With their streamlined bodies, keen sensory abilities and resilient immune systems, sharks are built to last: over 400 million years, at last count.
Leave it to Man, the world's scariest predator, to spoil their fun.
Vilified as evil killers good only for soup fixings, crab bait and deep sea "monster fishing," it appears that certain large and small shark species are vanishing from coastal waters worldwide.
The 1975 thriller "Jaws" was not the cause, but "the ultimate focus of this 'death fish from hell' phenomenon," says Samuel H. Gruber, a shark expert at the University of Miami.
Lightning strikes more often than a great white or tiger shark. Still, all sharks, like wolves, lions and other predators, are an unwitting foil for our "primeval fear of being eating alive," Mr. Gruber says.
For years, scientists and conservationists have worked to reverse sharks' bad rap.
"A new way of looking at them is in order," says Juan Sabalones, the senior aquarist who tends to the National Aquarium's shark collection.
True, sharks aren't cuddly Flippers, and have little personality. But, "they do have a place," Mr. Sabalones says. "They don't deserve to be eradicated. They are not a threat to mankind."
The National Aquarium in Baltimore has launched its own shark rehabilitation program. During Shark Fest '93, visitors can learn about these fascinating elasmobranches -- fishes with skeletons made of cartilage, not bone -- through exhibits, games, films and narrated feeding demonstrations.
Environmental groups and researchers, as well, wage shark education campaigns. Besides lobbying for tough fishing regulations, for example, the Washington-based Center for Marine Conservation (CMC) fosters shark awareness with tools such as "Shark Alert" -- a compact disc interactive program -- and a shark coloring book for children.
"Not just the environmental community, but citizens all over the country are waking up to the fact that fish are a public resource and need to be managed wisely," says Sonja Fordham, CMC fisheries specialist.
As "apex" predators, sharks play a vital role in the marine ecosystem "controlling and purifying the genetic strains of their prey by killing off the weak and sick and the old," Mr. Gruber says.
Because they reproduce slowly -- for example, sandbar sharks give birth to about five to 12 pups every other year at most -- sharks are vulnerable to over-fishing. An estimated 100 million sharks are caught or die as a result of pollution annually. Many believe that sharks in the Atlantic, Pacific and Gulf of Mexico are being killed faster than they can reproduce.
A shark fishery that "crashes" takes forever to rebuild, Mr. Sabalones says.
Sharks' perilous existence is attributed to several factors. Since the 1970s, shark meat has been promoted as a cheap, tasty source of protein. And, as the Pacific Rim nations gained prosperity, the market for shark fins, a pricey Asian delicacy, expanded the practice of live-finning -- stripping sharks of their fins and returning the helpless creatures to the sea.
Sport fishermen going for big cash prizes and valuable jaws as well as commercial fishermen who nab sharks unintentionally also contribute to shark declines, shark advocates charge.
Because of their free-ranging ways, sharks are hard to count. Although quantitative evidence proving shark depletion can be sketchy, "All of these discrepancies represent a case of uncertainly where we must err on the side of conservation and not over-fishing," says Ms. Fordham of CMC. "There's simply too much at risk."
Anecdotal evidence and surveys do suggest certain shark populations are disappearing rapidly. John A. Musick, head of the vertebrate ecology program at the Virginia Institute of Marine Science (VIMS) at Gloucester Point has monitored sharks in the mid-Atlantic region for 20 years and has found the shark population to be "less than a fifth of what it was 10 years ago."
The dusky shark, a species that frequents the East Coast, "has just been creamed," he says.
Other sharks, such as sand tigers and sandbar sharks -- though they are still fairly plentiful off the coast of Maryland and Delaware -- seemto be in decline in local waters as well. The lower Chesapeake Bay is the "single biggest nursery area" for sandbar sharks, Mr. Musick says. But because the females are being taken along coastal migration routes, fewer young are born there, he says.
Effects of loss
Little is known about the long-term ramifications of shark depletion. In an Australian fishery where shark counts plummeted, octopuses multiplied and practically eliminated the local spiny lobster, once an economic mainstay of the region.
On Florida's Gulf Coast, where hammerheads declined, their stingray prey has flourished, causing harm to many swimmers.
Shark protection efforts are beginning to pay off.
On April 26, the National Marine Fisheries Service issued federal restrictions on fishing for 39 major shark species along the Eastern U.S. coastline.
Funds for a tiger shark eradication program launched after several shark attacks in Hawaii last year were largely diverted to research.
West Coast environmentalists are in the early stages of calling for a shark conservation plan, and a bill protecting great white sharks is pending in the California legislature.
A Florida law protects inshore nurseries from commercial fishing.
And sport fishermen are now being invited to participate in tournaments where sharks are caught, measured and released.
The struggle to save the shark has reinforced a valuable lesson for environmentalists. By singling out one animal, like the dolphin or whale, for protection, the need to maintain the entire marine environment is neglected. All sea creatures, including the shark, matter to the "overall integrity of the oceans and the ecosystem," Ms. Fordham says.