26 



NUMBERS AT CEXTIMETEES. 



'Ilie North Shields samples of 24th July and 6th August are 

 larger as regards first 3'ear growth than the sample of 27th August. 

 The particulars here follow : — 



There is little difference between the Scarborough samples 

 of 12th August and 11th September, but it is noticeable that in 

 the latter sample fish with a first year groAvth mor^ than 10 cm. 

 are not so plentiful as in the August sample. The data are as 

 follows : — 



NUMBERS AT CENTIMETRES. 



It would appear from the above that summer feeding shoals 

 of fish with three winter rings receive immigrants throughout 

 the season, and that the time of joining the shoals bears some 

 relationship to growth as expressed for the first year, i.e., up to 

 the formation of the first winter ring. 



It has aheady been sho\^ii that there is considerable viiriation 

 in the age at which lirst maturity is reached. This variation 

 will be seen to accompany a variation in growth. Below are 

 given particulars relating to the Stornoway samples for fish with 

 three winter rings : — 



THIRD YEAR GROWTH. 



Numbers at Centimetres. 



Bate '^^''^'' 19 20 21 



Rings. 



10/2/20 3 _ — _ 



9/3/20 3 _ _ _ 



27/5/19 3 _. _ _ 



22/7/19 3 112 



23/9/19 3 _ — _ 



