NU'raiTIVE VALUE OF FISH AND SHELLFISH 



519 



Table 13. — Composition of the muscle tissue of the chinook salmon during the 



spawning migration 



The cliinoGk salmon of the Pacific coast is very important from 

 the standpoint of the hirge amount that is eaten fresh, because it is 

 the basis of the large mild-cure salmon industry, and finally because 

 of the large amount of it that is canned. A typical salmon river is 

 the Columbia River. From time immemorial the Indians have 

 come there to catch their salmon at certain seasons, and it was one 

 of the earliest salmon-canning districts to be developed by the white 

 man. From the standpoint of fuel value as well as economic value 

 in connection with canning operations the variation in the fatness 

 of the chinook salmon as it enters the Columbia River from salt 

 water and proceeds upstream to spawn has always been important. 

 It is also particularly interesting from a scientific standpoint, because 

 by taking fish at different points on the river, from tidewater to the 

 spawning beds, it is possible to study the changes in composition 

 and fuel value of the flesh as the fish approach the time of spawning. 



Greene (1919) has studied this problem in a most painsta,king way, 

 and in Table 13 it is easily seen that as the fish progress up the 

 Columbia River on their way to the spawning areas many hundreds 

 of miles from salt water their flesh suffers a deterioration, particularly 

 as regards the fat content and to a less extent in the matter of pro- 

 tein. It is evident that the flesh of the chinook salmon is gradually 

 depleted of its most valuable constituents — namely, its fat and 

 protein — in order to provide for the coming generation. This is also 

 very interesting for the reason that as tTie parents die soon after 

 spawning it would be a waste in the scheme of nature for large 

 amounts of valuable nutrients to remain in the flesh. (As a matter 

 of fact the bodies of the parents disintegrate after death and provide 

 the young fish with one of their first foods when they emerge from 

 the gravel after being hatched.) From the standpoint of the use 

 as food of spawning or spawned-out fish, it only needs to be pointed 

 out that the fuel value of such fish is relatively low and their flesh 

 is always watery and more or less unpalatable and lacking in the 

 characteristic firmness, flavor, and richiicss of the flesh of salmon 

 taken in salt water or very early in the spawning migration up the 

 rivers. 



VARIATIONS DUE TO LOCALITY 



From th« earliest days it has been known that the fish in certain 

 localities are unusually fat as compared with those taken from other 

 places, and fishing operations have often been conducted with this 

 in view. The variations in composition of the herring in European 

 waters have been studied very carefully by various investigators 

 but need not be discussed in this chapter on the composition of Ameri- 

 can food fishes. 



