ENVIRONMENT: Saving sharks from extinction

“During a late-night beach party on Amity Island, a young woman goes swimming in the ocean. While treading water, she is violently pulled under. The next morning, her partial remains are found on shore. The medical examiner ruling the death a shark attack leads Police Chief Martin Brody to close the beaches. Mayor Larry Vaughn overrules him, fearing it will ruin the town’s summer economy.

The coroner now concurs with the mayor’s theory that the girl was killed in a boating accident. Brody reluctantly accepts their conclusion until another fatal shark attack occurs shortly after. Amid an amateur shark-hunting frenzy, local professional shark hunter Quint offers his services for $10,000. Meanwhile, consulting oceanographer Matt Hooper examines the first victim’s remains and concludes the death was from a shark attack.”

That was how Wikipedia describes the 1975 American thriller directed by Steven Spielberg.  It was based from a bestselling novel written by Peter Benchley.  Now considered one of the greatest films ever made, Jaws became the highest-grossing film of all time until the release of Star Wars (1977).

Since then, people from all over the world take a closer look at sharks as something sinister, something deadly and something to be annihilated.  “They’re better left dead than alive,” someone commented.

It may be interesting to know that until the 16th century, sharks were known to mariners as “sea dogs.”  Until now, the etymology of the word “shark” is uncertain. One (now largely disproved) theory is that it derives from the Yucatec Maya word xok, pronounced ‘shok’.  Evidence for this etymology came from the Oxford English Dictionary, which notes shark first came into use after Sir John Hawkins’ sailors exhibited one in London in 1569 and posted “sharke” to refer to the large sharks of the Caribbean Sea.

However it got its name, shark is one of the most mysterious groups of creatures roaming the Earth today.  Science has identified more than 465 known species of sharks swimming in various oceans of the world.

“(Sharks) range in size from the small dwarf lantern shark (Etmopterus perryi), a deep-sea species of only 17 centimeters in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 meters in length,” Wikipedia bares.

Sharks are found in all seas and are common to depths of 2,000 meters or 6,600 feet. They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive and be found in both seawater and freshwater.

Interestingly, sharks predate the dinosaurs by 200 million years.  They are an apex predator at or near the top of their marine food chains, and they regulate the populations of species below them.

According to defenders.org, most sharks are especially active in the evening and night when they hunt. Some sharks migrate over great distances to feed and breed. This can take them over entire ocean basins. While some shark species are solitary, others display social behavior at various levels. Hammerhead sharks, for instance, school during mating season around seamounts and islands.

Some shark species, like the great white shark, attack and surprise their prey, usually seals and sea lions, from below. Species that dwell on the ocean floor have developed the ability to bottom-feed. Others attack schooling fish in a feeding frenzy, while large sharks like the whale and basking sharks filter feed by swimming through the ocean with their mouths open wide, filtering large quantities of plankton and krill.

In terms of speed, sharks swim (“cruise”) at an average speed of 8 kilometers per hour, but when feeding or attacking, the average shark can reach speeds upwards of 19 kilometers per hour.  That’s according to Wikipedia.

The shortfin mako shark, the fastest shark and one of the fastest fish, can burst at speeds up to 50 kilometers per hour.  The great white shark is also capable of speed bursts. These exceptions may be due to the warm-blooded nature of these sharks’ physiology. Sharks can travel 70 to 80 kilometers in a day.

Feared by most, sharks, however, are on the verge of extinction.  “One of nature’s oldest, most successful and least visible predators is in profound trouble,” wrote Sandra Blakeslee in an article which appeared in The New York Times.

As many as 90 percent of sharks in the world’s open oceans have disappeared.  Juliet Eilperin, author of Demon Fish, said that more than 73 million sharks are killed each year by fishermen who hack off their fins to sell as a coveted ingredient for soup.

The practice is called shark finning, where the shark’s fins are sliced off while the shark is still alive and throwing the rest of its body back into the ocean where it can take days to die.

A report said: “Shark fins are used as the principal ingredient of shark fin soup, an Asian ‘delicacy.’  Demand for shark fin soup has rocketed in recent years due to the increased prosperity of China and other countries in the Far East. Shark fin soup, which can easily cost $100 a bowl, is often served at wedding celebrations so that the hosts can impress their guests with their affluence.”

The rapid decline of great sharks in the world’s oceans is disrupting the marine ecosystem by allowing more lowly fish to thrive, according to Ian Sample, science correspondent of The Guardian.

Quoting a study done by a team of marine biologists led by Ran Myers at Dalhousie University in Halifax, Nova Scotia, he wrote: “Overfishing of the ancient predators has led to a sudden uprising of species they prey on, causing an abundance of skates, rays and smaller sharks, which are steadily devastating populations of shellfish, including scallops, oysters and clams.”

It is a common knowledge that when one predator disappears from an ecosystem, others that eat the same prey usually take over and keep the balance of the ecosystem in check. But in this case, where not one, but all, of the top predators are rapidly disappearing, “you lose the resiliency and buffering capacity of one species to step in for another,” Dr. Charles Peterson of the University of North Carolina told LiveScience.

In the Philippines, a country surrounded by large bodies of water, including the Pacific Ocean, Senator Juan Miguel Zubiri has filed a bill in the Senate seeking to prohibit, under pain of imprisonment and fine, all trade of not only sharks but rays as well.

Senate Bill 1245 or the “Sharks and Rays Conservation Act” seeks to impose penalties of up to 12-year imprisonment, or a fine of up to P1 million, or both, to violators of the ban, including those who “inflict injury on sharks and rays.”

In a statement released to media, Zubiri said: “No effort must be spared to protect the biodiversity of our waters as well as the natural balance of our marine ecosystem, for the enjoyment and economic benefit of future generations of Filipinos.”