numerous islands and banks, which undoubtedly have the most suitable environment for the fry of 

 herring and other fishes. At the same time, the herring larvae may drift to the south-west, in the 

 direction of Greenland. 



The origin of larvae hatched in spring, 15 to 25 mm. in length, which were caught in early 

 summer 40-60 miles south-easterly from Iceland, is rather obscure. Taning assumes that these 

 larvae were carried off the shelf by a current. This is quite possible, however, it is equally logi- 

 cal to suppose that these fry were brought from shallow waters situated between Iceland and the 

 Faeroes . 



The living conditions for herring fry during the first few years of their existence, parti- 

 cularly during the first winter, when the small fish are still unable to undertake prolonged 

 migrations and spend the winter in the area to which the current has carried them, are of great 

 interest from the viewpoint of the study of drift. These conditions are most interesting in the 

 Barents Sea, where year-old fish frequently penetrate into the most northern and eastern regions. 



We assumed that herring fry may be found at temperatures close to zero or even at sub- 

 zero temperatures (15) . More recent observations have confirmed this supposition . In all the 

 remote regions of the northern half of the Barents Sea, in its shallow south-eastern zone, the fry 

 sjjend the winter at temperatures either close to zero, or even several tenths of a degree below 

 zero. 



It has been proved now beyond doubt that Murman herring at the age of 8 - 11 months spend 

 the winter in the White Sea under the ice, since during the early spring we find them deep in the 

 Kandalaksha Bay. During the cruise of the exploratory vessel "Saratov" between Kanin Nos and 

 Shoina at the end of December, 1948, and in early January, 1949, we discovered a considerable 

 number of herring hatched during that year. 



During the drift, the herring fry find themselves under most diverse temperature conditions 

 depending upon the direction of the current. The fry drifting towards the north and into the northern 

 zone of Barents Sea are under identical temperature conditions throughout the course of the entire 

 migration, whereas the fry proceeding to Barents Sea, find themselves in the littoral zone where 

 the waters have a somewhat higher temperature . Over the vast territory of the Barents Sea the 

 fry encounter most diverse conditions of external environment. In the littoral zones of Murman, 

 in Kola and Motovka Bays, the young herring populate less saline waters having during the summer 

 a hig^ temperature level, which abruptly drops in the winter. The White Sea is characterized by 

 extremely sharp fluctuations in temperature . 



Finally, in the northern regions, the fry of herring are subjected to very low temperatures 

 during both winter and summer seasons . 



In each region, thene exist specific conditions governing feeding, season of growth, and 

 wintering. 



The majority of herring fry are found during their first year of development in salinities of 

 33-34, although in some cases we may find the fry in almost fresh water, such as found near the 

 rivers Teriberka, Voronya and Titovka. 



The drift of larvae and fry of herring occurs in the upper sea levels, where they also re- 

 main during the fall . In collections of the Polar Institute there are numerous samples of fry gather- 

 ed from the decks of exploratory and fishing boats, where during rough weather they were washed 

 aboard. After the winter homotherm, the fry change to the benthipelagic mode of existence. 



18 



