Shipworms are seen in their boreholes in a mangrove trunk near Curuca at the mouth of the Amazon River February 18, 2011. Although it resembles a worm, the shipworm is actually a type of mollusk related to the clam and is commonly eaten raw by the region's residents. Brazilian fisherman Jose Alfredo de Souza Costa, 31, began fishing for a living at the age of 12 in the region where the Amazon River, with its drainage basin covering about 40 percent of South America, forces a massive plume of freshwater estimated at 20 percent of the world's freshwater entering the oceans, into the Atlantic. Picture taken February 18, 2011. REUTERS/Paulo Santos (BRAZIL - Tags: ENVIRONMENT SOCIETY ODDLY TRAVEL FOOD)

Brazilian fisherman Jose Alfredo de Souza Costa pulls a shipworm out of a mangrove trunk near Curuca at the mouth of the Amazon River February 18, 2011. Although it resembles a worm, the shipworm is actually a type of mollusk related to the clam and is commonly eaten raw by the region's residents. Jose Alfredo, 31, began fishing for a living at the age of 12 in the region where the Amazon River, with its drainage basin covering about 40 percent of South America, forces a massive plume of freshwater estimated at 20 percent of the world's freshwater entering the oceans, into the Atlantic. Picture taken February 18, 2011. REUTERS/Paulo Santos (BRAZIL - Tags: ENVIRONMENT SOCIETY ODDLY TRAVEL FOOD)

Brazilian fisherman Jose Alfredo de Souza Costa shows a live shipworm he just pulled out of a mangrove trunk near Curuca at the mouth of the Amazon River February 18, 2011. Although it resembles a worm, the shipworm is actually a type of mollusk related to the clam and is commonly eaten raw by the region's residents. Jose Alfredo, 31, began fishing for a living at the age of 12 in the region where the Amazon River, with its drainage basin covering about 40 percent of South America, forces a massive plume of freshwater estimated at 20 percent of the world's freshwater entering the oceans, into the Atlantic. Picture taken February 18, 2011. REUTERS/Paulo Santos (BRAZIL - Tags: ENVIRONMENT SOCIETY ODDLY TRAVEL FOOD)

Brazilian fisherman Jose Alfredo de Souza Costa swallows a live shipworm he just pulled out of a mangrove trunk near Curuca at the mouth of the Amazon River February 18, 2011. Although it resembles a worm, the shipworm is actually a type of mollusk related to the clam and is commonly eaten raw by the region's residents. Jose Alfredo, 31, began fishing for a living at the age of 12 in the region where the Amazon River, with its drainage basin covering about 40 percent of South America, forces a massive plume of freshwater estimated at 20 percent of the world's freshwater entering the oceans, into the Atlantic. Picture taken February 18, 2011. REUTERS/Paulo Santos (BRAZIL - Tags: ENVIRONMENT SOCIETY ODDLY TRAVEL FOOD)

Brazilian fisherman Jose Alfredo de Souza Costa swallows a live shipworm he just pulled out of a mangrove trunk near Curuca at the mouth of the Amazon River February 18, 2011. Although it resembles a worm, the shipworm is actually a type of mollusk related to the clam and is commonly eaten raw by the region's residents. Jose Alfredo, 31, began fishing for a living at the age of 12 in the region where the Amazon River, with its drainage basin covering about 40 percent of South America, forces a massive plume of freshwater estimated at 20 percent of the world's freshwater entering the oceans, into the Atlantic. Picture taken February 18, 2011. REUTERS/Paulo Santos (BRAZIL - Tags: ENVIRONMENT SOCIETY ODDLY TRAVEL FOOD)