Part 16 (1/2)

”When the salmon come in from the sea,” the professor began, ”there is a great deal of hesitation among them sometimes before they go up the river to sp.a.w.n, and we want to find out whether they go back to the sea again, whether they swim directly up the stream, or whether they remain in the brackish water at the mouth of the river.”

”If you don't mind my saying so, what is the use of knowing?” asked Colin. ”I mean, what does it matter as long as the salmon sp.a.w.ns?”

”The salmon is one of the most important food fishes of the country,”

the professor said rebukingly, ”and it is as important for us to know all about its habits as it is to know about the way a grain of wheat grows.”

”I hadn't thought of that,” Colin said, a little shamefacedly. ”I suppose everything really is important, no matter how small.”

The professor smiled at him.

”If you have much to do with studying fish,” he said, ”or, indeed, with any kind of science, you will find out it is always the little things that tell the story. Take the grain of wheat again. If one kind of wheat ripens two days earlier on an average than another kind, you might think that so small a difference wouldn't be of great importance, but those two days might--and often do--make the difference between a good crop and one which is frost-bitten and spoiled.”

”That's a lot easier to see,” agreed the boy. ”But, sir,” he objected, ”you can pick out one little bit of a field and work on that, and it will 'stay put.' Fishes wander all over the place.”

”We want them to do so, my boy,” was the reply.

”How can you work on separate fish? One looks so like another!”

”And for that very reason we're going to tag them.”

”Tag them?”

”With a little aluminum b.u.t.ton fastened to their tail, just as bad youngsters fasten a tin can to a dog's tail. Every tag has a number, and we use aluminum because it corrodes rapidly in salt water.”

”Then I should think,” said Colin, ”that was the very reason why you shouldn't use it.”

”Why not?” asked the professor mildly. ”We know that the salmon are not going to stay in the salt water, because they are going up the river to sp.a.w.n. If, therefore, we catch a fish in the nets higher up stream, with the tag bright and s.h.i.+ning, we know that it hasn't been in salt water at all; if dull and just a little worn away, that the fish with that tag has been staying in the brackish water near the mouth of the river; but if it is deeply corroded, that the fish returned to sea for a time. As you see, a good deal of information is gathered that way. But in the morning you will have a chance to see how it is done, and then the results--when they are published--will seem more interesting.”

”Have you been a.s.sociated with the Bureau of Fisheries, Professor Podd?”

Colin asked.

”Not directly,” the other replied. ”I should have enjoyed it, and it seems to me a work of the first importance, but every man is apt to think that about his own work, or work that is like his own. But I can tell you what decided me, nearly twenty years ago, to give all my spare time to the fishery question.”

”What was that?” asked Colin.

”It was a phrase in a lecture that Dr. Baird, the founder of fish culture in America, was giving about the need of the work. He pointed out that there was more actual life in a cubic foot of water than in a cubic foot of land, and closed by saying, 'The work of conserving the Fisheries of the United States will not be finished until every acre of water is farmed as carefully as every acre or land.'”

”I never quite thought of it as farming,” said the boy.

”Nor had I, before that time,” the professor said. ”But ever since then I have seen that we of the present time are the great pioneers, the discoverers, the explorers of this new world. Instead of blazing our trail through a wilderness of trees we dredge our way through a wilderness of waters; instead of a stockade around a blockhouse to protect us against wild beasts and wilder Indian foes, we have but a thin plank between us and destruction; instead of a few wolves and mountain-lions to prey upon the few head of stock we might raise, we have thousands of millions of fierce, finny pirates with which to do battle, and we work against odds the old pioneers could not even have estimated!”

”That's great!” cried Colin, his eyes s.h.i.+ning.

”The surface of the sea,” the professor continued, warming to his subject, ”reveals no more of its mystery than the smoke cloud above the city tells the story of the wild race of life in its thronging streets, or than the waving tips of a forest of mighty trees reveal the myriad forms below. Each current of the ocean is an empire of its own with its tribes endlessly at war; the serried hosts of voracious fish prey on those about them, fishes of medium depth do perpetual war upon the surface fish, and some of these are forced into the air to fly like birds away from the Nemesis below.”

”And much is still unknown, isn't it?”

”We are discovering a new world!” was the reply. ”No one for a moment can deny the greatness of the finding of America, and Columbus and the other early navigators are sure of immortal fame, but even so, what was the New World they found to the illimitable areas of unknown life, in the bottom of the sea, that have been made known to man. Think of the wonder that has been revealed by the _Challenger_ and other s.h.i.+ps that have explored the ocean beds!”

”There is still a great deal unknown, isn't there?”