Seagrass beds in the USVI are found in shallow bays with calm waters, and always associated with long sandy beaches that are protected from strong wave action. Seagrasses consist of a suite of photosynthetic marine plants that reproduce both vegetatively and through flowering and seed production (Williams and Heck 2001, Duffy 2006, Björk et al. 2008). In the USVI these habitats are important for various fish, invertebrates, and sea turtles.
Seagrasses play a major role in providing physical structure on bottom sediment (Duffy 2006, Worm et al. 2006). They filter suspended sediment and nutrients from coastal waters, maintaining a transparent water column and increasing light availability for the seagrasses and other benthic plants and adjacent coral reefs (Zimmerman et al. 1991, Short et al. 1996). Their extensive leaf canopies and rhizome networks allows seagrasses to modify currents patterns and dampen wave actions, which influences and stabilizes the structure of benthic communities, reduces erosion rates, and contributes to coastal protection. (Zimmerman et al. 1991, Short and Wyllie-Echeverria 1996, Björk et al. 2008). As a benthic plant community, seagrass beds are extremely productive. They are associated with an abundance and variety of small fishes and invertebrates such as shrimp and crabs (Duffy 2006) and provide feeding grounds for green sea turtles, stingrays, conch, and others. The leaves and leaf detritus represent a food resource for many other marine animals (e.g., certain reef fishes, sea turtles, conch) that regularly visit seagrass areas to forage on both the plants and their animal associates.
Native seagrass beds in USVI are in decline for many reasons, including boating activity damage, sediment input from terrestrial erosion, decreasing water quality, and impacts from invasives (i.e., Halophila stipulacea). Less widespread but severe threats include dredging and filling projects and unsustainable fishing practices (Duarte 2002, Duffy 2006, Orth et al. 2006).