THE PIPE FISH (Syngnathus acus).
The fifth order, Teleostea, or bony fishes, constitutes a lengthy series. Among it must be placed the globular and phosphorescent sun-fish, the spiny globe-fish, the bony trunk-fish, and the cuirassed pipe-fish, the sea-horse, which has a head not unlike a horse, and floats vertically, the flying-fish, the eels, herrings, salmon, carp, cod, flat-fish, mullets, tunnies, and others too numerous to mention. It is for man’s purposes the most important of all the orders.
THE FLYING-FISH (Exocœtus exiliens.)
The flying-fish have been incidentally mentioned before in this work. Captain Basil Hall observed a flight of 200 yards; they have come on board a vessel fourteen or fifteen feet, and into the chains of a line-of-battle ship twenty feet above the water. They are considerably harassed by the attacks of other fish, and when they take to the air often fall victims to gulls and other sea-birds. Sharks and dolphins are their particular enemies. Their glittering, silvery brilliancy is most beautiful in the brightness of tropical seas.
Among the most important bony fishes must certainly be first placed the salmon, which includes three well-known species, Salmo salar (the salmon itself), S. fario (the salmon trout), and S. trutta (the trout). The early life of the salmon is interesting. The infant fry is primarily, of course, very helpless, and during the first two or three weeks of its existence carries about with it, as a provision for food, a portion of the yolk of the egg from which it was hatched. This generally lasts it from twenty to forty days. It is two years before the youngster ventures out to sea. In the first stage the young salmon is called a parr; during the second it is a smolt, i.e., a parr plus a covering of silvery scales. The smolt, which in the course of its two or more years’ stay in the river has only attained a growth of six or eight inches, returns from the sea in a couple of months weighing three or four pounds, and after six months ten or twelve pounds. It is now a grilse.
Dr. Bertram says of the salmon’s growth:—
“The sea-feeding must be favourable, and the condition of the fish well suited to the salt-water to ensure such rapid growth—a rapidity which every visit of the fish to the ocean serves but to confirm. Various fish, whilst in the grilse state, have been marked to prove this; and at every migration they returned to their breeding-stream with added weight and improved health. What the salmon feeds upon whilst in the salt-water is not well known, as the digestion of the fish is so rapid as to prevent the discovery of food in their stomachs when they are captured and opened. Guesses have been made, and it is likely that these approximate to the truth; but the old story of the rapid voyage of the salmon to the North Pole and back again turns out, like the theory upon which was built up the herring migration romance, to be a mere myth.
“None of our naturalists have yet attempted to elucidate that mystery of salmon life which converts one-half of the fish into sea-going smolts, whilst as yet the other moiety remain as parr. It has been investigated so far at the breeding-ponds at Stormontfield, but without resolving the question. There is another point of doubt as to salmon life which I shall also have a word to say about—namely, whether or not that fish makes two visits annually to the sea; likewise, whether it be probable that a smolt remains in the salt water for nearly a year before it becomes a grilse. A salmon only stays, as it is popularly supposed, a very short time in the salt water; and as it is one of the quickest-swimming fishes we have, it is able to reach a distant river in a very short space of time, therefore it is most desirable we should know what it does with itself when it is not migrating from one water to the other; because, according to the opinion of some naturalists, it would speedily become so deteriorated in the river as to be unequal to the slightest exertion....