Located on the South American Continental Shelf, Tobago is washed from the south by the turbulent Guyana Current and from the open Atlantic to the east by the North Equatorial Current.
The mixing of these currents, combined with periodic pulses of nutrient-rich water from the Orinoco River in the rainy season (June-December), generates an abundance of plankton. This plankton is the base for the unusually abundant and varied life found on Tobago's reefs.

The numerous fringing coral reefs surrounding Tobago are characteristically rich in filter-feeding animals, such as sponges and soft corals. The abundance of plankton also explains the massive size of some of the hard corals such as the giant boulder brain coral off Speyside, which is over 6 meters wide (see photo), and the huge barrel sponges that can be seen in the Columbus passage south of Tobago.

Above the reefs, Tobago is noted for enormous shoals of planktivorous fish that in turn attract schools of predatory fish such as jacks, barracuda, wahoo, tarpon and tuna. Other large animals frequently seen are sea turtles, reef sharks, hammerhead sharks, groupers, eagle rays and manta rays. These members of Tobago's marine megafauna are not only ecologically essential to the health and integrity of the reef's ecosystems; they are also some of the most valuable eco-tourism assets in the region. Tragically, some of these large animals are also some of the most vulnerable.

 

Photos courtesy Frontier Divers

Extracts from Environment Tobago Visit their website at www.scsoft.de/et/et2.nsf

The entire tropical ocean depends upon the coral reef for sustenance.

The reef itself may look like a collection of rocks or boulders, but actually it's a living, growing organism -- a colony of tiny (from less than a millimetre to a few centimetres in diameter) animals called coral polyps. These little polyps all work together to create huge and varied reefs, some of which are the largest structures on Earth, stretching hundreds of miles across. Buccoo Reef is the largest ... but there are reefs at many other bays all around Tobago.

The seas around Tobago support rich coral growth because of adequate temperature conditions (seldom below 23-25C), relatively clear water, with little suspended matter. Much like their relative the sea anemone, coral polyps have sticky tentacles with stingers (see The Amazing Cnidoblast ) to catch passing prey for food. At night, the polyps feast on small floating organic material called plankton, which populate the oceans. But their primary source of food is microscopic plant cells called zooxanthellae that actually live within the tissue of hard coral polyps. These plant cells also provide the coral's wide variety of colours.

Coral polyps grow in colonies, which means that each individual animal is attached to another, and then another. Food can be passed from one polyp to another through tubes connecting the polyps called coenosarcs. A colony can grow to be quite large. In the reef at Speyside is one of the largest brain corals known worldwide, over 10 feet in diameter! It contains many thousands of individual coral polyps all living together. A larger reef is formed by many coral colonies, often with many different kinds of coral. A reef may be hundreds of miles across, but it is still built by millions of tiny coral polyps. A coral polyp is an invertebrate animal -- that is... an animal with no backbone. However, coral polyps do have skeletons, which they make with limestone. Thousands of these tiny skeletons combine to become the structure of a reef. Ever so slowly, over hundreds or thousands of years, the coral polyps add limestone to their skeletons in layers, and grow outward and upward, expanding the coral colonies and the reef

LIFE ON THE REEFS

Coral reefs are best known for their breath-taking variety of colourful marine life which they harbour. Tobago's reefs boast an array of brightly-coloured fish including, among others, parrot fish, wrasses, spot-fin and other butterfly fish, trumpet fish, toadfish and angel fish. Reef fish feed on smaller organisms found within the confines of reef waters and, in some instances, on the coral themselves. Fishes however, are not the only colourful components of the reef ecosystem.

Many corals are themselves brightly-coloured, ranging from red through orange to grayish-white. In addition, there are the flambouyant sea whips, fans, brittle stars, molluscs and different varieties of sea urchins (sea eggs), some of which are transparent, and of different shapes and sizes. To say nothing of the sea anemones and sponges and various algae (sea weeds) which abound in the coral reef habitat.

Many corals are themselves brightly-coloured, ranging from red through orange to grayish-white. In addition, there are the flambouyant sea whips, fans, brittle stars, molluscs and different varieties of sea urchins (sea eggs), some of which are transparent, and of different shapes and sizes. To say nothing of the sea anemones and sponges and various algae (sea weeds) which abound in the coral reef habitat

Skyviews Inc has a detailed map of Tobago showing the coastline and beaches - with several interactive windows showing photos and info boxes. Visit their Tobago map page at :www.skyviews.com

Nature and Bird Tours www.tobagonaturetours.com with Peter Cox