Tobago Cays
The Tobago Cays are an archipelago located in the Southern Grenadines comprising five small islands and extensive coral reefs. The cays - Petit Rameau, Petit Bateau, Baradal, Petit Tabac and Jamesby - are all uninhabited and are a popular tourism destination.
The Tobago Cays are now the key element of the Tobago Cays Marine Park run by the Saint Vincent and the Grenadines government. The Marine Park consists of a 1,400-acre (5.7 km2) sand-bottom lagoon which encompasses the five cays, the inhabited island of Mayreau and the 4 km Horseshoe Reef. The Marine Park was listed as a regionally significant ecosystem under the SPAW Protocol in December 2014
The most extensive and well-developed coral reef complexes in Saint Vincent and the Grenadines occur on shallow shelves around the windward sides of Mayreau and Union Islands and the Cays themselves. In addition, principal vegetation types include beach vegetation and dry forest. With the exception of a small mangrove in Petit Rameau and salt pond in Mayreau, there are no wetlands in the Cays.
Major users of the area include: cruise ships (an estimated 50,000 visitors each year of which 10,000 visit the Cays); yachts (an estimated 3,000 yachts anchor in the lagoon each year); day charters (from nearby hotels); sport divers and snorkelers; and fishing enthusiasts.
The Grenadines are geologically older than St. Vincent and are situated on an extensive shallow bank of volcanic origin – known as the southern Lesser Antilles arc platform (SLAAP). The SLAAP is a product of Miocene uplift (23–16 Ma) and characterized by Eocene to Pliocene extrusive to intrusive igneous rocks along with sedimentary rocks such as limestone, marl, and chert, and epiclastic arc-derived volcaniclastic units composed of mudstone, sandstone, and conglomerate. The islands are composed of a variety of volcanic and sedimentary rocks. The area is an active subduction zone, and lies along the interface of the Caribbean and South American Tectonic plates. Kick ’em Jenny is an undersea volcano north of Grenada, and there is also another less active volcano named Kick ’em Jack in the area. The shallow bank of the Grenadines extends from St Vincent to Grenada, and has a natural boundaries of the Tobago Trough to the east and the Grenada Trough to the west, where the depth increases rapidly. The shallow bank creates ideal conditions for the formation of productive seagrass beds, mangroves and coral reefs.
Surrounding the Tobago Cays are several shallow fringing reefs around the islands, and a major bank-barrier reef known as Horseshoe Reef. Other major reefs in the park include World’s End Reef, Egg Reef and Mayreau Gardens. The fringing reefs around Mayreau and the Mayreau Gardens reef are considered to be the most biodiverse and healthy, with Horseshoe Reef and the reef around Petit Tabac being the next richest. Finally, the World’s End and Egg reef, as well as the other fringing reefs are considered to be the most degraded and least diverse in the park. The common corals on the reefs are Montastrea, Porites, Acropora, Millepora and Siderastrea species, as well as patches of soft corals such as Gorgonians (Sea Fans) and sponges. Large fish, such as barracuda and jacks, are occasionally found in the park, although most of the fish species are small. Algae and disease are prominent across all reefs and affect coral health. Surveys in 2007 concluded that most reefs were dominated by dead coral rubble and had live coral cover between 5% and 30%, and all reefs are considered to be in decline.
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