Tidal_PAD_V1_Sec4.pdf - Snohomish County PUD

Snohomish County PUD –Pre-Application Document
4 – Existing Environment
4.4.4.1 Dungeness Crab
Dungeness crab are broadly dispersed subtidally and favor a sandy or muddy seafloor (SCOD
2007). They are an important component of sandy-bottom communities and are located on the
surface of the sand as well as buried beneath it (ODFW 2006b). They are tolerant of salinity
changes and can be found in both marine and estuarine environments. Dungeness crabs are
endemic to the North Pacific and range from central California to the Gulf of Alaska. Scavenging
the sandy ocean floor for organisms that are partly or completely buried, their foraging behavior is
well adapted to the surrounding habitat. Dungeness crabs are carnivores, with a diet that can
include shrimp, mussels, small crabs, clams, and worms (SCOD 2007). Their persistence and
annual abundance are driven by meteorological and biological conditions (ODFW 2006b).
Dungeness crab (Cancer magister) is the most commercially important crab species along the
West Coast (ODFW 2001; DON 2006). It is a recruitment-based fishery that is subject to both
commercial and recreational harvest, with take being restricted by size, sex and season.
Dungeness crabs are found from the shallow intertidal habitat to depths of approximately 170 m in
areas with moderate to strong currents (Emmett et al. 1991; DON 2006). The crab’s affinity for
areas of strong current may concentrate several populations within range of the project sites.
Within Admiralty Inlet, crabs are known to occur in Killuit Harbor, Port Townsend and Oak Bay.
Dungeness crab are also concentrated in Deception Pass, Guemes Inlet, and Agate Passage. Crabs
were not identified, however, in Spieden Channel, San Juan Channel or Rich Passage (PSEP
1992).
4.4.4.2 Pink Shrimp
Pink shrimp spawn from March into early April (Pacific Marine Fishery Council [PFMC] 2004a,
2004b) and represent an important commercial fishery that begins on April 1 (ODFW 2005).
Although estimates of pink shrimp abundance are not available for the West Coast, over 70 percent
of the commercial catch occurs along the northern Oregon Coast (ODFW 2006a; PFMC 2004).
Concentrated populations are found in water depths over 90 m (ODFW 2005). Population
abundance appears to be driven almost entirely by environmental conditions and predator
abundance (Pacific whiting), which cause natural fluctuations in recruitment (i.e., addition of
4-84 January 31, 2008