WASHINGTON — The U.S. Department of Commerce declared a disaster for New England’s struggling groundfishing fleet for the 2013 season, opening the door for Congress to appropriate up to $100 million to help fishermen.

The declaration follows recent studies that find stocks of cod and other species are not recovering as quickly as expected despite the industry’s compliance with strict catch limitations. Gov. Paul LePage requested the disaster declaration last November.

“I’ve been in the business over 30 years, and this is the worst I have ever seen it,” said fisherman Tom Casamassa of Saco, one of the few Mainers still fishing for cod, haddock, flounder and other groundfish. Maine is home to just 45 boats in the groundfish fleet, as others have switched to lobster and other species.

“Talking to other fishermen, they are shaking their heads and don’t know what to do. … We’re really glad they moved ahead with the disaster declaration. From the sound of it, New England is really going to need it,” Casamassa said Thursday.

Cod fishing was once the economic backbone of much of New England, including Maine; but overfishing and other factors have depleted cod stocks, resulting in austere catch limits on the relatively few groundfish boats still operating. Now the fleet faces additional reductions of up to 70 percent in the amount of cod and other species they can land.

Many now fear that this once-robust fishery — often credited with helping build New England and Colonial America — is in jeopardy of disappearing. Maine is home to just 45 boats with federal permits, as most fishermen have switched to lobster and other species.

Like many of his colleagues, Casamassa has been forced to branch out into other fisheries such as shrimp, lobster and even dogfish — a kind of “trash fish,” to some — in order to survive. While he used to catch groundfish relatively close to shore, Casamassa now describes water down to 50 fathoms — or 300 feet deep — as “a desert.”

“The future challenges facing the men and women in this industry and the shore-based businesses that support them are daunting, and we want to do everything we can to help them through these difficult times,” Rebecca Blank, acting secretary of the U.S. Department of Commerce, said in a statement.

A statement by U.S. Sens. Olympia Snowe and Susan Collins and U.S. Reps. Mike Michaud and Chellie Pingree says they’re encouraged by the disaster declaration, which acknowledges that Maine’s fishermen are facing new and unprecedented challenges. The delegation’s statement says the declaration is a first step in a long effort to rebuild one of the nation’s first industries.

This is not the first Maine fishery to be granted disaster status, nor is it uncommon nationwide.

In 2010, for instance, shellfish harvesters in Maine were eligible for federal disaster assistance after the Commerce Department, which oversees NOAA, declared that the 2009 outbreak of red tide created a commercial fishing failure. Two other fisheries — salmon in Alaska and oysters and crabs in Mississippi — also were declared disasters on Thursday.

Numerous fishermen’s organizations, including the Maine Coast Fishermen’s Association that Casamassa belongs to, applauded the declaration.

“NSC views federal disaster relief as an important component of a plan for 2013 and beyond,” read a statement from the Northeast Seafood Coalition, whose members hold more than 500 groundfish permits. “It provides fishermen with an essential bridge to the future when fundamental, longer-term solutions can be implemented.”

Meredith Mendelson, deputy commissioner at the Maine Department of Marine Resources, said the declaration is federal acknowledgement that something other than “fishing pressure” is slowing the recovery of fish stocks.

“Fishermen have been staying within their catch limits for several years now,” Mendelson. “So it is not the fault of the industry. There is something else going on in the environment.”

A May report suggested that Gulf of Maine cod populations were at 58 percent of what managers believe are healthy levels, while Georges Bank cod were at 12 percent.

As a result, federal fisheries regulators reduced the quota for 2012 and are expected to slash the catch limits further in 2013 — some by as much as 70 percent from 2012 levels.

A letter from LePage and other governors said the money would be “used to provide both immediate economic relief to our region’s struggling groundfish industry and to make targeted investments that will allow the fleet to survive and become more sustainable in the years ahead.”

Although funding is not guaranteed, U.S. Sen. John Kerry of Massachusetts said Thursday that Senate Majority Leader Harry Reid has committed to include the $100 million for fishermen and fishing communities in emergency assistance legislation. That bill will be debated during the lame-duck session after the election, Kerry said Thursday.

Mendelson said discussions are ongoing about how to use any emergency assistance funding appropriated by Congress.

Options include funding additional research on why groundfish are disappearing, development of new gear to better target specific species or using the money to help offset other costs, such as the amount the industry pays for at-sea catch monitors.

Another option is direct relief payments to fishermen or “buys out” of permit holders.

However, Mendelson said disaster relief for fishermen is not the same as disaster relief for farmers.

“There have been direct payments (to fishermen) in the past, but there is no insurance like crop insurance,” Mendelson said.

Kerry made a similar comparison, saying fishermen are just as dependent on the vagaries of the ecosystem as farmers are and just as deserving of assistance when things go bad through no fault of their own.

“We put billions into the heartland of our country for farmers — billions, literally,” Kerry said. “When you have a massive layoff of an industry like that because of circumstances that are entirely outside the fishing industry’s control, we have to respond as a country.”

Casamassa said he and other fishermen hope money will be used to improve the research and science that guides NOAA catch limits.

“Nobody wants a handout. Everyone wants to fish,” he said in a conference call with reporters organized by the Maine Coast Fishermen’s Association and the Cape Cod Commercial Hook Fishermen’s Association. “There is a problem in the Gulf of Maine ecosystem, and we need to figure it out and to fix it.”

Maine’s congressional delegation, which had supported the state’s pursuit of a disaster declaration, cheered the announcement on Thursday and pledged to continue working to secure funding.

“It is now time for Congress to support this industry by lowering operating costs for this upcoming fishing year and by investing in the resource for the long-term through scientific research to better understand these challenges,” the delegation said in a joint statement. “This declaration is a first step in a long effort to rebuild one of our nation’s first industries.”