12 American Fisheries Society 



and 4,100 Calories for protein. It is shown that the dry 

 muscle substance in the Baird salmon muscle, which was 

 only 6.8% by weight of the standard fish, is composed 

 almost wholly of protein. The loss of the fat reduces 

 the true nutritive or fuel value of the flesh of the Baird 

 spawners to 2.3%, i. e., one-third of an equal weight of 

 flesh from the standard salmon. In a word, the 6.8 dry 

 pounds of apparent good food per hundred pounds of 

 fish has dropped off two-thirds in quality. 



To sum up this statement, the food material of the 

 salmon stored in its muscles when it begins its run to 

 the spawning ground is represented by 25.9% of the 

 total weight of the fish, whereas at the end of the spawn- 

 ing run it is represented by about one-third of 6.8% or 

 2.3% of the total weight of the fish, a loss of between 

 84% and 85% of the stored material. 



This material which is consumed from the muscles 

 is supplemented by additional material from the skin, 

 from the visceral organs, such as the stomach, intestines, 

 pyloric caeca, and to some extent from the liver. The 

 greatest changes in these latter organs are to be found 

 in the visceral mass in which the weight decreases from 

 an average of 265 gms. in the Monterey fish to 33 gms. 

 in the Baird fish, i. e., one-eighth of the original amount. 

 The weight of the liver, even in fish of the same length, 

 varies extremely from all stations, hence no very re- 

 liable data can be derived from the study of this organ. 

 The total weight of the skin and the viscera in fish from 

 Monterey is in round numbers 400 gms. or about 4% of 

 the fish weight. The absolute amount of nutritive sub- 

 stance furnished by these organs is small in comparison 

 with that supplied by the muscles. 



The disappearance of nutritive substance in these 

 changes is to be accounted for, as was said in the begin- 

 ning, by the expenditure of mechanical energy and by 

 the growth of the reproductive organs. The distribution 

 of materials as between these two factors is a most in- 

 teresting story in itself. 



