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MACKEREL
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MACKEREL , pelagic fishes, belonging to a small See also:family, Scombridae, of which the See also:tunny, bonito, albacore, and a few other tropical genera are members. Although the See also:species are fewer in number than in most other families of fishes, they are widely spread and extremely abundant, peopling by countless See also:schools the oceans of the tropical and temperate zones, and approaching the coasts only accidentally, occasionally, or periodically. The mackerel proper (genus Scomber) are readily recognized by their elegantly shaped, well-proportioned See also:body, shining in iridescent See also:colours. Small, thin, See also:deciduous scales equally See also:cover nearly the entire body. There are two dorsal fins, the anterior near the See also:head, composed of 11–14 feeble spines, the second near the tail with all the rays soft except the first, and behind the second dorsal five or six finlets. The ventral is immediately below the second dorsal, and is also followed by finlets. The caudal fin is See also:crescent-shaped, strengthened at the See also:base by two See also:short ridges on each See also:side. The mouth is wide, armed above and below with a See also:row of very small fixed See also:teeth. No other See also:fish shows finer proportions in the shape of its body. Every " See also:line " of its build is designed and eminently adapted for rapid progression through the See also:water; the muscles massed along the vertebral See also:column are enormously See also:developed, especially on the back and the sides of the tail, and impart to the body a certain rigidity which interferes with abruptly sideward motions of the fish. Therefore mackerel generally swim in a straightforward direction, deviating sidewards only when compelled, and rarely turning about in the same spot. They are in almost continuous See also:motion, their See also:power of endurance being equal to the rapidity of their motions. Mackerel, like all fishes of this family, have a See also:firm flesh; that is, the muscles of the several segments are interlaced, and receive a greater See also:supply of See also:blood-vessels and nerves than in other fishes. Therefore the flesh, especially of the larger kinds, is of a red See also:colour; and the See also:energy of their See also:muscular See also:action causes the temperature of their blood to be several degrees higher than in other fishes. All fishes of the mackerel family are strictly carnivorous; they unceasingly pursue their See also:prey, which consists principally of other fish and pelagic crustaceans. The See also:fry of clupeoids, which like-See also:wise swim in schools, are followed by the mackerel until they reach some shallow See also:place, which their enemies dare not enter. Mackerel are found in almost all tropical and temperate seas, with the exception of the See also:Atlantic shores of temperate See also:South See also:America. See also:European mackerel are of two kinds, of which one, the See also:common mackerel, Scomber scomber, lacks, while the other possesses, an See also:air-See also:bladder. The best-known species of the latter See also:kind is S. colias, the " See also:Spanish" mackerel;' a third, S. pneumatophorus, is believed by some ichthyologists to be identical with S. colias. Be this as it may, we have strong See also:evidence that the Mediterranean is inhabited by other species different from S. scomber and S. colias, and well characterized by their dentition and coloration. Also the species from St See also:Helena is distinct. Of extra-Atlantic species the mackerel of the See also:Japanese seas are the most nearly allied to the European, those of New See also:Zealand and See also:Australia, and still more those of the See also:Indian Ocean, differing in many conspicuous points. Two of these species occur in the See also:British seas: S. scomber, which is the most common there as well as in other parts of the See also:North Atlantic, See also:crossing the ocean to America, where it abounds; and the Spanish mackerel, S. colias, which is distinguished by a somewhat different See also:pattern of coloration, the transverse See also:black bands of the common mackerel being in this species narrower, more irregular or partly broken up into spots, while the scales of the See also:pectoral region are larger, and the snout is longer and more pointed. The Spanish mackerel is, as the name implies, a native of the seas of See also:southern See also:Europe, but single individuals or small schools frequently reach the shores of See also:Great See also:Britain and of the See also:United States. The See also:home of the common mackerel (to which the following remarks refer) is the North Atlantic, from the See also:Canary Islands to the Orkneys, and from the Mediterranean and the Black See also:Sea and the coasts of See also:Norway to the United States. Towards the See also:spring large schools approach the coasts. Two causes have been assigned of this See also:migration: first, the See also:instinct of finding a suitable locality for propagating their species; and, secondly, the See also:search and pursuit of See also:food, which in the warmer See also:season is more abundant in the neighbourhood of See also:land than in the open sea. It is probable that the latter is the See also:chief cause. In the See also:month of See also:February, or in some years as See also:early as the end of See also:January, the first large schools appear at the entrance of the See also:English Channel, and are met by the more adventurous of the See also:drift-See also:net fishers many See also:miles See also:west of the Scilly Islands. These early schools, which consist chiefly of one-See also:year and two-year-old fishes, yield sometimes enormous catches, whilst in other years they See also:escape the drift-nets altogether, passing them, for some hitherto unexplained See also:reason', at a greater See also:depth than that to which the nets reach, 1 The See also:term " Spanish mackerel " is applied in America to Cybium maculatum. Additional information and CommentsThere are no comments yet for this article.
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