Overview
Atlantic salmon are an anadromous migratory fish that begin their life in freshwater and migrate to the ocean to feed and grow, and then return to freshwater to spawn in rivers. The species name salar means the leaper. These fish are very fast swimmers and can jump very high - almost 12 feet!
Hundreds of thousands of Atlantic salmon used to migrate from the Atlantic Ocean to rivers in North America. As early as 1864, hatcheries began raising Atlantic salmon to supplement wild populations because of concerns over declining stocks due to overfishing and damming of rivers.
Today, only small numbers return to Maine and eastern Canada. The Gulf of Maine Distinct Population Segment is currently listed as endangered under the Endangered Species Act, and Critical Habitat was designated in 2009.
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Characteristics
Physical Characteristics
Adult Atlantic salmon that have spent one year in the ocean average 23” in length. If they spend a second winter in the ocean they average 30”. In rare cases, they reach 35 inches in length if they have spent 2 or 3 years in the ocean. The number of eggs a female carries, known as fecundity, increases with the size of the fish.
When they are about 6 inches long, they are called smolts and are ready to live in saltwater. They become silvery in color and migrate downstream back out to the ocean.
Atlantic salmon generally weigh 8 to 12 pounds.
Migration Behavior: Atlantic salmon are migratory. They are born in fresh water and then migrate to the ocean where they spend their adult lives growing and feeding. Atlantic salmon travel thousands of miles to their North Atlantic feeding grounds, usually near western Greenland. They remain for one to three years before returning to the river where they were hatched to reproduce. They can travel over 6,000 miles before coming back to rivers to spawn. They will sometimes travel 200 miles up river to find preferred places to spawn. The landlocked Atlantic salmon will migrate into the lakes’ tributary rivers to spawn.
Life Cycle
Atlantic salmon are an anadromous migratory fish that begin their life in freshwater and migrate to the ocean to feed and grow, and then return to freshwater to spawn in rivers. After spawning, adults bury their fertilized eggs under a foot of gravel in nests called redds. The eggs hatch in April and May, and after three to four weeks, the young salmon, called fry, swim up through the gravel to hunt for food. They will then spend two to three years in or very near the stream where they hatched, hunting for food under and between rocks, feeding, and growing. When they are about 6 inches long, they are called smolts and are ready to live in saltwater and migrate downstream back out to the ocean. There they will swim and surf the ocean currents to their feeding grounds near Greenland. They will spend one to three years in the ocean growing into an adult, and can travel over 6,000 miles before coming back to rivers where they were hatched, to spawn and reproduce.
Unlike Pacific salmon which die after spawning, Atlantic salmon can live to spawn several times during their lifetime. But because spawning and migration require a lot of energy, and because they can get eaten once they are back out in the ocean, repeat spawners are not the norm.
After spawning, adults bury their fertilized eggs under a foot of gravel in nests called redds. The eggs hatch in April and May, and after three to four weeks, the young salmon, called fry, swim up through the gravel to hunt for food.
Food
The adults seek cold freshwater to spend the summer, and move to swift-running gravelly rivers or streams to spawn in October and November. After hatching, the young fish emerge from the gravel, and concentrate in nursery habitats, typically riffle areas with adequate cover, shallow water depth and moderate to fast water flow.
Geography
Atlantic salmon are found in the North Atlantic from North America to Europe, and up into the Baltic sea. In North America, they were found from northern Quebec to Newfoundland, Canada and south to Long Island, New York in the United States. In the United States, they were once found in almost every river north from the Hudson River. Some North American salmon became “landlocked” in the Great Lakes and Lake Champlain after the retreat of the glaciers, and they do not migrate out to the ocean.
Timeline
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