2011) AND RECOMMENDATIONS FOR FUTURE SURVEYS February 2012 Prepared for: Fish and Wildlife Compensation Program – Columbia Basin 103-333 Victoria St. Nelson, BC Prepared by: Greg Andrusak, RPBio & Harvey Andrusak, RPBio Redfish Consulting Ltd. 5244 Highway 3A Nelson, BC V1L 6N6 Cover Photo: ‘Canyon section of lower Woodbury Creek in mid-October.’ Photograph taken on the 19th of October 2011 by Greg Andrusak. The Fish and Wildlife Compensation Program is a joint initiative between BC Hydro, the BC Ministry of Ministry of Forests, Lands and Natural Resource Operations (MFLNRO) and Fisheries & Oceans Canada (DFO) to conserve and enhance fish and wildlife populations affected by the construction of BC Hydro dams in Canada's portion of the Columbia Basin. Suggested Citation: G.F. Andrusak and H. Andrusak. 2012. Bull trout (Salvelinus confluentus) redd count surveys in select Kootenay Lake tributaries (2011) and recommendations for future surveys.. Report prepared for Fish and Wildlife Compensation Program – Columbia Basin(Nelson, BC) by Redfish Consulting Ltd. (Nelson, BC). FWCP Report No. XXX. XX pp. + app. Executive Summary The Fish and Wildlife Compensation Program – Columbia Basin (FWCP) annually funds two major compensation projects on Kootenay Lake: a large scale nutrient restoration project, and Meadow Creek kokanee spawning channel. A primary rationale for these projects is restoration of bull trout and Gerrard rainbow trout populations; however, there has been no lake-wide measure of bull trout abundance to use as a performance measure. The purpose of this study was to establish a first lake-wide index of spawning bull trout distribution and abundance in Kootenay Lake tributaries using redd counts. These counts, if repeated over the long term, will provide a valuable performance measure for evaluating the response of bull trout to FWCP compensation efforts and management decisions on the lake. During the fall of 2011, a comprehensive assessment of bull trout spawning was conducted in all Kootenay Lake tributaries below Duncan Dam with previously documented adfluvial bull trout presence. This report also includes results of a redd count on the Westfall River upstream of Duncan Dam, using data provided from a separate study. Approximately 260 km of stream habitat was surveyed to obtain spawner abundance and distribution in tributaries to the lake, slightly higher than the proposed 230 km. Including the Westfall River above the Duncan dam, another 21 km was surveyed, bringing the total to ~280 km. Surveys were conducted by separating the lake into three geographical groups, proximal areas included; Lardeau/Duncan tributaries (Group 1), Central Kootenay Lake tributaries (Group 2) and South Arm tributaries (Group 3). Despite the magnitude of the surveys, a number of potentially key bull trout tributaries were not assessed or identified, especially within the upper Duncan River, Lardeau River, Trout Lake basin and Kootenay River drainage. Initial reconnaissance surveys were conducted in September on most systems to identify locations of barriers to fish passage and observe the spatial extent of bull trout spawning within each stream. These surveys indicated spawning bull trout were distributed over a large geographic area within Kootenay Lake. Much of their distribution is inter-connected by large sub-basins (Duncan Reservoir) and rivers (Lardeau and Kootenay rivers) and within tributaries to these systems. However, many of the tributaries offer limited access to much of the available habitat for spawning as a result of naturally occurring barriers that obstruct fish passage. Some of the systems were dominated by glacial inputs with sections of moderate to steep gradients. Habitat within these steep gradient sections consisted of step-pool or cascade morphology, often proving difficult to survey. Some of the lower sections of tributaries, especially Hamill and Cooper creeks, were incised in steep bedrock canyons up to 500 m deep with a gradient of up to 25%, inaccessible by survey crews for safety reasons. Habitat within Redfish Consulting Ltd. Page i the lower gradient sections consisted of riffle-pool and/or cascade morphology and were less difficult to survey. Within a week of the reconnaissance surveys, redd surveys commenced at the beginning of October, and confirmed that bull trout spawning activity had peaked by mid- September with redd construction largely completed by mid-October. Most importantly, survey timing was ideal for most streams with good weather that provided excellent viewing conditions for conducting redd counts. Overall, a total of 1,711 redds were enumerated within the 19 tributaries below Duncan Dam, with an additional 114 redds counted in a tributary to the Duncan Reservoir, the Westfall River. Two prominent systems, namely the Kaslo River and Midge Creek, accounted for ~50% of all redds enumerated in all steams surveyed, with counts exceeding 400 redds each. A total of 512 redds were enumerated within the entire Kaslo River drainage, including 439 redds in the upper 21 km of the Kaslo River. Independent estimates of spawner numbers from resistivity counters provide the opportunity to convert redd counts into indices of adult escapement on select streams. An electronic resistivity counter, installed on the upper Kaslo River, enumerated ~1,180 bull trout kelts descending from the upper portion of the river following spawning. Using the calibrated electronic counts and the redd numbers observed in 2011 on the upper Kaslo River, a bull trout per redd ratio of 2.7 was obtained. This derived expansion factor in 2011 was slightly higher than the average of 2.4 bull trout derived over the previous four years. Using the range in the expansion factor of 1.9-2.4 bull trout per redd from data collected on Crawford Creek and the Kaslo river, accounting for harvest and iteroparity, it is conceivable that the spawning population utilizing Kootenay Lake tributaries exceeds 7,000 bull trout annually (see Discussion). In summary, redd counts provide a relatively cost effective monitoring tool to assess bull trout population trends in tributaries to Kootenay Lake. The success of FWCP initiatives, and future bull trout conservation and management decisions rely on the ability of biologists to accurately assess and monitor their status or abundance, particularly in response to management actions that are implemented. A series of recommendations are provided for establishment of appropriate, representative index streams for future monitoring of spawning bull trout within tributaries of Kootenay Lake. Redfish Consulting Ltd. Page ii Acknowledgements Funding for this project was provided by the Fish and Wildlife Compensation Program – Columbia Basin (FWCP). The FWCP is a partnership of BC Hydro, the BC Ministry of Forests, Lands and Natural Resource Operations (MFLNRO), BC Ministry of Environment, and Canada Department of Fisheries and Oceans. In kind support was also provided by several MFLNRO employees. Bull trout, an endemic char, are highly valued in the Kootenay Region and many dedicated people are involved in their protection, management and conservation. Specifically, Jeff Burrows (MFLNRO) and James Baxter (FWCP) are acknowledged for their efforts in management and conservation of these unique char. BC Hydro and Trevor Oussoren are acknowledged and thanked for their agreement to include the Westfall River data within this report. Stefan Himmer (contractor), Gary Pavan (contractor), Jimmy Robbins (contractor), Clint Tarala (contractor), Louise Porto (AMEC), Crystal Lawrence (AMEC), Murray Pearson, Matt Neufeld (MFLNRO) Sue Pollard (MFLNRO) and Albert Chirico (Ministry of Environment) are acknowledged for their hard work during the Kootenay Lake redd surveys. Jeremy Baxter (contractor), Ico de Zwart (MEC) and Al Irvine (MEC) are acknowledged for their hard work during the Westfall River redd surveys Special thanks to Dam Helicopters and owner/pilot Duncan Wassick who provided helicopter service for the reconnaissance and survey work. As well, Gary Pavan for organizing all GIS data and providing GIS maps. Thanks to Steve Arndt (FWCP) and James Baxter (FWCP) for review of this report Redfish Consulting Ltd. Page iii Table of Contents EXECUTIVE SUMMARY .............................................................................................................................I ACKNOWLEDGEMENTS .......................................................................................................................... III TABLE OF CONTENTS ............................................................................................................................. IV LIST OF TABLES .................................................................................................................................... VI LIST OF FIGURES ................................................................................................................................... VI INTRODUCTION .................................................................................................................................... 1 RATIONALE AND OBJECTIVES .............................................................................................................. 2 BACKGROUND ....................................................................................................................................