Almost 100 million sharks are being killed each year, with fishing rates outstripping the ability of populations to recover, scientists have estimated.
Sharks need better protection to prevent possible extinction of many species within coming decades, the researchers warned ahead of the latest global meeting to discuss the trade in threatened species.
The Convention on International Trade in Endangered Species (Cites) meeting will consider greater protection of vulnerable sharks, including porbeagles, oceanic whitetip and three types of hammerhead to prevent unsustainable international trade in them.
Sharks are targeted for their fins for use in shark fin soup, a delicacy in Asia. But as species which are slow growing and slow to reproduce, they are vulnerable to over-fishing.
The researchers estimated that global reported catches, unreported landings, discards and sharks caught and thrown back after their fins were cut off - a process known as finning - added up to 97 million fish caught in 2010.
The figure is only slightly down on the estimated 100 million caught in 2000, and could be anywhere between 63 million sharks and 273 million a year, said the research by North American scientists published in the journal Marine Policy. It is estimated between 6.4% and 7.9% of all sharks are being killed each year, leading to declines in several species.
Lead author Boris Worm, from Dalhousie University in Halifax, said: "Biologically, sharks simply can't keep up with the current rate of exploitation and demand. Protective measures must be scaled up significantly in order to avoid further depletion and the possible extinction of many sharks species in our lifetime."
Although some regions, including the European Union, have banned shark finning, commercial fisheries for fins, meat, liver oil, cartilage and other body parts is largely unregulated in much of the world, conservationists warn.
Under the proposals put forward for consideration by the Cites meeting, five shark species would be listed as Appendix II which would ensure that any international trade in them is sustainable and legal.
Environment Minister Richard Benyon said: "We want to see better protection for sharks and will be pushing for this strongly at Cites next week. I am keen to see trade controls introduced for vulnerable and endangered species like porbeagle, hammerhead and oceanic whitetip sharks and manta rays."