SALMON (Salmo salar), a well-known fish, forming the type of the family Sal Inonidw. The salmon inhabits both salt and fresh waters, and ranks prominent among the food fishes of the United States and other countries. It generally attains a length of from three to four feet, and an average weight of from 12 to 30 pounds. The typical color of the adult fish is a steel-blue on the back and head, becoming lighter on the sides and belly. Teeth are present in the upper and lower jaws, palate, and vomer or roof of the mouth; the edges of the tongue are also toothed or notched. The food consists of animal matter, and must vary with the change of habitat from salt to fresh water, and vice versa.
In the autumn the salmon quits the sea and ascends the rivers for the purpose of spawning, often having to surmount considerable obstacles, such as falls, and artificial structures; "salmon ladders" are placed in some streams to assist their progress. The eggs are deposited in a shallow trough or groove excavated in the gravelly bed of the river. After spawning, the salmon, both male and fe male, return to the sea under the name of spent fish, foul fish, or kelts, the fe males being further distinguished as shedders or baggits. In from 70 to 150 days the young fish emerges from the egg, and in its embryo state it is not unlike a tadpole, being on the average about one and a quarter inches in length. About 50 days later it assumes the appearance of a fish. It usually continues in the shal lows of its native stream for two years after hatching. When the season of its migration arrives, generally between March and June, the fins have become darker and the fish has assumed a silvery hue. It is now known as a "smolt" or "Salmon fry." The smolts now congregate into shoals and proceed leisurely seaward. On reaching the estuary they remain in its brackish water for a short time and then make for the open sea. The salmon •
returns, as a rule, to the river in which it passed its earlier existence. The fertility of the fish is enormous; it has been cal culated that over 150,000,000 of salmon ova are annually deposited in the Scotch river Tay alone.
For purposes of commercial supply, salmon are taken in nets of special con struction and of various forms, the fish ings being regulated by law. Stake nets supported on piles of wood and extending out into the sea, and "bag" or "drift" nets are the means most frequently em ployed in the British salmon fishery. The chief European salmon fisheries are those of the Tweed, Tay, North Esk, Dee, Spey, Severn, and some Irish rivers; there are important fisheries in some European and North American rivers. Immense quan tities of salmon are annually taken and canned on the Columbia and Frazer rivers.
Of the same genus as the common salmon is the salmon trout, the common river trout, Lochleven trout, etc. What is known as the "land-locked" salmon, which is found in Norway, Sweden, Maine, and New Brunswick, is so called be cause it remains in inland waters and does not descend to the sea. In the waters of Northwestern America are several salmon belonging to a distinct genus, Oncorhynchus, including the quinnat or king salmon, blue-black salmon or red fish, silver salmon, dog salmon, and humpback salmon. The quinnat (O. tchawytsch,a) has an average weight of 22 pounds. Both it and the blue-back sal mon (O. nerka) are caught in immense numbers in the Columbia, Sacramento, and Frazer (especially in spring), and are preserved by canning. Attempts have been made to introduce the quinnat into eastern North America and Europe. The salmon is one of the fishes that are im portant objects of Frsu CULTURE (q. v.). In 1918 the salmon catch in Alaska was 6,605,835 cases. 27,969 persons were em ployed. In 1919 4,583,688 cases of canned salmon were produced.