PORTLAND – For the second time in little more than a decade, Nabisco has halted production of its Crown Pilot Crackers, the hard, rectangular biscuits that generations of New Englanders loved to crumble into seafood chowder.

Without disclosing specific figures, the manufacturer said sales of the regional brand had declined sharply to the point where they were half of what they were about a decade ago.

“I realize this is disappointing to consumers, and it was definitely a difficult business decision to make,” said Laurie Guzzinati of Kraft Foods, which bought Nabisco in 2000.

Among those rattled by the decision was Donna Damon of Chebeague Island. In 1996 she spearheaded what proved to be a successful campaign to get Nabisco to bring back Crown Pilot Crackers after it stopped making them as part of a worldwide restructuring to shed niche brands and streamline operations.

Damon learned of Nabisco’s latest decision when she called the company Thursday to find out why she and other pilot cracker lovers had been having trouble finding the product in stores. As soon as she got the news, Damon began urging people who miss the biscuits to complain to the company.

The large crackers, known generically as ship’s bread or hardtack, have been a staple along the New England coast and were first made commercially in 1792 by a Newburyport, Mass., company that became part of the National Biscuit Co., or Nabisco, in 1898.

When Nabisco brought back Crown Pilot Crackers in 1997, it marked the brand’s revival by inviting its fans to join in celebrations aboard a boat that stopped in Boston, Gloucester, Mass., and Portland.

Production ceased just recently, according to Guzzinati, so there might still be some boxes in warehouses.