Zostera Marina

Appearance:   Grows in clumps; can form extensive underwater beds or meadows. The green leaves are 1⁄4 inch wide and can be up to 3 feet long.

 Habitat:   Found in brackish to entirely salt water of protected inlets and bays. Grows in sandy, silty, or gravelly substrates in the subtidal zone.

Seasonal Appearance:   Blooms early spring and summer

 Sensitivity to Human Action






Distinguishing Features and Behaviors:

          Eelgrass is a flowering underwater plant with 1⁄4-inch wide leaves that can reach lengths of 3 feet. Eelgrass grows in distinctive clumps, known as beds, in near-shore waters at depths ranging from 4 to 9 feet. Eelgrass beds are always completely submerged, and their roots, known as rhizomes, anchor the grass to sandy or muddy bottoms. From spring through late summer, eelgrass produces hundreds of seeds, which float with the current until they sink to the bottom.

Eelgrass is a true flowering plant, not a seaweed or an algae. Eelgrass is sometimes misidentified as saltmarsh cordgrass, a plant that grows at the edge of the shore in the intertidal zone and is commonly submerged at high tide.

Uprooted eelgrass can sometimes be found in bright green, tangled clumps or individual strands along the shore. Dead eelgrass appears brown or almost black and, when left out of water for a period of time, it becomes dry and papery.

Eelgrass is one of the Bay’s most important and vital habitats for a wide range of fish and wildlife, including flounder, scallops, and crabs. At the base of the food chain, many species of commercially valuable fish feed on, or take shelter in, these beds at some point in their lives. Eelgrass beds filter excess nutrients out of the water and help prevent shoreline flooding and erosion by stabilizing sediment and buffering wave action. Because it requires specific amounts of light and clean water, the presence of eelgrass is an indicator of healthy water quality.

Relationship to People:

            Historically, eelgrass beds flourished in many areas of Narragansett Bay and helped support a thriving commercial scallop industry. Increased water pollution, shoreline development, boat traffic, eelgrass wasting disease, and hurricane damage have significantly reduced the Bay’s eelgrass beds. The loss of eelgrass beds has affected Bay fish and wildlife populations and has virtually eliminated commercial scalloping in the Bay. Eelgrass is also sensitive to increased water temperatures, due to climate change. 

Beginning in 1994, work was instituted to map existing eelgrass beds and develop programs to restore and expand eelgrass beds in areas of Narragansett Bay through improved environmental management and eelgrass transplant projects.