The Maine Department of Marine Resources said Tuesday it will close a seven-square-mile area at the mouth of the Penobscot River to the harvesting of lobsters and crabs because “mercury contamination” has been found in lobsters there.

The closure will last a minimum of two years, according to a news release issued by Marine Resources Commissioner Patrick Keliher.

Keliher said the closure will take effect Saturday and will extend from Wilson Point, just north of Castine Village, across to Fort Point in Stockton Springs and north into the Penobscot River.

“This closure is being taken as a precautionary measure in response to information the Department of Marine Resources recently received about mercury contamination in muscle tissue from lobsters found in this area,” Keliher said in a statement.

The Department of Marine Resources said it became aware of the mercury levels in lobsters in November after it examined findings from a federal court-ordered study. State Toxicologist Andrew Smith was asked to do the analysis.

The Department of Marine Resources said it historically has relied on data collected by the U.S. Environmental Protection Agency’s Coastal Condition Assessment, which did its last study of Maine lobsters in 2010. That study did not detect mercury levels that exceeded safe consumption standards.

State officials said the new information came to light as the result of the court-ordered study, which stemmed from a federal lawsuit filed by the Maine People’s Alliance and the Natural Resources Defense Council against Mallinckrodt Inc.

The mercury that was found in lobsters from the study is believed to have come from the former HoltraChem plant in Orrington, which is just north of Bucksport, according to a report Tuesday in The Working Waterfront, a newspaper published by the Island Institute in Rockland.

The Working Waterfront said lobster and other marine creatures were tested as part of an ongoing lawsuit filed against Mallinckrodt, the current owner of the plant.

Environmentalists have said for years that HoltraChem dumped mercury into the river for years. The plant operated from 1967 to 2000.

After consulting with Smith, the Department of Marine Resources opted to implement what it described as a “discrete closure to ensure that no lobsters from this area make it into the marketplace.”

State officials point out that the seven-square-mile area is a small segment of the more than 14,000 square miles in the Gulf of Maine where lobsters are harvested.

“We chose to close this small area to harvesting for both commercial and recreational fishermen as a precautionary approach that protects public health and ensures consumer confidence that eating Maine lobster is safe and healthy,” Keliher said.

The commissioner said the two-year moratorium will give the state the time it needs to monitor mercury levels and develop its own data.

The Maine Marine Patrol will work with harvesters to ensure that all gear is removed from the area as soon as possible. The state said most local commercial harvesters have either stopped for the season or moved their operations down the bay.

In two years, the state will decide whether to reopen the area or continue the closure.