102 



HERRING INVESTIGATIONS. 



II.— SIZE. 



BY DOROTHY COWAN 



An analysis of the size of the herrings examined is given in 

 Table I. The size is expressed to the nearest centimetre, 20-6 

 to 21-5 being taken as 21 cm. 



It has not been considered necessary to publish a complete 

 analysis of size for age for all the samples examined, as this would 

 be a duplication of the data given in the Report of last year. There- 

 fore six samples only have been dealt with in this way. Data as 

 to the origin of these samples will be found in the list given by 

 Mr. Storrow. 



The first of these six samples was from Lerwick, 12th February, 

 1921. It was from a more south-easterly ground than any previous 

 sample of winter herrings from that port, and is interesting when 

 compared with a sample taken 21st February, 1920, 10 miles west 

 of the Shetlands. As will be seen from the table below there was 

 a great difference in size, the sample of this year being much 

 smaller. The majority of the fish in the 1920 sample were at 31 

 and 32 cm., whilst the latter sample ranged principally from 28 

 to 31 cm. 



Centimetres. 



Port. Date. 25 20 27 2S 29 30 31 32 33 31 35 Total. 



Lerwick ... 21/2/20 1 2 9 4 8 17 40 50 18 1 1 151 



Do. ... 12/2/21 8 10 38 32 49 20 12 2 183 



Herrings with four and five winter rings were more abundant 

 in the sau^le of 1921, but this is not sufficient to account for the 

 difference in size. From the data given below it will be obvious 



