In the southern half of the Norwegian Sea, we carried out but a few control driftings, so the 

 amount of fat herring existing in this region cannot be estimated on the basis of our observations . 

 The relatively large incidental catch of fat herring obtained in 1952 and 1953 may be due to the 

 abundance of the 1947 and 1948 year classes. We also wish to point out the high growth rate of fat 

 herring from the open zones of the Norwegian Sea. In certain samples, the three -year- old herring 

 were approximately 25 cm . in length . 



The distribution and migration of fat herring in the Barents Sea were subject to extensive 

 investigations conducted by the Polar Institute during the pre-war epoch in connection with the 

 organization of the marine herring fishery in the Murman region. Recognition for finding commer- 

 cial concentrations of fat herring in the Barents Sea should be given to S. V. Averintsev, who in 

 the simimer of 1933, on board the exploratory drifter -trawler "Kuzhma", explored the Murman 

 shelf and obtained commercial catches at several stations (1). 



Information on the fat herring distribution was considerably extended In 1937 as a result 

 of the investigations set up by the Polar Institute on board the exploratory boat "Avangard" (15) . 



In 1938 and 1939, the fishery on the fat herring concentrations in the southern zone of 

 Barents Sea was conducted by a fishing fleet. Investigations of the Polar Institute showed that fat 

 herring remain in the zone of the North Cape current and its ramifications over a considerably 

 smaller area than small herring. As a rule, the area of concentration extends towards the east as 

 far as 40-45° of eastern longitude. During the summer, the fat herring drift in an eastern dir- 

 ection via the North Cape current, migrating in the winter to the western zones of the sea in order 

 to avoid the low temperature . 



Fat herring enter the Littoral zone of the Murman region at the beginning of the hydrological 

 summer. As a rule, their concentrations arrive in the second half of July - at the beginning of 

 August. Fat herring leave this region in September- October. 



Lengthy observations made by the Polar Institute on the biological composition of herring in 

 the coastal zone of Murman showed a definite regularity in the fluctuations in age composition 

 occurring in this region. Four- and five-year-old herring usually prevail in August near the shores 

 of Murman, whereas in September their number considerably decreases, and the three-year-old 

 fish take their place. Still later, the two-year-old fish increase in number. 



When studying the biological composition of catches obtained in the coast regions, scientists 

 encountered a highly Interesting phenomenon which was at first incomprehensible, namely the de- 

 crease in mean length of herring In certain age groups during the course of the fishing season. 

 Initially, attempts were made to explain this phenomenon by the presence among the Murman her- 

 ring of races having different growth rates. Such theories have been refuted, however, by our work 

 of 1941. The decrease in size of fish was explained by the earlier movement of adult specimens 

 from the littoral zone. The study of a fat herring school from the western regions of the sea and 

 of the pre-spawning concentrations of the first-time spawners, confirmed our suppositions: we ob- 

 served that larger specimens disappeared from the Murman coast. At the same time, we observed 

 the opposite phenomenon in the western zones of the sea, i.e. accumulation of large specimens. 



The decrease in size of the four- and five-year-old fish is greater than that of younger 

 specimens, a result of their earlier movement to the western regions of the sea. This theory may 

 be illustrated by the mean lengths of different age groups during different months which have been 

 estimated for the periods of time between 1937 and 1939 and 1946 to 1950. The length of five-year- 

 old fish from August to September decreases by almost 1 cm., i.e. drops from 22.6 to 21.68 cm.; 

 in October, there are but a few five-year-old specimens In the littoral zone, so their length cannot 



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