SEA-FISHERIES LABORATORY. 171 



plaice of each monthly age during the first year of life. So far, 

 however, we have hardly enough data to enable us to do so 

 satisfactorily. 



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Age-Group GHHD T 











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Fig. 7. 

 The Ratio of Males to Females. 



We don't know what is the ratio of males to females in 



the first year of life, but it is probably one of equality. This 



is also the case (probably) for any year group up to about III. 



After that, however, a very curious thing happens ; the males 



diminish in number relatively to the females. This is shown 



by the following statement, based on the numbers of mature 



females and males over 23 cms. in length captured on the 



Sol way spawning grounds and adjacent regions in the spring 



of 1921 :— 



Size in cms. ... 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 



Females 0, 0, 1, 0, 2, 2, 2, 8, 5, 13, 11, 10, 17, 25, 11 



Males 51, 55, 64, 51, 51, 65, 51, 48, 45, 43, 46, 44, 37, 30, 22 



Size in cms. 



... 39, 



40, 



41, 



42, 



43, 



44, 



45, 



46, 



47, 



48, 



49, 



50, 



51, 



52, 



53 



Females 



... 19, 



20, 



16, 



29, 



20, 



25, 



22, 



8, 



19, 



3, 



6, 



4, 



3, 



6, 



5 



Males 



... 19, 



8, 



3, 



3, 



2, 



0, 



1, 



0, 



0, 



0, 



o, 



0, 



0, 



0, 







Size in cms 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65 



Females 0, 3, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1 



Males 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 



Thus, the females caught are always bigger and older fish 

 than the males. They grow a little faster. The interesting thing 

 is that the males apparently die off at a greater rate than do the 

 females, and this probably represents a general law among the 



