Maine is making it more difficult to fish for smelts in an effort to help the fish rebuild populations that have plummeted in the state and elsewhere in New England.

A Maine advisory committee unanimously decided Tuesday the state will enact the new regulations to protect the declining populations of the fish. Spawning runs have declined by more than 50 percent compared to the late 1970s and early 1980s, state officials said.

The new rules divide the state into three smelt management zones, with the strictest rules on the southern coast. The rules mean no smelt fishing in the southern part of Maine from March 15 to June 30. The tighter restrictions are meant to counteract a loss of smelt range that has “occurred rapidly, in less than 100 years with a pronounced population reduction in the past 20 years,” state records say.

Smelts are popular in Maine among winter ice fishermen, who flock to smelt camps where fishing shacks line rivers and coastal streams; and as a battered fried treat. They are traditionally fished through the ice in winter and with dip nets in spring, when they are spawning. But state officials shut down spring smelt fishing on the southern half of the coast last year.

The new rule proposal was unpopular among some fishermen and proprietors of smelt camps. Sharon James, who works at the James Eddy Smelt Camps in Dresden, said she would prefer the rules stay the way they are.

“We had a bad year last year, really bad. This year we’ve done pretty well, and from everything I’ve seen over the years, smelts run in cycles,” James said.

The new rules impose a one-quart daily limit on the middle of Maine’s coast and a two-quart daily limit on the eastern coast from March 15 to June 30. The southern and middle coast areas will also have four-quart daily limits for the rest of the year starting Dec. 1.