84 



The second and third samples from the Firth of Forth, taken 

 Februar}' and March, 1920, do not vary as to size for age to any 

 extent. In sample 1, caught 23rd January, the herrings with 

 four, five and six winter rings are smaller than those of the same 

 age in the following samples. That the analj^sis of total length 

 for the three samples varies will be seen from Table I. Sample 1 

 has a majority about 28 cm. ; sample II., while still keeping a 

 large number about 28 cm., has a larger number of fish under 24 

 to 27 cm. ; sample III. also has a number of smaller fish principally 

 about 24 cm., though large numbers are still under 27 and 28 cm. 

 This increase in the number of small fish is due to a change in the 

 age composition of the samples (Table II.), fish with three and four 

 winter rings bein^ more numerous in the later samples than in 

 sample I. 



It has been sho^^^l that the summer herrings decrease in size 

 for age as the fishing grounds come more to the south. This fact 

 is also true for the winter herrings as the following table will show. 

 Herrings with six winter rings have been taken, as they were the 

 fish most evenly represented in the samples. 



Two samples worth noting are the first sample from Stornoway 

 and the first one from I^erwick. They Avere taken May 27th and 

 28th resj)ectively. They had much the same age composition, 

 the Lerwick sample having more fish with over six winter rings. 

 In spite of this, the Lerwick fish are smaller than those from 

 Stornoway. Below is given an analj^sis of the two samples age 

 for age : — 



CENTIMETRES. 



