The Maryland Senate today tentatively approved a controversial effort to limit development along the Chesapeake Bay after Eastern Shore senators opposing it abandoned their attempt to delay action on the bill.

Instead of fighting the overwhelming support for the regulatory package proposed by the Chesapeake Bay Critical Areas Commission, the Eastern Shore representatives said they were maneuvering to secure approval of a separate measure that could open loopholes in the commission bill.

The commission bill is a compilation of land-use restrictions designed to protect the bay from more pollution. It passed today in a 41-to-5 roll call vote that is unusual for a preliminary vote. Roll call votes usually are reserved for final passage of the measure.

That vote came after extended debate and a brief attempt at a filibuster led by Eastern Shore Sens. Frederick C. Malkus (D) and Walter M. Baker (D).

"You're going to jam it down our throats," Malkus said of the new regulations in an emotional speech on the Senate floor. "You want us to revert back to wilderness."

Opponents of the proposed regulations have argued that Eastern Shore counties, which contain most of the state's bay shoreline, would be unfairly penalized for pollution that is created upstream in industrial areas such as Baltimore. Desired new development, they also argue, would be severely restricted under the proposals.

Baker and two Eastern Shore representatives in the House of Delegates, Clayton Mitchell and Daniel Long, have introduced bills they hope will blunt the effect of the new regulations and allow denser development in undeveloped "resource conservation areas."

Under the regulations drafted by the Critical Areas Commission, building would be limited in such areas to one house every 20 acres. Baker, Mitchell and Long would lift that restriction, in certain instances, to allow one house to be built on every eight acres.

Senate President Melvin A. Steinberg (D-Baltimore County), who ended Baker's filibuster attempt today by threatening to cancel hearings that had been scheduled for this afternoon on the bills sponsored by the Eastern Shore senators, said that the density control bill might have some merit.

"If they come up with the proper language, I'm willing to listen," Steinberg said.

"One [dwelling] per acre is a reasonable approach," said Sen. John C. Coolahan (D-Baltimore County). "And it won't invalidate the Chesapeake Bay regulations."

Administration officials, including Torrey C. Brown, secretary of the Department of Natural Resources, and Solomon Liss, chairman of the Critical Areas Commission, decried the bills by Eastern Shore senators as harmful.

"It's not the kind of [plan] you ought to weaken before you start," Brown said.

Liss, in testimony before the Senate Economic and Environmental Affairs Committee, said that the Eastern Shore bills would undercut the work of the bay commission. "To approve the criteria in the morning and even suggest making changes in the criteria in the afternoon is an attempt to gut the criteria and do by indirection what you could not do by direction."