22 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



987654 32 1 



Figure 14. — Scale of a lake trout 31.8 inches long with left pectoral fin missing; no regeneration. Caught September 10, 

 1947. Lake trout with left pectoral fin removed were released in September 1946. If marked, this fish should have 

 been 1 year old. Because of its large size, it probably was of more advanced age. Ten checks were read on the 

 scale. (See p. 59 for a discussion of the central check). The band of new growth is wide. The missing fin was an 

 abnormalitv. 



listed in table 6 because a fin of each appeared to 

 have been clipped and the ai\nuli on the scales 

 seemed well defined. However, the dates on which 

 new growth on the scales was begun are sulli- 

 ciently unusual to throw some doubt on the authen- 

 ticity of the fin-clip and the accuracy of the age 

 determination from the scales. 



The percentage of lake trout witli new growth 

 on tiieir scales increased slowly through April 

 and May, but rose rapidly through Jinie and 

 Jidy, passed the 50-percent level during the last 

 week of June, and reached the 100-percent level 

 the last half of August (table 6; fig. 17). Al- 

 though the season's growth was detectable on the 



