Marine Subtidal Mud and Mixed-Fines: Low Energy, Shallow

Surprisingly few complete surveys have been done in these habitats, which should be commonly found in bays and inlets. In general, they appear to have similar flora and fauna to their estuarine counterparts. Fish and bird faunas are diverse, especially when eelgrass is present. (See “Estuarine Intertidal Mixed-Fines.”)

Diagnostic Species

Zostera marina, the red alga Gracilaria pacifica, the small snails Lacuna spp., the anemone Epiactis prolifera.

Common Associates

Pebbles often have Laminaria saccharina, ulvoids, and a variety of red algae such as Sarcodiotheca gaudichaudii and Nitophyllum spp. attached to them. Also seen are the bivalves Clinocardium nuttalli, Mysella tumida, Psephidia lordi, Axinopsida serricata, Transennella tantilla, Tellina sp., and Modiolus rectus, polychaetes Owenia fusiformis, Armandia brevis, Ampharete spp., and sabellid tubeworms (in thick patches), Cancer magister, C. gracilis, and the pea crab Pinnixa occidentalis, the moon snail Polinices lewisii, nudibranchs Melibe leonina,

Melanochlamys diomedea, and Aeolidia papillosa, and the amphipod Allorchestes angusta. Herring spawn on the algae and eelgrass. Other common fish include tube-snout, bay pipefish, kelp greenling, buffalo and Pacific staghorn sculpins, Pacific sand lance, starry flounder, juvenile English sole, C-O sole, shiner and striped seaperch, penpoint gunnel, juvenile lingcod, and speckled sanddab.

Sites Surveyed

Indian Cove (Shaw Island), Brown Island and Beaverton Cove (near San Juan Island), Shoal Bay (Lopez Island), sites in Barkley Sound and Neah Bay.


Neushul, 1967; Shimek, 1977 and unpubl. data; Muenscher, 1916; Simenstad et al., 1988; R. Anderson, C. Staude, P. Gabrielson unpubl. data .