National Geographic : 1939 Feb
FISHING IN PACIFIC COAST STREAMS back and forth over the female when she is resting near the bottom of the nest, or he will nudge her in the side with his snout. Spawning occurs in the nest, the eggs and milt being shed at the same instant. At one time the greatest of all sockeye salmon streams was the Fraser River of British Columbia. The main part of the catch by Puget Sound fishermen was made as these fish were migrating to this magnificent salmon stream. But in 1913 and 1914 heavy slides occurred while a railroad was being built, blocking the migration of the sockeye to their spawning grounds. Up to the present the sockeye have not regained their former abun dance in this river, even though the obstruc tions to their migration have been removed. To remedy the lack of rebuilding of the sockeye salmon stock in the Fraser River, the United States and Canada, on July 28, 1937, ratified a treaty for the study of this species. Pink, or Humpback, Salmon (Oncorhynchus gorbuscha) Though pink, or humpback, salmon are found from northern Japan to Alaska and southward to central California, they are taken commer cially in large quantities only from Puget Sound northward. Throughout their range they pass part of their life cycle in the sea and part in streams (Color Plate X). In southeastern Alaska these fish begin their migration from the sea in late June and con tinue until late September, but do not migrate far upstream to deposit their eggs. They usually spawn in the smaller streams not far above tidewater, or in the smaller tributaries near the mouths of the larger rivers. Spawning does not begin in the streams until the middle of August, and the fry remain all winter, emerging from the gravel of their nest the next March or April, when they migrate directly to the sea at a length of about one inch. They remain in the sea for a year and a half and return to spawn at two years of age. While at sea they grow to an average of three to eight pounds. An 11-pound pink salm on is considered record size. Thus the spe cies is the smallest of the Pacific coast salmons. It differs from the other species of salmon in having very small scales, even smaller than those found on the steelhead trout. The name "humpback" is derived from the hump found on the back of the male while on its spawning grounds. A hooked snout, too, develops on the male as soon as it enters fresh water streams for spawning. The humpback is caused by the sudden formation of cartilagi nous tissues between the back of the head and the beginning of the dorsal fin. The hooked snout results from rapid elongation of bones in its upper part. For these and other salmon to be of com mercial value they must be caught while on their way to the stream mouths before they enter fresh water. Their flesh loses its best flavor by the time the humpback and hooked snout have developed. Only about 200,000 pounds of pink salmon were caught in the Pacific Coast States in 1934; nearly 300 million pounds were landed in Alaska that year. The fish is taken commer cially in purse seines, haul seines, and traps. Since it does not take the hook like the silver and chinook salmon, it is not considered a game fish. Chum, or Dog, Salmon (Oncorhynchus keta) The chum, or dog, salmon occurs from north ern Japan to Alaska and southward to the Sacramento River (Color Plate XI). Like fry of the pink salmon, the young go down to the sea immediately after they emerge from their nests and remain there until ma turity. In their third to sixth year they re turn to the fresh-water streams of their birth to spawn and die. This migration occurs in Alaska from June to November. At spawning time they have attained a length of from two to three feet and a weight of from 5 to 12 pounds, never more than 16 pounds. The careful observer has little difficulty in distinguishing the sexes of breeding salmon and trout, for the breeding male is usually more highly colored than his mate and his body is compressed (sides flattened), while that of the female is more rounded. Usually the snout is somewhat hooked or arched in the male; that of the female is normal. Experienced fish culturists are able to tell the sex of spawning salmonids by feeling them with their hands, the males having on the underside of the abdomen two hard ridges. The chum salmon builds nests on gravel riffles of streams and deposits its eggs in a man ner similar to that of other species of salmon and trout. Eggs and milt are discharged at the same time, and Nature has so beautifully co-ordinated each step in the breeding activi ties that the eggs, or ova, are fertilized the instant they are shed. Otherwise they would probably not be fertilized at all, for the cur rent would carry the sperm downstream from the nest. The chum salmon is not sought by sports men, since it does not take artificial lures or bait. The commercial catch is taken in traps, purse seines, and other nets. The flesh is pale pink and, when canned, rather light yellowish. It is especially good for freezing, salting, and smoking, but is of an inferior quality when canned. In former years the chum salmon was not taken very exten sively for commercial purposes, but in more recent times, for example in 1934, more than 73 million pounds were caught in Alaska and nearly 11 million in the States.