As a consequence of industrial and agricultural development, most of the runs native to New England have been extirpated. Self-supporting runs of Atlantic salmon in the United States now persist only in eastern Maine. Restoration and rehabilitation efforts, in the form of stocking and fish passage construction, are underway in the Connecticut, Pawcatuck, Merrimack, Penobscot, and eastern Maine rivers of New England. Atlantic salmon life history is extremely complex owing to its use of both freshwater and marine habitats and long ocean migrations. Atlantic salmon spawn in freshwater during fall.
Eggs remain in gravel substrates and hatch during winter, and fry emerge in spring.
Juvenile salmon, commonly called parr, remain in freshwater two to three years in New England rivers depending on growth. Tagging data for New England stocks indicate that young salmon migrate as far north as the Labrador Sea during their first summer in the ocean. Those remaining at sea feed in the coastal waters of Canada, mostly Newfoundland and Labrador, and West Greenland. Historically, it has been in these foraging areas that commercial gillnet fisheries for salmon occurred. After their second winter at sea, most U.S. salmon return home to spawn.