For many for us, sharks are feared because they kill people. Little do we know that the reverse situation—that which involve people killing sharks—is also happening, and at an alarming rate.

Experts warned that the unabated killing of sharks could drastically affect the health of the ocean and, in turn, the survival of humans. They said the mass slaughtering of sharks could affect the ecological balance, leading to significant decreases in the diversity of species and food shortages for humans in the long-run.

Eight researchers recently published a study on the journal Marine Policy, estimating some 100 million sharks being killed around the world every year.

In 2010 alone, the researchers estimate that 63 to 273 million sharks were killed.

The study noted that sharks have become "exceptionally vulnerable to overfishing."

What is the reason behind this high mortality rate among sharks? The researchers point to the high demand for shark fin soup, which is known to be a luxury item in Chinese communities.

Dr. Demian Chapman, one of the researchers, noted however that to be able to produce shark fin soup, fishermen end up not just with the fin but other parts of the shark as well.

"The problem is that the fins are so valuable that now people are not 'finning' the sharks at sea—they're keeping the whole thing. But it is still dead; the finning bans have not stopped the root problem," Chapman explained.

Some countries like Canada, the United States and even members of the European Union have passed regulations to restrict hunting down sharks for fins, but to no avail.

To further complicate the problem, shark populations that are being wiped out by overfishing do not reproduce fast.

"There is a really razor-thin level of mortality that sharks can experience before their population trajectory becomes negative—that is really what's been happening," Chapman said.

"They are not reproducing fast enough to keep up with the rate we are pulling them out of the ocean," he added.

The researchers proposed "adequate conservation and management of shark populations" around the world to prevent their continued depletion.

"Protective measures must be scaled up significantly in order to avoid further depletion and the possible extinction of many shark species in our lifetime," ecologist Boris Worm, who is also part of the study, said.