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Site description (2007 baseline):
Site location and context
The site is located on the southeastern coast of St. Thomas and includes several mangrove cays (Bovoni Cay, Patricia Cay, Cas Cay) and lagoons (bays) around them.
There is a protected cove on the northwestern side of Saba with a small sandy beach. Behind the beach is a relative open, flat area adjacent to the west pond. A nature trail was developed some years ago but has mostly grown over. A bird observation blind is located near the pond shore and overlooks the pond and vicinity. Offshore of both Saba and Flat Cay are modest sized coral reefs.
The islands are publicly owned by the territorial government of the U.S. Virgin Islands and legally protected against terrestrial visitors during the seabird nesting season (April - October). Saba Island is vegetated by scrub-thorny brush and introduced guinea grass on the north facing slopes.
Observed in summer 2006: Brown Pelican, Magnificent Frigatebird, Little Blue Heron, Snowy Egret, Great Egret, Green Heron, Laughing Gull, Scaly-napped Pigeon, White Crowned Pigeon, Zenaida Dove, Common Ground-Dove, Green-throated Carib, Gray Kingbird, Yellow Warbler, Bananaquit, Lesser Antillean Bullfinch.
Non-bird biodiversity: Marine sponges, sting rays, small schools of fish, and an occasional barracuda or shark occupy the surrounding waters. There is a small cove at one outlet (“false outlet”) of the lagoon that has a good diversity of littoral sea life.
The site is dominated by several red mangrove islands surrounded by shallow (1-2 meters) lagoons that open to the sea through several channels. The main shoreline is vegetated with red and black mangroves and buttonwood where undisturbed but includes marinas with docks and moorings and a major landfill (Bovoni). The cays are rocky and sparsely vegetated with brush, sea grape, manchineel and pipe organ cactus.
Marina boat use of the lagoon is limited to the shoreline and easternmost channels suitable for boats. The mangroves can serve as a “hurricane hole” during storms for some boats.
Pressure/threats to key biodiversity
Turpentine Run discharges its waters into the lagoon adjacent to the horse race track and may carry a mix of heavy metals, raw sewage, and pathological bacteria. Tests conducted during the summer of 2006 indicated variable levels of these and other contaminants in the waters of the stream.
The Bovoni dump is located along the northwestern shoreline and limited controls of leaching and flow of soluble wastes into lagoon waters. This is the largest dump on St. Thomas and is nearing its limit for solid and liquid wastes. Concerns about automotive fluids leaking from the site have been noted. The most advanced sewage treatment facility is also located at Bovoni and appears to have significantly reduced the issue of human sewage discharge into coastal waters.
The marina contains numerous medium to large yachts, some of which are live aboard vessels. There is no waste pump out facility on St. Thomas so sewage and bilge wastes enter the lagoons from boats.
Conservation responses/actions for key biodiversity
Informal monitoring of the mangroves and birds has been conducted by the tour guides of the Eco-Tours company located between the mouth of Turpentine Run and the marinas.
Mangrove Lagoon and cays are protected habitats by the USVI Dept. of Planning and Natural Resources (DPNR) with restricted boat dockage and moorings. Access to the lagoons is open but limited to visitors with boats, kayaks, etc.
Jim Corven
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Mangrove Lagoon (Virgin Islands (to USA)). Downloaded from
https://datazone.birdlife.org/site/factsheet/mangrove-lagoon-iba-virgin-islands-(to-usa) on 23/12/2024.
