Sharks consistently rank near the top of lists of American’s greatest fears. In reality, they have much more to fear from us than we do from them. Because of our actions, many species of sharks are on the verge of extinction. A recent International Union for the Conservation of Nature Shark Specialist Group report shows that fully 1/3 of open-ocean species of sharks are in danger of extinction in the next few decades. Many shark species have had population declines of over 90% in the last few decades.
The life history strategy of sharks is very different from that of other commercially exploited fishes, and this makes them more vulnerable to overexploitation. Several species of sharks don’t reproduce until they are older than ten years old, and some only have a few young every other year (or in some cases, every three years). It’s easy to see how this inability to rapidly replace themselves could become an existential problem when modern industrial fishing techniques are involved.
While few sharks are targeted for their flesh, which is considered unpalatable except for a few species, most species are targeted for their fins. The fins, which have absolutely no meat, flavor, or nutritional value whatsoever, are made into an Asian delicacy called shark fin soup. They provide only texture to the spiced chicken broth. While it is impossible to know exactly how many sharks are killed in this global, largely unregulated fishery, the best scientific estimates we have say that the number is as high as 73 million each year.
Being targeted isn’t the only thing problem facing sharks-bycatch is another major threat to many shark species. Millions of sharks each year are killed by fishing gear simply because they are swimming near what fishermen are trying to catch- the ultimate example of being in the wrong place at the wrong time. Though few fisheries are blameless from a bycatch perspective, particular culprits include the shrimp trawling fishery, the tuna purse seine fishery, and the billfish longline fishery.
Since sharks serve as apex predators in most marine ecosystems, their declines pose major troubles both to the environment and to the countless humans who depend on that environment for food and to make a living.
The problem is a major one, and we need to solve it.
David Shiffman is a Masters student at the College of Charleston, where his research focuses on the feeding ecology and conservation of local sharks. He writes about shark issues for the marine biology blog Southern Fried Science (southernfriedscience.com), and is actively involved in educating the public about these important and misunderstand animals. To learn more about sharks, follow him on twitter @WhySharksMatter.