it has served as a model organism for several important ecological and evolutionary studies. Marine communities Trinidad's western and southern coastal waters are highly influenced by the outflow of freshwater from the adjacent Orinoco River of Venezuela which is less than away from Trinidad at the closest point. As such, the waters here are fairly low in salinity and high in sediment/nutrient content and relatively shallow. These facts coupled with the highly sheltered nature of the Gulf of Paria and the Columbus Channel respectively, create ideal breeding/spawning grounds for many marine fishes and invertebrates, including shrimp. Various 'sporting' fish are present in the waters of both islands and include huge grouper, marlin, barracuda and dolphin-fish. Fish popularly caught and eaten include carite, kingfish and red snapper. As mentioned in the section above on the reptilian fauna of Trinidad and Tobago, a number of species of marine turtles including the leatherback turtle, hawksbill turtle, loggerhead turtle, olive ridley turtle and green sea turtle frequent the waters around and/or nest on some of the beaches of both islands. Whales and dolphins were far more common to Trinidad and Tobago's waters in earlier times, but the very rigorous whaling industry of the 19th century decimated the population of whales in the Gulf of Paria (called 'Golfo de Balena' or Gulf of Whales by Christopher Columbus). Today, dolphins may still be regularly observed, particularly off the shore of the northwestern Chaguaramas peninsula. Pilot whales have been observed to beach themselves on a few occasions during the 1990s and a small pod of killer whales were caught in a fisherman's net during the 1980s. Whale sharks (the largest of all fishes) have been observed around the oil rigs in the southern part of the Gulf of Paria. Hammerhead sharks are commonly caught by fishermen and shark flesh is considered a delicacy among the human population of both islands. The waters of Tobago are less affected by the outflow of fresh water from the Orinoco and as such are far more saline and clearer than that of Trinidad. A number of coral reefs are thus able to exist around Tobago, the most famous being the Buccoo Reef. Tobago's reefs are reputedly home to the largest examples of brain coral. Also present are huge and gentle manta rays, impressive moray eels, parrot fish, angel fish and a host of other colourful tropical coral reef species. See also