Sharks: A Bad Image, but Oceans Value Them
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This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty. And I'm Faith Lapidus.
This week, we will tell about sharks -- a fish with a public relations problem.
A picture in the newspaper shows a person standing next to a huge shark. The body of the shark is hanging with its head down. A scale is measuring its weight.
The lines below the picture say the shark was a very big one. Or perhaps it was one of the biggest ever caught in the area. The person who brought in the fish looks extremely pleased. That person won a battle with what has been called one of nature's fiercest creatures.
Some people, however, do not approve of catching sharks. They do not think all sharks are terrifying enemies. They know that studies show lightning and snakebites threaten people more than shark attacks.
Activists for sharks note that the fish are valuable in the ocean. Sharks eat injured and diseased fish. Their hunting means that other fish do not become too great in number. This protects other creatures and plants in the ocean.
Environmental activists worry that some kinds of fish are in danger of dying out. The National Oceanic and Atmospheric Administration estimated that fishing operations kill more than one hundred million sharks every year. Sharks are harvested for meat and cartilage, liver oil and, especially, for their fins. Many of the animals die when people harvesting other kinds of fish pull in sharks by accident.
George Burgess leads the International Shark Attack File at the Florida Museum of Natural History of the University of Florida. He says shark attacks increased during the past century for a good reason. Hundreds of millions of people now use the world's oceans, more than in the past.
Professor Burgess says the first ten years of the twenty-first century are expected to register the most attacks of any ten-year period.
Yet the International Shark Attack File reports that the number of shark attacks has, in fact, decreased in recent years. During this period, there was an average of sixty-three attacks worldwide each year. That compares with a high of seventy-nine in two thousand.
The file gives some likely reasons for the decrease. One reason is that overfishing of sharks and related fish has reduced the size of some shark populations.
Another is that more people are careful to stay away from waters where sharks swim. And the file says workers responsible for boating and beach safety may be doing a better job of warning people when sharks are seen.
The International Shark Attack File describes shark attacks as either provoked or unprovoked. An unprovoked attack means the person is alive when bitten. It also means the person must not have interfered with the shark.
Some divers interfere with sharks on purpose. They want to get the attention of sharks, perhaps to take pictures of them. The diver may put food in the water to get the animal to come close. Sharks do not normally want to be with people. But their excellent sense of smell leads them to food.
Some experienced divers say they may not face danger when near a shark. But they say the next person who comes near the shark may be in trouble. The animal's experience with being fed may make it connect food with people.
Some divers, filmmakers and nature photographers enter a shark's territory while inside containers made of steel. Others wear heavy metal equipment for protection. And others get near sharks wearing only normal diving equipment.
Close contact with sharks has its critics. Some people say it represents invasion of the animals' territory for no good reason. But exciting films may increase public interest and sympathy for the animals.
Many people wanting to save sharks have formed activist groups. For example, a group called Shark Safe helped prevent the killing of sharks at a fishing competition in Florida earlier this month. Event organizers had said the goal would be to catch and release sharks.
But the Shark Safe Project said the stated goal of "bringing in the big one" would lead to killing of the biggest sharks. The big ones are the most likely to reproduce.
The Shark Safe Project planned a demonstration against the competition. The demonstration never took place, however. Instead, the event organizers changed their plans. Participants were to catch the sharks as expected. But all sharks were to be released.
The Shark-Free Marinas Initiative is a campaign aimed at helping sharks worldwide. Under the Initiative, people could not bring a killed shark to a participating marina. People transporting captured sharks to the boat landing for weighing and killing would also be rejected.
The initiative cooperates with several other programs, including the Cape Eleuthera Institute in the Bahamas islands. The Institute is an educational center that also operates a shark research program.
In late two thousand seven, a United Nations conference reported that one kind of shark, the basking shark, is in danger of dying out. The numbers of basking sharks have been decreasing for the past half-century. The animals are the second largest shark, after whale sharks. They swim with their mouths open, cleaning the water as they move. They take up and eat objects like fish eggs and tiny sea organisms.
Scientists want to know how and where basking sharks travel.
Recently, experts on both sides of the Atlantic Ocean were interested in a huge basking shark discovered in eastern Canada. The remains of the eight-meter long animal were found on a rocky beach in Saint John, New Brunswick. Experts said the cause of death is unknown.
Donald McAlpine heads the zoology collection at the New Brunswick Museum in Saint John. He said scientists removed the head and some backbones from the shark for examination. Mr. McAlpine said pictures of the animal were sent to scientists in Britain. The British scientists had requested the pictures to learn if the shark was the same fish they had observed on their side of the Atlantic.
Sharks can be identified by their individual markings and sometimes by healed wounds.
For years, the travels of basking sharks have been a mystery to scientists. Basking sharks from the northeastern United States are not seen in the winter. They seem to disappear from cool waters of the Atlantic and Pacific Oceans. Yet studies published in the journal Current Biology are providing clues about the mystery.
The studies found that the sharks went to warmer waters of the Atlantic during the winter. The animals did a good job of staying hidden from sight. They swam in waters from two hundred to one thousand meters deep.
Like Americans living in cold climates, some of the sharks traveled to Florida for the winter. Others went even further south. One spent a month in waters near Brazil.
One of the investigators was Gregory Skomal of the Massachusetts Division of Marine Fisheries. He says the fish probably get to eat more plankton in the warmer waters.
Today, a major threat to sharks comes from shark fin soup. The popularity of the soup has increased greatly over the years. Fisheries can earn a lot of money for even one kilogram of shark fins.
Finning, as it is called, is big business. It means cutting the fins off a live shark. Fishermen cut off the shark's fins and throw the animal back into the water. The shark then bleeds to death on the bottom of the ocean.
Many animal-protection groups and people worldwide have denounced finning as cruel. Some areas have banned this activity. But it is hard to enforce the ban in many places.
Ann Luskey is an activist for the world's sea environment. She lives on a boat and often dives to watch underwater life. Her three children took part in an unusual recording project. The family hopes the music will attract attention to the need for taking good care of the earth and its seas.
One of the recordings is a hip-hop song called "Shark Fin Soup." It urges people not to eat the soup because it threatens sharks.
This SCIENCE IN THE NEWS was written by Jerilyn Watson. Brianna Blake was our producer. I'm Faith Lapidus. And I'm Bob Doughty. Listen again next week for more news about science in Special English on the Voice of America.