DESCRIPTION
In 2014 the Skagit Fisheries Enhancement Group implemented the Thatcher Bay Nearshore Restoration Project on Blakely Island in the San Juan Islands. The Project area consists of intertidal beaches and tideflats with approximately 2 acres of intertidal habitat, which was historically the site of a sawmill. To conduct the restoration, 12,000 cy of wood waste was removed and disposed of offsite from the 2-acre area; the dredge footprint was then backfilled with clean sand. Restoration activities generally occurred between elevations +5 feet mean lower low water (MLLW) and +0 feet MLLW. The goal of the project was to eliminate toxic sulfide contamination by removing the wood waste, in order to restore forage fish spawning habitat and improve benthic flora and fauna habitat. The purpose of this project was to collect data to document the effectiveness of the restoration activities.
,
Parameters that were monitored as part of this project included conducting grain size and conventional chemical analysis of the beach sediments (structural), the species, frequency and diversity of benthic macroinvertebrates (functional) and forage fish spawning within the project area (functional).
Sediment quality sampling and analysis were performed during low tide events in June of 2015 and May of 2017. Benthic invertebrate prey resource monitoring was also performed during the same mobilizations as sediment quality sampling. The scope of work was followed for all data collection. Three replicate samples were taken from the restoration site and three replicate samples were taken from a reference site. Samples were composited into one sample and sent to separate labs for analysis. Data from sediment samples was compared to pre-project sediment sampling conducted in 2009 for the Sediment Characterization Report necessary for the DMMO permit approval. All sediment sampling was conducted according to the approved SAP required by the DMMO. Benthic and epibenthic macroinvertebrate assemblages were analyzed by experts at WWU. Reports document that the diversity of species using the site have increased overtime. Lab results and reports have been uploaded to PRISM.
Forage fish spawning can occur year round in the San Juan Islands therefore we attempted to document forage fish use quarterly. During 2015 we successfully visited the site quarterly thanks to an excellent partnership with the Samish Tribe who provided boat transportation. All forage fish spawning documentation followed the WDFW protocols. Samples were collected at Thatcher Bay as well as two reference sites located at other nearby Islands. Forage fish samples were also collected in May of 2017. The June 2015 sample documented the use of surf smelt eggs at the restoration site. This was the first documentation of forage fish using the site pre or post restoration.