"Hie wintering zones of the summer herring are concentrated to the south of the island. 

 After wintering in the spring-summer jjeriod (May, June), the summer herring begins to move 

 along the east and west coasts and by the beginning of the fishing season it has reached the northern 

 fattening grounds, which it does not leave until the reproduction period. Then the maturing fish of 

 the summer race depart for the southern coasts. Probably this departure is also made along the 

 west and east coasts since the largest number of herring of this race are observed always to the 

 north-east and comparatively few are found in the northern and central regions. The second fat- 

 tening period occurs immediately after spawning. Part of the younger herring, which spawn later, 

 apparently fetten in the southern regions. There is no doubt that the herring which we found in 

 late July and early August to the north-west of Isa Fjord was moving to the north along the west 

 coast. The feeding ground after spawning Is considerably broader than the feeding ground of the 

 pre-spawning period. The limit of the latter may be considered 67 N while the limit of the post- 

 spawning feeding ground is wider and reaches 68 N. One may assume that with the approach of 

 winter the summer herring leaves for the southern regions . 



The fundamental difference in the age composition of the summer herring in the northern 

 regions as compared with the south - namely the predominance of the older age groups in the north 

 and of the younger age groups in the south - lead one to the conclusion that there is a certain dis- 

 association in the areas of their distribution. The northern coasts of the island are frequented prin- 

 cipally by the older age groups; the younger herring of the summer race keep to the southern 

 shores. 



A plan of the life cycle of the Iceland summer herring is given in Figure 12. 



To conclude our work, we may mention that the area of the summer herring is more limited 

 than the area of the spring Atlantic -Scandinavian herring. The spawning grounds of the summer 

 herring are known at present in the Iceland reg^ion; there is every reason to suppose that spawning 

 also occurs in the Faroes region. Summer herring are found very rarely off the coasts of Norway 

 (15) and even more rarely in the northern part of the Norwegian Sea. 



The Iceland summer herring is sharply distinguished from the bank herring of the North 

 Sea, which has a much lower growth rate and a comparatively short lifetime (not more than 8-10 

 years). 



Summer-spawning herring are known on the south-west coast of Greenland and also in the 

 region of Nova Scotia and Fundy Bay. Off Greenland, the summer herring reproduce along the 

 south-western coast in the region of Cape Farewell, where its spawning has been established by 

 Paul Hansen (8). In the same regions, herring reproducing in the summer were discovered in 1914- 

 1918 by a Canadian expedition. The summer herring of Iceland is more closely related to the her- 

 ring of the Greenland region, and it is possible that these two groups of summer -spawning herring 

 may intermix within the Denmark Strait. 



According to Hansen's latest researches (1953), adults of the summer herring off Green- 

 land have a wider distribution. They are found along the northern coast from 65°37'N to 72 20'N 

 and along the west coast to 62°N. 



Hansen says that from the number of vertebrae the young sexually immature herring of the 

 Greenland region may be assigned tentatively to the summer race. 



In the waters of the Julianehaab region, 20 young herring aged one year were once fetched 

 up in a seine. In the Frederikshaab region, there have on several occasions been catches of a 

 fairly large number of small herring aged 2-3 years. From this, Hansen concludes that in some 



197 



