Maryland officials are expected today to relax regulations and allow harvesting of smaller crabs, reversing action taken last year to give the crustaceans a chance to rebound from over-crabbing and the declining health of the waters where they live.

The action, which would have to be ratified by a House of Delegates committee, is the first environmental initiative by the administration of Gov. Robert L. Ehrlich Jr. (R). It is being hailed by watermen as a new era in which the economic interests of the crabbing industry are being considered for the first time in a decade.

Environmental groups, though, questioned the wisdom of the move, particularly because there have been no signs that the stock of crabs is increasing.

Natural Resources Secretary C. Ronald Franks is expected to announce that he will decrease the minimum catch size of hard crabs to 5 inches and so-called peeler crabs, which are about to shed their shells, to 3 inches. That reverses a decision last year that required hard crabs to be at least 51/4 inches from one tip of the carapace to the other; peelers, 31/2 inches; and soft-shell crabs, which have already shed their shells, 3 inches.

State officials declined to confirm details of the announcement. But watermen and environmentalists said they were told that the rollbacks would still keep the state within the range of the harvest reductions it initiated to prevent the crab population from crashing.

Maryland Watermen's Association President Larry Simns said the changes will help watermen at the beginning of the year, when crabs are small to begin with.

"They get more money for crabs at the first of the year, so that helps them, too," he said. "The governor worked hard to try to give watermen what they wanted without decimating the crab stocks. We think this does this and still protects the resource."

Chesapeake Bay Foundation officials, however, said the new regulations, which would go into effect when the season starts April 1, go too far in easing restrictions.

Theresa Pierno, the Maryland director of the foundation, said Franks's deputy, Pete Jensen, called to invite her to today's announcement at the City Dock of Annapolis, but she declined.

"It's a weakening of our crab regulations at a time when we should be erring on the side of caution," she said.

Winter dredge surveys of hibernating crabs showed no improvement in the size of reproduction-age stocks, she said. Maryland committed three years ago to reduce harvest pressure by 15 percent and leave more crabs to breed.

The regulations put in place last year had brought the state to that goal, Pierno said. Rolling them back this year -- even if it is only until Aug. 1, as the state is expected to propose -- puts Maryland at risk of failing to meet its harvest reduction goals.

"Realistically, there is no science they can point to that suggests this is the right thing to do at this time," Pierno said.

Virginia regulators have imposed no new rules this year to reduce harvests in its waters of the bay.