20 



In 1913, the predominant year class for these herrings had 

 four winter rings. There is no doubt then that we are deahng 

 here with an altogether different shoal of fish from the drift net 

 herring of the Northumberland coast. Had they belonged to the 

 same shoal and been recruited from the Xorthumberland coast 

 herring as these approached maturit}^ there should have been in 

 1914 not onlj^ a high percentage of fish with five winter rings, but 

 also a still higher percentage with four winter rings, seeing that 

 in 1913 almost 50 per cent, of the Northumberland coast herring 

 had then three winter rings. 



The question then arises as to Avhat becomes of the Northum- 

 berland coast herring on approaching maturity. There is at j)resent 

 Uttle evidence to throw any light on this point, but the following 

 suggestion is put forward. 



It will be noticed that the fish of sample 11, caj)tured further 

 to the south than those of samples 3 to 10, were on the whole older 

 than those from our local waters. In 1909, Hjort had samples 

 of herrings taken at Grimsby and Lowestoft, and the age composi- 

 tion of these was as follows : — * 



WINTER RINGS. 



2 3 4 5 6 7 8 9 10 11 12 



Grimsby — 



30/9/1909 ... 3-3 29-2 42-7 13-9 5-2 1-9 1-2 1-9 0-6 



Lowestoft — 



9/11/1909 ... 1-5 7-8 25-1 26-6 13-8 9-9 10-2 2-5 1-7 0-7 0-2 



Lowestoft is further to the south than Grimsby, and is in the 

 vicinity of what must be regarded with our present knowledge as 

 the chief spaw^iing ground of the southern North Sea herring. 



It is evident that the young herrings during larval and post- 

 larval stages are carried some considerable distance from the 

 spawning ground, and pass their first year in relatively shallow 

 waters. In the next year they partake of a summer migration 

 still in a denatant direction. The summer migration has a corres- 

 ponding winter contranatant migration. These migrations con- 

 tinue yearly, the fish migrating into deeper water each winter, 

 and returning towards the coast each summer until the call of 

 maturity comes, when they join the spawning migrants, probably 

 the summer after the fourth or fifth winter ring has been formed. 



* Publications de Circonstance, No. 53, pp. 144 and 151. 



