Estuarine Subtidal Mud: Partly Enclosed, Deep
These habitats are found in the heads and centers of inlets in Puget Sound where there is little water motion and the bottom is soft. They tend to retain fine sediments, wood, and other organic debris, and support large populations of deposit feeding clams and tube-dwelling polychaetes. Salinities are relatively constant, varying seasonally less than do shallower waters.
-15-30 m:
Diagnostic Species
Acila castrensis, Alia (= Mitrella) gausapata.
Common Species
The bivalves Axinopsida serricata and sometimes Panope abrupta, the brittle star Amphiodia urtica, the crab Cancer gracilis, the small snails Alvania sp. and Barleeia sp., the sea whip Virgularia spp., the cephalopod Rossia pacifica, and the polychaetes Tharyx spp., Nephtys cornuta, Sternaspis scutata, Spio cirrifera, and other lumbrinerids and pectinariids. Polluted bays tend to be dominated by capitellids, cirratulids, and nematodes.
Sites Surveyed
Similk Bay, Samish Bay, Sequim Bay, Bellingham Bay, Port Gardner, Sinclair Inlet, numerous sites in Puget Sound proper.
Sources
Mayer, 1973; Lie, 1974; Battelle, 1986; R. Harman, R. Shimek, R. Anderson unpubl. data.
>20 m (Deep Basins):
Diagnostic Species
The heart urchin Brisaster latifrons, the sea cucumber Molpadia intermedia, the bivalves Macoma carlottensis and Axinopsida serricata, and the sea whip Stylatula elongata.
Common Species
The bivalves Nucula spp., Yoldia scissurata, and Acila castrensis, the polychaetes Pectinaria californiensis, Ampharete acutifrons, Glycera capitata, Travisia pupa; dorvilleids (especially Schistomeringos spp.), Glycinde picta, Tharyx multifilis, Nephtys cornuta, and Laonice serrata; the cephalopod Rossia pacifica, the crustacean Euphilomedes producta; fish: English, rock, and Dover sole, shiner sea perch, Pacific tomcod, ratfish.
Sites Surveyed
Deep basins of Puget Sound, Hood Canal, Port Gardner, Strait of Georgia, and Bellingham Bay.
Sources
Lie, 1968, 1974; Wennekens, 1959; Harman et al., 1977; Webber, 1978; Battelle, 1986; Nichols, 1987; Kisker, 1976; R. Anderson, C. Staude, R. Shimek unpubl. data.