21 



two samples .examined in 1915 is added for the purpose of com- 

 parison : — 



Winter Rings, 



It will be seen from the above that the older fish are each 

 year becoming less m number. In 1915 there was only 11 per cent, 

 which had more than five winter rmgs, and in 1914 and 1913 the 

 percentages were 20 and 31 respectivel3^ This agrees with the 

 decrease in size to which attention has already been drawn. 



It would appear that the catches made from this shoal during 

 1916 should contain a fairly high percentage of herrings with four 

 whiter rings, but as the shoal is coming to be composed mamly 

 of younger fish than in previous years the percentage of fish with 

 four winter rings may be lessened somewhat by younger fish jom- 

 ing the shoal, and may not form the predominant year group. 



Size and Age. — Table I. contains particulars relating to the 

 size and age of the samples examined. 



The average sizes of the different year groups, as calculated 

 from the table, are as follows : — 



Winter Rings. 



The size of the fish with two winter rings and the age com- 

 position of the shoal leads one to the conclusion that whilst the 

 more rapidly grown fish of the third summer may join the shoal 

 of adult fish, the majority of the recruits of the adult shoal do not 

 join the shoal until after the third winter ring has been formed. 



