Federal ocean regulators say a new fishing plan has a chance to rebuild the New England cod stock, which is a goal even many commercial fishermen have long regarded as far fetched. Atlantic cod were once a cornerstone of the New England economy, but the catch has plummeted after years of overfishing, environmental changes and restrictive quotas. Most of the cod sold in the U.S. comes from overseas because many American fishermen avoid the fish-and-chips staple altogether.