In some circles, shark fin soup is said to connote wealth and generosity. It's supposed to be lucky, too.

Unless you're the shark.

Shark fins can cost more than $350 a pound, a powerful lure for fishermen. By conservative estimates, at least 25 million sharks are killed each year for their fins. Some researchers say the number is 73 million or more. Fishermen often slice the fins off live sharks and leave the crippled fish to drown.

The practice of finning is not only cruel, researchers say it's contributing to an accelerating decline in the global population of sharks, with a ripple effect on other sea life.

There is some evidence that consumption of shark fin soup is declining as more people learn about finning. At least two airlines have stopped accepting shark fins as cargo, according to the Bloomberg news service, and several others are reviewing their policies.

More needs to be done. And with conservation groups focusing attention on finning, eight states and three U.S. territories have enacted laws to protect sharks. Here in California, a ban on the sale or trade of shark fins took effect on July 1, having survived legal challenges.

Less than two weeks later, however, federal regulators may be on the verge of undermining laws in California and other states.

What's truly inexplicable is the regulators' stated purpose is to implement a law passed by Congress in 2010 with the intent of preventing finning in U.S. waters. The federal law requires that sharks be landed with their fins attached but, as conservation groups point out, that leaves ample room for finning. Moreover, the law doesn't address imported fins, a commodity that has been covered by the state and territorial statutes.

At issue now is a rule under consideration by the National Oceanic and Atmospheric Administration. The proposed rule says state and territorial shark fin laws are pre-empted if they are found to be inconsistent with federal fishery management plans or regulations. That could block efforts to stop the trade in shark fins or, at a minimum, tie them up in court.

More than 60 members of Congress, a bipartisan group including North Coast Rep. Jared Huffman, signed a letter asking the agency to revise the rule. "The practice of cutting the fins off of living sharks and dumping them back in the ocean is not only cruel but unsustainable and incredibly wasteful," said Huffman, D-San Rafael, a cosponsor of California's law.

Sharks evoke both fear and fascination — the stalker of Peter Benchley's "Jaws," the sharp-toothed predator near the top of the ocean's food chain. Yet nearly a third of shark species are at risk of extinction. With their decline, species hunted by sharks experience population growth, with potentially devastating impacts on smaller fish, including some relied on by humans for food. In short, there's a relationship between a healthy shark population and healthy oceans.

At a time when Congress and state legislators are acting to preserve these animals, there's no place for a regulation that could instead preserve the barbaric practice of finning, in turn further threatening the species. Acting NOAA administrator Kathryn Sullivan should sink this rule and start over.