President Obama will designate a section of the Atlantic Ocean off Cape Cod on Thursday as a national monument, banning commercial fishing in the area by 2023 in an effort to protect the region’s ecosystem.
The move, which the president will formally announce at the Third Annual Our Ocean Conference in Washington, won praise Wednesday from environmental groups but drew condemnation from the fishing industry.
Obama administration officials said the designation will create the first marine national monument in the Atlantic. The protected area, dubbed the Northeast Canyons and Seamounts Marine National Monument, is located approximately 130 miles off the southeast coast of the Cape.
It comprises 4,913 square miles and includes three underwater canyons deeper than the Grand Canyon, four underwater mountains known as seamounts, and many rare and endangered species such as sei whales and Kemp’s ridley turtles, administration officials said.
Under terms of the designation, red crab and lobster fisheries will have a seven-year grace period before they have to exit the monument area, and other commercial fishing operators will have 60 days to leave.
“The Northeast Canyons and Seamounts Marine National Monument will preserve an unspoiled underwater ecosystem and help protect deepwater corals and endangered marine animals,” Secretary of State John F. Kerry said in a statement, noting that the announcement follows Obama’s expansion last month of the Papahanaumokuakea Marine National Monument in the Pacific.
In announcing that expansion, the administration cited the federal Antiquities Act, which it said allowed the president to take the action.
But on Wednesday, the Southern Georges Bank Coalition, which has representatives from local fisheries and industry groups including the Massachusetts Lobstermen’s Association, criticized the new designation off the Cape.
In a letter to Christina W. Goldfuss of the White House Council on Environmental Quality, attorneys for the coalition wrote that “millions of dollars of lost revenue are at stake” for local fisheries, and they questioned the legality of the move.
The coalition’s attorneys said the Antiquities Act “does not allow for designation of any part of the water column as a monument.”
A separate statute “granted regional fishery management councils authority over fishery management activities,” they said.
The letter said the New England Fishery Management Council, which regulates commercial fishing in the region is taking steps to protect deep sea areas using “public transparent processes prescribed in detail by law.”
Environmental advocates, however, lauded the president’s action.
“From valleys deeper than the Grand Canyon, to peaks as high as Mount Washington, to the hundreds of diverse and endangered species that call this place home, the Northeast Canyons and Seamounts is the embodiment of a treasure worthy of such permanent protection,” Bradley Campbell of the Conservation Law Foundation, said in a statement.
Administration officials said that a study from the National Oceanic Atmospheric Administration showed waters in the Northeast are projected to rise three times faster than the global average.
In addition, officials said, climate change is threatening fish stocks in the region — such as salmon, lobster, and scallops — and the monument will provide a refuge for at-risk species.
The administration said it will support the local fishing industry and build on existing programs including low-interest loans for vessel rehabilitation, acquiring new boats, and gear repair, as well as programs aimed at reducing costs for fishermen.
Some elected officials in Massachusetts have raised concerns about the plan, including Mayor Jon Mitchell of New Bedford, whose city is home to a commercial fishing port.
Last month, Mitchell wrote a letter to the administration outlining “serious concerns about the impact a monument would have on the commercial fishing industry here in New Bedford” and across the region.
In a statement Wednesday, Mitchell, a Democrat, said the designation “presents a challenge to certain elements of the commercial fishing industry in the Northeast.”
“While I believe the industry generally was in a position to manage the implications of the so-called ‘sea mount’ area of the monument, the inclusion of the ‘canyons’ area would have benefited from more industry input,” Mitchell said, adding that “these types of decisions should be subjected to the more robust regulatory processes under the Magnuson-Stevens Act, which has successfully led to the protection of sea canyons . . . without unduly burdening the commercial fishing industry.”
His concerns were echoed by Senator Edward J. Markey, who called the president’s action an “important milestone” for conservation but said he was “concerned that the impacts of this marine monument designation on the fishing community in New England were not fully minimized.”
Markey thanked the administration for the seven-year grace period for red crabs and lobster boats and said “great challenges remain for fishermen, lobstermen, and the shoreside companies that work with them. . . . I thank President Obama for his effort to protect this unique area and urge him to continue to work with all stakeholders in support of a thriving fishing industry.”
A spokesman for Governor Charlie Baker said in a statement that the “administration is deeply disappointed by the federal government’s unilateral decision to undermine the Commonwealth’s commercial and recreational fishermen with this designation.”
Michael Levenson of the Globe staff contributed to this report.