WDFW's Puget Sound Steelhead Monitoring Program

Joseph Anderson, Washington Department of Fish and Wildlife

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In Puget Sound, WDFW has an ongoing monitoring program designed to measure steelhead abundance, productivity, spatial structure and diversity. Evaluation of spawning adults and emigrating smolts, an approach commonly called “Fish In, Fish Out,” segregates freshwater productivity from marine survival, and has served as the dominant paradigm governing WDFW’s long term anadromous fish monitoring. Steelhead adult abundance estimates are based primarily on redd surveys, with long-term time series for 17 Puget Sound populations identified by the Technical Recovery Team. Redd survey are also the primary method for evaluating spatial structure. Statistically robust smolt abundance estimates derived from weirs and traps operated by WDFW are only available for four populations and generally have shorter time series than spawning data. However, in contrast to redd surveys, smolt traps permit estimation of precision and uncertainty in abundance via mark-recapture approaches. Owing to sampling challenges, few Puget Sound steelhead populations have both adult and smolt data required to partition freshwater productivity and marine survival. WDFW’s monitoring program addresses diversity by measuring important life history parameters such as age composition, migration timing, and size at migration. In addition, WDFW is pursuing new research tools outside the traditional “Fish In, Fish Out” framework to understand more complex patterns of diversity and their contribution to population persistence. These include the use of otolith microchemistry to measure the reproductive contribution from anadromous vs. resident parents, and the use of genomic tools to evaluate hatchery introgression. Overall, WDFW’s monitoring program provides population-level data necessary to evaluate the effectiveness of recovery actions and adaptively manage Puget Sound steelhead.