WASHINGTON — Fishermen and charter boat captains from Maine to Louisiana rallied outside the Capitol Wednesday to demand changes to federal fishing limits they say are putting them out of business.

Participants in the ”United We Fish” rally want to loosen federal catch restrictions imposed to protect vulnerable fish stocks.

Bryan Lowery, who fishes for scallops near Ocean City, Md., said the rules are particularly frustrating now because scallops are so plentiful. Yet instead of his usual 100 fishing trips, Lowery said he expects to take just nine this year.

”They’ve just put us out of business,” Lowery said, referring to the National Marine Fisheries Service, which enforces the fisheries law.

Similar complaints came from cod fishermen from Massachusetts and from those who fish for red snapper in the Carolinas. In Gloucester, Mass., ”you can walk on the cod,” said Mayor Carolyn Kirk, one of the speakers at the lunchtime rally, which drew at least 2,000 people.

”This is all about families. This is all about jobs. This is all about all of us trying to survive,” said Bob Zales of Panama City, Fla., a rally organizer.

Jim Hutchinson Jr. of the Recreational Fishing Alliance said the law sets unrealistic recovery goals based on flawed science.

A federal official defended the law, saying it imposes science-based, annual catch limits to protect vulnerable fish.

”Ending overfishing is the first step to allowing a fish stock population to rebuild to a level where the stock can be fished sustainably for the long term,” said Eric Schwaab, assistant administrator for fisheries at the National Oceanic and Atmospheric Administration.