This once abundant seagrass of southern New England estuaries has undergone widespread reductions during the last forty years. Eelgrass (Zostera marina) is a true submerged aquatic plant, found from the low tide mark to about 3 meters water depth, and should not be confused with the salt marsh cordgrass (Spartina alterniflora) of the upper intertidal zone. Healthy eelgrass beds comprise an essential fish and shellfish habitat, providing protection and abundant food for juveniles of several species, including tautog, sea bass, squeteague, cunner, tomcod, winter flounder, sticklebacks, and scallops. Although eelgrass can respond positively to increased nutrient availability, phytoplankton and macroalgae grow quicker. As the water becomes cloudy with blooming phytoplankton, the eelgrass is starved for light and is unable to maintain growth and health. The eelgrass beds gradually thin and the estuarine area occupied by eelgrass shrinks. With the loss of eelgrass, fish abundance and diversity decline dramatically.