Northwest Fisheries Science Center

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Document Type: Report
Center: NWFSC
Document ID: 7388
Title: Monitoring population responses to estuary restoration by Skagit River chinook salmon
Author/Editor: Correigh M. Greene, E. M. Beamer
Year: 2012
Institution: Intensively Monitored Watershed Project Annual Report, National Marine Fisheries Service, Seattle
Date: 2012

This report focuses on results of population monitoring through 2010 and addresses three general questions:  1) Are salmon limited during the early estuarine life stages by capacity and connectivity constraints?  2) Does broad-scale restoration influence local population density? and 3)  Has estuary restoration resulted in population- or system-level responses?  

Our results showed that 1) restoration in the Skagit River tidal delta is needed to address capacity and connectivity limitations, 2) local restoration did improve rearing densities for juvenile Chinook salmon, and 3) system-wide responses can be detected using a before/after control impact BACI design.  In addition, it appears capacity limitations still exist in the Skagit River tidal delta, as judged from recruitment patterns, and that further tidal delta restoration is warranted.  Thus far, we estimate that the amount of restoration work completed in the tidal delta is roughly 10% of goal of the Skagit River Chinook Recovery Plan, and our monitoring work corroborates this estimate.