The Lesser Antilles, Trinidad and Tobago
Agard, J.B.R.; Gobin, J.F. (2000). The Lesser Antilles, Trinidad and Tobago, in: Sheppard, C.R.C. (Ed.) Seas at the millennium: an environmental evaluation: 1. Regional chapters: Europe, The Americas and West Africa. pp. 627-641
In: Sheppard, C.R.C. (Ed.) (2000). Seas at the millennium: an environmental evaluation: 1. Regional chapters: Europe, The Americas and West Africa. Pergamon: Amsterdam. ISBN 0-08-043207-7. XXI, 934 pp., meer
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| Auteurs | | Top |
- Agard, J.B.R.
- Gobin, J.F.
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| Abstract |
All the islands of the Lesser Antilles have coasts that border on both the tropical western Atlantic and the Caribbean Sea. Major sills in the passages between these islands control water flow into the Caribbean Sea from the Atlantic Ocean. Horizontal motion below the average sill depth of the Antillean Arc (1200 m) is almost stagnant. These islands are probably the most important physiographic features of the Caribbean Sea as they act as the gatekeepers to the integrity of the Caribbean marine environment. The coastal marine environments around the islands are generally oases of high production associated with shallow waters, coral reefs, mangrove swamps, estuaries and coastal lagoons surrounded by deep oligotrophic seas. The oceanography of the southern Lesser Antilles is strongly influenced by the outflow of two of the world's largest river systems, the Amazon and the Orinoco. Superimposed on this regime are the periodic passage of large eddies of Amazon water from the Guyana Current. The marine production of offshore waters is generally low due to the relatively stable thermocline, which in the absence of significant upwelling prevents the mixing of nutrient-rich deep waters with surface waters. The main seasonal variation of the islands is due to rainfall. The passage of hurricanes are other periodic events that occasionally have significant impacts on the marine biota of these islands. Penaeid shrimp dependent on estuarine conditions and muddy bottoms are the most valuable fishery resource harvested on the continental shelf between Trinidad and Venezuela. Pelagic fishes offshore (e.g. flyingfish, kingfish, dolphinfish, tuna, swordfish, sharks) and inshore (e.g. kingfish, jacks, herrings and anchovies) are the main commercial fisheries resource exploited among the islands in the area of mixed water stretching from the north coast of Trinidad to St. Vincent. In the clear blue oligotrophic waters from St. Lucia to the Virgin Islands the only significant fisheries are for lobsters and conchs inshore, and for tuna offshore. Only Trinidad and Tobago and the French islands of Martinique and Guadeloupe show any noticeable increase in fish catches from 1990 to 1995. Large commercial fishing vessels from several nations not indigenous to the sub-region frequently exploit the limited fish stocks within the Exclusive Economic Zone of these islands. In many cases, these vessels operate without the knowledge and consent of island governments. All of the islands have fisheries legislation but a shortage of trained personnel and the high cost of effective fisheries patrols in offshore as well as inshore waters and marine parks hinder their effective enforcement. In these islands human impacts on the marine environment are significant because population density is high ranging from 83 km-2 in Anguilla to 614 km-2 in Barbados. Ongoing deforestation is a serious problem affecting the coastal zone in Trinidad and Tobago, Guadeloupe, Martinique, St. Lucia and the British Virgin Islands. Artisanal fishing methods such as trawling for shrimp, cutting mangrove roots to harvest oysters, and over-harvesting of edible sea urchins, lobsters and conch, also damage marine habitats. Beach sand mining is the major human-induced cause of coastal erosion in the Eastern Caribbean. Marine pollution from inadequately treated sewage effluents is a problem on every island because of the lack of adequately maintained centralised sewage treatment facilities. The annual number of tourist visitors in individual islands is substantially greater than their resident population in 12 out of 14 instances, excluding only Dominica and Trinidad. Airport and marina construction to provide facilities for tourists have resulted in the filling in of coastal mangroves and increasing sedimentation in coral reef and seagrass areas. The development of heavy industry in the coastal zones of the various territories is very limited except for the island of Trinidad. Dense petrochemical-related shipping traffic passing through narrow straits around Trinidad and Tobago make this area a high-risk zone for marine pollution from shipping accidents. The Lesser Antillean countries are signatories to several important international conventions and programs, which are geared to protect the marine and coastal environment. However, the record of implementing the provisions of these conventions is very poor. Further, there are few significant ongoing marine investigations in the sub-region except for those undertaken through the Caribbean Coastal Marine Productivity (CARICOMP) network of Marine Laboratories, Parks and Reserves. The islands will have to significantly increase their environmental protection efforts if they are to stem the tide of pollution and natural resource depletion. |
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