Research Expedition Aimed at Halting Loss of Black Coral

By Gale Mead
for National Geographic News
June 8, 2001
Aboard a research ship trolling the waters off Mexico's Yucatán
Peninsula, Mexican marine biologist Claudia Padilla trained last spring
to earn her "wings"—or, perhaps more apt, her "fins"—as the
pilot of a deep-sea submersible vessel.

The one-person craft, called DeepWorker 2000, is capable of exploring life in the ocean at depths of up to 2,000 feet (600 meters). It gives Padilla unprecedented access to the ancient paleo-shoreline just beyond the coast of the Yucatán Peninsula.

Beginning 165 feet (50 meters) below the surface and plunging to 350 feet (100 meters) and beyond, an area that was once a surf-pounded cliff is now home to a rich variety of fish, sponges, algae, and soft corals. One of the most imperiled of these creatures is the object of Padilla's research: black coral.

Highly sought for its use in jewelry and handicrafts, black coral (order Antipatharia) is under threat around the world. In Mexico, fortune seekers take extraordinary risks scuba-diving as deep as 250 feet (75 meters) to gather "trees" of black coral.

Their efforts have severely depleted the coral on the coast of Isla Cozumel, where most of Yucatán's black-coral hunters live. As a result, the divers have pushed southward in search of black coral habitats that have not yet been plundered.

One of the primary goals of Padilla's work is to determine how far down in the sea black coral is able to grow.

"The coral collectors have always maintained that dense colonies of black coral remain, in waters deeper than the collectors are able to work," Padilla said. They use that assumption to justify their harvesting of the coral in areas where it is accessible, arguing that deeper, undisturbed colonies can help repopulate shallower areas that have been stripped by collectors.

"But if such deeper colonies do not exist," Padilla added, "the effects of the industry may be greater than previously believed."

Better Deep-sea Access

Padilla and her research colleagues are focusing on the most recent areas of black coral encroachment, at the sparsely populated southern tip of Yucatán, between the remote towns of Majahual and Xcalak.

Their research vessel, the McArthur, is owned by the U.S. National Oceanic and Atmospheric Administration, which is a partner with the National Geographic Society in a five-year project called Sustainable Seas Expeditions.

The program, led by marine biologist National Geographic Explorer-in-Residence Sylvia Earle, is in its third season of ocean exploration, marine science, and public education and outreach aimed at protecting marine life and ecosystems. Padilla's research is being done under the program.

The use of cutting-edge technologies for underwater exploration is a key aspect of the Sustainable Seas project. Without such equipment, scientists must rely on conventional scuba diving, which limits them to brief dives and prevents the study of marine life, such as black coral, at extreme depths.

"In contrast, with DeepWorker, scientists have the luxury of time," said Earle. "Instead of minutes, we have hours in which to survey the habitat, and collect vital video images showing the density and health of the corals."

Said Padilla: "DeepWorker will enable us to see for ourselves whether, as coral collectors believe, black coral colonies are thriving in deeper waters."

Need for Conservation

In more than 20 hours of deep-sea operations using the submersible, Padilla and others have been recording their observations and obtaining film footage of colonies of black coral.

The resulting images have discouraging implications. The trees of black coral seen at the sites explored so far are not robust—sparsely distributed, small, and in marginal health. Moreover, the scientists found that black corals were increasingly rare at depths below 230 to 250 feet (70 to 80 meters). The "natural reserve" referred to by commercial coral collectors does not appear to exist, at least in this area.

Although the situation is troubling, Padilla and her colleagues are hopeful that coral populations can be revived, and that the results of their research will help guide conservation efforts in the region.

As part of government efforts to preserve black coral and other marine species, Mexico has designated protected areas, such as the Sian Ka'an Ecosphere Reserve, and regulated the collection of black coral.

Over several days of diving in the submersible, Padilla was able to learn more about the status of black coral in the area than she otherwise could have obtained in many weeks of research using conventional diving techniques.

One of the latest dives was at Punta Erradura, an area heavily affected by coral collecting until the site was depleted and divers abandoned the area two years ago. Emerging from the submersible, Padilla reported that although most large coral colonies have been removed, there are still colonies of three commercially important species, which perhaps, over time, can provide a foundation for renewal.

Pleased to be involved in the expedition, Padilla said: "The work we did here has helped add to our knowledge of the life in the least-known part of Mexico: the part that is under water."

New Age of Exploration

In addition to the research on black coral, the expedition to the Yucatán Peninsula is giving researcher Jose Mondragon an opportunity to study how local coral reefs are being affected by the transportation of petroleum products through the Yucatán Channel.

Scientists in the Sustainable Seas Expedition are also collecting coral and algae samples for further analysis by researchers at a number of academic institutions in the United States and Mexico. The project is also educating children and college students in the region about underwater ecology.

"It's often said that the great age of exploration has ended, that there's nothing left to explore," said Earle. "In reality, less than 5 percent of Earth's undersea wilderness has been seen by humans, even once. The greatest age of exploration for this planet is truly just beginning."

Research and exploration under the Sustainable Seas program in 2001 will also be done in the waters off Belize, Cuba, Texas, and Florida. The ship was scheduled to move in early June to the Northern Gulf of Mexico, where it will explore underwater life at the Flower Garden Banks National Marine Sanctuary 110 miles (175 kilometers) offshore from Galveston, Texas.

(c) 2001 National Geographic Society

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