Taiwan, one of the world's major shark catchers, announced plans on Sunday to tighten measures against hunting the ocean predator for its fin, the island's top fisheries official said Sunday.

Taiwan fishermen are already barred from tossing sharks back into the water to die after slicing off the fin -- a delicacy in Chinese cuisine -- and are required instead to ship back the carcass.

But the measures have failed to stifle criticism from conservationists who say loopholes in the law allow finning to continue.

Under new laws to take effect early next year, it will be an offence to remove a shark's fin onboard a fishing vessel.

"Any violators may be fined, barred from leaving ports, have their catches confiscated or even have their fishing boat licences revoked, depending on how seriously they contravene the measures," Fisheries Agency chief James Sha told AFP.

Sha defended local fishermen, insisting that, unlike their counterparts in Africa and Southeast Asia, they are unlikely to toss the bodies of the sharks into the water as feared by some conservationist groups.

"They have no reason to dump the meat of the sharks as local consumers eat them and they can be sold here at good prices here," he said.

The new measure has been welcomed by the Environmental and Animal Society of Taiwan (EAST), which estimates that up to four million sharks are slaughtered in Taiwan each year.

Environmental groups estimate that up to 73 million sharks are killed each year around the world for fins, leading to declines of up to 90 percent of some species of sharks -- which have plied the oceans since the age of the dinosaurs.

Despite campaigns from activists, demand for shark fins is seen as growing as China becomes increasingly prosperous.