AUGUSTA — Republican Gov. Paul LePage expressed his disapproval of a proposal to designate areas within the Gulf of Maine as a Marine National Monument.

LePage on Friday sent two letters to President Barack Obama and Maine’s U.S. congressional delegation regarding separate proposals for monuments that LePage said will have a negative effect on Maine people.

The president has authority to establish National Monuments under the federal Antiquities Act.

This specific proposal for the Gulf of Maine would designate Cashes Ledge and undersea canyons and seamounts as a Marine National Monument, according to a statement from LePage’s office.

The change, according to the statement, would affect fishermen from a variety of sectors, including those for offshore lobster, tuna, herring and groundfish.

“Maine’s economy is heavily dependent on natural resources-based industries and these types of designations harm working Mainers the most,” LePage wrote. “These National Maritime Monuments [sic] serve only one purpose — excluding commercial fishing activity from certain segments of the ocean.”

LePage is also asking Obama for more information about any possible time line for the designation.

In a separate letter to Maine’s U.S. congressional delegation, LePage reiterated his concerns, including that a proposal for new federal park in northern Maine could also be turned into a national monument by the president.

“I am hearing more and more that national park proponents are considering seeking a National Monument designation after their proposal was defeated at the polls in Medway and East Millinocket,” LePage wrote. “A National Monument designation makes Maine timber off limits to the forest products industry. As you all know, so much of Maine’s economy relies on access to our natural resources. The president’s authority under the Antiquities Act puts Mainers at risk by making these natural resources off limits.”

LePage is asking Maine’s federal lawmakers to oppose the designations and to take the initiative to reform the Antiquities Act.