50 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 25. — Weights of the marked lake troui at capture and as ralriilated for the end of each year of life ' 



[Weight in ounces] 



I Weights calculated with length-weight formula from calculated lengths shown in table 20. 



3, ' ^ 



I 

 UJ 



5 



I 14 





2 3 



YEARS OF AGE 



Figure 26. — Calculated growth in length and weight of 

 marked lake trout [summation of ann\ial increments of 

 growth]. 



addition of weight increased sharply from 2.1 

 ounces in the second year to 3.4, 5.2, 7.3, and 6.7 

 ounces in succeeding years. The calculated incre- 

 ments of weight of fish in the older age groups 

 (especially age-group VI) would have been larger 

 except for selective mortality of the more rapidly 

 growing lake trout which resulted in reduction of 

 the average length increment (table 25, and 

 fig. 26). 



Calculated weights obtained by summation of 

 the mean increments of growth in weight were 

 slightly smaller than weights of the fish at capture 

 for tlie same reason that the calculated lengths 

 were smaller than the measured lengtlis. The 

 differences in weight ranged between 0.2 and 2.6 

 ounces as shown in the following tabulation: 



Year of life 2 3 4 5 6 



Weight from summa- 

 tion of calculated 



increments 3.0 6.4 11.6 18.9 25.6 



Age group II III IV V VI 



Weight at capture 4.4 9.0 11.8 20.6 26.9 



PROGRESS OF SEASON'S GROWTH 



As a first approach to the estimation of the 

 progress of the growth of lake trout during the 

 growing season, tabulations were prepared of the 

 sizes attained by the age groups of the marked 

 fish at capture in each month of the year. 



