A Review of Hatchery Reform Science in Washington State
Total Page：16
File Type：pdf, Size：1020Kb
A review of hatchery reform science in Washington State Joseph H. Anderson, Kenneth I. Warheit, Bethany E. Craig, Todd R. Seamons and Alf H. Haukenes Washington Department of Fish and Wildlife Final report to the Washington Fish and Wildlife Commission January 23 2020 Table of Contents ABSTRACT ........................................................................................................................................ 4 INTRODUCTION ............................................................................................................................. 10 BENEFITS OF HATCHERIES ............................................................................................................. 13 Harvest benefits ........................................................................................................................ 13 Economic benefits ................................................................................................................. 14 Social and cultural benefits ................................................................................................... 15 Treaty rights and tribal values ............................................................................................... 17 Mitigation .............................................................................................................................. 18 Conservation benefits ............................................................................................................... 19 Population conservation ....................................................................................................... 19 Ecosystem benefits ................................................................................................................ 24 Research and education benefits .............................................................................................. 26 RISKS OF HATCHERIES ................................................................................................................... 27 Fishery risks ............................................................................................................................... 27 Genetic risks .............................................................................................................................. 30 Risk of reducing within-population genetic diversity ............................................................ 31 Among population genetic diversity ..................................................................................... 33 Domestication ....................................................................................................................... 34 Ecological risks ........................................................................................................................... 37 Ecological risk mechanisms ................................................................................................... 37 Competition ...................................................................................................................... 37 Predation ........................................................................................................................... 41 Disease .............................................................................................................................. 42 Facility effects ................................................................................................................... 46 Review of population scale studies ....................................................................................... 46 HATCHERY REFORM ...................................................................................................................... 52 Broodstock management – reducing the risk of fitness loss from domestication ................... 53 HSRG broodstock management guidelines ........................................................................... 54 HSRG broodstock management targets ................................................................................ 59 Integrating HSRG broodstock management targets into phases of recovery and relating targets to current status of Chinook populations ................................................................. 61 Genetic models informing broodstock management ........................................................... 64 Ford model ........................................................................................................................ 64 Ford (2002) -based demographic model .......................................................................... 68 Baskett and Waples model ............................................................................................... 69 Controlling pHOS ................................................................................................................... 72 Broodstock and escapement management – within population genetic diversity .................. 74 Program size .............................................................................................................................. 75 Rearing strategies ...................................................................................................................... 81 Release strategies ...................................................................................................................... 84 Mass marking ............................................................................................................................ 88 Disease management ................................................................................................................ 90 2 Adaptive management .............................................................................................................. 92 EMERGING SCIENCE ...................................................................................................................... 95 CONCLUSIONS AND RECOMMENDATIONS ................................................................................. 101 Overarching themes ................................................................................................................ 102 HSRG recommendations ......................................................................................................... 104 Knowledge gaps and major assumptions of current hatchery management ......................... 108 ACKNOWLEDGEMENTS ............................................................................................................... 112 REFERENCES ................................................................................................................................ 113 DEFINITION OF TERMS ................................................................................................................ 135 TABLES ......................................................................................................................................... 137 FIGURES ....................................................................................................................................... 146 APPENDIX 1 – PUGET SOUND CHINOOK SALMON DEMOGRAHICS ........................................... 151 APPENDIX 2 – HATCHERY EFFECT PARAMETER DESCRIBED ....................................................... 157 APPENDIX 3 – COMPARISON OF pHOS and pNOB BROODSTOCK MANAGEMENT OPTIONS ACROSS A RANGE OF PARAMETER VALUES ................................................................................ 158 APPENDIX 4 – THE DEMOGRAPHIC MODEL ................................................................................ 160 3 ABSTRACT Here we review the science of hatchery reform, describing the benefits of hatcheries, the risks of hatcheries, and the major operational options available to hatchery mangers for balancing the benefit-risk trade-off. Our review is a component of a larger evaluation of the Washington Department of Fish and Wildlife’s (WDFW) hatchery and fishery reform policy, adopted in 2009, that embraced the recommendations of the Hatchery Scientific Review Group (HSRG). Thus, we explicitly aim to synthesize new and emerging science available in the last ten years, towards the goal of helping inform whether a revision to the policy is warranted. We focus on Pacific salmon and steelhead hatcheries, with strong emphasis upon examples from Washington State to illustrate key concepts. Hatchery benefits have received much less research attention than hatchery risks. The goals of hatcheries are typically classified as providing harvest opportunities or improving the conservation status of natural populations. Harvest opportunities, which are heavily subsidized by hatcheries in Washington State, provide economic benefits, sociocultural benefits, and satisfy legal obligations, including fulfilling the treaty rights of Native American Indian tribes. We provide a brief overview of these benefits, but they are not the focus of this paper. Regarding conservation, hatcheries have proven successful at preserving unique genetic lineages. Hatchery-origin fish also commonly spawn naturally in rivers throughout Washington State, both intentionally and unintentionally. Depending on the circumstances, this can have short-term conservation value to population demographics, but must be carefully weighed against long-term genetic risks. However, the evidence that hatcheries have increased the abundance of natural-origin adult salmon, a