MACKEREL, make-rel. The common mackerel (Scomber scombrus) is the best-known and most important member of the family Scombricke and one of the most valuable of food-fishes, ranking in this respect behind the cod and herrings only. The mackerel is a compactly built fish of smooth and regular outline, the fusiform figure tapering accurately to the pointed snout, so that it cleaves the water easily. The large, deeply-forked tail is sup ported on a slender peduncle, provided with two small keels on each side, and preceded by a dorsal and a ventral series of finlets of five each. A soft dorsal and a counterpart anal fin are placed exactly opposite each other and be hind the level of the vent, and the anterior dorsal fin is supported by usually 11 delicate spines. Very numerous and small scales cover the body nearly uniformly, but are absent from the head. The large mouth is provided with numerous small sharp teeth. The gill-rakers are long and the air-bladder is wanting. The color of the back is deep blue, marked by about 35 nearly vertical wavy black lines; below, the fish is silvery white. A recent close study of the species on the European side of the Atlantic establishes the existence there of local races, as in the herring, but it appears that the Amer ican representatives, while constituting a race distinct from the European, are more homo geneous.
The mackerel is an abundant fish on both sides of the north Atlantic, on the American side ranging from Cape Hatteras to the Straits of Belle Isle, and on the European from north ern Norway to the Canary Islands and through out the Mediterranean. While a true pelagic fish of wandering and migratory habits and, like most such, capricious in its movements, the great body of mackerel approaches the Ameri can coast and moves along it northward as the temperature of the water rises to about 45° F. On the approach of winter they retire to a greater distance from the land, tut a few re main throughout the year near the coast. Mackerel swim in great schools at or near the surface; one such covering an area of 10 square miles, and another estimated as contain ing 1,000,000 barrels, have been observed. The local movements of the schools are largely regu lated by the food-supply, which consists of small pelagic fishes, various kinds of small crustaceans, etc., which are pursued with great eagerness. On the other hand, the bluefish and other carnivorous fishes, porpoises, squids and fish-eating birds, are relentless enemies. Spawning takes place in the open sea, not far from the coast from Vineyard Sound to the Gulf of Saint Lawrence, and durine the months of May, June and early July. The eggs are about one millimeter in diameter, contain an oil-drop and float at the surface, where the young fish develop and live. They grow rapidly and are about five inches long by the end of the first half year, when they are known as "spikes)); "blinkers)) are about one year old and six or seven inches long; "tinkers" are seven to nine inches long and are supposed to be two years old. At the age of three or four
years the mackerel is mature and from 12 to 18 inches long. The very largest specimens weigh about four pounds and have a length of 22 to 23 inches.
The .mackerel fishery is of the greatest im portance in the New England States and Nova Scotia, and in Norway, Ireland and Great Britain. In Europe the fishery is prosecuted almost exclusively by means of small boats and hand lines, but in America is chiefly carried on in staunch sea-going schooners, most of which hail from Gloucester, Mass., and which are equipped with purse seines, by means of which entire schools are surrounded and captured. The fishing begins off Cape Hatteras in March or April and the schools are followed north ward as they appear successively on the New Jersey, New England and Canadian coasts. In addition to the operations of this mackerel fleet, local fisheries are carried on along much of the coast, with pound-nets, gill-nets and hand-lines. The spring and local catches are generally sold fresh, the summer catch being split and salted. The product of the fishery has been peculiarly subject to fluctuations, due in large part to alternating periods of abundance and scarcity of the fish. Colonial writers refer to its great plenty, and statistics of the catch inspected in Massachusetts show a somewhat regular recurrence of such periods at intervals of about 20 years. From 350,000 barrels in 1880 and 395,000 in 1881, the catch steadily declined to 75,000 in 1886, and 18,000 in 1891, since which time it has greatly fluctuated.
For 1914-15 the number of fry distributed was 4,847,000, and in the succeeding year 1,946, 000. In 1915 the returns for salted mackerel were 19,691 barrels, exceeding the previous year by 4,170 barrels, while the total catch of fresh mackerel was 71,564 barrels against 68,582 in the previous year. The returns for New England up to 30 June 1916 show an increase of 63 per cent in quantity and 73 per cent or $259,354 in value. In the spring of 1916 mack erel reached the unheard-of price of 40 cents apiece for the larger fish. The Canadian prov inces in 1914-15 give 143,712 hundredweights, as against 215,442 hundredweights in the previous year,— a decline in values of $453,473; the quantity in 1915-16 was 180,990 hundredweights, representing an increased value $180,990 over 1914-15. An elaborate account of the American mackerel fishery will be found in Brown Goode's 'Materials for a History of the Mack erel Fishery> (Report of the United States Fish Commission, 1884); for some recent views see Moore, 'Report National Fishery Congress> (Washington 1898) ; and for methods of pres ervation, Stevenson, 'The Preservation of Fishery Products for Food> (Bulletin of United States Fish Commission, 1898).