In the months of July and August it would be difficult to find a stream, large or small, swift or slow, lake, pool, or muddy estuary, east and west of the Cascade Mountains, that has not in it immense shoals of that most irritable and pugnacious little fish the stickleback, ever ready on the slightest provocation to engage in a battle. Let friend or foe but rub against his royal person, or come nearer his private subaqueous garden than he deems consistent with safety or good behaviour, in a moment the spines are erected like spear-points, the tiny eyes glow with fury, the colours decking his scaly armour intensify, and flash with a kind of phosphorescent brightness, until the diminutive gladiator looks the impersonation of rage and fury; but as we cultivate his acquaintance, and gain a better knowledge of his real character, we shall discover that his quarrelsome disposition is not so much attributable to a morose temper, and a love of fighting for fighting’s sake, as to a higher and more praiseworthy principle.
No amount of thinking would lead one to imagine that his pugnacity arises from intense parental affection: a love of offspring, scarcely having a parallel in the living world, prompting him to risk his life, and spend a great deal of his time in constantly-recurring paroxysms of fury and sanguinary conflicts, in which it often happens that one or more of the combatants gets ripped open or mortally stabbed with the formidable spines arming the back. Skill in stickleback battles appears to consist in rapidly diving under an adversary, then as suddenly rising, and driving the spines into his sides and stomach. The little furies swim round and round, their noses tightly jammed together; but the moment one gets his nose the least bit under that of his foe, then he plies his fins with all his might, and forcing himself beneath, does his best to drive in his spear, if the other be not quick enough to dart upwards and escape the thrust; thus squaring they fight round after round until the death or flight of one ends the combat.
I have often, when tired, lain down on the bank of a stream, beneath the friendly shade of some leafy tree, and gazing into its depths watched the sticklebacks either guarding their nests already built, or busy in their construction. The site is generally amongst the stems of aquatic plants, where the water always flows, but not too swiftly. He first begins by carrying small bits of green material, which he nips off the stalks, and tugs from out the bottom and sides of the banks; these he attaches by some glutinous material, that he clearly has the power of secreting, to the different stems destined as pillars for his building. During this operation he swims against the work already done, splashes about, and seems to test its durability and strength; rubs himself against the tiny kind of platform, scrapes the slimy mucus from his sides, to mix with and act as mortar for his vegetable bricks. Then he thrusts his nose into the sand at the bottom, and bringing a mouthful scatters it over the foundation; this is repeated until enough has been thrown on to weight the slender fabric down, and give it substance and stability. Then more twists, turns, and splashings, to test the firm adherence of all the materials that are intended to constitute the foundation of the house, that has yet to be erected on it. The nest or nursery, when completed, is a hollow, somewhat rounded, barrel-shaped structure, worked together much in the same way as the platform fastened to the water-plants; the whole firmly glued together by the viscous secretion scraped from off the body. The inside is made as smooth as possible, by a kind of plastering system; the little architect continually goes in, then turning round and round, works the mucus from his body on to the inner sides of the nest, where it hardens like a tough varnish. There are two apertures, smooth and symmetrical as the hole leading into a wren’s nest, and not unlike it.
All this laborious work is done entirely by the male fish, and when completed he goes a-wooing. Watch him as he swims towards a group of the fair sex, enjoying themselves amidst the water-plants, arrayed in his best and brightest livery, all smiles and amiability: steadily, and in the most approved style of stickleback love-making, this young and wealthy bachelor approaches the object of his affections, most likely tells her all about his house and its comforts, hints delicately at his readiness and ability to defend her children against every enemy, vows unfailing fidelity, and, in lover-fashion, promises as much in a few minutes as would take a lifetime to fulfil. Of course she listens to his suit: personal beauty, indomitable courage, backed by the substantial recommendations of a house ready-built, and fitted for immediate occupation, are gifts not to be lightly regarded.
Throwing herself on her side, the captive lady shows her appreciation, and by sundry queer contortions declares herself his true and devoted spouse. Then the twain return to the nest, into which the female at once betakes herself, and therein deposits her eggs, emerging when the operation is completed by the opposite hole. During the time she is in the nest (about six minutes) the male swims round and round, butts and rubs his nose against it, and altogether appears to be in a state of defiant excitement. On the female leaving he immediately enters, deposits the milt on the eggs, taking his departure through the backdoor. So far, his conduct is strictly proper, but, I am afraid, morality in stickleback society is of rather a lax order. No sooner has this lady, his first love, taken her departure, than he at once seeks another, introduces her as he did the first, and so on wife after wife, until the nest is filled with eggs, layer upon layer—milt being carefully deposited betwixt each stratum of ova. As it is necessary there should be two holes, by which ingress and egress can be readily accomplished, so it is equally essential in another point of view. To fertilise fish-eggs, running water is the first necessity; and as the holes are invariably placed in the direction of the current, a steady stream of water is thus directed over them.
For six weeks (and sometimes a few days more) the papa keeps untiring sentry over his treasure, and a hard time he has of it too: enemies of all sorts, even the females of his own species, having a weakness for new-laid eggs, hover round his brimming nest, and battles are of hourly occurrence; for he defies them all, even to predatory water-beetles, that, despite their horny armour, often get a fatal lance-wound from the furious fish. Then he has to turn the eggs, and expose the under ones to the running water: and even when the progeny make their appearance, his domestic duties are far from ended, for it is said (although I have never seen him do it), ‘When one of the young fish shows any disposition to wander from the nest, he darts after it, seizes it in his mouth, and brings it back again.’
There are three species that come into the fresh-waters of British Columbia, to nest and to hatch their young:—
Gasterosteus serratus, the Saw-finned Stickleback (Ayres, Proc. Cal. Acad. Nat. Sc. 1855 p. 47).—Sp. Ch.: Body entirely plated; peduncle of tail keeled; the three dorsal spines conspicuously serrated on their edges; anterior fin a little in advance of the base of the pectoral; insertion of ventrals in advance of the second dorsal spine—their own spines serrated on both edges; posterior margin of caudal somewhat hollowed. The colour of the freshly-caught fish is greyish-olive along the dorsal line; but on the sides, particularly in the male, it shades away into an iridescence, like that seen on mother-o’pearl, again changing to pure silvery-white on the abdomen.
Gasterosteus Pugettii, the Puget Sound Stickleback (Grd., Proc. Acad., Nat. Sc. Phil., viii. 1856).—Sp. Ch.: Body only in part plated, peduncle of tail not keeled; the three dorsal spines without serrations; the anterior one inserted immediately behind the base of the pectorals; ventrals inserted anterior to the second dorsal spine. The colour is very much like that of G. serratus, but more decidedly purplish on the sides the eyes bright red in both species, when fresh from the water.
Gasterosteus concinnus, the Tiny Stickleback (Rich., F. B. A., p. 57, vol. iii.).—Sp. Ch.: Head one-fourth of the total length, mouth small, and teeth but feebly developed; dorsal spines nine, seventh and eighth smaller than the preceding ones, the ninth longer than any of the others. The abdomen is protected by a bony cuirass, and the ventrals represented by two spines. All the spines are moveable, and destitute of serrations. Colour of the back a bright sea-green, sides purplish-pink, shading away to a silvery-white on the belly the entire body speckled with minute black spots.