The Atlantic Salmon was proposed to be threatened on September 29, 1995. They are decreasing and the current estimated population is approximately 160 adults. They live in one distinct population segment that composed of 7 rivers. The rivers are in Maine: Sheepscot, Duck Trap, Narraguagas, Pleasant, Machias, East Machias, and Dennys Rivers.
The original range of Atlantic Salmon in the United States was from the Housatonic River in Connecticut, north to the tributaries of the St. John River in New Brunswick, Canada. The historic Atlantic Salmon in the United States had been estimated to have approached 500,000 fishes which began to disappear from U.S. rivers 150 years ago and currently, only remnant populations occur in a limited number of rivers in Maine.
They have a very complex life cycle that extends from spawning and juvenile rearing in fresh water rivers to extensive feeding migration in the high seas. Adults ascend to rivers of New England in the beginning of spring. The migration peaks in June and continues into the fall. Young Atlantic Salmons grow and feed in the rivers from one to three years then migrate to the ocean. The Atlantic Salmons of the U.S. are highly migratory. They take long migrations from the mouths of U.S. rivers to the northwest Atlantic Ocean where they are distributed widely. Most of them spend 2 winters in the ocean before returning to fresh water for spawning. Those that return after only 1 winter are call grilse.