Under the Sea Wind (10 page)

Throughout that day development proceeded at a furious pace, as though in haste to make ready for the hatching that was soon to come. On the lengthening tail a thin flange of tissue appeared—the fin ridge from which a series of tail finlets, like a row of flags stiff in the wind, was later to be formed. The sides of an open groove that traversed the belly of the little fish, beneath and protected by the plate of more than seventy muscle segments, grew steadily downward and in midafternoon closed to form the alimentary canal. Above the pulsating heart the mouth cavity deepened, but it was still far short of reaching the canal.

Throughout all this time the surface currents of the sea were pouring steadily to the southwest, driven by the wind and carrying with them the clouds of plankton. During the six days since the spawning of the mackerel the toll of the ocean's predators had continued without abatement, so that already more than half of the eggs had been eaten or had died in development.

It was the nights that had seen the greatest destruction. They had been dark nights with the sea lying calm under a wide sky. On those nights the little stars of the plankton had rivaled in number and brilliance the constellations of the sky. From underlying depths the hordes of comb jellies and glassworms, copepods and shrimps, medusae of jellyfish, and translucent winged snails had risen into the upper layers to glitter in the dark water.

When the first dilution of blackness came in the east, warning of the dawn into which the revolving earth was carrying them, strange processions began to hurry down through the water as the animals of the plankton fled from the sun that had not yet risen. Only a few of these small creatures could endure the surface waters by day except when clouds deflected the fierce lances of the sun.

In time Scomber and the other baby mackerel would join the hurrying caravans that moved down into deep green water by day and pressed upward again as the earth swung once more into darkness. Now, while still confined within the egg
,
the embryonic mackerel had no power of independent motion, for the eggs remained in water of a density equal to their own and were carried horizontally in their own stratum of the sea.

On the sixth day the currents took the mackerel eggs over a large shoal thickly populated with crabs. It was the spawning season of the crabs—the time when the eggs, that had been carried throughout the winter by the females, burst their shells and released the small, goblin-like larvae. Without delay the crab larvae set out for the upper waters, where through successive moltings of their infant shells and transformations of appearance they would take on the form of their race. Only after a period of life in the plankton would they be admitted to the colony of crabs that lived on that pleasant undersea plateau.

Now they hastened upward, each newborn crab swimming steadily with its wandlike appendages, each ready to discern with large black eyes and to seize with sharp-beaked mouth such food as the sea might offer. For the rest of that day the crab larvae were carried along with the mackerel eggs, on which they fed heavily. In the evening the struggle of two currents—the tidal current and the wind-driven current— carried many of the crab larvae to landward while the mackerel eggs continued to the south.

There were many signs in the sea of the approach to more southern latitudes. The night before the appearance of the crab larvae the sea had been set aglitter over an area of many miles with the intense green lights of the southern comb jelly Mnemiopsis, whose ciliated combs gleam with the colors of the rainbow by day and sparkle like emeralds in the night sea. And now for the first time there throbbed in the warm surface waters the pale southern form of the jellyfish Cyanea, trailing its several hundred tentacles through the water for fish or whatever else it might entangle. For hours at a time the ocean seethed with great shoals of salpae—thimble-sized, transparent barrels hooped in strands of muscle.

On the sixth night after the spawning of the mackerel the tough little skins of the eggs began to burst. One by one the tiny fishlets, so small that the combined length of twenty of them, head to tail, would have been scarcely an inch, slipped out of the confining spheres and knew for the first time the touch of the sea. Among these hatching fish was Scomber.

He was obviously an unfinished little fish. It seemed almost that he had burst prematurely from the egg, so unready was he to care for himself. The gill slits were marked out but were not cut through to the throat, so were useless for breathing. His mouth was only a blind sac. Fortunately for the newly hatched fishlet, a supply of food remained in the yolk sac still attached to him, and on this he would live until his mouth was open and functioning. Because of the bulky sac, however, the baby mackerel drifted upside down in the water, helpless to control his movements.

The next three days of life brought startling transformations. As the processes of development forged onward, the mouth and gill structures were completed and the finlets sprouting from back and sides and underparts grew and found strength and certainty of movement. The eyes became deep blue with pigment, and now it may be that they sent to the tiny brain the first messages of things seen. Steadily the yolk mass shrank, and with its loss Scomber found it possible to right himself and by undulation of the still-rotund body and movement of the fins to swim through the water.

Of the steady drift, the southward pouring of the water day after day, he was unconscious, but the feeble strength of his fins was no match for the currents. He floated where the sea carried him, now a rightful member of the drifting community of the plankton.

8
Hunters of the Plankton

THE SPRING SEA
was filled with hurrying fishes. Scup were migrating northward from their wintering grounds off the Capes of Virginia, bound for the coastal waters of southern New England where they would spawn. Shoals of young herring moved swiftly just under the surface, rippling the water no more than the passing of a breeze, and schools of menhaden, moving in closely packed formation with bodies flashing bronze and silver in the sun, appeared to the watching sea birds like dark clouds ruffling to a deep blue the smooth sheet of the sea. Mingled with the wandering menhaden and herring were late-running shad, following in along the sea lanes that led to the rivers of their birth, and across the silvery warp of this living fabric the last of the mackerel wove threads of flashing blue and green.

Now, above the water where these hurrying fishes jostled the new-hatched mackerel, there fluttered for the first time that season the little flocks of Oceanites, the petrel, come back to the sea from the far south. The birds moved lightly from place to place on the level plains or the gentle hills of the sea, settling down daintily over some surface-drifting bit of plankton, hovering like butterflies come to sip the nectar from a flower. The little petrels know nothing of the northern winter, for then, in the southern summer, they have gone home from the sea to the far South Atlantic and Antarctic islands where they rear their young.

Sometimes for hours on end the surface of the sea was white with spurting spray as the last of the spring flights of gannets, bound for the rocky ledges of the Gulf of St. Lawrence, plunged from high in the air, pursuing their fish prey far beneath the surface with strong strokes of wings and webbed feet. As the southward drift of the water continued, the gray forms of sharks appeared more often in pursuit of the menhaden schools; the backs of porpoises flashed in the sun; and old, barnacled sea turtles swam at the surface.

As yet Scomber knew little of the world in which he lived. His first food had been the minute, one-celled plants in the water which he drew into his mouth and strained through his gill rakers. Later he had learned to seize the flea-sized crustaceans of the plankton and to dart into their drifting clouds, snapping up the new food with quick snatches. Along with the other young mackerel he spent most of his days many fathoms below the surface and at night rose again to move through dark water that sparkled with the phosphorescent plankton. These movements were made involuntarily as the young fish followed his food, for as yet Scomber knew little of the difference between day and night or the sea's surface and its depths. But sometimes when he climbed with his fins he came into water that was a shining golden green, where moving forms burst upon his vision with swift and terrible vividness.

In the surface waters Scomber first knew the fear of the hunted. On the tenth morning of his life he had lingered in the upper fathoms of water instead of following down into the soft gloom below. Out of the clear green water a dozen gleaming silver fishes suddenly loomed up. They were anchovies, small and herringlike. The foremost anchovy caught sight of Scomber. Swerving from his path, he came whirling through the yard of water that separated them, open-mouthed, ready to seize the small mackerel. Scomber veered away in sudden alarm, but his powers of motion were new-found and he rolled clumsily in the water. In a fraction of a second he would have been seized and eaten, but a second anchovy, darting in from the opposite side, collided with the first and in the confusion Scomber dashed beneath them.

Now he found himself in the midst of the main school of several thousand anchovies. Their silver scales flashed on all sides of him. They bumped and jostled him as he sought in vain to escape. The shoal surged over and beneath and around Scomber, driving furiously onward just under the shining ceiling of the sea. None of the anchovies was now aware of the little mackerel, for the shoal itself was in full flight. A pack of young bluefish had picked up the scent of the anchovies and swung into swift pursuit. In a twinkling they were upon their prey, fierce and ravening as a pack of wolves. The leader of the bluefish lunged. With a snap of razor-toothed jaws he seized two of the anchovies. Two clean-severed heads and two tails floated away. The taste of blood was in the water. As though maddened by it, the bluefish slashed to right and left. They drove through the center of the anchovy school, scattering the ranks of the smaller fish so that they darted in panic and confusion in every direction. Many dashed to the surface and leaped through into the strange element beyond. There they were seized by the hovering gulls, companion fishers of the bluefish.

As the carnage spread, the clear green of the water was slowly clouded with a spreading stain. A strange new taste came with the rusty color and was drawn in by Scomber with the water he passed through mouth and gills. The taste was disquieting to a small fish that had never tasted blood or experienced the lust of the hunter.

When at last pursued and pursuers had passed, the thudding vibrations of the last carnage-mad bluefish were stilled and Scomber's sense cells received once more only the messages of the strong, steady rhythms of the sea. The little mackerel's senses were numbed by the encounter with the swirling, slashing, buffeting monsters. It was in the bright waters of the surface that he had looked upon the racing apparitions, and now they had passed he made his way down from brightness into green dusk, led down fathom by fathom by the reassuring quality of the gloom which concealed whatever terrors might lurk near by.

With the descent Scomber came into a cloud of feed, the transparent, big-headed larvae of a crustacean that had spawned in these waters the week before. The larvae moved jerkily through the water, waving the plumelike legs that sprang in two rows from the slender bodies. Scores of young mackerel were feeding on the crustaceans and Scomber joined them. He seized one of the larvae and crushed its transparent body against the roof of his mouth before he swallowed it. Excited and eager for more of the new food he darted among the drifting larvae; and now the sense of hunger possessed him, and the fear of the great fishes was as though it had never been.

As Scomber pursued the larvae in emerald haze five fathoms under the surface he saw a bright flash sweep in a blinding arc across his sphere of vision. Almost instantly the flash was followed by a second blaze of iridescent glitter that curved sharply upward and seemed to thicken as it moved toward a shimmering oval globe above. Once more the thread of the tentacle crept down, all its cilia ablaze in the sunlight. Scomber's instincts warned him of danger, although never before in his larval life had he encountered one of the race of Pleurobrachia, the comb jelly, the foe of all young fishes.

Of a sudden, like a rope swiftly uncoiling from a hand above, one of the tentacles was dropped more than two feet below the inch-long body of the ctenophore, and thus swiftly extended it looped around the tail of Scomber. The tentacle was set with a lateral row of hairlike threads, as barbs grow from the shaft of a bird's feather, but the threads were filmy and tenuous as the strands of a spider's web. All the lateral hairs of the tentacle poured out a gluelike secretion, causing Scomber to become hopelessly entangled in the many threads. He strove to escape, beating the water with his fins and flexing his body violently. The tentacle, contracting and enlarging steadily from the thickness of a hair to that of a thread and then to that of a fishing line, drew him closer and closer to the mouth of the comb jelly. Now he was within an inch of the cold, smooth-surfaced blob of jelly that spun gently in the water. The creature, like a gooseberry in shape, lay in the water with the mouth uppermost, keeping its position by an easy, monotonous beating of the eight rows of ciliated plates or combs. The sun that found its way down from above set the cilia aglow with a radiance that half blinded Scomber as he was drawn up along the slippery body of his foe. In another instant he would have been seized by the lobelike lips of the creature's mouth and passed into the central sac of its body, there to be digested; but for the moment he was saved by the fact that the ctenophore had caught him while it was still in the midst of digesting another meal. From its mouth there protruded the tail and hinder third of a young herring it had caught half an hour before. The comb jelly was greatly distended, for the herring was much too large to be swallowed whole. Although it had tried by violent contractions to force all of the herring past its lips it was unable to do so and had perforce to wait until enough of the fish was digested to make room for the tail. Scomber was held in further reserve, to be eaten after the herring.