ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 7 



alevins that live to attain the fry stage, and that the eggs not so 

 covered are either consumed by active natural enemies or are de- 

 stroyed by the vegetable mold known as fimgns. The experiments 

 have shown that the burial of freshly fertilized eggs of Pacific 

 salmon in sand or gi^avel to the depth stated does not smother them, 

 but that eggs so treated will hatch, and the resulting alevins will 

 possess the instinct and power to work their way gradually to the 

 surface after the disappearance of the food sacs, at which stage of 

 development they are not attacked by fungus. Eggs buried under 

 from 2 to 3 inches of gravel w^ere found to produce alevins coming 

 to the surface before the sacs had been absorbed, and they were 

 therefore subject to fungus, a very large percentage of them being 

 destroyed in that way, as well as by the more-developed forms of 

 aquatic life. The sacs of fry resulting from eggs buried less than 4 

 inches deep are so thinly covered when they reach the surface that 

 few, if any, of the fish survive the effects of fungoid growths, and, as 

 such growths are very common in the beds of streams where large 

 numbers of salmon have spawned and died, it follows that very 

 heavy losses of eggs must occur on eggs naturally deposited. 



The yield of eggs from the chinook salmon will average from 3,000 

 to 6,000 per fish. The eggs are of a deep, salmon-red color, measur- 

 ing about one-fourth of an inch in diameter, and are heavier than 

 water. 



In view of the enormous annual catch of this salmon for com- 

 mercial purposes, the necessity for its propagation became mani- 

 fest at an early period in the history of the Pacific fisheries. For- 

 tunately, it is readily susceptible of artificial production on a large 

 scale; otherwise the supply in western rivers would by this time 

 have m-aterially fallen off. Since tlie work began in 1873 on the 

 McCloud River it has gi'own to larger proportions. It now engages 

 the attention of all the coast State governments, as well as that of 

 the Federal Government, and the work is steadily growing in im- 

 portance. 



As the salmon ascend the rivers they are caught by gill nets, fyke 

 nets, pounds, weirs, seines, wheels, and other devices, but in the 

 Sacramento and Columbia Rivers the greater numbers are caught 

 as they head upstream with gill nets drifting with the current or 

 tide. In the rivers they are comparatively safe from enemies, but 

 immense numbers are destroyed at the mouths of the streams by seals 

 and sea lions. 



This species has been introduced into Australia, New Zealand, and 

 Europe, but so far as is known New Zealand is the only country 

 where its acclimatization has been effected. Efforts have been made 

 to establish it in Atlantic streamb of the United States, but with- 

 out permanent results. In some of the fresh-water lakes of New 

 England the chinook salmon has been introduced purely for angling 

 purposes. In such instances permanent fisheries can not be ex- 

 pected save by restocking. 



BLUEBACK SALMON. 



This species {Oncorhynchus nerha) is known in different regions 

 under the names of blueback, redfish, Eraser River salmon, and sock- 

 eye. It ranks first of the salmon in commercial value, being es- 



35286°— 21 10 



