Atlantic Salmon, Salmo salar
Identifying characteristics: (Non-Native Fish) Two dorsal fins including one adipose fin, and 45 to 49 caudal peduncle scales. Caudal peduncle is generally narrow and tapered. Adults have black spots on sides, mostly above the lateral line. Narrow pointed, vomerine tongue with four to six small teeth. Maxillary usually extends to rear edge of eye or only slightly beyond. Dark pectoral fins, caudal fin may be slightly forked and nine or 10 rays in anal fin.
Atlantic salmon are known throughout the world to be an exciting sport fish. This native of the North Atlantic Ocean was first successfully introduced to the Great Lakes in 1972 when Michigan stocked some 20,000 young Atlantic salmon in the Boyne and Au Sable rivers. Currently Great Lake Atlantic salmon stockings are maintained by a spawning run on the St. Marys River, where eggs and milt are collected at the Lake Superior State University Aquatic Research Laboratory.
Spawning migrations vary by stream of origin, but the St. Marys River run typically begins in mid-summer and runs until November when spawning commences. The female chooses a gravel-bottomed riffle above or below a pool, and there she digs a nest, or redd. As she lays her eggs in this depression, the male simultaneously releases sperm. Then the female pushes gravel back over the eggs. When spawning is finished the adults may rest in the river for some time and then return to the lake, as Atlantic salmon are iteroparous and can potentially spawn multiple times. Males may remain in rivers all winter.
Eggs hatch the following spring but the newly hatched young don't emerge from their gravel nest until late spring. At that stage of their development, they stay in the stream's fast water, eating and growing for two or three years, or until they are about six inches long. Then they move downriver to the Great Lakes, where they grow rapidly, and weigh three to six pounds after one year. Some return to their spawning grounds after this first year while others wait an extra year or more, growing to a weight of six pounds or more. In the spring, Atlantic salmon prefer the upper, warmer layers of the lake near shore. In the summer they retreat to deeper, cooler water. When fall approaches they again come shoreward as they head toward their spawning stream as the cycle repeats.
Salmon in the lake eat crustaceans, but especially seek out smelt, alewives and any other available forage. While on their spawning run they do not feed, but will often strike out of aggression. Atlantic salmon are preyed upon by predatory fish and birds while they are young.
Atlantic salmon in the Great Lakes are caught using a number of techniques including trolling methods used for Chinook and coho salmon fishing.
For more information on how and where to catch Atlantic salmon see our Michigan Fish and How to Catch Them and Better Fishing Waters.
Atlantic salmon graphic courtesy of Joseph R. Tomelleri and copyrighted.