In order to find out to what extent the intensive fishing of young fish of different year class- 

 es affects the catches of adult fish of the year classes in question, we decided to estimate the cor- 

 relational dependence between the catches of small and large herring of individual year classes . 

 The dependence between the catches of small and large herring proved to be not a direct, but an 

 inverse relation. All the abundant year classes that were subjected to intensive fishing at an early 

 age provided the fishing industry with relatively small catches of large herring and, vice versa, 

 the year classes which were left relatively intact until they became sexually mature provided the 

 fishing industry with maximum catches of adult fish. Thus, the 1904, 1918, 1923, 1943 and 1944 

 year classes from which there were eliminated but 2 to 5 billion young specimens, provided the 

 fishing industry with 4-6 billion adult fish, whereas the 1925, 1932, 1934, 1937, 1938 and 1939 year 

 classes that were subjected to intensive fishing prior to the occurrence of sexual matxirity, yielded 

 subsequently but a small number of large herring - i.e. from 1 to 3 billion specimens. 



Mass extermination of young herring intensifies the harmful effect of poor year classes 

 and reduces considerably the abundance of good years . 



We think that even a stock as numerous as that of the Atlantic-Scandinavian herring, cannot 

 be subjected to fishing of its juveniles and adults without changing the structure of its spawning 

 population. At the same time, changes in the said structure will disturb the stability of the repro- 

 ductive cajjacity of the stock, since fluctuations in the number of specimens forming different year 

 classes will be conditioned under such circumstances by both the survival rate of young specimens 

 as well as by the amount of eggs deposited; on the other hand, the productivity of the fishing indus- 

 try will decrease, and fluctuations in the catches will be greater as a result of the reduction of the 

 niunber of age groups of herring which are fished. 



Particular attention should be given to the fict that the compoimd structure of the spawning 

 population of Atlantic-Scandinavian herring is an important means of adaptation, ensuring a certain 

 stability in the number of specimens forming their stock. It protects the race against the possi- 

 bility of a drastic reformation of its stock under the effect of fluctuations . 



It seems to us indisputable that the maximum catches of Atlantic-Scandinavian herring may 

 be ensured only on condition of the rational organization of fishing, the maximiun preservation of 

 young fish being its chief element. 



Conclusions 



1. In the ligjit of the investigations of Soviet and foreign scientists, Atlantic -Scandinavian 

 herring form a specific race differing from other races of Atlantic sub-species in the range and 

 living conditions, spawning season, growth rate, age structure of the spawning population, as well 

 as a number of other morphological characteristics (such as body proportions , number of verte- 

 brae, etc.). 



2. The life of the Atlantic-Scandinavian herring proceeds in the main north of the under- 

 water ridges extending from Greenland to the shores of the Scandinavian peninsula. 



The waters of Atlantic origin penetrating via the Faeroe-Shetland channel, between Iceland 

 and Greenland, between Iceland and the Faeroes, as well as the regions of contact of these waters 

 with polar water volumes and waters of continental origin, are the environment in which Atlantic- 

 Scandinavian herring exist. 



3 . Reproduction of Atlantic-Scandinavian herring takes place in the southern zone of their 

 range, off the shores of Norway, along the northern and eastern edges of the continental shelf of 



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