Lake Tahoe Region Aquatic Invasive Species Management Plan CALIFORNIA ‐ NEVADA DRAFT September 2009 Pending approval by the Aquatic Nuisance Species Task Force This Aquatic Invasive Species Management Plan is part of a multi-stakeholder collaborative effort to minimize the deleterious effects of nuisance and invasive aquatic species in the Lake Tahoe Region. This specific product is authorized pursuant to Section 108 of Division C of the Consolidated Appropriations Act of 2005, Public Law 108-447 and an interagency agreement between the U.S. Army Corps of Engineers and the California Tahoe Conservancy. This product was prepared by: Suggested citation: USACE. 2009. Lake Tahoe Region Aquatic Invasive Species Management Plan, California - Nevada. 84 pp + Appendices. Cover photo credits: Lake Tahoe shoreline, Toni Pennington (Tetra Tech, Inc.); curlyleaf pondweed, Steve Wells (PSU); Asian clams, Brant Allen (UCD); bullfrog (USGS), zebra mussels (USGS); bluegill and largemouth bass (USACE) ii i Table of Contents Acknowledgements................................................................................................................ iii Acronyms ............................................................................................................................... iv Glossary.................................................................................................................................. vi Executive Summary ............................................................................................................ ES‐1 1 Introduction..................................................................................................................... 1 1.1 Geographic Scope: Lake Tahoe Region...................................................................... 1 1.2 Existing Authorities and Programs.............................................................................. 4 1.3 Gaps and Challenges................................................................................................... 9 1.4 Plan Oversight............................................................................................................. 9 2 AIS Management Approach ........................................................................................... 10 2.1 Prevention................................................................................................................. 10 2.2 Monitoring ................................................................................................................ 11 2.3 Control/Eradication .................................................................................................. 11 2.4 Education .................................................................................................................. 12 2.5 Research.................................................................................................................... 13 2.6 Adaptive Management ............................................................................................. 13 3 Problem Definition and Ranking .................................................................................... 14 3.1 Background ............................................................................................................... 14 3.2 Pathways of Introduction ......................................................................................... 15 3.3 Non‐native Species Present or Threatening Lake Tahoe.......................................... 20 3.4 Non‐native Species Types ......................................................................................... 36 4 Plan Development ......................................................................................................... 44 5 Management Plan Goals and Objectives........................................................................ 45 6 Current/Short‐ and Long‐term Strategies and Actions.................................................... 46 6.1 Objective A: Management Plan Implementation and Updates............................... 46 6.2 Objective B: Coordination & Collaboration ............................................................. 49 6.3 Objective C: Prevention ........................................................................................... 51 6.4 Objective D: Monitoring, Detection, and Response ................................................ 54 6.5 Objective E: Long‐term Control/Eradication ........................................................... 58 6.6 Objective F: Research and Information Transfer..................................................... 61 6.7 Objective G: Laws & Regulations ............................................................................. 63 7 Implementation Table.................................................................................................... 65 8 Plan Review ................................................................................................................... 75 9 Research Considerations................................................................................................ 75 10 Literature Cited.............................................................................................................. 78 i List of Figures Figure 1. Lake Tahoe Region (Source: TRPA) ................................................................................. 3 Figure 2. Model of Increasing Costs Based on Invasion Process and Management Response. From CDFG (2008) as Adapted from Lodge et al. 2006.................................................. 11 Figure 3. Distribution of Eurasian watermilfoil (M. spicatum) and curlyleaf pondweed (P. crispus) in Lake Tahoe from 1995 to 2006 (Anderson 2007) ......................................... 21 Figure 4. Potential distribution of submersed plants (e.g., curlyleaf pondweed and Eurasian watermilfoil) in Lake Tahoe............................................................................................ 22 Figure 5. Survey locations with (indicated by “yes”) and without (indicated by “no”) non‐native warm water fishes May‐November 2006 (modified from Kamerath et al. 2008) ......... 28 Figure 6. Asian clams densities from discrete locations in Lake Tahoe July – October 2008 (Wittmann et al. 2008) ................................................................................................... 30 Figure 7. Distribution of quagga and zebra mussels in the western U.S. (http://nas.er.usgs.gov/taxgroup/mollusks/zebramussel/maps/southwest_quagga.pdf. Accessed July 21, 2009) .................................................................................................. 32 Figure 8. Potential quagga and zebra mussel habitat in Lake Tahoe, assuming survival depth ≤130 meters.................................................................................................................... 33 Figure 9. Lake Tahoe AIS Management Plan Development Timeline.......................................... 44 List of Tables Table 1. Federal, State, and Regional Agencies, Regulations and Programs in the Lake Tahoe Region and Associated AIS Activities................................................................................ 7 Table 2. Inter‐Region Recreational Waterbodies ........................................................................ 17 Table 3. Intra‐Region Recreational Waterbodies ........................................................................ 17 Table 4. Aquatic Herbicides Registered in by California Department of Pesticide Regulation (CDPR), Nevada Department of Agriculture (NDA) and/or the U.S. Environmental Protection Agency (USEPA) ............................................................................................ 26 Table 5. Non‐native Species Management Types........................................................................ 37 Table 6. Non‐native Species Presently In or Threatening the Lake Tahoe Region...................... 38 Table 7. Lake Tahoe Region AIS Management Plan Objectives................................................... 46 Table 8. Lake Tahoe Region AIS Management Plan Implementation Table................................ 66 Appendices Appendix A Regulations and Programs Appendix B Lake Tahoe AIS Vessel Inspection Implementation Plan 2009 ‐ 2010 Appendix C Small Watercraft Screening Process Appendix D Contributors and Resources Appendix E Potential Economic Impacts Appendix F AIS of Concern Appendix G Summary of Comments ii Acknowledgements The Lake Tahoe Region AIS Management Plan was prepared by Toni Pennington, Rob Plotnikoff, Harry Gibbons, Ridge Robinson, James Carney, Jeff Barna, Kari Kimura, Darlene Siegel, and Jack Carroll of Tetra Tech, Inc. Funding for this project was made possible through an interagency agreement between the U.S. Army Corps of Engineers and the California Tahoe Conservancy. Project management and strategic planning was provided by Phillip Brozek (USACE). The Lake Tahoe AIS Coordination Committee (listed below) was critical in guiding plan development, completing the implementation table, and addressing stakeholder comments. The authors wish to thank Ron Smith (USFWS) for reviewing an early draft of the plan and members of Lake Tahoe AIS Working Group for providing essential information on prevention, control, and outreach efforts and review of species information. In particular we thank (in alphabetical order): Nicole Cartwright (TRCD), Dr. Sudeep Chandra (UCD), Harry Dotson (TKPOA), Susan Ellis (CDFG), Lisa Fields