Beamer, E., Brown, B., Wolf, K., Henderson, R. and Ruff, C., 2016. Juvenile Chinook Salmon and Nearshore Fish Use in Habitat Associated with Crescent Harbor Salt Marsh, 2011 through 2015. Skagit River System Cooperative, La Conner, WA. pp. 43.

Crescent Harbor Salt Marsh and shoreline are part of the Puget Sound nearshore located within the Whidbey Basin (Figure 1). Crescent Harbor Salt Marsh is part of a group of nearshore habitats referred to as pocket estuaries. Pocket estuaries are partially enclosed bodies of marine water that are connected to a larger estuary (such as Puget Sound) at least part of the time, and are diluted by freshwater from the surrounding watershed upland at least part of the year (after Pritchard 1967).With respect to Puget Sound Chinook salmon, these small estuaries are differentiated from larger scale river estuaries because the watersheds they are associated with are too small to support spawning Chinook salmon populations; thus we call them non-natal estuaries with respect to juvenile salmon use (Beamer et al. 2003). Pocket estuaries are an important habitat for wild Chinook salmon fry early in the year once they leave their natal estuary and enter nearshore areas of Whidbey Basin (Beamer et al. 2003, Beamer et al. 2006).
Restoration and protection of Crescent Harbor Salt Marsh was identified as a priority in the Skagit Chinook Recovery Plan (page 204 in SRSC & WDFW 2005) because of its importance to early rearing of wild fry migrant Chinook salmon stocks. The restoration project area lies within the confines of Naval Air Station Whidbey Island (NASWI), and with the U.S. Navy as a willing land owner, restoration was completed by Skagit River System Cooperative (SRSC) and NASWI in 2009 through funding by the Salmon Recovery Funding Board (SRFB) and the Estuary and Salmon Restoration Program (ESRP). Restoration design built upon an initial assessment and restoration plan completed for NASWI and Island County Public Works (PWA and UW WET 2003). Restoration actions mainly consisted of: a) increasing tidal connectivity within the historic marsh area, and b) replacing the system’s outlet channel tide gate with a Mabey-Johnson bridge, thus restoring tidal flooding and fish access to more than 200 acres of Crescent Harbor Salt Marsh (Figure 2). More information about the restoration actions can be found at: https://skagitcoop.org/programs/restoration/crescent-harbor-salt-marsh/.
In response to the completed restoration at Crescent Harbor Salt Marsh, we monitored fish use of the restored areas and its adjacent nearshore beaches from 2011 through 2015 over the juvenile Chinook salmon rearing period for pocket estuaries (January through June). The fish monitoring design for the Crescent Harbor Salt Marsh Restoration Project is a post-treatment (i.e., after restoration) stratified (lobes within the restored area) design. Limited pre-restoration project fish data for Crescent Harbor Salt Marsh are reported in PWA and UW WET (2003) for comparison.
Monitoring questions addressed in this report are:
1. How does local environment vary by year, season, and spatial strata within the Crescent Harbor Salt Marsh Restoration Project?
2. What fish species are present within the restored area?
3. How does juvenile Chinook salmon density vary by year, season, and spatial strata within the Crescent Harbor Salt Marsh Restoration Project?
4. How does seasonal juvenile Chinook salmon density in the restored Crescent Harbor Salt Marsh compare with nearby natural pocket estuaries?