Several members of Congress representing coastal states, as well as Gov. Neil Abercrombie, are voicing concern about a proposed federal regulation that could pre-empt state bans on buying or selling shark fins.

Democratic Rep. Jared Huffman of California has been joined by representatives of New York, Florida and Guam in seeking changes to a proposal they say would take away a state tool to protect shark populations.

California, Hawaii, New York and several other states have passed regulations on the sale and trade of shark fins, which are used in a soup considered an Asian delicacy. California’s ban on the sale, trade and possession of shark fins will go into effect Monday.

A letter from the representatives and the delegate from Guam states that a proposed rule by the National Oceanic and Atmospheric Administration’s fisheries management division, the National Marine Fisheries Services, would undermine those laws.

The proposal says state and territory shark fin laws are pre-empted if they are found to be inconsistent with federal fishery management plans or regulations.

Conservation and animal-welfare groups have begun circulating petitions against the proposal, but representatives of the fishing industry have argued that federal pre-emption is necessary to maintain fishing of commercially viable shark species.

Congress passed and President Barack Obama signed the Shark Conservation Act of 2010 in an effort to strengthen federal laws against shark finning in U.S. waters and require that sharks be landed with their fins still attached. Since then the fisheries service has been crafting regulations to implement the act.

Conservation and animal advocacy groups said fishermen have been able to sidestep the rules by taking only the fins of sharks and dumping the carcasses back into the sea.

Jill Hepp, director of shark conservation at The Pew Charitable Trusts, said states should have the right to go beyond federal rules in protecting shark populations.

"If this goes forward as they are proposing, this has the potential to undermine the states’ shark fin trade ban, and it would be a considerable setback for global shark conservation," Hepp said.

State Sen. Clayton Hee, who wrote the bill that made the 50th state the first to ban the possession, sale and distribution of shark fins, said Friday that the changes would benefit corporations outside the United States involved in the trade. Hee said he can’t think of another incentive for the rule changes unless the agencies are arguing that there are too many sharks in the ocean.

"It’s baffling to me why a government agency would work to rid the ocean of its health by taking sharks," Hee said.

Abercrombie said the state’s law must be preserved.

"This model legislation symbolizes Hawaii’s concern for the welfare of all creatures," he said. "We oppose federal pre-emption of the Hawaii law. Our law is working as intended. We have educated fishers and restaurants, and they are complying."

A group representing Pacific island legislatures, including Hawaii’s, passed a resolution earlier this week asking a federal agency to respect its efforts to protect sharks.

The Association of Pacific Island Legislatures, meeting at the state Capitol on Thursday, also called upon the National Marine Fisheries Service not to pre-empt the Hawaii law.

About 26 million to 70 million sharks are caught worldwide per year, according to the Western Pacific Regional Fishery Management Council.

The deadline for comment on the proposed federal rules is July 8. Written comments may be submitted to the National Marine Fisheries Service, NOAA, Attn. Kim Marshal, 1315 East-West Highway, Silver Spring, MD 20910; by fax to 301-713-1193; or at regulations.gov. More information can be viewed at www.gpo.gov/fdsys/pkg/FR-2013-05-02/html/2013-10439.htm.