CHAPTER IV.

_HAIR-TAILS, HORSE-MACKERELS, SEA-BATS, DORIES, MACKERELS, SUCKING-FISHES, WEAVERS, FROG-FISHES, ANGLER-FISHES, BULL-HEADS, AND GURNARDS._

BY W. P. PYCRAFT, A.L.S., F.Z.S.

Of the family of HAIR-TAILS perhaps the most important members are the SCABBARD- or FROST-FISH and the SNOEK. The first is common in the Mediterranean and the warmer parts of the Atlantic, extending northwards to the south coast of England, where it occurs at rare intervals. It is also known in New Zealand, where it is called the Frost-fish, and furthermore is regarded as one of the most delicious fish of the colony, its flesh being fine, tender, and of delicate flavour. On this account it is much in demand, but the supply is very uncertain. The conditions of capture, indeed, of this fish are unparalleled in the annals of fishing, for it can be taken neither with the rod nor the net. The would-be captor has to wait patiently under favourable conditions on the seashore for the fish to come and cast itself up on the beach. This happens with tolerable certainty during the autumn and winter months, when the sea is calm and the nights frosty. Then the frost-fish come ashore alive, wriggling through the surf on to the beach. Two explanations have been offered for this extraordinary conduct. One is that the fish commits suicide; being pursued by a shark or other enemy, it prefers uncertain life on land to certain death at sea! The other and more probable hypothesis has it that the air-bladder of the fish becomes distended to enable it to reach the surface for food--for it is a deep-sea fish--and that the keen, frosty air prevents it from compressing the bladder and returning to the depths; thus it gradually drifts into shallow water, is hurled shorewards by the surf, and finally wriggles itself on to the beach to die. The long stretches of sandy beach a few miles from Dunedin are a favourite resort for frost-fish catching. Two or three men camp out at the foot of the cliffs overhanging the beach, pitching a tent and lighting a huge fire, so as to render life bearable during the long vigils. The "fishing" consists in perambulating the beach up and down shortly before dawn, and keeping a sharp look-out in the surf for the silver streak which betokens the approach of a victim. As soon as a fish is descried, all that remains to be done is to seize hold of it and drag it ashore, if it has not already stranded itself, and then dispatch it.

The BARRACUDA, or SNOEK, is likewise a New Zealand species, attaining a length of 5 feet. It is found also at the Cape and South Australia. In New Zealand the flesh is exported to Mauritius and Batavia as a regular article of commerce, being worth £17 per ton.

The HORSE-MACKERELS, or SCADS, are represented by some very bizarre-looking forms. It is a large family, belonging to tropical and temperate seas. One species, the COMMON HORSE MACKEREL, is common in British seas. Many members of the family have the hinder portion of the body on each side armed with large plates, well seen in the accompanying photographs; others have the median fins produced into long filamentous processes. All are eatable, and some highly esteemed as food. One of the most remarkable is the PILOT-FISH of tropical and temperate seas, occurring occasionally off the British coasts. It derives its name from its habit of accompanying ships and large sharks. From this habit of accompanying ships it was regarded by the ancients as a sacred fish, since they considered it pointed out the way to embarrassed sailors, and announced the vicinity of land by suddenly disappearing. The close companionship between the pilot-fish and the shark has excited much comment, many observers believing that the former was of great use to the latter in guiding it to its food. How this is done is graphically described by Dr. Meyer, who writes: "The pilot swims constantly in front of the shark; we ourselves have seen three instances in which the shark was led by the pilot. When the shark neared the ship, the pilot swam close to the snout or near one of the pectoral fins of the animal. Sometimes he darted rapidly forwards or sidewards, as if looking for something, and constantly went back again to the shark. When we threw overboard a piece of bacon fastened on a great hook, the shark was about twenty paces from the ship; with the quickness of lightning the pilot came up, smelt at the dainty, and instantly swam back again to the shark, swimming many times round his snout and splashing, as if to give him exact information as to the bacon. The shark now began to put himself in motion, the pilot showing him the way, and in a moment he was fast upon the hook." As Dr. Günther remarks, commenting on this account, one may entertain reasonable doubts as to the usefulness of the pilot to the shark in this instance! It is probable that the pilots follow the sharks for the sake of feeding on fragments scattered by the latter, and also for the sake of picking off the parasites with which sharks, in common with other large fish, are infested; furthermore, the pilot, being but a small fish, obtains greater security from enemies when in the company of its giant friend. The habit of seeking the company of more powerful or otherwise offensive animals is apparent also in other members of this family, the young of the horse-mackerel seeking shelter beneath the "umbrella" of a jelly-fish till they are big enough to defend themselves.

But the most remarkable members of this family are the SEA-BATS. Few in species and confined to the Red Sea, Indian Ocean, and Western Pacific, they are nevertheless in those regions very common. Although not used as food-fishes, they are of extreme interest on account of their shape, which is nearly oval and much compressed from side to side, and the form of their fins, which in some species are excessively developed. Young sea-bats differ markedly from the adults in the much greater length of the fin-rays, so much so that they have frequently been described as distinct species.

We pass now to the DORIES, which recall the Sea-bats in the oval and compressed form of the body. The resemblance to sea-bats is, indeed, so close that the latter are frequently described as dories. The mouth of the members of this family is so constructed that, when opened, the upper jaw is thrust forward, and the whole mouth forms a kind of long tube. Dories inhabit the seas of the temperate regions, two species being fairly common in British waters. The best known of these two is perhaps the John Dory, the largest specimens of which attain to a weight of 18 lbs. Mr. Cunningham has described the very peculiar way in which the dory captures its prey. "It does not," he writes, "overtake it by superior speed like the mackerel, or lie in wait for it like the angler, but stalks it and approaches it by stealth. It is able to do this in consequence of the extreme thinness of its body and the peculiar movement of its hinder dorsal and ventral fins. The dory places itself end on towards the fish it desires to devour, and in this position it is evident that it excites no alarm on the part of its prey. The appearance of the dory, seen in this way, is a mere line in the water, to which no particular significance can be attached. I have not particularly noticed the effect of the ribbons of membrane which project from the dorsal fin. But I have observed that the movements of the dory are very gradual, except in turning; it alters the position of its body by a turn of the tail or side-fins, and then swims forward by vibrating the second dorsal and ventral, a movement which causes very slight disturbance of the water. The appearance of the dory in these actions is suggestive of suppressed excitement, his eyes being fixed on his prey. I do not recollect seeing him actually swallow another fish, but have no doubt that he gets near enough to a sprat, for example, without alarming it, to seize it by the sudden elongation of his curious jaws." The way in which these jaws are elongated is admirably shown in the photograph on page 622.

Passing now to the Mackerel Family, we arrive at a group of considerable importance from an economic point of view. Extremely active, migrating, and predaceous, mackerel swim in shoals and seize their prey with great voracity, hunting merely by sight, and snapping at anything moving through the water, especially if it is silvery, like a small surface-fish. The various species differ greatly in size, ranging from the Common Mackerel of about 18 inches long to the giant Tunny weighing nearly half a ton.

COMMON MACKEREL swim in vast shoals, or "schools," as they are called, and one half a mile wide and at least twenty miles long is on record. Mackerel feed on the young of other fish and small fish generally, and, when these are not to be had, on minute crabs and shrimps. They are very prolific, a single mackerel laying from 430,000 to 540,000 eggs.

The TUNNIES are amongst the largest of the surface-fishes of the ocean. Abundant in the Mediterranean Sea, they occur occasionally in British waters. For centuries the flesh of the tunny has been held in high regard as food, and it is frequently seen in the Lisbon markets at the present day. The flesh, which is as red as beef, is cut up and sold by weight. The BONITO closely resembles the tunny, but is a much smaller fish, which preys largely upon flying-fishes, which it follows for long distances.

Peculiarly interesting are the SUCKING-FISHES. The name by which they are commonly known is bestowed on account of the presence of a large oval sucker, placed on the top of the head and extending backwards over the shoulders--an organ formed by modification of the back-fin. By means of this sucking-disk these fishes are enabled to attach themselves to sharks, turtles, ships, or any large object floating in the sea. The hold which they obtain is so strong that it is almost impossible to remove them by force. Being poor swimmers, this method of transportation enables them to pass rapidly to fresh feeding-grounds.

The natives of Zanzibar, Cuba, and Torres Straits are said to employ sucking-fishes in the capture of sleeping turtles, the fish being secured by a ring round the tail, and liberated as soon as a sufficiently near approach to the quarry has been made. About ten different species are known, the bulkiest of which attains a length of 2 feet and a weight of about 8 lbs., a longer but more slender species measuring 3 feet.

Carnivorous, of small size, and feeble swimming-powers, the family of the WEAVERS are remarkable rather for their disagreeable qualities than anything else, though at least one species is declared to be excellent eating. The STAR-GAZER is a particularly ugly-looking fish, especially noteworthy in that the eyes, which are on the top of the head, can be raised and depressed at pleasure, whilst the heavy jaw is armed with a freely moving tentacle, which, waving about in the current of water drawn in at the mouth, serves as a lure to attract small fishes, the rest of the body being concealed between stones at the bottom of the sea.

The COMMON WEAVER is a well-known British fish, much dreaded on account of the poisonous wounds which it inflicts unless most carefully handled, the poison being introduced by the spines of the back-fin and gill-cover. No special poison-organs seem to be developed, but the mucous secretion around the spines has poisonous properties. As the flesh of this fish is extremely palatable, fishermen remove the spines at once directly after capture. Should a wound be inflicted, great suffering and occasionally death follows.

Passing over one or two unimportant groups, we come to the family of the FROG-FISHES, which, but for the fact that many of its members are poisonous, calls for no special comment here. One species, however, from the coasts of Central America, possesses the distinction of having the most highly developed poison-organs of any fishes, being equalled only by the Venomous Snakes. The poison-weapons are a spine on the gill-cover and two spines of the back-fin. The former is of the same shape as the hollow venom-fang of a snake, perforated at both ends. A little bag containing the poison lies at the base of the spine, and when pressed by the spine as it makes its puncture ejects its contents into the body of the latter, whence it escapes from the hole in the top. The structure of the back-spines is similar.

The family of the ANGLER-FISHES contain more strange forms than any other. Living on the sea-bottom and seeking their prey by stealth, angler-fishes do not need powerful swimming-muscles; consequently the size of the body and tail has become considerably reduced, so that the head, relatively to the rest of the body, is unusually large. The head, jaws, and belly are indeed of great size and capacity. The side or paired fins are not used for swimming, but have become modified to serve as feet, enabling the fish to shuffle along the ground. A further remarkable feature of these fishes is seen in the back-fin, the rays of which are very long, the foremost being provided with a flag-like flap of skin at the top, extremely sensitive to touch, and playing a very important part in the capture of food. It seems that the fish commonly lies concealed on the sea-bottom, with this "flag" erected. From its general resemblance to the surrounding seaweed it is quite inconspicuous, so that passing fishes take no trouble to avoid it. If by any chance they should touch it, however, the jaws beneath open instantly, and the unfortunate trespasser is suddenly engulfed. This elaborate and sensitive mechanism has been likened to a spring-trap, which is always set, and never betrays its presence. It seems probable, however, that this flag serves also as a lure, passing fishes being occasionally attracted by the waving flap of skin. Should they become sufficiently curious as to proceed to touch it, capture in the manner above described is certain. Certain deep-sea forms have a luminous organ in the place of the flap of skin, and this certainly seems to act only as a lure.

Angler-fishes are found all over the world; some, as we have seen, are bottom-fishes, some inhabit deep sea, whilst others lie hidden amongst floating seaweed, to which they cling by means of their arm-like fins. Only one species occurs in British waters. Its method of spawning is remarkable, in that the eggs are laid in the form of large raft-like sheets, which float on the surface of the sea. The number of eggs laid by a single fish has been computed to be 1,345,000. A single sheet of spawn may measure from 2 to 3 feet in breadth and from 25 to 30 feet long.

The BULL-HEADS and GURNARDS, constituting the next family, are characterised by the spiny armature of the head and the great size of the breast-fins. The former are represented in British waters by four species, one of which, the MILLER'S-THUMB, inhabits fresh-water. The marine species include the SEA-SCORPION and FATHER-LASHER.

The BULL-HEADS on the Indian and Australian coasts are represented by the closely allied FLAT-HEADS, or CROCODILE-FISHES, in which the head, as its name implies, is much depressed, and fully armed with spines, which are highly poisonous, and cause a violent irritation. These fishes live in shallow water, lying on the bottom, with which their colours harmonise so completely that they are practically invisible. The very large ventral fins--those seen in the photograph immediately behind the breast-fins--are of great use in locomotion.

The GURNARDS are well-known fishes, common on the coasts of Britain, and extending from tropical to arctic seas. Their curiously shaped heads give them a very quaint appearance. One of the most remarkable peculiarities of these fishes is the separate condition of some of the rays of the breast-fins, which form finger-like organs, used to feel the ground and rake over loose stones, to discover small shrimps and other animals hidden underneath. Furthermore, the gurnards are peculiar in that they are enabled to communicate one with another by means of sounds produced by the expulsion of air from one compartment of the air-bladder to another. The females are much more common than the males, and also slightly larger. The young are remarkable for the enormous size of the breast-fins, though even in the adult these are unusually large.

Close allies of the Gurnards are the FLYING-GURNARDS, which, by reason of the extreme development of the breast-fins, are enabled to take flying leaps out of the water. One species is common in the Mediterranean. The flying-gurnard is not to be mistaken for the true "flying-fish," or flying-herring, described later.

The curious mail-clad ARMED BULL-HEAD, or POGGE, commonly taken in shrimp-nets, is an ally of the flying-gurnard.

----