A group of New York legislators on Tuesday unveiled a draft law banning trade in shark fins, saying the practice, which serves the market for Chinese shark fin soup, was decimating the ocean predators.

If enacted, New York would join California, Hawaii, Oregon and Washington as US states outlawing the sale, possession and trade in the fins, which fishermen slice off, often before tossing the rest of the much less valuable shark back in the water.

"The decimation of the shark population is a serious concern as it has a detrimental trickle-down effect for the entire oceanic food chain," New York state senator Mark Grisanti said in a statement.

"With the shark population in serious peril, and other countries and states passing legislation to protect sharks, New York should be a leader in extending protection to these magnificent animals," he said.

"Action to ban the barbaric practice of shark fining is long overdue," said state assembly member Alan Maisel. "Sharks occupy the top of the marine food chain and are a critical part of the ocean ecosystem."

Maisel said he hoped ultimately for a nationwide ban on the trade.

Last week, President Barack Obama was criticized by environmentalists for getting take-out from a Chinese restaurant in San Francisco that has shark fin soup on the menu. The White House said he had not ordered the soup.

Environmentalists say that tens of millions of sharks are killed each year as fishermen slice off their fins for dinner tables, leaving them to die in the water. Sharks have few offspring, compounding risks to their survival.

The United States banned finning in its waters in 2000. Obama in January 2011 signed the Shark Conservation Act that toughened regulations by banning imports of fins that are not attached to corresponding shark carcasses.

Michael Hirshfield, chief scientist with Oceana, which is campaigning for the protection of sharks, said demand for the delicacy was "responsible for the slaughter of these magnificent creatures so essential to the health of our oceans."

"Oceans without sharks are oceans out of balance, which means trouble for everyone who depends on oceans for food, jobs and enjoyment," he said.

Marie Levine, executive director of the Shark Research Institute compared the practice to mutilating other animals.

"If we found dogs and horses with their legs severed, bleeding and dying, the public outrage would be deafening. The difference is that finning takes place at sea, out of sight," she said.