Saturday, June 09, 2007

Great White Shark: Myth or Reality?

Year after year, beach season brings accounts of harrowing shark attacks as people around the world plunge into the surf to escape summer's heat.

But the reality is that these fearsome predators kill an average of four people worldwide every year, while humans kill anywhere from 26 million to 73 million sharks annually, according to recent calculations by an international team of scientists.

With the latter toll mounting rapidly in recent years, there has been a growing realization that something must be done to prevent sharks from disappearing from the planet.

Last month, Mexico, which has a large shark fishery, enacted a law that protects three species, bans the practice of shark "finning" - slicing off the fins of a newly caught shark and tossing the animal back in the ocean to die - and requires authorities to monitor the activities of large shark-fishing boats. Yesterday, officials from around the globe began meeting in the Hague, Netherlands, to decide whether to put tight controls on the trade in two heavily fished species, spiny dogfish and porbeagle, under the Convention on International Trade in Endangered Species.

"For most of human history, sharks have been seen as a threat to us," David Balton, the U.S. deputy assistant secretary of state for oceans and fisheries, said in a recent interview. "Only recently are we beginning to see we're a threat to them."

Unprovoked shark attacks off U.S. shores have risen over the last century as Americans have flocked to the coasts and researchers have collected more careful statistics. Yet the number of deaths worldwide has dipped slightly in recent years, according to the International Shark Attack File, compiled by the American Elasmobranch Society and the Florida Museum of Natural History. Occasionally, the number of deadly attacks spikes, as it did in 2000, when sharks killed 11 people.

The declines in shark populations have been steep, as documented recently by scientists using technologies including satellite tracking and DNA analysis.

In March, a team of Canadian and U.S. scientists calculated that the number of scalloped hammerhead and tiger sharks may have declined along the East Coast by more than 97 percent between 1970 and 2005, and that the population of bull, dusky and smooth hammerhead sharks dropped by more than 99 percent. Globally, the World Conservation Union describes 16 percent of 328 surveyed shark species as threatened with extinction.

From Mexico to Indonesia, much of the hunt for sharks is driven by the growing demand for shark-fin soup, a prized delicacy that conveys a sense of status in Asian countries whose citizens are enjoying newfound wealth.

On a recent spring afternoon in the tiny camp of El Chicharon outside Las Barrancas, two brothers, Francisco and Armando Bareno, returned to shore with a catch of two dozen mako and blue sharks. At the edge of the water, they began slicing off the fins so they could pack them separately onto a truck bound for Mexico City, more than 1,000 miles away.

The fins are so much more valuable than the meat that, without the fin market, many fishermen might not bother to hunt sharks at all: The Bareno brothers get $100 for each 2.2 pounds of the dried fins they deliver.

Francisco Bareno said in Spanish that he did not really like the work that much.

"It's dangerous," he said. "But I have to live."

The fishermen catch sharks by various means, including gill nets and long lines studded with hooks that they leave out for hours or sometimes days. They are worried about making a living under restrictions the government has adopted - including the shark-finning ban, and placing observers on larger boats to assess the state of sharks off Mexico's coast and to protect great white, basking and whale sharks.

Ellen Pikitch directs the Pew Institute for Ocean Science and was coauthor of a 2006 paper in the journal Ecology Letters estimating the toll of the shark-fin trade. Over the last decade, she said, there has been a shift in policymakers' attitudes toward one of the most feared species on Earth.
"We've been getting signals from all around the world that sharks are under increased pressure," Pikitch said in an interview. "The pendulum has swung, and the momentum has shifted. It took a long time to get across the idea that sharks could be in trouble."


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