It's summer time, and the living is easy, with many vacationers heading for the coast. But once there, the bravest of people find that swimming is uneasy, thanks to the fear that their worst nightmare may be lurking nearby. Is that dark shadow under the water some seaweed, driftwood or ... a shark?
Steven Spielberg took Peter Benchley's novel and put this primeval fear on the screen in his 1975 film "Jaws," making a generation of swimmers imagine the lurking throb of the music every time they enter the water. The fascination hasn't abated: This has been Shark Week, the Discovery Channel's annual look at scary sharks in their habitat, the same one people swim in.
The sharks-as-killers dread isn't all imagined. Some species of sharks are among the best killers in nature, sleek with mouths full of razor-sharp teeth. But our finned fears obscure several truths: Not all sharks are man-eaters; plenty of them never hurt humans. Shark attacks are relatively rare.
Indeed, it's the sharks that should be afraid of the people. According to a study two years ago by the International Union for Conservation of Nature, a global environmental network, 32 percent of 64 species of open ocean (pelagic) sharks studied are threatened with extinction, primarily due to overfishing. Unhappily for the sharks, their fins are sought to make the Asian delicacy shark fin soup, and new markets have developed for their meat. While so-called "finning" -- cutting the fin from the shark and discarding its body -- has been banned in international waters, the report says, enforcement standards are lenient.
As sharks tend to be slow to mature and have relatively few young, the results have been disastrous. A report issued in June by the Pew Environment Group -- "Sharks in Trouble: The Hunters Become the Hunted" -- cites a 2000 study that said up to 73 million sharks are killed for their fins every year but many scientists believe at least 100 million sharks are killed annually for various reasons. Shark populations have declined by as much 70 to 80 percent, the study says.
Why should anyone care, especially the fearful bather? Because, as the study says, sharks "play an important role in maintaining the structure and function of the marine ecosystem. The loss of sharks can cause dramatic shifts in the marine environment, including a cascade of indirect effects resulting from changes in the abundance of other organisms." The consequences can include the collapse of important fisheries.
But it's not all bad news. One of the recommendations of the Pew study is the establishment of shark sanctuaries where shark fishing is banned; fortunately, these protective zones are on the rise. The Pacific island nation of Palau was the first, and other sanctuaries have been established in Honduras, the Maldives and the Bahamas.
Something to ponder after Shark Week: As much as we fear them, sharks have their useful place in nature. What we should fear more is oceans without them.