CANADIAN TAGGING EXPERIMENTS WITH SPAWNED SALMON. 



77 



Net increase or loss. By applying the methods of Hutton and of Calderwood it is pos- 

 sible to obtain the percentage of net gain or loss in weight for the salmon from the 

 time it first reached the coast for spawning purposes. The salmon loses weight during 

 the pre-spawning fast, at spawning, and during the post-spawning period. Hutton has 

 computed this loss of weight at the completion of spawning and Calderwood has esti- 

 mated the loss of weight during and after spawning. By these computations it is possible 

 to approximately determine from the known weight after spawning the original weight 

 of the salmon when it reached the coast on its first spawning journey and thus to deter- 

 mine the net loss or gain in weight, since after spawning the kelt must first make up the 

 weight it has lost before it can show a true net gain in weight. The results of these 

 computations are given in table 11. 



TABLE 11. 



Per Cent Net Gain or Loss in Weight, Computed According to the Methods of Hutton and Calderwood. 



G — gain 

 L — loss 



Kelts. Of the salmon recaptured as kelts 19 were males and 36 were females. The 

 recaptures were made both up and down stream from the point of liberation. These 

 salmon were taken in the following months: 



TABLE 12. 



Salmon Recaptured as Kelts. 



Of the 19 males the 16 which were gone over winter were absent from four to 7.3 

 months, averaging a little over 6.2 months. All had lost from one-half to four pounds, 

 averaging slightly less than two pounds. The per cent lost ranged from 8.3 to 38.9 per 



