CHAPTER I.
FISH LIFE AND GROWTH.
Classification of Fish—Their Form and Colour—Mode and Means of Life—Curiously-shaped Fish—Senses of Smell and Hearing in Fish—Fish nearly Insensible to Pain—The Fecundity of Fish—Sexual Instinct of Fish—External Impregnation of the Ova—Ripening of a Salmon Egg—Birth of a Herring—Proposal for a Marine Observatory in order to note the Growth of our Sea Fish—Curious Stories about the Growth of the Eel—All that is known about the Mackerel—Whitebait: is it a Distinct Species?—Mysterious Fish: the Vendace and the Powan—Where are the Haddocks?—The Food of Fish—Fish as a rule not Migratory—The Growth of Fish Shoals—When Fish are good for Food—The Balancing Power of Nature.
Fish form the fourth class of vertebrate animals, and, as a general rule, they live in the water; although in Ceylon and India there are found species that live in the earth, or, at any rate, that are able to exist in mud, not to speak of some that are said to occupy the trees of those countries! The classification of fishes as given by Cuvier is usually adopted. That eminent naturalist has divided these animals into those with true bones, and those having a cartilaginous structure; and the former again are divided into acanthopterous and malcopterous fish. Other naturalists have adopted more elaborate classifications; but Cuvier’s being the simplest has in my opinion a strong claim to be considered the best; at least it is the one generally used.
A fish breathes by means of its gills, and progresses chiefly by means of its tail. This animal is admirably adapted for progressing through the water, as may be seen from its form, which has been imitated more or less closely by the builders of ships, the makers of weavers’ shuttles, and others. Fish are exceedingly beautiful as regards both form and colour. There are comparatively few persons, however, who have an opportunity of seeing them at the moment of their greatest brilliancy, namely, just when they are brought out of the water. I allude more particularly to some of our sea fish—as the herring, mackerel, etc. The power of a fish to take on the colour of its hiding-place may be mentioned. I found, a few weeks ago, some young fish of various kinds in the Tweed at Stobo, which were, when in the water, quite undistinguishable from the vegetable matter among which they were taking shelter. It is not an easy matter to paint a fish so as accurately to transmit to canvas its exquisite shape and glowing colours. The moment it is taken from its own element its form alters and its delicate hues fade; and in different localities fish have, like the chameleon, different colours, so that the artist must have a quick eye and a responding hand to catch the rapidly-fleeting tints of the animal. Nothing, for instance, can reveal more beautiful masses of colour than the hauling into the boat of a drift of herring-nets. As breadth after breadth emerges from the water the magnificent ensemble of the fish flashes with ever-changing hues upon the eye—a wondrous pantomimic mixture of glancing blue and gold, and silver and purple, blended into one great burning glow of harmonious colour, lighted into brilliant life by the soft rays of the newly-risen sun. But, alas for the painter! unless he can instantaneously fix the burnished mass on his canvas, the light of its colour will be extinguished, and its beauty be dimmed, long before the boat has reached the harbour. The brightly-coloured fish of the tropics are indeed gorgeous, as is the plumage of tropical birds; but as regards excellence of flavour, beautifully-blended colours, and especially as a food power, they cannot for a moment be compared with that plentiful poor man’s fish—the beautiful common herring of our British waters.
If the breathing apparatus of a fish were to become dry the animal would at once be suffocated. A fish when in the water has very little weight to support, as its specific gravity is about the same as that of the water in which it lives, and the bodies of these animals are so flexible as to aid them in all their movements, while the various fins assist either in balancing the body or in helping it to progress. The motion of a fish is excessively rapid; it can dash along in the water with lightning-like velocity. Many of our sea fish are curiously shaped, such as the hammer-headed shark, the globe-fish, the monkfish, the angel-fish, etc.; then we have the curious forms of the rays, the Pluronectidæ, and of some others that I may call “fancy fish;” but fish of all kinds are admirably adapted to their mode of life and the place where they live—as for instance, in a cave where light has never penetrated there have been found fish without eyes. Fresh-water fish do not, however, vary much in shape, most of them being very elegant. Fish are nearly insensible to pain, and are cold-blooded, their blood being only two degrees warmer than the element in which they swim. It is worthy of being noted also that fish have small brains in comparison to the size of their bodies—considerably smaller in proportion than in the case of the birds or mammalia, but the nerves communicating with the brain are as large in fish, proportionately, as in either the birds or mammalia. So far as personal knowledge goes, I believe the senses of sight and hearing are well developed in most fish, as also those of smell and taste, particularly the sense of smell, which chiefly guides them to their food. We may take for granted, I think, that fish have a very keen sense of smell—more so than most other animals; and thus it is that strong-smelling baits are so successful in fishing. The French people, for instance, when fishing for sprats and sardines, bait the ground with prepared cod-roe, which, by the way, adds very largely to the expense of that branch of fishing in the Bay of Biscay. I may also remind my readers, as an evidence of fish having a strong sense of smell, that salmon-roe used to be a deadly trout-bait, but fishing with salmon-roe is now illegal. It has been said by some naturalists that fish do not hear well, but that assertion is contrary to my own experience; for on making repeated trials as to the sense of hearing in fish, I found them as quick in that faculty as they are sharp in seeing; and have we not all read of pet fish being summoned by means of a bell, and of trouts that have been whistled to their food like dogs? Water is an excellent conductor of sound: it conveys a noise of any kind to a greater distance, and at nearly as great a speed as air. Benjamin Franklin used to experiment on water as a conductor, and soon arrived at the conclusion that its powers in this way were wonderful. By striking two stones together, the experimenter will find that the sound is conveyed to a great distance, and also that it is very loud. Most kinds of fish are voracious feeders, and prey upon each other without the slightest ceremony; and the greatest difficulties of the angler are experienced after the fish have had a good feed, when even the most practised artist, with his most seductive bait, will not induce them to nibble, far less to bite. Many of our fish have a digestion so rapid as only to be comparable to the action of fire, and in good feeding-grounds the growth of a fish usually corresponds to its power of eating. In the sea there exists an admirable field for observing the cannibal propensities of the fish world, where shoals of one species have apparently no other object in life than to chase another kind with a view to eat them; and what goes on in the sea on a wholesale scale is imitated on a smaller scale in the loch and the river. To compensate for the waste of life incidental to their place of birth and their ratio of growth, nature has endowed this class of animals with an enormous power of reproduction. Fish yield their eggs by tens of thousands or millions, according to the danger that has to be incurred in the progress of their growth.
All fish are enormously fecund; indeed there is nothing in the animal world that can in this respect be compared to them, except perhaps a queen bee, which has fifty or sixty thousand young each season; or the white ant, which produces eggs at the rate of fifty per minute, and goes on laying for a period of unknown duration; not to speak of that terrible domestic bugbear which no one likes more particularly to name, but which is popularly supposed to become a great-grandfather in twenty-four hours. The little aphides of the garden may also be noted for their vast fecundity, as may likewise the common house-fly. During a year one green aphis may produce one hundred thousand millions of young; and the house-fly produces twenty millions of eggs in a season!
When I state that the codfish yields its eggs in millions, and that a herring of six or seven ounces in weight is provided with about thirty thousand ova, it will at once be seen that the multiplying power of all kinds of fish is enormous; but then the drain on fish life, consequent on the habitat of these animals, is immense, or at least of corresponding magnitude. Although there may be thirty thousand eggs in a herring, the reader must bear in mind that if these be not vivified by the milt of the male fish, they just rot away in the sea, and never become of any value, except perhaps as food to some minor monster of the deep. Millions upon millions of the eggs that are emitted by the cod or the herring never come to life at all—many of them from the want of the fructifying power, and others from being devoured by enemies. Then, again, of those eggs that are so fortunate as to be ripened, it is pretty certain, I think, from minute and careful inquiry, that fully ninety per cent of the young fish perish before they are six months old. Were only half of the eggs to come to life, and but one moiety of the young fish to live, the sea would so abound with animal life that it would soon be impossible for a boat to move in its waters. But we can never hope to realise such a sight; and when it is considered that a single shoal of herrings consists of millions and millions of individual fish, and takes up a space in the sea far more than that occupied by the parks of London, and yet gives no impediment to navigation, my readers will see the magnitude of our fish supplies; but, from the destruction of fish life by natural causes, the breeding supply is kept down to an amount that cannot, in my opinion, be very far from the point of extermination; and hence I am prepared to argue the urgent necessity of regulation, continued statistical inquiry, and the adoption of fish-culture as an adjunct to the natural supplies.
The figures of fish fecundity are quite reliable, and are not dependent on mere guessing or imagination, because different persons have taken the trouble, the writer amongst others, to count the separate eggs in the roes of some of our fish, in order to ascertain exactly their amount of breeding power. It is well known that the female salmon yields her eggs at the rate of about one thousand for each pound of her weight, and some fresh-water fish are still more prolific; the sea fish, again, far excelling them in reproductive power. The sturgeon, for instance, is wonderfully fecund, as much as two hundred pounds weight of roe having been taken from one of these fish, yielding a total of 7,000,000 of eggs. I have in my possession the results of several investigations into the question of fish fecundity, which were conducted with careful attention to the details, and without any desire to exaggerate: these give the following results:—Codfish, 3,400,000; flounder, 1,250,000; sole, 1,000,000; mackerel, 500,000; herring, 35,000; smelt, 36,000. Mr. Frank Buckland, who some time ago investigated this part of the fish question, quite corroborates such numbers as being correct, having found equally great quantities in fish dissected by himself.