Man O War Shoal Marine Park

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c - Biological features


Brief description of dominant and particular habitats (marine and terrestrial)*: List here the habitats and ecosystems that are representative and/or of importance for the WCR (i.e. mangroves, coral reefs, etc):

 There are four main habitats in the Man O War Shoal Marine Park;

Open water: supporting planktonic and pelagic sea creatures including fish and migratory species such as dolphin and turtles.  

Coral reefs: Patch reefs, spur and grove reefs, cryptic habitats all home to species of hard and soft coral, many other animal and plant species. These depend on nutrient poor, stable water conditions to survive.

Sea grass beds: highly productive habitats dominated by one or two species of seagrass. The blades of the seagrass are home to many more species and the habitats provides a nursery and foraging ground for many marine animals.

Sandy Bottom: extensive areas of sand that support many benthic organisms including, invertebrates and bottom living fish.

There is, of course, regular exchange between each of these habitats for feeding and reproduction and continuous movement of water and animals between the deep waters surrounding St Maarten, the coral reefs, seagrass and mangrove areas . As the waters adjacent to St Maarten are relatively shallow, without much exchange between coastal and deep water currents, corals and other organisms on reefs to the north of Man O War Shoal Marine Park are exposed to any terrestrial influences. This includes freshwater runoff, sediments, nutrients and any form of pollution, which all stress and eventually kill marine organisms.

Detail for each habitat/ecosystem the area it covers:

Marine / coastal ecosystem categories
Detail for each habitat / ecosystem the area covers
Size (estimate) Description and comments
unit Area covered
Coral reefs
Man of War Shoal Marine Park ha 700 Most reefs around St. Maarten are patch reefs, small isolated reef areas that develop from the substrate. The upper reef slopes have spur and groove features i.e. coral ridges alternated by sand channels. The spurs are typically dominated by massive coral species. Algae, sponges and corals have established themselves on the spurs. The sandy groove areas support little coral or algae growths because of the mobile, scouring nature of the sand. The grooves often open out to an area of rubble and coarse sand. During a survey carried out in 2000-2001, experts involved with The Reef Environmental Education Foundation survey counted 153 species of reef fish over 24 different coral reef sites. The five most common species encountered were; Blue Tang (Acanthurus coeruleus), Bluehead (Thalassoma bifasciatum), Sergeant Major (Abudefduf saxatilis), Spotted Goatfish (Pseudupeneus maculatus), Ocean Surgeonfish (Acanthurus bahianus). The five least common species encountered were; Yellowtail Hamlet (Hypoplectrus chlorurus), Tiger Grouper (Mycteroperca tigris), Shortstripe Goby (Gobiosoma chancei), Orange Filefish (Aluterus schoepfii), Chain Moray (Echidna catenata). Reef Sharks (Carcharhinus perezi) are seen frequently around St Maarten and have become a tourist attraction. Other sharks are infrequently seen at various points around the island indicating that they are present but cryptic, including; Blacktip Sharks (Carcharhinus limbatus). There are also periodic sightings of rays including manta rays, stingrays and spotted eagle rays. Most sightings come from the dive sites of Man O War Shoal Marine Park. A joint survey between Nature Foundation St Maarten and ReefKeeper International in 2001 looked in detail at the coral reefs at 3 dive sites; Hen & Chicken, Molly Béday and Mike’s Maze. At Hen and Chicken dive site the most abundant species was Fire coral (Millepora alcicornis, Millepora squarrosa). Fire coral and Boulder star coral (Montastrea annularis) were the most abundant at Molly Béday. Symmetrical Brain coral (Diploria strigosa), Fire coral and Mustard hill coral (Porites asteroides) were the most abundant at Mike’s Maze. Rough star coral (Isophyllastrea rigida) and Ten-ray star coral (Madracis decactis) were the least evident species of coral, only covering 1.3% of the study site at Molly Beday. See Attachment 3 for further details. Elkhorn coral (Acropora palmata) and Staghorn coral (Acropora cerviconis) are not common in St Maarten’s waters. By contrast, Pillar Coral (Dendogyra cylindrica), sponges and soft corals such as sea fans, sea whips and other gorgonians are abundant. Countless species of invertebrates such as Banded Coral Shrimp (Stenopus hispidus), Lobster (Panulirus argus), Queen Conch (Stombuis gigas), Helmet Conch (Cassis flammea), Long Spined Urchin (Diadema antillarium), Lettuce sea slug (Tridachia crispate), Azure Vase Sponge (Callyspongia plicifera) and the Cushion Sea Star (Oreaster reticulates) live on the coral reefs of St Maarten. As do many different species of algae from the aptly named Sea pearl (Ventricaria ventricosa) and Mermaids Tea Cup (Udotea cyathiformis) to the reef building crustose coralline algae’s.
Sea grass beds
Man of War Shoal Marine Park ha 15 The seagrass stands around St Maarten are dominated by Turtle grass (Thalassia testudinum) together with Manatee grass (Syringodium filiforme) and banks of calcareous alga (Halimeda sp). Through a succession of growth, seagrasses can turn vast areas of unconsolidated sediments into highly productive plant dominated, structured habitat with a diversity of microhabitats. There are limited although significant amounts of seagrass beds within the Man of War Shoal Marine Park. Significant invertebrates in the seagrasses of St Maarten include a much reduced population of Queen Conch (Strombus gigas), Cushion Stars (Oreaster reticulata), Sea Cucumber (Holothuria mexicana), Sea Urchins (Tripneustes venricosus, Lytechinus variegates, Meoma ventricosa) and the Upside Down Jellyfish (Cassiopeia frondosa). In February 2011 staff of the Nature Foundation encountered the invasive seagrass H. stipulacea within the Simpson Bay Lagoon.
Sand cover
Man of War Shoal Marine Park ha 1500 Little is known about the sandy habitats between the shores of St Maarten and the off-shore coral reefs. The habitat is understood to be home to various species of crustacean, sea stars, shrimps and nudibranch. Marine plants also exist in some areas including species of seagrass and algae.
Deep ecosystems
Man of War Shoal Marine Park ha not given Deeper open water environments are full of phytoplankton (microscopic plants) which form the basis of the complex food web, supporting not only the island’s coral reefs and associated animals but also zooplankton (microscopic animals) which are often the juvenile stages of species found in other habitats. There are no known studies of the plankton communities around St Maarten. The open water supports pelagic fish populations, most of which are highly migratory such as Tuna (Thunnus sp.), Dolphin (Dorado / Coryphanaena hippurus) and Wahoo (Acanthocybium solandri) as well as Marlin (Makaira SP.) and swordfish (Xiphias gladius). In general, these fish are found passing within the territorial waters of St Maarten, on occasion they can be found within the Man of War Shoal Marine Park itself. All four Caribbean species of turtle can be found in St Maarten’s water: Hawksbills (Eretmochelys imbricate), Green Turtles (Chelonia mydas), Leatherbacks (Dermochelys coriacea) and Loggerheads (Caretta caretta) are a very occasional visitor. A number of Cetaceans are regular visitors both to the reefs and the waters around St Maarten, including; Baleen Whale Species (Balaenoptera sp.), Pilot Whales (Globicephala macrorhynchus), Dwarf Sperm Whales (Kogia simus), Humpback Whales (Megaptera novaeangliae), Gervais's Beaked Whales (Mesoplodon europaeus), Killer Whales (Orcinus orca), Melon-Headed Whales (Peponocephala electra), Sperm Whales (Physeter macrocephalus), Pantropical Spotted Dolphins (Stenella attenuate), Striped Dolphin (Stenella coeruleoalba), Spinner Dolphins (Stenella longirostris), Bottlenose Dolphins (Tursiops truncates), Cuvier's Beaked Whales (Ziphius cavirostris). There are a number of birds that live almost exclusively in the open ocean environment, using St Maarten as a breeding ground or migratory stop over. These include Gulls such as Laughing Gulls (Larus atricilla), terns and cormorants.
Terrestrial ecosystems
Size (estimate)
unit Area covered