Oyster sanctuaries in five Chesapeake Bay tributaries selected by Maryland for large-scale restoration projects will get an extra level of protection from commercial harvest under legislation approved in Annapolis this week.

Maryland lawmakers gave final approval Wednesday to a bill that requires legislative approval to alter the sanctuaries where major reef restoration work is either completed, under way or planned. It now goes to Gov. Larry Hogan.The Maryland General Assembly has passed a bill that would bar changing the boundaries of oyster sanctuaries in five Bay tributaries without legislative approval. (Dave Harp)

The bill, backed by the General Assembly’s leadership and by environmental groups, passed the Senate by a vote of 32 to 14. The House had approved it nearly two weeks earlier, 98 to 40.

 Alison Prost, Maryland executive director for the Chesapeake Bay Foundation, issued a statement hailing its passage.

“This legislation is crucial to the recovery of Maryland’s oyster population,” she said, adding that the bivalves are the foundation of the Bay ecosystem. They filter the water, and the reefs they build with their shells provide habitat for fish, crabs and other aquatic creatures.

As part of the Chesapeake Bay Watershed Agreement, Maryland pledged nearly five years ago to restore oyster populations in five of its Bay tributaries by 2025. Restoration is essentially complete in Harris Creek and in various stages of construction or planning in the other four — the Tred Avon, Little Choptank, St. Mary’s and Manokin rivers.

This bill bars any change to the sanctuaries’ boundaries without legislative approval. They were created by regulations issued by the state Department of Natural Resources and are off-limits to commercial harvest. But the DNR could change that by revising the rules, and it has been considering doing so.

The legislation comes in the wake of a scientific assessment finding that Maryland’s stock of market-sized oysters declined by half from 1999 to 2018. The study, conducted by the DNR and the University of Maryland Center for Environmental Science, also found that more than half of the state’s waters open to commercial harvest were being overfished.

Two years ago, lawmakers had blocked a move by the DNR to open some of the state’s oyster sanctuaries to harvest, saying no changes could be made until that stock assessment was complete. The DNR had been responding to appeals from watermen as commercial harvests began to decline after a modest rebound.

A spokeswoman for the governor said he is reviewing the legislation. He has a week to decide whether to sign or veto the bill, or let it become law without his signature. It passed both chambers of the Assembly with veto-proof majorities.

DNR officials unsuccessfully sought amendments to this year’s legislation that would have given them flexibility in setting the five sanctuary boundaries. They noted that watermen and environmentalists participating in the OysterFutures consensus-building process had agreed last year to open up part of the Little Choptank for limited “rotational” harvest every few years.

The measure passed Wednesday prohibits the harvest of any oysters in the restoration sanctuaries, unless they are in areas that the DNR has leased to a private individual for aquaculture. It also bars the removal of any juvenile “seed” oysters that could be transported elsewhere for grow-out to market size. Robert T. Brown, president of the Maryland Watermen’s Association, said he had hoped lawmakers would accept an amendment to open an area in the St. Mary’s River for the removal of seed oysters because it has been used for that purpose in the past.

The legislation further specifies that each tributary’s restoration plan will attempt to bring back more than 50 percent of the restorable oyster habitat there. That provision aims to prevent state natural resources officials from shrinking the scale of restoration in the St. Mary’s and Manokin, which are still in the planning stages. The DNR did downsize the work it had originally planned to do in the Little Choptank, limiting it to just half of the restorable habitat.

The bill also requires that reefs are to be built using substrate that has been proven to maximize oyster density. That provision effectively directs the DNR and its federal agency partners to use granite in building new reefs, supporters say, as surveys have found the highest densities of oysters growing on that material in Harris Creek. Watermen question that and contend that granite reefs interfere with crabbing.

(As originally posted, the story misstated the deadline by which the governor must act on the bill. The Bay Journal regrets the error.)