20 THE AGE AND GEOWTH OF SALMON AND TEOUT. 



statistical analyses which I have drawn up are based upon the investigation 

 of a very large number of specimens of both salmon and trout. 



The amount of data necessary in order to obtain reliable statistics 

 largely depends on the number of divisions into which our material has to 

 be separated in the course of our investigations. 



In the case of salmon the material examined consisted of many 

 hundreds of fish, and I consider it beyond doubt that the data obtained are 

 sufficient in quantity to be of distinct statistical value. 



So far as trout are concerned my material generally consisted of about 

 50 to 150 individuals from each locality, and in order to ascertain whether 

 the quantity examined was sufficient in number to avoid error I compared the 

 results of two separate examinations from specimens taken from the same 

 locality, either simultaneously or in different years. The results are given 

 in the following tables : 



(1) ANALYSIS OF TKOUT FROM THE M0LNBUQT BIVER, AGDENES (Of. Table XXIII.). 



(2) ANALYSIS OF TROUT FROM KROKAA NEAR BR0NN0Y 

 (Of. Tables XXXIII., XXXIIIs.). 



The specimens in the third table were caught with nets at either end 

 of the lake about 500 metres from the shore. 



An examination of these figures shows that it is only in a few cases 



