"Because if you do, the salmon will struggle against the meshes of the net, bruise himself, and probably scrape off some scales. I told you how easy it is for a fish to get diseased if he loses any of his scales. If you keep the net about four inches below the water, the fish has the resistance of the water to fight against, and it will tire him out quickly without doing any harm."
"All right," Colin answered, and commenced scooping for the fish. In a minute or two he had a large twenty-pounder in the net and he raised it until the bottom was a little below the water, as he had been told.
"You're right about getting wet!" cried Colin, laughing, as the salmon began to whirl and plunge and dance in the net, sending a shower of water all over him and nearly blinding him by the force
with which the drops of water struck as they were splashed upwards by the powerful strokes of the fish's tail.
The instant the salmon stopped struggling, the hatchery boatman seized it by the tail with a strong grip, swung it clear out of the net and over his left arm, laying it immediately on the measuring platform. This consisted merely of a wide board with an upright at one end, a rule giving both metrical and standard measures being nailed to the side of the board. Instantly the measurer called out the length and the professor noted it down, the hatchery foreman—famous for his expertness in judging the weight of a fish—calling out the weight to be recorded. Laying down his pencil, the professor then, with a small punch, made a tiny hole in the tail-fin of the salmon, the fish having been thrown over the captor's left arm again, slipped an aluminum button through the hole, and riveted it securely. The entire process took less than a minute and a half, and by the time the salmon had been released and tossed into the water again, Colin was ready with another fish.
"I don't see why the fish don't die as soon as they come out of the water!" exclaimed Colin.
"For nearly a minute, some fish breathe bet
ter out of the water than in it," the professor answered, "but after that the gills stick together and the fish strangles. Two or even three minutes will not injure salmon, and some fish will recover if they are out of water for hours. Indeed, there are some fish that live out of water most of the time."
"Live out of water?" the boy said in surprise.
"Certainly. Some kinds of fish, at least, can't stay in the water very long, but remain perched up on the rocks."