Scandinavian herring within the borders of the entire area inhabited by these fish, from the south- 

 western coast of Norway and Iceland to Western Spitsbergen and Novaya Zemlya. 



These investigations enabled us to solve the problem of seasonal distribution of commer- 

 cially important concentrations of herring in North Atlantic waters . On the basis of these data, 

 the fishing industry of the Soviet Union organized an extensive herring fishery in this particular 

 zone of the ocean . 



The present article presents data and observations collected by the Polar Scientific 

 Research Institute of Fisheries and Oceanography over the course of almost two decades . 



It is quite obvious that methods of investigation were bound to change during such a long 

 period of time. Nevertheless, aside from the technical means employed, or of the tasks faced by 

 the investigators - be it a study of the drift of herring larvae or solution of some practical problems 

 connected with the fishing fleet - the research conducted by the Polar Scientific Research Institute 

 of Fisheries and Oceanography was based on the thorough and complex study of organism and 

 environment in their indissoluble interrelation and interaction. 



During the study of different phases of the development of herring, we always considered 

 the interrelation of different cycles with the preceding phenomena and the degree to which these 

 latter determined the subsequent stages of biological development. Captains of exploratory and 

 fishing ships participated in the research set up by the Polar Institute . At all stages of research 

 the conclusions were verified throu^ practical fishing, since all these investigations were prac- 

 tical in character and set up to solve practical problems . 



Throui^out the entire period of research, the task of establishing migration paths and con- 

 ducting observations on the movement of herring, proved to be the most difficult. This always has 

 been one of the most difficult problems in fishery investigations . Particular difficulties arose when 

 the scientists attempted to determine the migratory habits of marine fishes, which are known to be 

 extremely active and migrate over great distances. 



F . Heincke (48) made the first attempt to solve the problem of migrations of fishes . He 

 believed that a more thorough study of the morphological structure of herring from different 

 regions would enable us to follow their distribution in the oceans during migrations. F. Heincke 

 was able to solve the problem of migrations along the most general Unes only . He succeeded in 

 proving that there exist in Eurof)ean coastal waters different races of herring populating limited 

 areas and differing from each other in structural characteristics, and the seasons and conditions 

 for spawning. 



The method employed by F . Heincke did not provide detailed information on the migrations 

 of the different races of herring isolated by this investigator, because the nxunber of herring 

 samples at his disposal, obtained outside the customary fishing grounds, proved insufficient, and 

 because the characteristics of different herring races, as defined by Heincke, did not apply to 

 young, sexually immature specimens, due to the fact that morphological characteristics strongly 

 vary with age . 



Later on, the method suggested by F. Heincke was somewhat modified. Researchers dis- 

 posed of the analysis of numerous plastic characteristics and concentrated on meristic indices. 

 Determination of the number of vertebrae was considered particularly important and, in the 

 opinion of a number of scientists, including Lissner (58), Schnakenbeck (69) and LeGall (57), it 

 furthered the knowledge of migrations of herring of different races . However, the study of the 

 varying number of vertebrae showed that this characteristic is also subject to considerable 



