Atlantic Salmon
Only farm-raised Atlantic salmon are found in U.S. seafood markets.
Commercial and recreational fishing for Atlantic salmon in the United States is prohibited. In addition, the Gulf of Maine distinct population segment (DPS) of Atlantic salmon are protected under the Endangered Species Act.
Appearance
- Atlantic salmon have a spindle-like body shape – rounded, broad in the middle, and tapered at each end. The shape is somewhat flattened toward the sides, which is typical of salmon species.
- The head is relatively small, about one-fifth of the body length. The underside paired fins are prominent, especially on juveniles.
- Spawning adults darken to a bronze color after entering freshwater and darken further after they spawn. When spawning has been completed, they are often referred to as kelts or black salmon. Their silver color returns after they re-enter the sea.
Biology
- Atlantic salmon are anadromous – they leave the ocean to return to freshwater streams and rivers to breed.
- Females lay an average of 7,500 eggs in gravel nests, called redds.
- Eggs incubate slowly due to cold winter water temperatures. About 9 to 20 percent of the eggs survive to the fry stage.
- Fry remain buried in the gravel for about 6 weeks and emerge in mid-May.
- They quickly disperse from the redds and develop camouflaging stripes along their sides, entering the parr stage.
- Parr eventually undergo a physiological transformation called smoltification that prepares them for life in a marine habitat. During smoltification, fish imprint on the chemical nature of the stream or river to enable them to find their way back to where they were born. After smoltfication is complete in the spring, smolts migrate to the ocean to grow, feed, and mature.
- Atlantic salmon growth rates are variable and depend on several factors including season, habitat quality, age, sex, and population density.
- They grow much faster in saltwater than in freshwater. After 2 years at sea, adult salmon can grow to an average length of 28 to 30 inches and weight of 8 to 12 pounds.
- Unlike the Pacific salmon species, Atlantic salmon do not die after spawning, and adults can repeat the breeding cycle. They live for 4 to 6 years.
- Juvenile Atlantic salmon mostly prey on invertebrates and terrestrial insects while in freshwater and on amphipods (small, shrimp-like crustaceans), krill, and fishes while at sea.
- Larger adult Atlantic salmon mainly prey on fish such as Atlantic herring, alewife, rainbow smelt, capelin, mummichogs, sand lances, flatfish, and small Atlantic mackerel.
- Birds, marine mammals, and fish prey on Atlantic salmon.
Where They Live
Range
- Atlantic salmon are the only salmon native to the Atlantic Ocean.
- There are three groups of wild Atlantic salmon: North American, European, and Baltic. The North American group, including the Canadian and U.S. populations, was historically found from northern Quebec southeast to Newfoundland and southwest to Long Island Sound.
- In the United States, Atlantic salmon were once native to almost every river north of the Hudson River. Due to the effects of industrial and agricultural development (including habitat destruction, dams, and historic overfishing), most populations native to New England were eradicated. Now, the only native populations of Atlantic salmon in the United States are found in Maine.
Habitat
- Atlantic salmon are anadromous—they leave the ocean to return to freshwater streams and rivers to breed.
- After hatching, young Atlantic salmon (called parr) remain in rivers or streams for the first 1 to 2 years of life, preferring shallow, cool, fast-flowing water with shade.
- After this period, the salmon migrate to open ocean waters where they spend about 2 to 3 years feeding, then return to their natal streams or rivers to spawn during the fall.
Source: NOAA Fisheries