spawn somewhat later than off the south-western shores of Norway. This impression was formed 

 because the spawning period Is somewhat later for the herring that recently attained sexual matur- 

 ity (the first-time spawners), and which had spawned In the Malangen Bank in early April, 1939. 

 Investigations of the past few years have proved that spawning is mainly completed by early March, 

 and the mass hatching of larvae is observed in early April . 



The entire slope of the Lofoten shelf is washed by Atlantic waters and consists almost en- 

 tirely of hard bottom In the form of large -grained sand, gravel, shells and, occasionally, stones. 

 The bottom temperature on Lofoten shelf during the spawning period is 4.5 - 7.5°C. The salinity 

 fluctuates between 32 and 35.1. 



The main data on the environmental conditions for reproduction of Atlantic -Scandinavian 

 herring are presented in Table 1 . 



A comparison between the spawning conditions in different regions shows a great similar- 

 ity between them. In all the regions, the spawning takes place within relatively short periods of 

 time: from the middle of February or beginning of March to the middle or end of April at a temper- 

 ature of 4-5°C to 6-7. 5°C and salinity of 32 to 35.3. The spawning regions are located at a con- 

 siderable depth -- from 40-50 to 100-120 meters and, in the region of Lofoten, spawning occurs at 

 a depth of more than 150 meters along the slope of the continental shelf, near great ocean depths . 

 The spawning regions along Iceland's southern coast are situated in the Irminger current, which is 

 a warm water branch of the North Atlantic current. 



Spawning grounds along the south-western coast of Norway and on Viking Bank are washed 

 by waters reaching the shores of Norway through the deep water channel oriented towards the 

 Danish Straits . The spawning groimds located in the vicinity of Faeroes are also markedly affected 

 by the warm Atlantic waters. Finally, the Lofoten spawning grounds are situated near the slope 

 of Norway's north-western shore, washed by the warm Norwegian current waters proceeding to- 

 wards the western shores of Spitsbergen, and Into the Barents Sea . 



DRIFT OF FRY AND CONDITIONS FOR ITS 



EXISTENCE DURING THE FIRST FEW YEARS OF DEVELOPMENT 



The drift of the fry plays a very Important role in the life of the Atlantic-Scandinavian herr- 

 ing. The importance of these movements can hardly be overestimated. From the very first day 

 following the hatching of larvae and over the course of the next several months, the fry are in- 

 dissolubly boimd to the waters in which they were hatched . 



According to the data of our scientists, the drift of yoxmg fish discontinues when they are 

 either carried away into the littoral zone, or sink to the bottom. The movement of water masses 

 determines the region of future development of young herring. Thus, the larvae hatched In the 

 region of Lofoten Islands may be found under most diverse conditions of existence: they may be 

 carried to the shores of western Spitsbergen, Murman, Novaya Zemlya, or into the White Sea. 

 The differences In the rate of development, age at which sexual maturity is attained, and the dis- 

 tance covered during return migration of the herring larvae are determined by the living conditions 

 for fry in each of these regions . In other words, drift affects the entire life cycle of yoimg herring. 



The pattern of drift of the fry of Norwegian herring was drawn for the first time by Meek 

 (59), who illustrated their drift from the south-western shores of Norway to the northern shores of 

 Norway. The existence of this drift had been assumed earlier by Sars (68), who proved at the end 

 of the past century that the fry from the northern provinces of Norway, fat herring from more 



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