Sharks Falling Prey To Humans' Appetites

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The problem is compounded by population declines of other fish species. As worldwide demand for fish increases, the stocks of some species have been overfished. As a result, sharks are targeted by fishermen in areas where they were previously left alone.

A Costly Delicacy

While shark meat has become an important staple of some diets, in other cultures the animal holds a more special place on the menu. Because shark fins, which can net fishermen more than $25 per pound, are more profitable than shark flesh, fishermen sometimes take merely the fin.

Once the rigid, cartilage-supported fins are sliced off, the sharks are then dumped overboard, either already dead or doomed to die. After being dried and processed, the fins eventually end up in shark fin soup, a popular and expensive delicacy in Chinese cuisine.

"It's a big problem, because there is lots of demand and little regulation of finning," said Christine Snovell of the National Coalition for Marine Conservation. "These fins are worth a tremendous amount of money, so the law of supply and demand is in effect."

"Fins to these sharks are analogous to the horns of rhinos," added Hueter. "Even fishermen who catch sharks unintentionally, as bycatch, will now take the fins—otherwise they are throwing money away."

Sharks are also a tremendous source of cartilage. Unlike many fish, which have bony skeletons, shark skeletons are made entirely of cartilage, which grows throughout the animal's life. Shark cartilage pills are advertised as cure-alls for any number of ailments and diseases.

Scientists like Hueter, however, are skeptical about the efficacy of shark cartilage pills in treating disease in humans. "There's research ongoing," he said, "but as far as we can tell it's not having major value in terms of fighting diseases, although that is how it's being marketed."

Shark carcasses serve other purposes as well. Different parts of the animal are put to commercial use in products ranging from cosmetics to hemorrhoid cream—which makes liberal use of shark liver oil.

Altering the Ocean Ecosystem

The popularity of shark products means that the animals are being pulled from our oceans faster than ever before. Dropping shark populations could spell big trouble for the ocean ecosystems so crucial to life on Earth.

"Sharks are an apex predator," points out Snovell, "like lions or wolves on land. If you remove that important link from the top of the food chain, you're going to have some real problems all the way down the line."

Shark biology compounds the problem. Sharks have a long life span, don't reach sexual maturity until they are 12 to 20 years old, and even then have a low reproductive rate. Reduced populations mean fewer sharks reproducing, at well below the replacement rate necessay to keep pace with the number lost to fishing fleets.

This reproductive timetable was in balance with an ecosystem in which a limited number of sharks sat atop the food chain. It may prove inadequate, however, to sustain shark populations in an ocean ecosystem increasingly dominated by humans.

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