NECHAKO RESERVOIR IMPACTS OF TIMBER SALVAGE ON FISH AND FISH HABITAT 1997 STUDIES Prepared for: MINISTRY OF ENVIRONMENT, LANDS AND PARKS, SKEENA REGION BC Environment PO Box 5000 Smithers, BC V0J 2N0 Prepared by: M. B. Winsby, G.C.Taylor and D.R. Munday HATFIELD CONSULTANTS LTD. Suite 201 - 1571 Bellevue Avenue West Vancouver, BC V7V 1A6 Tel: (604) 926.3261 Fax: (604) 926.5389 Email: [email protected] MARCH 1998 TABLE OF CONTENTS Page LIST OF TABLES ........................................................................................................................iii LIST OF FIGURES ..................................................................................................................... iv LIST OF APPENDICES ............................................................................................................... v ACKNOWLEDGEMENTS ........................................................................................................... vi EXECUTIVE SUMMARY ............................................................................................................vii 1.0 INTRODUCTION ........................................................................................................... 1 2.0 STUDY AREA AND METHODS ................................................................................... 3 2.1 STUDY AREA ...............................................................................................................3 2.1.1 Overview of Nechako Reservoir ..................................................................... 3 2.1.2 General Features of Ootsa Lake .................................................................... 3 2.1.3 Fish Sample Sites ........................................................................................... 6 2.1.3.1 Ootsa Lake.....................................................................................7 2.1.3.2 Tahtsa Reach...............................................................................11 2.1.3.3 Eutsuk Lake.................................................................................11 2.2 STUDY METHODS .....................................................................................................11 2.2.1 Fish Capture .................................................................................................12 2.2.1.1 Gillnet Capture ............................................................................12 2.2.1.2 Minnow Trapping ........................................................................14 2.2.1.3 Electrofishing ..............................................................................14 2.2.1.4 Biological Measurements ............................................................14 2.2.2 Underwater Noise Measurement .................................................................. 14 2.2.3 Data Analysis and Interpretation .................................................................. 15 3.0 RESULTS ................................................................................................................... 17 3.1 EARLY SUMMER FISH CAPTURE PROGRAM.......................................................... 17 3.2 LATE SUMMER FISH CAPTURE PROGRAM ............................................................ 17 3.2.1 Andrews Bay................................................................................................. 17 3.2.2 Wells Creek bay ............................................................................................ 21 3.2.3 Whiting Creek bay ......................................................................................... 24 3.3 UNDERWATER NOISE ..............................................................................................26 4.0 DISCUSSION............................................................................................................... 30 4.1 TIMBER REMOVAL OPERATIONS DURING 1997 .................................................... 30 4.2 SHORT-TERM EFFECTS OF TIMBER REMOVAL .................................................... 30 4.2.1 Species Composition ....................................................................................30 BCE710:04/08/2005 i 4.2.2 Abundance .................................................................................................... 31 4.2.2.1 Rainbow Trout.............................................................................. 32 4.2.2.2 Kokanee....................................................................................... 32 4.2.2.3 Mountain Whitefish...................................................................... 33 4.2.2.4 Northern Squawfish..................................................................... 33 4.3 EFFECTS OF UNDERWATER NOISE........................................................................ 34 4.3.1 Sound Characteristics of Timber Harvesting Equipment............................... 34 4.3.2 Sound Attenuation Rates............................................................................... 36 4.3.3 Implications of Underwater Sound from Timber Harvesting Activities on Fish................................................................................................................ 36 4.4 DATA LIMITATIONS AND UNCERTAINTIES ............................................................ 37 5.0 CONCLUSIONS AND RECOMMENDATIONS ........................................................... 39 5.1 CONCLUSIONS ..........................................................................................................39 5.2 RECOMMENDATIONS ...............................................................................................40 5.2.1 Fish Protection Measures ............................................................................. 40 5.2.1.1 Tentative Timing Windows ..........................................................41 5.2.1.2 Distances/Locations ....................................................................41 5.2.2 Future Studies ..............................................................................................41 5.2.2.1 Lake Sampling ............................................................................41 5.2.2.2 Stream Reconnaissance Surveys ...............................................42 6.0 REFERENCES ............................................................................................................ 43 APPENDICES BCE710:04/08/2005 ii LIST OF TABLES Page Table 2.1 Glossary of common and scientific names of species identified during current or previous investigations........................................................................ 13 Table 3.1 Species composition of gillnet catches at sites in Andrews Bay, August/September 1997...................................................................................... 18 Table 3.2 Catch per unit effort of gillnet catches at sites in Andrews Bay, August/September 1997...................................................................................... 18 Table 3.3 Species proportions and Shannon-Weiner Function for communities sampled at Wells Creek Bay, Whiting Creek Bay, and Andrews Bay, August/September 1997.............................................................................. 20 Table 3.4 Species composition of gillnet catches at sites in Wells Creek bay, August/September 1997...................................................................................... 22 Table 3.5 Catch per unit effort of gillnet catches at sites in Wells Creek bay, August/September 1997...................................................................................... 22 Table 3.6 Species composition of gillnet catches at sites in Whiting Creek Bay, August/September 1997...................................................................................... 25 Table 3.7 Catch per unit effort of gillnet catches at sites in Whiting Creek Bay, August/September 1997...................................................................................... 25 Table 3.8 Floating gillnet catch per unit effort (no. of fish/h) - all species, Nechako Reservoir August/September 1997 ..................................................................... 26 Table 3.9 Results of underwater sound measurements near timber harvesting operations............................................................................................................ 27 Table 4.1 Catch per unit effort for all species captured in Ootsa Lake floating gillnets, fall 1996 and late summer 1997............................................................. 32 BCE710:04/08/2005 iii LIST OF FIGURES Page Figure 2.1 Nechako Reservoir fish and fish habitat study area .............................................. 4 Figure 2.2 Ootsa Lake pre- and post-impoundment area....................................................... 5 Figure 2.3 Sample site locations for fisheries evaluation, Ootsa Lake, early and late summer 1997 ........................................................................................................ 7 Figure 2.4 Sample site locations for fisheries evaluation, Tahtsa Reach, early and late summer 1997.................................................................................................. 8 Figure 2.5 Sampling site locations for fisheries evaluation, Eutsuk Lake, early and late summer 1997.................................................................................................. 9 Figure 3.1 Catch per unit effort for floating gillnets in Andrews inner bay, 1996