Eelgrass   Zostera marina



One of several species of seagrass in Puget Sound, eelgrass is the largest with perennial blades that are over 3/16 inch wide and several feet or more long.  Normally it occurs in somewhat sheltered intertidal and shallow subtidal areas favoring clear water that allows photosynthesis to depths of a minus 20 feet or so.  Eelgrass, like other seagrasses, are flowering plants that have invaded the sea.  They sink their roots in muddy sand producing flowers and seeds. Beds also expand through the growth of rhizomes.  This species occurs in marine waters throughout the northern hemisphere.


Eel grass occurs in small to large beds where it dramatically changes the ecological setting of the area.  The roots stabilize the sediments while the blades not only trap sediment but offer shelter for a wide range of animals and other plants.  Animals commonly found in the beds are hydroids, nudibranchs, anemones, jellyfish, starfish and urchins, various crab including Dungenese along with a wide variety of smaller crustaceans, various sculpins, pipefish, tubesnouts and several kinds of perch and juvenile salmon.  Eelgrass is also an important spawning substrate for Herring.


An eelgrass bed produces a considerable amount of vegetable matter per year making it very important as a food source for a variety of both large and small animals including the Brandt sea goose and the American Wigeon duck.


Another species of eelgrass that occurs locally is the introduced Dwarf Eelgrass (Zostera japonica) which is much smaller and occurs higher in the intertidal zone in small beds.  It is characterized by short, narrow leaves.  It was introduced with the first shipments of Japanese oysters.