Great Salt Pond is located in south-central St. Maarten, north of Philipsburg. It is bordered on all sides by downtown Philipsburg and its suburbs. It is the largest permanent saline lagoon saltwater pond on the island; it covers an area of 2.25 km² (225 hectares) and is up to 10 metres (33 feet) deep. Great Salt Pond serves as a natural water catchment basin for much of the runoff water from surrounding hills. It is unprotected, and its shorelines have been completely cleared of their native mangroves and grasses for urban development. This site is primarily used for landfill and land reclamation purposes. Great Salt Pond has been designated as a national monument based on its cultural and historical significance. The area was heavily used for the production of salt from the 1630s to the 1920s and many artifacts of this salt-production era remain, such as the rock walls throughout the pond.
Birdlife International has designated Great Salt Pond as an Important Bird Area for St. Maarten. The area has been denominated as IBA AN003. The area is especially significant as a stop-over site for Laughing Gull (Larus atricilla), with up to 5,800 gulls congregating prior to the breeding season. Great Salt Pond also provides a habitat for regionally threatened species: the White-cheeked Pintail (Anas bahamensis), Caribbean Coot (Fulica caribaea) and Ruddy Duck (Oxyura jamaicensis).
Because Great Salt Pond is one of the few remaining wetlands on the island, it is a critical habitat for shorebirds and waterbirds. The pond shelters populations of fish, such as mullet, molluscs, and small invertebrates such as fiddler crab, which provide a great source of food for the birds. Species found here include a variety of herons (Yellow-crowned Night Heron (Nyctanassa violacea), Green Heron (Butorides virescens) and Snowy Egret (Egrettathula)), plovers, sandpipers and migratory shorebirds. The only bird species known to breed here is the Black-necked Stilt (Himantopus mexicanus). Environmental Protection in the Caribbean (EPIC) has been conducting regular waterbird population counts at Great Salt Pond since 2001.
Great Salt Pond is contaminated by sewage runoff from surrounding neighbordhoods and by runoff from the landfill located on Pond Island, in the middle of Great Salt Pond. The area is also under severe pressure from development, and parts of the pond have been filled in with sand for future road construction.Source: BirdLife International. (2008). Important Bird Areas in the Caribbean: Key sites for Conservation. Cambridge, UK: BirdLife International. (BirdLife Conservation Series No. 15).