Bonytail (Gila elegans) (BONY) Basic Conceptual Ecological Model for the Lower Colorado River 2018 Updates 1. Eggs & Early Larvae G1-2 R5-1 S1-2 5. Spawning 2. Fry & Adults Juveniles S5-4 G2-4 G4-4 P4-5 S2-4 S4-4 4. Established Adults G3-4 3. Newly- S3-4 Stocked SHR Adults Photo courtesy of the Bureau of Reclamation March 2019 Lower Colorado River Multi-Species Conservation Program Steering Committee Members Federal Participant Group California Participant Group Bureau of Reclamation California Department of Fish and Wildlife U.S. Fish and Wildlife Service City of Needles National Park Service Coachella Valley Water District Bureau of Land Management Colorado River Board of California Bureau of Indian Affairs Bard Water District Western Area Power Administration Imperial Irrigation District Los Angeles Department of Water and Power Palo Verde Irrigation District Arizona Participant Group San Diego County Water Authority Southern California Edison Company Arizona Department of Water Resources Southern California Public Power Authority Arizona Electric Power Cooperative, Inc. The Metropolitan Water District of Southern Arizona Game and Fish Department California Arizona Power Authority Central Arizona Water Conservation District Cibola Valley Irrigation and Drainage District Nevada Participant Group City of Bullhead City City of Lake Havasu City Colorado River Commission of Nevada City of Mesa Nevada Department of Wildlife City of Somerton Southern Nevada Water Authority City of Yuma Colorado River Commission Power Users Electrical District No. 3, Pinal County, Arizona Basic Water Company Golden Shores Water Conservation District Mohave County Water Authority Mohave Valley Irrigation and Drainage District Native American Participant Group Mohave Water Conservation District North Gila Valley Irrigation and Drainage District Hualapai Tribe Town of Fredonia Colorado River Indian Tribes Town of Thatcher Chemehuevi Indian Tribe Town of Wickenburg Salt River Project Agricultural Improvement and Power District Unit “B” Irrigation and Drainage District Conservation Participant Group Wellton-Mohawk Irrigation and Drainage District Yuma County Water Users’ Association Ducks Unlimited Yuma Irrigation District Lower Colorado River RC&D Area, Inc. Yuma Mesa Irrigation and Drainage District The Nature Conservancy Other Interested Parties Participant Group QuadState Local Governments Authority Desert Wildlife Unlimited Lower Colorado River Multi-Species Conservation Program Bonytail (Gila Elegans) (BONY) Basic Conceptual Ecological Model for the Lower Colorado River 2018 Updates Prepared by: David P. Braun Sound Science, LLC Lower Colorado River Multi-Species Conservation Program Bureau of Reclamation Lower Colorado Region Boulder City, Nevada http://www.lcrmscp.gov March 2019 Braun, D.P. 2019. Bonytail (Gila elegans) (BONY) Basic Conceptual Ecological Model for the Lower Colorado River, 2018 Updates. Submitted to the Lower Colorado River Multi-Species Conservation Program, Bureau of Reclamation, Boulder City, Nevada, by Sound Science, LLC, Boise, Idaho, under contract No. R16PC00028. ACRONYMS AND ABBREVIATIONS BONY bonytail (Gila elegans) ca. circa (approximately, in reference to a date) CAP critical activity or process CEM conceptual ecological model CF controlling factor CHLP Cibola High Levee Pond DNA deoxyribonucleic acid DO dissolved oxygen g gram(s) HE habitat element IPCA Imperial Ponds Conservation Area km kilometer(s) LCR lower Colorado River LCR MSCP Lower Colorado River Multi-Species Conservation Program LSO life-stage outcome m meter(s) mg/L milligram(s) per liter mm millimeter(s) mtDNA mitochondrial deoxyribonucleic acid n number NISIC National Invasive Species Information Center NRC National Research Council PADCNR Pennsylvania Department of Conservation and Natural Resources pH potential of hydrogen (expressing acidity or alkalinity) PIT passive integrated transponder POM particulate organic matter RASU razorback sucker (Xyrauchen texanus) Reclamation Bureau of Reclamation SL standard length TL total length UCRB Upper Colorado River Basin USDA U.S. Department of Agriculture USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey YOY young of year Symbols °C degrees Celsius (aka Centigrade) ≥ greater than or equal to < less than % percent CONTENTS Page Foreword ................................................................................................................ v Updates to Chapter 1 – Introduction .................................................................. 1 BONY Reproductive Ecology ................................................................................ 1 Update on BONY Reproductive Ecology: BONY Evolutionary Environment1 Update on BONY Reproductive Ecology: Reproductive Participation and Fertility .............................................................................................................. 6 Update on BONY Reproductive Ecology: Hybridization ............................... 7 Update on BONY Reproductive Ecology: Spawning Triggers ....................... 7 Conceptual Ecological Model Purposes ................................................................. 8 Conceptual Ecological Model Structure ................................................................. 8 Updates to Chapter 2 – BONY Life Stage Model .............................................. 9 Evidence for BONY Life Stages............................................................................. 9 Proposed BONY Life Stages .................................................................................. 9 Updates to Chapter 3 – Critical Biological Activities and Processes ............. 13 Chemical Stress ..................................................................................................... 13 Competition........................................................................................................... 14 Disease .................................................................................................................. 14 Drifting .................................................................................................................. 14 Egg Settling and Adhesion.................................................................................... 15 Foraging ................................................................................................................ 15 Hybridization ........................................................................................................ 16 Mechanical Stress ................................................................................................. 18 Predation ............................................................................................................... 18 Resting/Hiding ...................................................................................................... 22 Swimming ............................................................................................................. 23 Thermal Stress ...................................................................................................... 25 Updates to Chapter 4 – Habitat Elements ........................................................ 27 Aquatic Macrophytes ............................................................................................ 27 Aquatic Vertebrates .............................................................................................. 30 Birds and Mammals .............................................................................................. 32 Fishing Encounters................................................................................................ 35 Genetic Diversity .................................................................................................. 35 Infectious Agents .................................................................................................. 36 Invertebrates and Particulate Organic Matter ....................................................... 36 Macrohabitat Structure.......................................................................................... 36 Mesohabitat Structure ........................................................................................... 38 Monitoring, Capture, Handling ............................................................................. 41 Post-Rearing Transport and Release ..................................................................... 42 i Page Pre-Release Conditioning ..................................................................................... 44 Substrate Texture/Dynamics ................................................................................. 46 Turbidity ............................................................................................................... 46 Water Chemistry ................................................................................................... 48 Water Depth .......................................................................................................... 49 Water Flow, Turbulence ....................................................................................... 50 Water Temperature ............................................................................................... 50 Updates to Chapter 5 – Controlling Factors .................................................... 51 BONY Monitoring and Conservation Programs................................................... 51 Channel and Off-Channel Engineering