National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Long-term Monitoring of Coho Salmon and Steelhead During Freshwater Life Stages in Coastal Marin County 2017Annual Report Natural Resource Report NPS/SFAN/NRR—2020/2149 ON THIS PAGE Field staff transfer fish captured while performing electrofishing surveys to recovery buckets using nets for passing in Redwood Creek, Marin County, CA. Photo courtesy of Martha Ture ON THE COVER A male hatchery reared coho salmon moves upstream to spawn in Redwood Creek, Marin County CA. Photo courtesy of National Park Service Long-term Monitoring of Coho Salmon and Steelhead During Freshwater Life Stages in Coastal Marin County 2017Annual Report Natural Resource Report NPS/SFAN/NRR—2020/2149 Michael Reichmuth,1 Brentley McNeill,2 Sarah Carlisle2 1National Park Service, San Francisco Bay Area Network Inventory and Monitoring Program Point Reyes National Seashore 1 Bear Valley Road Point Reyes Station, California 94956 2Point Reyes National Seashore Association, Coho and Steelhead Monitoring Program 1 Bear Valley Road Point Reyes Station, California 94956 June 2020 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes a range of reports that address natural resource topics. These reports are of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Report Series is used to disseminate comprehensive information and analysis about natural resources and related topics concerning lands managed by the National Park Service. The series supports the advancement of science, informed decision-making, and the achievement of the National Park Service mission. The series also provides a forum for presenting more lengthy results that may not be accepted by publications with page limitations. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. This report received informal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data. Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available in digital format from the San Francisco Bay Area Network website and the Natural Resource Publications Management website. If you have difficulty accessing information in this publication, particularly if using assistive technology, please email [email protected]. Please cite this publication as: Reichmuth, M., B. McNeill, and S. Carlisle. 2020. Long-term monitoring of coho salmon and steelhead during freshwater life stages in coastal Marin County: 2017 annual report. Natural Resource Report NPS/SFAN/NRR—2020/2149. National Park Service, Fort Collins, Colorado. NPS 612/170783, 641/170783, 112/170783, June 2020 ii Contents Page Figures.................................................................................................................................................... v Tables ................................................................................................................................................... vii Executive Summary .............................................................................................................................. ix List of Acronyms .................................................................................................................................. xi 1 Introduction ......................................................................................................................................... 1 1.1 Background............................................................................................................................... 3 1.2 Fishes Monitored by this Protocol ............................................................................................ 3 1.3 Monitoring Rationale................................................................................................................ 4 1.3.1 Monitoring Questions ....................................................................................................... 5 1.3.2 Monitoring Objectives ...................................................................................................... 5 1.4 Watershed Background ............................................................................................................ 6 2 Sampling Design and Methods ........................................................................................................... 8 2.1 Adult Coho and Steelhead Escapement Surveys ...................................................................... 8 2.1.1 Adult Coho and Steelhead Escapement Survey Field Methods ....................................... 8 2.1.2 Changes to Methodology ................................................................................................ 12 2.2 Outmigrant Coho Smolt Trapping .......................................................................................... 12 2.2.1 Outmigrant Coho Smolt Trap Field Methods ................................................................. 13 2.2.2 Changes to Methodology ................................................................................................ 13 2.3 Juvenile Coho and Steelhead Surveys .................................................................................... 14 2.3.1 Basinwide General Systematic Surveys ......................................................................... 14 2.3.2 Index Reach Monitoring ................................................................................................. 14 2.3.4 Changes to Methodology ................................................................................................ 15 2.4 Smolt and Juvenile Coho and Steelhead Condition................................................................ 15 3 Monitoring Results ............................................................................................................................ 16 3.1 Rainfall ................................................................................................................................... 16 3.2 Data from Escapement Surveys .............................................................................................. 16 iii Contents (continued) Page 3.2.1 Olema Creek ................................................................................................................... 16 3.2.2 Cheda Creek Coho and Steelhead Escapement .............................................................. 20 3.2.3 Redwood Creek Coho and Steelhead Escapement ......................................................... 21 3.2.4 Pine Gulch Creek Coho and Steelhead Escapement ...................................................... 24 3.3 Spring 2017 Outmigrant Coho Smolt Trapping Results ........................................................ 25 3.3.1 Coho Smolt Outmigration Environmental Conditions and Timing ................................ 25 3.3.2 Olema Creek Smolt Trapping Coho and Steelhead Results ........................................... 27 3.3.3 Redwood Creek Smolt Trapping Coho and Steelhead Results ...................................... 29 3.3.4 Coho and Steelhead Smolt Size and Condition .............................................................. 30 3.3.5 Smolt Trap Summary of Non-salmonid Total Catch...................................................... 35 3.4 Juvenile Coho and Steelhead Basinwide 2017 Results .......................................................... 35 3.4.1 Olema Creek ................................................................................................................... 35 3.4.2 Redwood Creek .............................................................................................................. 39 3.4.3 Pine Gulch Creek ............................................................................................................ 43 3.5 Coho and Steelhead 2015 Index Reach Monitoring Results .................................................. 45 3.5.1 Olema Creek ................................................................................................................... 45 3.5.2 Redwood Creek .............................................................................................................. 47 3.5.3 Pine Gulch Creek ............................................................................................................ 49 4 Discussion ......................................................................................................................................... 52 5 Literature Cited ................................................................................................................................