// 13 



Length (cm . ) 



Figure 4. Dimensions of young herring caught in February 1936. (Fridriksson). 



Age and Rate of Growt h 



According to our material, the length of life of the summer -spawning herring reaches in 

 individual cases 17-19 years. 



Of all the herring that have summer and autumn spawning in the north-east sector of the 

 Atlantic, the summer herring of Iceland and the Faroes have the greatest life-span, and this sharp- 

 ly distinguishes them from the bank herring of the North Sea, the life-span of which does not exceed 

 8-10 years /Bchnakenbeck 1931 (16), Le Gall 1935 (1427. Througjiout the entire period of our re- 

 searches in the Iceland region, summer-spawning herring were discovered from 2 to 19 years and 

 in the region of the Faroes, according to the material for 1954, from 3 to 15 years (Tabls 2). The 

 dominant groups in the first region were herring from 4 to 15 years and in the second region from 

 4 to 12 years. 



In determining the age of bank herring, which reproduce at the end of the summer and in 

 auttunn, ^one must take into account that7' according to Johansen's observations (10), no ring is 

 formed in the first winter . In the works of other authors devoted to study of bank herrings , the 

 ring formed in the second winter is counted as the first ring. No ring is formed in the first winter 

 in the autumn -spawned sprat either (L. A. Rannak, 1947). 



Examining the very large quantity of scale material for the summer -spawning herring, we 

 came to the conclusion that in a large number of the specimens the first annual ring is formed in 

 the first winter . According to the data of the converse calculation it corresponds to a length of 3 to 



173 



