As mackerel are very voracious, they greedily devour all sorts of bait, but they are chiefly taken by the drift-net. The drift-net is twenty feet deep and a hundred and twenty feet long, well buoyed at the upper edge, but without weights at the bottom. The meshes, made of fine twine tarred to a reddish colour for preservation, are calculated to admit the head of the fish and catch it by the gills, so as to prevent its withdrawal. A fleet of mackerel-boats dragging these large nets, which are extended vertically in the sea, or float between the two tides, is well represented in Pl. XXXII.
The flesh of the mackerel is fat and high flavoured. Among the ancients a liquid was extracted from this fat called garum, which was considered a very nourishing preparation. The price of this liquid was very high; in modern measures it was valued at about sixteen shillings the pint. It was acrid, half putrefied, and very nauseous, but it had the property of rousing the appetite and stimulating the digestive organs. Garum played the part of a condiment at a period when the exciting array of Indian spices was unknown. Seneca charges it, as we do pepper and other hot spices taken in excess, with destroying the stomach and health of gourmands. This garum is spoken of by the traveller Pierre Belon, writing in the sixteenth century, as being held in great estimation at Constantinople in his time. Rondelet, the author of a very remarkable book published in 1554, who ate garum at the table of William Pellicier, Bishop of Maguelonne, thought he could trace the liquid not to the mackerel, but to one of the Sparoïdes (Sparus smaris).
The mackerel possesses phosphorescent properties which cause it to shine in the dark, especially after death, when decomposition has commenced.
The mackerel is not only voracious, but, in spite of its small size, it has the hardihood to attack fishes much larger and much stronger than itself. It is even said that they love human flesh. According to the naturalist bishop, Pontoppidan, who lived in the sixteenth century, a sailor belonging to a vessel which had cast anchor in one of the Norwegian ports, when bathing one day in the sea, was assailed by a shoal of mackerel. His companions came to his relief; the eager band were repulsed with great difficulty, but not till it was too late: the unfortunate sailor was so exhausted that he died a few hours after. By a natural law of compensation the ubiquitous mackerel is surrounded by numerous enemies; the larger inhabitants of the ocean eagerly devour them. Certain fishes, in appearance very weak, such as the muræna, fight them with great advantage.
Closely connected with the mackerel and other Scombridæ, we have the Bonita of the Tropics. This is a fish of considerable size, celebrated by its pursuit in great shoals of the flying-fish, of which we have already spoken. The Bonita (Thynnus pelamys) is not unlike the mackerel in shape, but less compressed, and upwards of twenty-five to thirty inches long. It is occasionally found on our coast, but only as an accidental visitor, for its true home is the Tropics. It is a beautiful fish of a fine blue colour, with short pectoral fins and four longitudinal bands on each side of the belly. It is easily harpooned from the dolphin-striker, and appears to have the power of generating electricity. Any one grasping the living fish is violently shaken as in palsy, "agitans," so much so that the most resolute son of Neptune cannot control his speech; every attempt culminates in an unintelligible spasmodic sputter. The instant the bonita is dropped, the muscles resume their routine action.
Fig. 392. The Sword-fish (Xiphias gladius).
The Sword-fish, Xiphias gladius (Fig. 392), so called from the upper jaw being elongated into a formidable spear or sword, was known to the ancients, and has borne the name which recalls its salient characteristic from very early times. In short, it is recognized at a glance from its organic structure, and from the resemblance of its prolonged horizontal and trenchant muzzle to the blade of a sword. With the ancients it was Ξιφίας, and Gladius; with the moderns it is the Sword-fish, the Dart, the Spece spada, and l'Espadon épée.
This fish attains a great size, being found in the Mediterranean and Atlantic, in company with the tunny, from five to six feet in length. Its body is lengthy, and covered with minute scales, the sword forming three-tenths of its length. On the back it bears a single long dorsal fin; the tail is keeled, the lower jaw is sharp, the mouth toothless, the upper part of the fish bluish-black, merging into silver beneath. It seems to have a natural desire to exercise towards and against all the arm with which Nature has furnished it; it darts with the utmost fury upon the most formidable moving bodies; it attacks the whale; and there are numerous and well-authenticated instances of ships being perforated by the weapon of this powerful creature.
In 1725, some carpenters having occasion to examine the bottom of a ship which had just returned from the tropical seas, found the lance of a sword-fish buried deep in the timbers of the ship. They declared that, to drive a pointed bolt of iron of the same size and form to the same depth, would require eight or nine blows of a hammer weighing thirty pounds. From the position of the weapon it was evident that the fish had followed the ship while under full sail; it had penetrated through the metal sheathing, and three inches and a half beyond, into the solid frame.