MUSEUM NOTES

Southland Times, Issue 23922, 14 September 1939, Page 16

MUSEUM NOTES

SWORDFISH LORE The swordfish have been putting on a grand show for fishermen and sailors for centuries. They are the largest, strongest, fastest and most pugnacious bony fishes in the sea. Occasionally swordfish put on a show that is decidedly not for ■ the benefit of men in small boats, and writers of the sea of all ages tell of the swordfish’s daring, amazing power and untamed ferocity. Ships with wooden hulls six inches thick have been pierced by their bony swords. These unyielding weapons have even penetrated copper sheaths. Swordfish are nature’s submarines. They are U-boats and torpedoes combined, self-directed and self-propelled. They carry no explosives, but in front of their heads they carry a wicked, pointed, destructive bony battering-ram. Swordfishes have turned ships and their crews back to port for repairs and they are combatants that command respect.

The sight of swordfish as they leap in the air is spectacular while their “walking” on the surface of the sea, even though the act is momentary, is dramatic. Their attacks upon their enemies are courageous, be- they big sea-beasts or man-made boats that look like sea-beasts. The recent visit of American scientists was made not only to secure specimens of swordfish in New Zealand waters but also to study the group as a whole. Many arguments have raged over the number and naming of the different kinds in different seas and such expeditions help to add to the sum total of human knowledge.

The swordfish of American waters form a trinity of piscine personalities. The true swordfish (Xiphias) is probably the fastest; the sailfish (Istiophorus) is the most graceful; the marlin (Makaira) is the most pugnacious. Fishermen of all countries have names for the swordfish. The Spaniards call it Espadon emperador, the emperor’s broadsword; the French say Empereur; the Portuguese think of a needle when they say Aguhao; the Dutch think of the sword and say Zwardfis; the modern Italians speak of the Sifia, which means sword, the ancient Romans said Gladius, and the Greeks said .piiphias for the same reason. The present day scientific name of the swordfish is Xiphias gladius, a bit of Greek and Latin meaning sword. Xiphias is an ancient name, at least 2350 years old. Aristotle used it when he described the leaping antics of the species. For a while just before 1758 the swordfish laboured an unwieldy scientific name of seven Latin words—Xiphias rostr. apice ensiforme, pinnis ventralibus nullis. After a name like that, Xiphias gladius is comparatively easy. NATURE’S STREAMLINING The outstanding feature of the swordfish is, of course, its long, broad, solid, bony snout. It is a reaping organ that harvests its food from migratory schools of fish of the sea, and a weapon of terrific power in its battles with its enemies .real or imaginary. The sword is prolongation of the upper jaw, formed by the coalescence of the maxillary and premaxillary bones. In baby swordfish the two jaws are of equal length and the two maxillary bones that form the snout are separate.

The true swordfish adult has the longest and broadest snout and the sailfish and marlin run a dead heat for second place. Baby swordfish, sailfish and marlins are fully equipped with long, strong teeth, but as they grow older the teeth degenerate. The baby fishes, although they lack an effective sword, have in addition to welldeveloped teeth, an elaborate system of protective spines which project from the head, cheeks and body surfaces. They are miniature barbed-wirq fortresses, apparently playing a defensive role in their struggle for survival and biding their time until they are full-grown and fully armed with effective weapons for offensive tactics.

A fully developed swordfish is probably the fastest swimming creature in the world and its body is a perfect example of nature’s success in designing streamline forms. The greatest thickness of the swordfish’s body is found about a third of its body’s length behind the head; the body then tapers gradually towards the tail. These proportions meet the standard requirements of the best engineering principles for streamline forms. The body surface is smooth, for the scales are embedded beneath a thick sheath of skin. The fins of the back and belly fit snugly into grooves in the body. In the swordfish proper, a pair of apparently superfluous ventral fins are entirely absent, and in the sailfish and marlin they are degenerate organs. The remaining fins of the back and belly are used as brakes which must often not be applied in time, for the fish has been known to have projected itself into objects like the hulls of wooden vessels from which it cannot extricate its sword. No one has accurately determined the speed of a swordfish, but Professor Richard Owen is often quoted as saying, from his testimony in an English court of law, that: “Its velocity is equal to that of a swivel (a cannon that swings on a pivot) shot and is as dangerous as a heavy artillery projectile.” The vertebrae have powerful interlocking processes designed to give power and resist shock.