Seagrass in the USVI

Did you know that seagrass beds are an essential part of marine ecosystems? Seagrass is a marine flowering plant found in coastal waters throughout the globe. It provides crucial habitats for the development of juvenile organisms such as fish and lobster. Seagrass beds are also the primary food source of green sea turtles native to the Virgin Islands. During intense storms deep rooted seagrass beds can aid in sediment retention maintaining the beaches we have come to love. Seagrass beds also play an essential role in keeping our seawater clean.

The USVI is home to three major seagrass species; shoal grass (Halodule wrightii), manatee grass (Syringodium filiforme) and turtle grass (Thalassia testudinum). In recent years the existence of these species has become jeopardized due to specific human actions. Construction and vegetation clearance increases sedimentation into the ocean that smothers local seagrass communities. Boat anchoring in seagrass beds can cause direct seagrass mortality.

Recently an invasive seagrass species, Halophila stipulacea, has been established in the Caribbean. This species was first observed in Grenada in 2002 and is now found throughout the VI. Little is known about H.stipulacea and its effects on native seagrass species. Concerns of this new species include its competition with local seagrass and its overall effect on USVI ecosystems. This species has been seen to rapidly colonize Caribbean coastal areas. In some aspects its rapid growth may be beneficial in sediment retention and providing food for juvenile organisms; however, some believe this rapid colonization is due to the lack of predation by the endangered Green Sea Turtles and other herbivorous organisms.

Keep an eye out for the seagrass species pictured below. Have you noticed any changes in seagrass presence around your favorite beach? Keep in mind that you can make a difference in seagrass health and in turn marine ecosystem health by using a mooring buoy, limiting land clearing, properly disposing of trash and simply being aware of the seagrass beds around your islands!