Marine Subtidal Mixed-Fines: Moderate to High Energy, Shallow

These habitats consist of mixed sand and shell substrata, sometimes with some gravel or mud. They may be very rich, with algae on pebbles as well as having a diverse infauna. Glaucous-winged and other gulls, and surf scoters feed extensively in shallow areas.

Diagnostic Species

The bivalves Psephidia lordi and Mysella tumida, polychaetes Mediomastus sp. and Prionospio steenstrupi.

Common Associates

Moderate-energy sites have pebbles with small laminarians, the red algae Gracilaria lemaneiformis, Sarcodiotheca gaudichaudii, and other foliose reds. Invertebrates include phoxocephalid amphipods and Isochyroceros spp., the bivalves Crenella decussata, Tellina sp., Astarte spp., Saxidomus giganteus, Clinocardium nuttallii; and scallops (Chlamys spp.), the polychaetes Scoloplos spp., Glycymeris subobsoleta, Exogone spp., chaetopterids, Platynereis bicanaliculata, and Micropodarke dubia, the crabs Cancer spp. and Pugettia gracilis, the snails Alia tuberosa and Lacuna spp., the tanaid Leptochelia savignyi, the seastar Pisaster brevispinus, and ophiuroids. Slightly calmer areas have more Macoma spp. and may contain geoducks, although the latter were not recorded in any of the surveys.  Exposed sandy areas may contain razor clams (Siliqua pat- ula) or sand dollars (Dendraster excentricus).  Epibenthic crustaceans are likely to be abundant, and these as well as the infauna provide food for sculpins, pile and shiner perch, juvenile English sole, sand sole, starry flounder, juvenile Pacific tomcod, and sturgeon poacher.

Sites Surveyed

West Beach and Partridge Point (Whidbey Island), Pillar Point, Dungeness Spit, Jamestown, North Beach, and Kydaka Beach (all in Strait of Juan de Fuca), Beckett Point (Discovery Bay) (extremely rich site).


Nyblade, 1979b; Webber, 1980 and unpubl. data; R. Shimek unpubl. data.