AP PHOTO BY PAT WELLENBACH Red fish are stacked at a fish broker in Portland on Monday. Federal regulators have issued a new set of commercial fishing regulations that they say will relieve pressure on fish populations in the Northeast while allowing the fishing industry to survive.

PORTLAND, Maine — Federal regulators on Monday issued a new set of commercial fishing regulations they say will relieve pressure on fish populations in New England waters while allowing the fishing industry to survive.

The new rules will mean a 9 percent reduction in total fishing revenue for the region, according to the National Marine Fisheries Service. That’s less than half the cut that would have resulted had a measure proposed in January been approved.

The rules, which go into effect May 1, take into account concerns for troubled fish stocks as well as the economic realities of the troubled fishing industry, said National Oceanic and Atmospheric Administration Administrator Jane Lubchenco.

“This final rule is a compromise,” she said. “It’s a compromise of the economic situation facing fishing families while retaining real conservation benefits.”

The new rules aim to relieve pressure on populations of cod, flounder and other bottom-dwelling fish in waters primarily off New England. They are intended to be an interim measure until regulators develop a broad new set of rules, scheduled to go into effect May 1, 2010.

Conservation groups have said severe cuts are needed to help depleted stocks. But fishermen have warned that regulations proposed in January — rules that would have slashed their fishing time by 50 percent or more — could have driven them out of business.

The final regulations are still painful for many fishing sectors.

For instance, they enlarge the fishing area in waters off southern New England, where each fishing day at sea is counted as two days against a vessel’s allotment. They also put catch limits on certain species and prohibit southern New England vessels from keeping certain types of flounder they catch in their region.

In the end, they result in an 18 percent reduction in how much time fishermen can spend at sea.

But the rules also cushion the blow for some fishermen. They abandon a plan to expand an area in the Gulf of Maine where fishermen would have their allowable fishing time cut. They also decrease the minimum size of haddock, thereby allowing more to be caught.

In all, the regulations will result in an estimated loss of $17.4 million in fishing revenues, Lubchenco said.

“The rule will impact each vessel differently depending on where they fish, what gear they use and other factors,” she said.

The rules are an improvement for fishermen in the Gulf of Maine, but not necessarily so for those in southern New England, said Maggie Raymond of South Berwick. Raymond and her husband own a fishing boat based in Boston.

“While we’re relieved some changes were made, nobody’s getting off easy because there’s going to be a significant economic impact on fishermen and fishing communities,” she said.

At the Portland Fish Exchange, where 70 fishing boats brought their catch last year, general manager Bert Jongerden said some fishermen will throw up their hands in disgust at the rules, while others will be thankful.

“You’ll still see boats going out of business. You’ll still see shoreside businesses going out of business,” he said. “We’re being regulated to death here.”

Peter Shelley, vice president of Boston-based Conservation Law Foundation, said he has mixed feelings about the regulations. They offer less protection to fish populations, he said, but they represent a step forward toward the next regulatory regime that is being developed by the regional New England Fishery Management Council.

“We’re willing to take a bit of a hit on these fish stocks if the council delivers,” Shelley said. “That’s an open question.”