BOSTON – New England fishery managers have defied a congressional mandate to rebuild fish stocks, a federal judge ruled in a decision likely to lead to more severe restrictions on fishermen.

U.S. District Court judge Gladys Kessler, citing the government’s “record of inaction and delay,” agreed with conservation groups who sued the government, charging that regulators didn’t follow laws to restore depleted groundfish stocks, such as cod and flounder.

Last Friday’s ruling in U.S. District Court in Washington was released Wednesday. The suit was filed by Oceana, a Washington-based conservation group, on behalf the Conservation Law Foundation and several environmental groups.

Federal managers will meet with the plaintiffs Jan. 25 to discuss how to rebuild depleted stocks, as required by the Sustainable Fisheries Act of 1996.

That almost certainly means more restrictions, with stricter quotas, trip fishing limits and area closures among the many options.

“It would appear to me that no action is really not an option,” said Teri Frady of the National Marine Fisheries Service, which regulates New England fisheries.

Fishermen, who complain that they already are crippled by existing restrictions, say the ruling will drive more small-boat fishermen out of business, even as groundfish stocks rebound.

“It’s another nail in the coffin,” said Gloucester fisherman Russell Sherman. “It makes me sick.”

“What does this judge know about fishing?” said Bob MacKinnon, president of the Massachusetts Bay Inshore Commercial Groundfishermen’s Association, based in Marshfield. “It’s disastrous.”

Attorney Eric Bilsky of Oceana said “short-term pain” for fisherman may be necessary to correct the devastation of overfishing. Everyone will benefit in the long run, he said.

“We do have to pay for what we’ve been doing and set things right,” he said.

“The [fishing] industry … must take some if not a large part of the responsibility for the mismanagement that’s been occurring,” Bilsky added.

The plaintiffs alleged the NMFS didn’t act to adequately prevent overfishing or decrease bycatch – fish unintentionally caught and discarded – on 12 depleted stocks.

The Sustainable Fisheries Act requires fish populations to be rebuilt to levels where a “maximum sustainable yield” – the most fish that can be caught without hurting the stock – can be caught on a continuing basis.

The act set a deadline of November 1999 to have necessary rules in place. Regulators concede they didn’t meet the deadline, adding that the process is slow because it requires consensus from varied interests.

“The council has been very deliberative, maybe too deliberative,” said Patricia Fiorelli, spokeswoman for the New England Fishery Management Council, which proposes rules to NMFS.

The plaintiffs also charged federal managers with breaking the law by failing to devise ways to accurately report and minimize bycatch.

Kessler ruled that “by keeping intact the status quo, Defendants refuse to give effect to the clear will of Congress. … Therefore, the Court concludes the Defendants acted arbitrarily, capriciously and contrary to law.”

Frady said that though it hasn’t met federal deadlines, the NMFS is on track to reach 10-year goals for rebuilding battered groundfish stocks. Haddock and flounder have seen rebounds, and a July report said spawning cod in the Gulf of Maine increased from about 10,000 metric tons in 1998 to 23,000 in 2001, a 130 percent increase.