CALIFORNIA FISH AND GAME. 



105 



first place, we know that the fish is in its third year, and by the appli- 

 cation of the well-tested criteria of investigators of scale growth, it may 

 be safely stated that the nucleus represents roughly the growth of the 

 first year, the area A-D that of the second, and D-E the third, a part 

 of the latter having been effaced by absorption. 



The nuclear growth record a.s traced in these scales is exactly dupli- 

 cated by that of scales removed from some small yearlings of the same 

 lot at the time of their liberation. Such scales are represented by 

 figure 46. 



The nucleus of the scale represented by figure 43 is much like that 

 of a naturally spawned fish which has spent its first year in the river. 



Fig. 42. Spawning operations at Klamathon. E. V. Cassell, taking eggs from 

 a female king salmon. Photograph by E. A. McGregor. 



A scale that is believed to be of such an individual is represented by 

 figure 44, This type of nucleus is very different from that of a salmon 

 which entered the sea at an earlier period in its life, near the time that 

 scales make their appearance. A scale of such a fish which was taken 

 in its third year is shown in figure 43, where the first year's growth 

 extends to A. 



Attention was directed to the lack of homogeneity in the area A-D, 

 which is presumed to represent the growth history of the second year. 

 Two very evident intermediate checks appear, one at B, the other and 

 later one at C. The area enclosed by the check B is composed of circuli 

 which are somewhat narrower than the others, possibly characteristic 

 of slower growth. It might be presumed that this area is one of river 

 growth, attained while the fish lingered in the astuary, where food 



