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Sealife
In the Soup

For years marine biologists have worried about the notoriously secretive shark-fin trade in Asia. Shark-fin soup is a staple at Chinese celebrations and is popular on Chinese menus in the United States and Europe. Scientists’ fears were confirmed when the first hard numbers surfaced last fall, revealing that as many as 73 million sharks are killed each year worldwide, many of them for their fins alone. The results of the study, which was published in the October 2006 issue of Ecology Letters, is considered a conservative estimate for shark kills. 

A number of factors complicate efforts to accurately count and manage shark populations. In an unsavory process known as “finning,” fishermen slice the fins off the animal and throw the bodies into the sea to leave more room in the hull for fins or other catch. Only the fins reach the ports, making it nearly impossible to identify species and to assess true catch numbers. In addition, millions of sharks are snagged as bycatch, or hooked by longlines from swordfish or tuna-fishing vessels.

A team led by Shelley Clarke, an American fisheries scientist based in Japan and Hong Kong, penetrated Asian markets and tapped into fin-auction records, then used a sophisticated modeling technique to convert the statistics into shark weight. The researchers hope the data will be used to influence the management of shark populations, some of which are approaching dangerously low levels.

Shark meat, with its high urea content, has not been considered commercially important enough to warrant management and legal protections in many of the world’s fisheries. “There are a lot of fish under threat these days, and a lot of them are more commercially valuable than sharks,” says Clarke. 

Even so sharks have long been prized for their fins. For centuries the Chinese have enjoyed the luxury of shark-fin soup, with the cartilaginous fin rays forming the “noodles.” According to lore, the longer the noodles, the longer one’s life will be. Today’s thriving Asian economy has only intensified demand, and shark fins can fetch $400 a pound in the region’s markets.

The IUCN 2006 Red List of Threatened Species says that 20 percent of shark and ray species now face extinction. Clarke’s study suggests that the catch rate for the blue shark, in particular, is nearing or exceeding its sustainable level. “We have enough information about how vulnerable sharks are that we could put in some reasonable limits while we get the specific information that we need,” says Sonja Fordham, director of the shark conservation program at The Ocean Conservancy, in Washington, D.C. “Too often lack of data is used as an excuse for inaction, and sharks are paying the price.”—Amanda Leigh Haag