Fish hydrophones in the San Juans
Today Val and Scott re-deployed a Vemco VR2 fish tag receiver at Lime Kiln State Park. This receiver, provided for this pilot study to Beam Reach by Fred Goetz, will help marine scientists understand how juvenile and adult salmon use the San Juans, in addition to any other passing fish that have been “tagged” (surgically-implanted) with 69 kHz acoustic tags. We at Beam Reach are most interested in the behavior and distribution of adult Chinook salmon, and secondarily any other potential prey of the endangered southern resident killer whales.
The photos above show the mooring prior to being snorkeled down to the pier block that remained from the previous deployment (last November).
Two other VR2s have been provided by Kurt Fresh of NOAA. (Their serial numbers are: 100910; 100913.) One will be deployed on the west side of San Juan Island; the other will be placed near Cattle Pass.  We’ve mounted them on short (~2.25m) mooring lines (1.25cm diameter 3-strand poly), supported by single yellow shrimp pot floats (see below). The base of the receivers will be ~0.75-1m above the bottom. The floats will be ~1m above the top of the receivers. The mooring weights are either ~25kg concrete slabs (35cm x 35 cm x 15 cm; see below) or paint buckets filled with cement. Both types of weights have metal hoops or chain for attaching the mooring line and for lowering during deployments from a boat.
Data and analysis from these deployments will be documented in the Beam Reach science wiki
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