Saba National Marine Park

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Chapter 3. SITE DESCRIPTION

c - Biological features

Habitats

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):


 

Coral reefs: around Saba, shoal reefs (The Pinnacles), fringing reefs and cryptic habitats are 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: patches of 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.

Rocky intertidal areas: Rocky shores form the transition between terrestrial and marine environments, and are thus exposed to very different physical conditions. In the course of a day, rocky shores are covered with seawater at high tide and exposed directly to the air at low tide. On Saba, rocky shores are found in close vicinity to the fringing coral reefs. The rocky shores on Saba are formed from boulders or lava flows, with one exceptional habitat of pools being found near the airport.

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 Saba and the habitats in the Marine Park .

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
Sea Mounts ha not given There are eight pinnacles around Saba. Five deeper pinnacles on one site 1km to the west of Saba, given the names Third Encounter, Twilight Zone, Outer Limits, Mt. Michel, Shark Shoals. Here shallower pinnacles around the island, with sandy bottoms beyond 25m (80ft) depth; Man O’ War Shoals which does not break the surface, Diamond Rock and Green Island with are both guano encrusted islets.. The deeper pinnacles have been protected them from any storm damage or anchor damage in the past. This has resulted in a diverse habitat with large and abundant soft corals and sponges. The volcanic protrusions themselves attract large numbers of fish including predatory species such as jacks, groupers and sharks. Caribbean Reef Sharks, Nurse Sharks and Black Tip Sharks are the most common, with occasional sightings of Hammerhead Sharks, Bull Sharks and Tiger Sharks. Passing Humpback Whales, Manta Rays and Whale Sharks are also seen on occasion. The larger species of animals are not as common at the shallow pinnacle sites. The exposed and cryptic surfaces are home to many species of invertebrates that feed on the plankton rich waters nourished by the strong local currents. Shoals of Blue Tangs (Acanthurus coeruleus), Bigeye Tuna (Thunnus obesus) and juvenile Barracuda (Sphyraena sp.) frequent these areas. The dark volcanic sand around these sites is home to fish species including Flying Gurnards (Dactylopteridae sp.), Batfish (Ogcocephalus sp.), Sand Tile Fish (Malacanthus plumieri) and Jawfish (Opisthognathidae. Sp).
Fringing boulder reef ha not given Encrusted andesites and rock with most common 11 coral species being: Agaricia spp., Colpophyllia spp., Diploria labyrinthiformis, Diploria strigosa, Madracis decactis, Millepora spp., Montastraea annularis, Montastraea cavernosa, Porites astreoides, Porites porites, and Stephanocoenia michelinii. Of these, Montastraea annularis was most dominant overall, followed by Agaricia spp., Millepora spp. and Diploria strigosa. The coral reefs are home to many fish species including Fairy baslets (Gramma loreto), Angel fish (Holocanthus sp. and many others) Groupers, Triggerfish, Scorpion fish, Moray eels (e.g. Gymnothorax moringa), Wrasse and Chromis, Parrot fish and roaming shoals of Blue Tangs (Acanthurus coeruleus). Aside from corals and fish, many other creatures inhabit the reef and other underwater habitats. These include a variety of sponges such as Giant Barrel Sponges (Xestospongia muta), Stove-pipe sponges (Aplysina archeri), Azure Vase Sponges (Callyspongia plicifera), Ball Sponges (Cinachyra sp.) and Elephant Ear Sponges (Agelas clathrodes). Countless other invertebrates inhabits the reefs such as Conch, Brittle stars, Magnificent Sea Urchin (Astropyga magnifica), Zooanthids, Crinoids, Brittle stars, Cork Screw Anemones (Bartholomea annulata), Giant anemones (Condylactis gigantea), Spiny Lobsters (Panulirus argus), Pederson shrimp, Arrow Crab (Stenorhynchus seticornis), Decorator Crabs (Microphrys bicomuta) and nudibranchs such as the Lettuce Sea Slug (Tridachia crisp ate). A number of different plant species live on the reef and sandy habitats, the most common being Encrusting fan-leaf algae (Lobophora variegata), and Dictyota sp. Other species found include calcareous algae (with calcium in their structure) such as Pink Coralline algae and Leaf Algae (Halamida sp.). Mats of Red Algae grow in some areas. Seaweeds such as Sargassum and Green Feather Algae (Caulerpa sertulanoides) provide habitat and food for other animals.
Biogenic reef ha not given Located at the Giles Quarter reef complex; reef habitat formed on limestone. More information in Attachment 16.
Sea grass beds
Seagrass ha not given The patchy, yet significant seagrass stands around Saba are dominated by Turtle grass (Thalassia testudinum) together with Manatee grass (Syringodium filiforme) and species 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 Saba National Marine Park. Significant invertebrates in the seagrasses of Saba include a much reduced population of Queen Conch (Strombus gigas), Cushion Stars (Oreaster reticulata), Sea Cucumber (Holothuria mexicans) and Sea Urchins (Tripneustes venricosus, Lytechinus variegates, Meoma ventricosa).
Rocks
Rocky shores ha not given Rocky shores form the transition between terrestrial and marine environments, and are thus exposed to very different physical conditions. In the course of a day, rocky shores are covered with seawater at high tide and exposed directly to the air at low tide. On Saba, rocky shores are found in close vicinity to the fringing coral reefs. The rocky shores on Saba are formed from boulders or lava flows, with one exceptional habitat of pools being found near the airport. Various forms of algae dominate the intertidal area, since other organisms find it difficult to cope with extreme heat, desiccation and ultraviolet ray stress. Species of snails graze on algae contributing to bioerosion of the substrate. Bivalves such as mussels and barnacles often make their home on rocky shores. Intertidal communities in the Caribbean are restricted to a relatively small area because of the small tides (a maximum tidal range of around 45cm).
Sand cover
Sandy bottom ha not given Little is known about the sandy habitats in Saba National Marine Park. The habitat is understood to be home to various species of animals and plants including crustaceans, sea stars, shrimp, nudibranch, worms and fish. Marine plants also exist in some areas including species of seagrass and algae
Other marine ecosystems
Volcanic habitats ha not given There are marine hot springs and dark sand habitats in the Saba National Marine Park that may have particular significance.
Terrestrial ecosystems
Size (estimate)
unit Area covered