Don could never have explained what drew him at once toward those four echoes at the southern fringe of the school. It was true that they were a little apart from the rest, but others had fallen as far behind. There is some sixth sense that a man acquires when he has stared long enough into a sonar screen—some hunch which enables him to extract more from the moving flecks than he has any right to do. Without conscious thought, Don reached for the controls and started the turbines whirling once more.
The main body of the whale pack was now sweeping past him to the east. He had no fear of a collision; the great animals, even in their panic, could sense his presence as easily as he could detect them, and by similar means. He wondered if he should switch on his beacon. They might recognize its sound pattern, and it would reassure them. But the still unknown enemy might recognize it too, and would be warned.
The four echoes that had attracted his attention were almost at the center of the screen. He closed for an interception, and hunched low over the sonar display as if to drag from it by sheer will power every scrap of information the scanner could give. There were two large echoes, some distance apart, and one was accompanied by a pair of smaller satellites. Don wondered if he was already too late; in his mind’s eye he could picture the death struggle taking place in the water less than a mile ahead. Those two fainter blips would be the enemy, worrying a whale while its mate stood by in helpless terror, with no weapons of defense except its mighty flukes.
Now he was almost close enough for vision. The TV camera in Sub 5’s prow strained through the gloom, but at first could show nothing but the fog of plankton. Then a vast, shadowy shape appeared in the center of the screen, with two smaller companions below it. Don was seeing, with the greater precision but hopelessly limited range of light, what the sonar scanners had already told him.
Almost at once he saw his incredible mistake: the two satellites were calves. It was the first time he had ever met a whale with twins, although multiple births were not uncommon. In normal circumstances, the sight would have fascinated him, but now it meant that he had jumped to the wrong conclusion and had lost precious minutes. He must begin the search again. As a routine check, he swung the camera toward the fourth blip on the sonar screen—the echo he had assumed, from its size, to be another adult whale. It is strange how a preconceived idea can affect a man’s understanding of what he sees; seconds passed before Don could interpret the picture before his eyes—before he knew that, after all, he had come to the right place.
“Jesus!” he said softly. “I didn’t know they grew that big.” It was a shark, the largest he had ever seen. Its details were still obscured, but there was only one genus it could belong to. The whale shark and the basking shark might be of comparable size, but they were harmless herbivores. This was the king of all selachians—Carcharodon—the Great White Shark. Don tried to recall the figures for the largest known specimen. In 1990, or thereabouts, a fifty-footer had been killed off New Zealand, but this one was half as big again.
These thoughts flashed through his mind in an instant, and in that same moment he saw that the great beast was already maneuvering for the kill. It was heading for one of the calves, and ignoring the frantic mother. Whether this was cowardice or common sense there was no way of telling; perhaps such distinctions were meaningless to the shark’s tiny and utterly alien mind.
There was only one thing to do. It might spoil his chance of a quick kill, but the calf’s life was more important. He punched the button of the siren, and a brief, mechanical scream erupted into the water around him.
Shark and whales were equally terrified by the deafening shriek. The shark jerked round in an impossibly tight curve, and Don was nearly jolted out of his seat as the autopilot snapped the sub onto a new course. Twisting and turning with an agility equal to that of any other sea creature of its size, Sub 5 began to close in upon the shark, its electronic brain automatically following the sonar echo and thus leaving Don free to concentrate on his armament. He needed that freedom; the next operation was going to be difficult unless he could hold a steady course for at least fifteen seconds. At a pinch he could use his tiny rocket torps to make a kill; had he been alone and faced with a pack of orcas, he would certainly have done so. But that was messy and brutal, and there was a neater way. He had always preferred the technique of the rapier to that of the hand grenade.
Now he was only fifty feet away, and closing rapidly. There might never be a better chance. He punched the launching stud.
From beneath the belly of the sub, something that looked like a sting ray hurtled forward. Don had checked the speed of his own craft; there was no need to come any closer now. The tiny, arrow-shaped hydrofoil, only a couple of feet across, could move far faster than his vessel and would close the gap in seconds. As it raced forward, it spun out the thin line of the control wire, like some underwater spider laying its thread. Along that wire passed the energy that powered the sting, and the signals that steered the missile to its goal. It responded so instantly to his orders that Don felt he was controlling some sensitive, high-spirited steed.
The shark saw the danger less than a second before impact. The resemblance of the sting to an ordinary ray confused it, as the designers had intended. Before the tiny brain could realize that no ray behaved like this, the missile had struck. The steel hypodermic, rammed forward by an exploding cartridge, drove through the shark’s horny skin, and the great fish erupted in a frenzy of terror. Don backed rapidly away, for a blow from that tail would rattle him around like a pea in a can and might even damage the sub. There was nothing more for him to do, except to wait while the poison did its work.
The doomed killer was trying to arch its body so that it could snap at the poisoned dart. Don had now reeled the sting back into its slot amidships, pleased that he had been able to retrieve the missile undamaged. He watched with awe and a dispassionate pity as the great beast succumbed to its paralysis.
Its struggles were weakening. It was now swimming aimlessly back and forth, and once Don had to sidestep smartly to avoid a collision. As it lost control of buoyancy, the dying shark drifted up to the surface. Don did not bother to follow; that could wait until he had attended to more important business.
He found the cow and her two calves less than a mile away, and inspected them carefully. They were uninjured, so there was no need to call the vet in his highly specialized two-man sub which could handle any cetological crisis from a stomachache to a Caesarean.
The whales were no longer in the least alarmed, and a check on the sonar had shown that the entire school had ceased its panicky flight. He wondered if they already knew what had happened; much had been learned about their methods of communication, but much more was still a mystery.
“I hope you appreciate what I’ve done for you, old lady,” he muttered. Then, reflecting that fifty tons of mother love was a slightly awe-inspiring sight, he blew his tanks and surfaced.
It was calm, so he opened the hatch and popped his head out of the tiny conning tower. The water was only inches below his chin, and from time to time a wave made a determined effort to swamp him. There was little danger of this happening, for he fitted the hatch so closely that he was quite an effective plug.
Fifty feet away, a long gray mound, like an overturned boat, was rolling on the surface. Don looked at it thoughtfully, wondering how much compressed air he’d better squirt into the corpse to prevent it sinking before one of the tenders could reach the spot. In a few minutes he would radio his report, but for the moment it was pleasant to drink the fresh Pacific breeze, to feel the open sky above his head, and to watch the sun begin its long climb toward noon.
Don Burley was the happy warrior, resting after the one battle that man would always have to fight. He was holding at bay the specter of famine which had confronted all earlier ages, but which would never threaten the world again while the great plankton farms harvested their millions of tons of protein, and the whale herds obeyed their new masters. Man had come back to the sea, his ancient home, after aeons of exile; until the oceans froze, he would never be hungry again…