Scientists in Brazil Find New Reefs Rich with Marine Life
FORT LAUDERDALE, Florida, July 9, 2008 (ENS) – Off the Brazilian coast, where the narrow continental shelf widens far out into the Atlantic Ocean, marine scientists have discovered reefs that they believe double the size of Brazil’s largest and richest reef system, the Abrolhos Bank.
The newly discovered area is far more abundant in marine life than the previously known Abrolhos reef system, which is partially protected by the government of Brazil as one of the world’s most unique and important reefs.
The researchers from Conservation International, the University of Espirito Santo and the University of Bahia announced their discovery in a paper presented Tuesday at the International Coral Reef Symposium now udnerway in Fort Lauderdale.
“We had some clues from local fishermen that other reefs existed, but not at the scale of what we discovered,” said Rodrigo de Moura, Conservation International Brazil marine specialist and co-author of the paper.
A black grouper on Abrolhos Bank
(Photo by R.B. Francini-Filho
courtesy Conservation International)
“It is very exciting and highly unusual to discover a reef structure this large and harboring such an abundance of fish,” he said.
Located about 70 kilometers from the coast of Bahia state, the Archipelago of Abrolhos is a marine national park, which protects part of the shallow reefs already known to science.
The Abrolhos Bank is considered one of the world’s most important reefs because it is inhabited by a high number of marine species found only in Brazil, including species of soft corals, mollusks and fish found only on the Abrolhos shelf.
The Mussismilia coral genus, a relic group remnant of an ancient corals that went extinct long ago elsewhere in the Atlantic, is the dominant coral of the Abrolhos reef, which is structured in unique mushroom-like shapes.
Seven researchers from the three institutions used a boat with side-scan sonar equipment, which produces a three-dimensional map of the seabed.
They mapped the new reef structures in areas ranging from 15 to 200 kilometers (nine to 124 miles) offshore of the coastal city of Caravelos and in depths ranging from 20 to 73 meters (60 to 220 feet).
“Due to their relative inaccessibility and depth, the newly discovered reefs are teeming with life, in some places harboring 30 times the density of marine life than the known, shallower reefs,” says Guilherme Dutra, Conservation International’s director of marine programs in Brazil.
Dog snapper on the Abrolhos Bank
(Photo by R.B. Francini-Filho courtesy
“That’s the good news,” he said. “The bad news is that only a small percentage of marine habitats in the Abrolhos are protected, despite mounting localized and global threats.”
Localized threats include overfishing, coastal development and large scale land conversion to agriculture, shrimp farms, pollution, oil drilling and sedimentation.
Global threats include climate change and ocean acidification.
“The local fishermen always mentioned holes,” Dutra told ENS in an interview, “but we didn’t know what they were. Then we mapped some holes in the bank – 50 meters across and 20 meters deep – just in the middle of the shelf. Here it extends 200 kilometers from the coast at a depth of nearly 70 meters, not like most of the Brazilian coast along which is shelf is very narrow.”
The researchers had been monitoring the shallow reefs of the Abrolhos Bank since 2000, when they started to find some large fish and pieces of coral that were not part of the shallow reef ecosystem they had been observing.
“The areas we mapped are all outside the nationally protected area,” said Dutra, who plans future dives on the newly discovered reefs.
“We are doing another phase of the research right now with a remotely operated vehicle in which the University of Sao Paolo is also a partner,” Dutra said. “We can see what kinds of corals and fish are there and what kinds of structures are on the bottom.”
“These studies reveal the complexity and connectivity of the reefs in the Abrolhos region and will support conservation planning,” said Dutra.
The studies are part of the Marine Management Area Science Program coordinated by Conservation International with the participation of research institutions around the world, and supported by the Gordon and Betty Moore Foundation and individual donors.
Now that the discovery has been announced, Dutra says Conservation International and fellow scientists will try to get the government of Brazil to extend protection to the newly found reefs.
“These new reefs are really important for biodiversity and for the abundance of fish in the shallow areas,” he said.
The conservationists will work with officials at the Environment Ministry to achieve protection, but Dutra says success depends upon their ability to call the attention of the government as a whole to the importance of the newly discovered reefs.