The Incredible White Shark

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In June of 1975, a movie called “Jaws” hit the theaters. It was my second year working as a lifeguard at Jones Beach State Park, and by mid-summer the blockbuster movie’s impact on beachgoers was palpable. It seemed that everyone was carrying a paperback copy of Peter Benchley’s novel of the same name in their beach bag, and shark talk dominated the idle chatter of the mainstand crew.Later that summer, the sighting and report of a large dorsal fin close inshore brought a quick, thoughtless and deadly response from the police: they shot and killed a harmless ocean sunfish.

The white shark (Carcharodon carcharias) is widely distributed around the world, found in all oceans except the Arctic. In terms of size, the largest on record measured 20 feet in length and 3,500 pounds in weight. There is much that remains unknown about its habits and behavior, although it is considered semi-solitary, traveling alone except when a large food source is available. A dead whale can attract more than one white shark.

Unlike most fish, white sharks lack a swim bladder, relying instead on their very large, oil-filled liver for some buoyancy. Still, they must continually swim to avoid sinking.

They also differ from most other fish in having five to seven gill slits, not one, on each side of the body. It was once thought that sharks needed to be in constant motion in order to have water pass through their gills. But researchers have documented several species resting on the ocean floor, motionless except for muscles around the gill slits pulsating to move water through them.

In recent years there has been an increase in the number of reported white shark sightings in the New York and Cape Cod region, including the dead, relatively small individual that washed ashore in Napeague last week. Measuring four feet in length and weighing 75 pounds, this was most likely a newborn shark pup, one of a litter of up to ten.

It seems that, 40 years after Jaws, attitudes toward these apex predators may have changed somewhat. Sure, the element of fear is still there. But there’s also a sense of awe and respect. This may reflect a better understanding of the white shark and its role in the ecosystem.

Montauk’s recent no-kill shark tournament, along with the tag-and-release research being done on Cape Cod, have shown that many shark species are truly global creatures, traveling thousands of miles in a single year, including crossing the Atlantic ocean. A recent study published earlier this year confirmed that white sharks live up to 70 years.

Sharks have a number of interesting sensory adaptations. Their olfactory sense is a combination of smell and taste that allows them to find chum slicks, blood, or dead marine mammals, from quite a distance. As it gets closer, it can “hear” with its tiny, internal ears and sensitive lateral lines along its flanks that detect vibrations in the water caused by sound.

It also has excellent sight. But juvenile white sharks often prey on fish and invertebrates partially buried in bottom sediments, and to hunt them they relay on a series of pores in their snouts called ampullae of Lorenzini. This sensory structure detects electrical currents generated by muscle movements, including heartbeats.

Despite all these sensory structures, it appears that sharks sometimes don’t know exactly what they are biting into, and they will often release an animal after an exploratory chomp. Mature white sharks (14 feet or greater in length) prey on marine mammals—seals, porpoises and whales—that have a high fat content. Researchers have stripped seals of all their fat and put both the fat and non-fat parts in the water. Sharks ate only the fat.

Seal-like surfers in wetsuits on rare occasions get the exploratory bite, but no more. Unfortunately, an exploratory bite by a large white shark can do serious damage. Still, shark-human encounters are rare, and human fatalities caused by sharks are extremely rare: there was one in the United States in 2013.

Twenty-five years after “Jaws”, in July of 2000, Peter Benchley appeared at a news conference in Hong Kong with an appeal to help sharks.

“Sharks have experienced an unprecedented and uncontrolled attack, and are much more the victims than the villains,” he stated. Asia is the largest consumer of sharks and shark products. Finning sharks and throwing the fish back in the sea to die is not only wasteful and unsustainable, but the loss of this large predator is having a major impact on the ocean ecosystem.

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