"Then," said the other, "it is easy to see that the respective size of land and water has very little to do with the general fishery question. But if a seal or a fish must come to the land or to narrow rivers to spawn, it follows that man possesses the power to determine whether spawning shall continue or not, doesn't it?"
"Yes," agreed Colin, "I suppose it does."
"And if you protect the seals, the herd will increase."
"It ought to."
"Very good. That is just the work we are doing here. The salmon come into fresh water to spawn—just like shad and a number of other species of fish—and when you kill a salmon just about to ascend the river, you destroy at the same time the thousands of eggs she bears."
"But I thought salmon were always caught running up a stream?" said Colin in surprise.
"They are," was the quick response; "by far the larger number are caught that way, and as long as a certain proportion go up the stream there's no great harm done. But if every one of the salmon is caught, as happens when nets are put all the way across a stream, there will be none to spawn, and in a few years there will be no fish in that river."
"Do the fish always return, when grown up, to the river in which they spawned?"
"That is disputed. But the large proportion of such fish do not travel very far from the mouth of the river in which they were born and the natural impulse for fresh water at spawning-time leads them naturally to the nearest stream. So, it is imperative that some fish be allowed to go up-stream, or in other words, that salmon-catchers allow a certain proportion to escape their wheels and nets."