Wayne Pacelle is president and chief executive of the Humane Society of the United States. He blogs at humanesociety.org/waynepacelle.

The Shark Conservation Act of 2010 was designed as a statutory shield to protect the world’s troubled shark populations. Any sensible person would deduce this.

Few could have anticipated, however, that the National Marine Fisheries Service would pervert the act and use it as a regulatory spear against millions of sharks, against conservation and against common sense.

Apparently for the benefit of a few noisy interests, the fisheries service has proposed a rule to implement the legislation in a way that would preempt state and territory laws prohibiting the sale of shark fins — an ingredient in a few insipid and ecologically disastrous products such as shark fin soup. The federal government does not regulate such sales activity — nor does it intend to — so the rule would effectively nullify state laws that would reduce demand for shark fin products in this country.

My head spins.

Millions of Americans understand two important facts:

First, apex predators, including sharks, are vital to maintaining the balance and health of the world’s oceans and our coastal ecosystems. There is no credible argument to the contrary.

Second, world populations of sharks are in precipitous decline. One-third of the 468 species are in danger of extinction.

Why are shark populations in such deep trouble? Soup is one of the big reasons, as well as the cause of unbelievable suffering. A shark is caught in the open ocean, its fins are sliced off and the suffering animal is thrown, alive, back into the water. Here is what 11-year-old Sawyer Chandler of Texas says about the process on her anti-finning Web site:

“Imagine, sinking deeper and deeper into the sea just waiting to be eaten, bleed to death, or hit the very bottom and not have water flowing through your gills and drown. Is that ok?”

No, it is not.

The National Marine Fisheries Service can’t really believe that nullifying state laws to stop this sort of wanton cruelty is acceptable.

Eight states have banned the sale of shark fins: California, Delaware, Hawaii, Illinois, Maryland, New York, Oregon and Washington. (So, far, 914 state legislators have voted in favor of the fin bans and only 87 against.) The same policy is in place in all three U.S. Pacific territories: American Samoa, the Commonwealth of Northern Mariana Islands and Guam. Moreover, in recognition of the plight of sharks and the wastefulness of finning, the practice is prohibited in state and federal offshore waters.

Together, these measures save the lives of countless sharks. The United States is second only to Asia as an importer of shark fins. Almost 90 percent of the fins that enter this country come through dealers in Hong Kong, where fins from finned sharks, illegal fisheries and endangered shark species are laundered.

Bolder action is needed. Other large states, including Florida and Texas, should lead by enacting prohibitions similar to those in California, Illinois and New York.

And the Obama administration needs to immediately change course and use the Shark Conservation Act as Congress intended: to complement state and territory laws, not to kill them off. The Justice Department, at the request of the fisheries service, recently weighed in against state laws in a pending court case involving California’s landmark ban. If ever there were a tone-deaf case of federal overreaching, this is it.

About the only argument on behalf of finning, thin as thin can be, is that it has cultural roots in Asian weddings and other celebratory occasions and therefore should be allowed to continue. It is notable that California’s shark fin ban was co-authored by Paul Fong, a Chinese American member of the state assembly from Cupertino. The New York law was sponsored by Grace Meng when she was a representative from Queens. She, too, is of Chinese descent.

The fact is, prohibitions on shark finning have broad support among people of all ethnicities and nationalities — and it’s time for new traditions when it comes to human dealings with sharks. If we have our wits about us, we should leave their fins intact.