Animals

Illegal Shark Fishing Uncovered at 'Sanctuary'

Illegal shark fishing in a Pacific sanctuary is detected by monitoring tagged sharks.

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Reef sharks are being illegally fished out of one of the world's largest shark "sanctuaries," according to environmentalist Philippe Cousteau and colleagues who made the discovery while filming the documentary "Nuclear Sharks" at the Marshall Islands National Shark Sanctuary.

When the 768,547-square-mile sanctuary was established five years ago in the central Pacific, conservation groups unanimously praised its formation, but the new evidence suggests that laws banning commercial fishing of sharks within the sanctuary are not being enforced.

"The system is broken and illegal fisheries are laughing all the way to the bank," Patric Douglas, executive producer of "Nuclear Sharks, told Discovery News.

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Cousteau and his wife Ashlan Gorse, who also worked on the project, added in a joint statement that the Marshall Islands National Shark Sanctuary is three times the size of the California and in the middle of the ocean "so it's an extremely tough place to police, a fact that illegal fishermen know as well."

Douglas and his team, which also included marine biologist Luke Tipple, traveled to the region for an entirely different reason: to document marine life now surrounding what was once the site of 67 nuclear tests, including a devastating hydrogen bomb test at Bikini Atoll in 1954 during the Cold War. Part of the project involved tagging grey reef sharks and tracking their movements over an eight-month period.

Photo: Production still from "Nuclear Sharks." Credit: Photo taken by Johnny Friday, courtesy of Patric Douglas
Photo: Production still from "Nuclear Sharks." Credit: Photo taken by Johnny Friday, courtesy of Patric Douglas

"Reef sharks are not pelagic species, so they tend to stay near their reef habitats," Douglas said. "We started to notice that 55 percent of the tagged individuals -- mostly small 4-foot females -- began to quickly head west, which is not normal behavior for these sharks."

Image: Data tracks emitted from a tag affixed to a reef shark from the Marshall Islands National Shark Sanctuary. Researchers believe that the shark was illegally fished, with its fin transported to a port for sale. Credit: Google Earth, Patric Douglas

Douglas sent tracking information for 15 of the tags to Darcy Bradley of the Bren School of Environmental Science & Management at the University of California, Santa Barbara. Bradley said that the data was far from what she had expected.

"When I started to have a look at the data, what I found was far from what I expected," she said. "The tags were certainly not on sharks: the traveling speed was far too fast and the tags were clearly at the surface. The speed and direction of movement also allowed me to rule out the possibility that the tags were freely drifting."

Image: Data tracks emitted from a tag affixed to a reef shark from the Marshall Islands National Shark Sanctuary. Researchers believe that the shark was illegally fished, with its fin transported to a port for sale. Credit: Google earth, Patric Douglas
Image: Data tracks emitted from a tag affixed to a reef shark from the Marshall Islands National Shark Sanctuary. Researchers believe that the shark was illegally fished, with its fin transported to a port for sale. Credit: Google earth, Patric Douglas

"Instead," she continued, "it seemed that nine of the 15 tags were probably on boats, the sharks had likely been illegally fished, and a project with an ecological objective had suddenly become something entirely different."

Douglas said that the destination points for some of the tags were ports in Guam and the Philippines. He and his colleagues strongly suspect that the sharks were killed for their fins, which can fetch top dollar in markets for customers using them in shark fin soup. Often the rest of the shark's body is thrown away. Since the small tags were originally placed on the sharks' fins, the devices likely wound up in the ports along with the fins.

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Prior research shows that it is not hard for a vessel to become a "ghost ship" by turning off, eliminating, or modifying its Automated Identification System (AIS) equipment meant to track and identify watercraft.

Douglas said he has since learned that ghost or pirate ships often venture out in pairs, with one sometimes meeting the other in remote parts of the ocean to allow for exchange of illegally taken catches, helping to further erase movements. He suspects that such activity in the Marshall Islands National Shark Sanctuary increases at around the end of October when trade-winds strengthen. Facilitated by the winds, some fishermen can then save up to 30 percent in fuel costs, he said.

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Tom Letessier of the Zoological Society of London leads a team that helps to monitor shark and wildlife populations in other marine sanctuaries, including the world's oldest in Palau, located in the western Pacific, and another in the Chagos Archipelago within the Indian Ocean. The Chagos Archipelago sanctuary is actually proving to be a success story, at least so far, because recent research found that it has higher than expected fish population.

Nevertheless, Letessier told Discovery News, "We find that some illegal fishing is still occurring inside the reserves, in part because these are attractive fishing grounds, but also because they are, by definition, large and remote and thus hard to enforce and patrol. In addition, places like Palau and the Marshall Islands may lack enforcement resources."

Letessier believes that new technologies may offer economic solutions to the problems. These may include remote surveillance using Synthetic Aperture Radar on satellites, as well as video and acoustic systems mounted on ocean gliders or fixed on land.

Bradley added that these and other possible solutions need to be supported in a global effort because "we cannot continue to place the burden of enforcement on small island nations that host most of the world's shark sanctuaries." Douglas, Cousteau and Gourse agree, and point out that the same or similar technologies can apply to monitoring endangered terrestrial species, such as rhinos and elephants.

Cousteau and Gorse remain hopeful, given the central Pacific site's difficult past.

They said, "As we saw in the Marshall Islands, even after man destroyed everything in its path with nuclear bombs, nature was able to bounce back. Nature is resilient and, if left alone, she will flourish. We, as humans, just have to ask ourselves if we will give her that chance."