THE PLAN Status of Oregon Coastal Stocks of Anadromous Salmonids, 1999-2000 Report Number: OPSW-ODFW-2001-3 Status of Oregon Coastal Stocks of Anadromous Salmonids, 1999-2000 Oregon Plan for Salmon and Watersheds Monitoring Report No. OPSW-ODFW-2001-3 March 2, 2001 Steve Jacobs Julie Firman Gary Susac Coastal Salmonid Inventory Project Western Oregon Research and Monitoring Program Oregon Department of Fish and Wildlife 28655 Highway 34 Corvallis, OR 97333 Funds supplied in part by: Sport Fish and Wildlife Restoration Program administered by the U.S. Fish and Wildlife Service, (Contract F171-R-3) Anadromous Fisheries Act administered by the National Marine Fisheries Service, (Contract NA77FA0443) Pacific Salmon Treaty administered by the National Marine Fisheries Service, (Contract NA97FP0059) State of Oregon Citation: Jacobs S., J. Firman, and G. Susac 2001. Status of Oregon coastal stocks of anadromous salmonids, 1999-2000; Monitoring Program Report Number OPSW-ODFW-2001-3, Oregon Department of Fish and Wildlife, Portland, Oregon. CONTENTS EXECUTIVE SUMMARY................................................................................. 1 FALL CHINOOK ....................................................................................................................... 1 COHO .................................................................................................................................... 2 CHUM .................................................................................................................................... 3 STEELHEAD............................................................................................................................ 3 INTRODUCTION..................................................................................................... 4 SURVEY PROGRAM DESIGN ................................................................................................ 5 SURVEY PROCEDURE........................................................................................................... 5 ASSESSMENT OF SURVEY CONDITIONS .................................................................................... 7 CHAPTER 1: FALL CHINOOK SALMON....................................... 9 CURRENT MONITORING PROGRAM .................................................................................... 9 ASSESSMENT UNITS ........................................................................................................... 10 METHODS ............................................................................................................................. 12 SURVEY DESIGN................................................................................................................... 12 MEASURES OF SPAWNING ESCAPEMENT................................................................................ 12 RESULTS AND DISCUSSION............................................................................................... 16 ASSESSMENT OF SURVEY CONDITIONS .................................................................................. 16 SPAWNING TIMING................................................................................................................ 16 INDEX OF SPAWNER ABUNDANCE .......................................................................................... 18 TRENDS IN SPAWNER ABUNDANCE ........................................................................................ 18 CHAPTER 2: COHO SALMON............................................................... 24 CURRENT MONITORING PROGRAM .................................................................................. 24 ASSESSMENT UNITS ........................................................................................................... 25 METHODS ............................................................................................................................. 28 MEASURES OF SPAWNING ESCAPEMENT................................................................................ 28 ESTIMATES OF COHO SALMON SPAWNER POPULATION ABUNDANCE ....................................... 30 RESULTS AND DISCUSSION............................................................................................... 37 ASSESSMENT OF SURVEY CONDITIONS .................................................................................. 37 SPAWNING TIMING................................................................................................................ 38 ii MEASURES OF SPAWNER ABUNDANCE .................................................................................. 40 TRENDS IN SPAWNER ABUNDANCE ........................................................................................ 41 SPAWNER DISTRIBUTION....................................................................................................... 42 ESTIMATES OF SPAWNER ABUNDANCE .................................................................................. 45 ABUNDANCE BY ESU AND GCA............................................................................................. 51 OCCURRENCE OF HATCHERY COHO IN NATURAL SPAWNING GROUNDS................................... 54 CHAPTER 3: CHUM SALMON............................................................... 59 CURRENT MONITORING PROGRAM .................................................................................. 59 ASSESSMENT UNITS ........................................................................................................... 59 METHODS ............................................................................................................................. 60 SURVEY DESIGN................................................................................................................... 60 MEASURES OF SPAWNING ESCAPEMENT................................................................................ 60 RESULTS AND DISCUSSION............................................................................................... 60 ASSESSMENT OF SURVEY CONDITIONS .................................................................................. 60 SPAWNING TIMING................................................................................................................ 61 INDEX OF SPAWNING ABUNDANCE ......................................................................................... 61 TRENDS OF SPAWNER ABUNDANCE....................................................................................... 63 CHAPTER 4: STEELHEAD........................................................................ 68 CURRENT MONITORING PROGRAM .................................................................................. 68 ASSESSMENT UNITS ........................................................................................................... 68 STUDY OBJECTIVES............................................................................................................ 69 METHODS ............................................................................................................................. 70 RESULTS .............................................................................................................................. 70 OBJECTIVE 1 RESULTS (SURVEY FEASIBILITY) ....................................................................... 70 OBJECTIVE 2 (SURVEY RELIABILITY)...................................................................................... 73 ACKNOWLEDGEMENTS ............................................................................ 79 REFERENCES ....................................................................................................... 79 iii EXECUTIVE SUMMARY This report provides an assessment of the status of adult anadromous salmonids inhabiting coastal basins of Oregon. Status is monitored through spawning surveys. Species or races monitored through these surveys are fall chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), chum salmon (O. keta) and steelhead (O. mykiss). Assessments cover through the 1999 brood year for salmon and the 2000 brood year for steelhead. Status is generally assessed along two levels of geographic aggregation: Evolutionary Significant Units (ESUs) and Gene Conservation Areas (GCAs). ESUs were defined by the National Marine Fisheries Service in conducting reviews for protection under the federal Endangered Species Act. GCAs are usually subsets of populations within ESUs and were defined by the Oregon Department of Fish and Wildlife either as part of the implementation of the Wild Fish Management Policy or as part of monitoring associated with implementation of the Oregon Plan for Salmon and Watersheds. Fall Chinook The Oregon Coastal ESU includes fall chinook inhabiting coastal basins south of the Columbia River mouth through the southern portion of Cape Blanco. Indices of spawner abundance in this ESU show a significant increase over the past 50 years. There are four GCAs within the Oregon Coastal ESU. Spawner abundance trends are available for each GCA over a 13-year period form 1986-99. Overall, counts of spawners in all GCAs show healthy levels of abundance, however there are some differences in the patterns of trends. Fall chinook in the Nehalem/Ecola and Mid-South Coast GCAs have remained stable. Fall chinook in the North-Mid Coast GCA have declined 5% per year during this period, whereas fall chinook in the Umpqua GCA increased dramatically. The declining trend of fall chinook in the North-Mid