National Geographic : 1912 May
THE CAZADERO DAM, ON THE COLUMBIA RIVER, OREGON Note the fish ladder just to the right of the dam. The fish attack the fall along its entire length, but the best place from which to photograph them is in the corner under the head of the ladder. The Cazadero Dam is 40 feet high, so of course it is impassable, but the fish never seemed discouraged. Morning and evening, all during the run, they leaped at the foot of the apron, apparently undaunted by the heavy blows received in landing on the bucket or the rocks (see photos, pages 506 to 515). The hatchery is located in a curve of the big flume leading from the dam, and about a quarter of a mile downstream. Photo and note by Shirley C. Hulse. nets, and giving canners all the raw ma terial they can use. The next year the species is so scarce as to be practically absent. In 1907 the Puget Sound canners pre pared 433,423 cases of humpbacks, but in 1908 they were able to secure only enough fish to make 6,075 cases. In 1909 the pack was 370,993 cases, while in 1910 only io8 cases could be filled. During the six even years immediately preceding 1908 the statistics show no humpbacks whatever canned. This periodicity is an indication of the age of the fish when mature. In the case of the blueback, a large run, with the deposition of a large quantity of spawn, has its major effect four years later in the same region-that is, the normal life of this species, from its birth as an egg to its death as a parent, is four years. The humpback, on the other hand, is a biennial species, a heavy run, with a cor responding egg crop, having its effect two years later. Dr. Charles H. Gilbert, who has made prolonged studies of the Pacific salmon in the interests of the government, announces, as a practically accurate statement of fact, that the humpback dies on its second birthday. In view of the excellent quality of the humpback and its growing importance as a fresh and preserved fish, the govern ment now proposes to make a determined effort to establish in Puget Sound a large run during the off years. This experi ment will extend over several seasons, and will involve the transfer from Alaska of perhaps a hundred million humpback eggs for hatching on Puget Sound. If successful it will prove tremendously im portant commercially, and incidentally the efficacy of artificial propagation will be submitted to a crucial test.