Status of White Sturgeon in the Lower Fraser River
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EA 1613 STATUS OF WHITE STURGEON IN THE LOWER FRASER RIVER REPORT ON THE FINDINGS OF THE LOWER FRASER RIVER WHITE STURGEON MONITORING AND ASSESSMENT PROGRAM 1999-2004 LIMITED environmental research associates BY 1 TROY C. NELSON 2 WILLIAM J. GAZEY 3 KARL K. ENGLISH AND 4 MARVIN L. ROSENAU FOR FRASER RIVER STURGEON CONSERVATION SOCIETY VANCOUVER, BC DECEMBER 2004 1 LGL Limited environmental research associates, 3299 137 A Street, Crescent Beach, BC V4P 2B5 2 W. J. Gazey Research, 1214 Camas Court, Victoria, BC V8X 4R1 3 LGL Limited environmental research associates, 9768 Second Street, Sidney, BC V8L 3Y8 4 UBC Fisheries Center, 2259 Lower Mall, UBC, Vancouver, BC V6T 1ZY THE STATUS OF WHITE STURGEON IN THE LOWER FRASER RIVER DECEMBER 2004 TABLE OF CONTENTS LIST OF TABLES............................................................................................................iii LIST OF FIGURES..........................................................................................................iv LIST OF APPENDICES...................................................................................................vi LIST OF PHOTO PLATES ..............................................................................................vi EXECUTIVE SUMMARY...............................................................................................viii INTRODUCTION............................................................................................................. 1 Project Background ..................................................................................................... 2 Project Objectives........................................................................................................ 3 Brief Overview of White Sturgeon................................................................................ 3 Immigration and Emigration......................................................................................... 5 FIELD AND ANALYTICAL METHODS............................................................................ 5 Study Area................................................................................................................... 5 Data Recording............................................................................................................ 6 Fish Handling Procedures ........................................................................................... 6 Documentation of Capture Location ............................................................................ 7 River Kilometer......................................................................................................... 7 Zone..... ................................................................................................................... 7 Tagging........................................................................................................................ 8 PIT Tags and Tag Readers...................................................................................... 8 Tag Recoveries ........................................................................................................... 8 PIT Tags................................................................................................................... 8 External Tags ........................................................................................................... 9 Biosampling ................................................................................................................. 9 Fishing Effort ............................................................................................................... 9 Data Management ....................................................................................................... 9 Data Security and Backup........................................................................................ 9 Data Entry .............................................................................................................. 10 Population Estimation................................................................................................ 10 Bounding................................................................................................................ 12 Definition of Variables ............................................................................................ 12 Growth Model......................................................................................................... 13 Data Compilation.................................................................................................... 14 Population Model....................................................................................................... 16 Removal Estimate .................................................................................................. 17 Sensitivity............................................................................................................... 17 RESULTS...................................................................................................................... 18 Population Estimates................................................................................................. 18 Growth . ................................................................................................................. 18 Removal Estimate .................................................................................................. 20 Sensitivity............................................................................................................... 20 Movement Patterns ................................................................................................... 20 DISCUSSION................................................................................................................ 21 Population Estimates................................................................................................. 21 Comparison of Population Estimates with Historic Commercial Catch................... 22 LGL LIMITED environmental research associates PAGE I THE STATUS OF WHITE STURGEON IN THE LOWER FRASER RIVER DECEMBER 2004 Length Analyses ........................................................................................................ 23 Sturgeon Age at Length ......................................................................................... 23 Sturgeon Length by Location ................................................................................. 23 Sturgeon Movement and Migration............................................................................ 24 Fraser River Recaptures of White Sturgeon Tagged in the Columbia River .......... 25 RECOMMENDAITONS ................................................................................................. 26 ACKNOWLEDGEMENTS ............................................................................................. 29 REFERENCES.............................................................................................................. 30 TABLES FIGURES APPENDICES PHOTO PLATES LGL LIMITED environmental research associates PAGE II THE STATUS OF WHITE STURGEON IN THE LOWER FRASER RIVER DECEMBER 2004 LIST OF TABLES Table 1. Sampling zones used for population estimation of white sturgeon. Table 2. Sampling regions used for population estimates of white sturgeon. Table 3. Parameter estimates for linear and non-linear growth models. Table 4. Numbers of sturgeon examined for marks, and numbers of recaptures, by month and sampling zone. Table 5. Number of sturgeon recaptured and examined for a mark by sampling zone of release and recapture. Table 6. Proportion (corrected) of sturgeon recaptured by sampling zone of release. Table 7. Numbers of marked sturgeon releases available for recapture by sampling zone and month. Table 8. Population estimates for white sturgeon in the Lower Fraser River, by sampling region, as of 31 December 2001 Table 9. Population estimates for white sturgeon in the Lower Fraser River, by sampling region, for the study sampling periods before and after 1 January 2002. Table 10. Population estimates for white sturgeon in the Lower Fraser River, by size class, as of 31 December 2001. Table 11. Population estimates for white sturgeon in the Lower Fraser River, by size class, as of 31 December 2001, for the period before 1 January 2002. Table 12. Population estimates for white sturgeon in the Lower Fraser River, by size class, as of 31 December 2001, for the period after 1 January 2002. Table 13. Population estimates for white sturgeon for sampling region C, by size class, as of 31 December 2001, for period before 1 January 2002. Table 14. Population estimates for white sturgeon for sampling region C, by size class, as of 31 December 2001, for period after 1 January 2002. Table 15. Catch curve using mid-point of size class and time required to grow from 50 cm. LGL LIMITED environmental research associates PAGE III THE STATUS OF WHITE STURGEON IN THE LOWER FRASER RIVER DECEMBER 2004 Table 16. Sensitivity analysis of population estimates for white sturgeon in the lower Fraser River, calculated over the expected range of rates of undetected marks and removal. LIST OF FIGURES Figure 1. Map of the Fraser River watershed and its location in BC, and the general study area for the Lower Fraser River Sturgeon Monitoring and Assessment Program 1999-2004. Figure 2. Illustration of the general study area that identifies the location of the four main sampling