Researchers find most shark fins in fish markets are from species caught in coastal zones, not the open ocean

A team of researchers affiliated with several institutions in the U.S. has found that most shark fins sold around the world in fish markets come from sharks caught in coastal zones rather than in the open ocean. In their paper published in the journal Biology Letters, the group describes their genetic study of fish market fin samples and the habitat modeling that they conducted for sharks.

Despite efforts by conservationists and legal protections in some jurisdictions, fishermen around the world continue to catch sharks which are prized for their fins. The fins are typically used to make shark fin soup, which is considered a delicacy in some circles. Conservationists have been assuming that most sharks are taken from the open ocean, where it is difficult to monitor fishing activities. In this new effort, the researchers have found evidence that such assumptions are wrong. Most fin sharks that wind up in fish markers have been cut off of sharks caught in coastal zones around the world.

To get a better handle on the source of fins sold in fish markets (primarily in Asia), the researchers obtained 5,000 samples from a large number of fish markets in San Francisco, Hong Kong, Vancouver and several along Brazil's coast. They subjected them to genetic analysis to learn more about them. The analysis not only revealed the species of the samples, but where in the world they came from. They also used habitat modeling to give them a better idea of where the sharks were caught.

The researchers found that more of the samples were from endangered species than was expected. But more importantly, they also found that most of the samples they tested came from sharks caught off the coast of only a handful of countries, including Mexico, Japan, Indonesia, Brazil and Australia. They suggest this finding represents an opportunity to reduce the trade in shark fins because it is much easier to stop fishing efforts in coastal waters than the open ocean.