NEST-BUILDING FISHES.
Not alone in color do fishes resemble birds. In the home-life and love of offspring a close resemblance obtains. Many are nest-builders, erecting structures quite as complicated as those of some birds, and hardly less elaborate in design and finish.
Floating along some woodland stream, or strolling along its grass-fringed margin, we have watched the domestic life of the Sun-fish, the Eupomotis vulgaris of writers, that mottled, bespangled beauty that seems always on hand to be caught by the angler in default of more noble game.
Where delicate grasses grow, and floating lily-pads cast their shadows, there among the winding stems the Sun-fish builds its home. Moving in pairs in and out among the lilies near the shore, as if jointly selecting a site for a nursery, they may be seen. The spot is generally a gravelly one, and, once determined upon, no time is lost in pushing the work to a speedy conclusion. For several inches around the space is cleared of stems or roots, and these are carefully carried away. The smaller roots are swept aside by well-directed blows of their tails, or by mimic whirlpools which the fishes, standing over the nest, create by their fins. The stones are next taken up, the smaller ones in their mouths, the larger being pushed out bodily, or fanned away by the sweeping process, until an oval depression, with a sandy bottom, finally appears. About the sides the stems of aquatic verdure, which seem to have been purposely left, may be seen standing, and these now naturally fall over, oftentimes constituting the nest a perfect bower, with walls bedecked with buds, while the roof is a mat of white lilies floating upon the surface. Here the eggs are deposited, the male and female alternately watching them.
NEST OF COMMON SUN-FISH.
Male and Female Defending It from Attack of Cat-fish.
While the Sun-fish is always recognized as the most peaceful of the finny tribe, and only chasing in wanton playfulness its neighbors, it is otherwise when the passions are wrought to a high pitch of excitement through the play of amatory influences in the spring-time. Let a stranger, a bewhiskered cat-fish, approach the bower, and war is at once declared. The little creatures snap at the intruder with anger and defiance. Their sharp dorsal fins stand erect, the pectorals vibrate with repressed emotion, while the violent movements of their powerful tails evince a readiness and determination to stand by their home at all hazards. Indeed, so vigorous is their charge, that even large fishes are forced to retreat, and, as the Sun-fishes build in companies, the intruder often finds himself attacked by a whole colony of them.
Nearly all the Sun-fishes are nest-builders, some forming arbors, as we have seen, others scooping out nests on sandy shoals, while one, the Spotted Sun-fish, is more democratic, affecting muddy streams, where, on the approach of cold weather, it makes a nest in the muddy bottom, and there it lies dormant till the coming spring.
Who has not made friends with the Dace—Rhinichthys atronasus? He is a veritable finny jester. We have watched him in his watery retreat, and, perhaps unseen, have played the spy upon his domestic proceedings.
Life is a gala time to these little fishes. They have seemingly never a care or a bother. In jest they join in the chase of some curious minnow that intrudes upon their presence, suddenly changing their course to dash at some resplendent dragon-fly that hovers over the leafy canopy of their home, and as quickly darting off again to attack some bit of floating leaf or imaginary insect.
All is not play, however, even among the Dace. The warm days of June usher in the sterner duties, the nesting-time. Male and female join in the preparation, and a locality, perhaps in shallow water in some running brook, is selected. Roots, snags and leaves are carried away, both fishes sometimes found tugging away at a single piece, taking it down-stream, and working faithfully and vigorously until, in a few hours, a clearing over two feet in diameter is the result.
There the first eggs are laid. The male, who has retired, soon appears from up-stream, bearing in his mouth a pebble, which is placed in the centre of the clearing. Now they both swim away, but soon returning, each bearing a pebble, that is also dropped upon the eggs. Slowly the work proceeds, until a layer of clean pebbles apparently covers the eggs. A second layer of eggs is now deposited by the female, and these are covered by pebbles as the others had been, the industrious little workers scouring the neighborhood for them, seemingly piling up eggs and stones alternately until the heap attains a height of eight inches or more. These heaps vary in shape, some being pyramidal, and others dome-shaped.
Such patience as these finny housekeepers manifest is not appreciated by man. The gleaners of the golden fields, in whose waters our little friends are found, have not discovered their secret, and think the curious piles the washes of the brook itself. But their purpose is the protection of their eggs. In swift-running streams, which these fish are so wont to affect, the eggs would be washed away, and, driven against rocks and snags, would be destroyed, or, even escaping destruction, would, by the undulating movement to which they would become subjected, be rendered impossible of incubation. Besides, were they not thus protected, even though there was no danger of being washed away, they would become easy prey to the attacks of carnivorous fishes.
Unlike as the Lamprey-eels are in structure to the Dace, yet in their habits of erecting a nest they are very similar. Upon our Eastern sea-board they are a common species, inhabiting both salt and fresh water. In the early spring they follow the shad up the rivers, occasionally preceding them, and search about for suitable localities in which to deposit their spawn. They clean away the stones as the Dace were seen to do, bending their long bodies in coils, which they use in pushing aside the accumulation on the bottom. To the unlearned the appearance of two Eels, each three feet in length, twisting and seemingly coiling about each other, would be indicative of war. But having cleaned for themselves a smooth spot, the Lampreys proceed to place stones. Irregularly-shaped stones of small size are easily and quickly transported in their mouths, but when stones that weigh several pounds are to be brought, the tactics they adopt are worthy of an engineer. As the spots chosen for the rearing of their submarine castles are ordinarily subjected to a swift current, the largest stones, which it would be thought impossible for them to move, are looked for up stream. A suitable one found, and a favorable position presented, the sucking mouth is fastened to it, and by a convulsive effort, the tail of the fish being raised aloft, the heavy stone is lifted from its place, the current pushing against the fish and stone, bearing them along several feet before they sink. Another effort of the fish, and the rock is again raised and carried down stream, until finally, by repeated liftings and struggles, the ingenious, persevering nest-builder is swept down to the nest, where the load is deposited. This laborious work is carried on until the pile has attained a height of two or three feet, and a diameter of four. No special form seems to be necessary. The nest is generally oval, compact and well devised to contain the eggs, which are carefully deposited within, thus affording protection in its numerous interstices for the young when they hatch. When about six inches long, the young Petromyzon marinus, which is a strange little fellow, is devoid of teeth, and blind, and possesses so many characteristics distinct from the parent, that for a long time he was considered a separate species, and even assigned a place in a different genus. Enormous nests are sometimes built. John M. Batchelder, Esq., describes one, which he saw in the Saco River, Maine, that was about fifteen feet long, and from one to three feet in height, its position and triangular shape in vertical section being well adapted for securing a change of water, and a hiding-place for the young. The operation of building was very methodical, a hundred and more Eels being at work upon the structure. Water-worn stones, chips of granites and fragments of bricks, sometimes weighing as much as two pounds and transported by a single individual, were utilized in the building.
BLACK-NOSED DACE.
Constructing Their Nest of Pebbles.
More remarkable, however, than any previously described, are the nests of the Fresh-water Chub, Semotilus bullaris, which is known in some localities as the Stone Toter. This fish attains a length of about fifteen inches. The finest nests are on the shores of Westminster Island, but they are common on nearly every island that has a sandy, gravelly shore among the many that make up the Thousand Islands. The nest is a pile of stones, sometimes measuring ten feet across at the base, four feet in height, and containing a good-sized cart-load of stones, weighing in all perhaps a ton. Stones from small pebbles to some four inches in length were used, and as some of the nests are placed at considerable distances from the gravel-beds, and each stone represented a journey, the amount of labor performed, when it is considered that tens of thousands of stones must have been used in the building, certainly was incredible. Each stone is brought in the mouth of the Chub and dropped over the piles, one or more fishes working at the same heap. Some plan is evidently followed in the work, the first deposit of stones being small, and dropped so as to form a circle or semi-circle. The largest heaps are undoubtedly the work of successive years, the nests being annually added to during the last of May or June, when the Chubs are seen lying in the heaps, at which time the eggs are probably deposited. All the labor of piling up is to protect them from predatory fishes, a necessary and wise provision, as cat-fish, rock-bass, perch and others prey upon the eggs.
In gravelly beds the Trout excavates a simple nest, a mere depression in the sand, that is not at all incomparable to the nest of some species of gulls. A furrow in the gravelly bottom of a river, often ten feet in length, the depression being made as fast as it is required, is the nest of the Salmon. In Canadian rivers these nests can be easily distinguished by the lighter marking in the bottom.
Few persons of the many who delight to drift along our sea-shores are unfamiliar with the Toad-fish. So closely does he in shape and color resemble a moss-covered stone that his enemies are deceived. Intrenched among the weeds and gravel, which the mother-fish carelessly throws aside, after the fashion of some of the gulls, the young are reared, their yolk-sacs enabling them to cling to the rocks of the nest soon after birth. There, under the watchful eye of the parent, they remain until old enough to swim away.
But the most vigilant of all nest-builders is the Four-spined Stickleback—Apeltes quadracus. In some neighboring stream, that sooner or later finds its way to the ocean, he may be found. There are different species of these fish, but their architectural ideas are pretty much the same. They vary mainly in the locations they select for nesting. Some place the nests upon the bottom, concealed among the sea-weed found there, while others hang theirs from some projecting ledge, or swing it in the tide from the sunken bough of some overhanging tree. As is unusual, the work of nidification is solely performed by the male Stickleback, the female taking no part in the labor. The spawning season having arrived, he, assuming a bright nuptial lustre, shows remarkable activity in selecting a site for an edifice, and transporting the building material thither. Fragments of all kinds of plants, gathered often at a distance, are brought home in his mouth. These are arranged as a sort of a carpet, but as there is danger of the light materials being carried away by the current, they are weighted down by sand to keep them in their places. Having entwined them with his mouth to his complete satisfaction, he then glides gently over them on his belly, and glues them with the mucus that exudes from his pores. More solid materials, sometimes bits of wood, sometimes bits of straw, which he seizes with his mouth, are adjusted to the sides of the floor to constitute the walls. He is now very particular. If the piece cannot be properly adjusted to his building, and he does not lose patience in his efforts to fit it in, he carries it to some distance from the nest and leaves it. After the side walls are erected, a roof of the same materials with the floor is laid over the chamber. Firmness is given to the whole structure by passing over it with his body, the light and useless particles being fanned away by the action of his fins and the vibratory movements of his tail. In carrying on his building operations care is taken to preserve a circular opening into the chamber, his head and a great part of his body being thrust therein, thus widening and consolidating it, and rendering it a fit receptacle for the female. When choosing material, the fish has been seen testing its specific gravity by letting it sink once or twice in the water, and if the descent was not rapid enough finally abandoning it.
Of the exact method used by the fish in binding the nest together we are indebted to Prof. Ryder. The male fish spins from a pore or pores a compound thread, using his body to insinuate himself through the interstices through which he carries the thread. The thread is spun fitfully, not continuously. He will go round and round the nest perhaps a dozen times, when he will rest awhile and begin anew. Its shape is somewhat conical before completion. The thread is wound round and round the nest in a horizontal direction, and when freshly spun is found to consist of six or eight very thin transparent fibres, which have alternated tapering ends where they are broken off. Very soon after the thread is spun, particles of dirt adhere to it, and render it difficult to interpret its character. The nest measures one-half of an inch in height, and three-eighths in diameter.
The time occupied in collecting materials and constructing the nest is about four hours, and when all is ready the male starts out to seek a female, and, having found her, conducts her with many polite attentions to the prepared home. The eggs being deposited, the male establishes himself as a guardian of the precious treasures, not even suffering the female to approach it again. Every fish that comes near, no matter how large, is furiously assailed. He gives battle valiantly, striking at their eyes and seizing their fins in his mouth. His sharp dorsal and ventral spines are very effective weapons in his defence. Constant watchfulness upon the part of the male is needed, for, if he go away for only a few moments, the sticklebacks and other fish lurking in the vicinity rush in and devour the eggs in an instant. A whole month he is occupied in providing for the safety of his offspring. About the tenth day he employs himself in tearing down the nest and carrying the material to some little distance. The fry may now be observed in motion. And these the male continually nurses, suffering no encroachment, and if the young brood show a tendency to stray beyond bounds, they are driven back within their precincts, until they are strong enough to provide for their own living, when both old and young disappear together.
But nothing in the lives of all these little nest-builders is more interesting than the intelligence they display and the facility with which they adapt themselves to circumstances. They seem to be able to grasp almost instantly the conditions of the environment, and to employ a wise discrimination in suiting them to their wants. Hardly two nests are alike. Marked differences in details of structure, configuration and surroundings are apparent, which prove that these creatures are controlled by reason, rather than instinct, in the elaboration of their homes. That they have some means of communicating their desires to each other cannot be doubted. When the male has laid hold of a stem, a pebble or a stick that completely baffles all effort at removal, his mate seems summoned to his assistance, and the united strength of the pair accomplishes the object to be gained. There is ever noticeable in whatever the sexes undertake some concert of action which would put to shame the boasted intelligence of man himself. The Sun-fishes, as has been said, nest in companies. When the combined effort of two individuals is unable to expel an invader, the entire community, as by a single mighty impulse, rises up against the foe. There is evidence of some form of society, even though simple in its organization, where individual members league themselves together for mutual protection and defence. Other examples might be cited to give the reader a common-sense estimate of the comparatively high order of intelligence that characterizes the actions of many of our fishes.