36 A TEXTBOOK OF OCEANOGRAPHY 



various edible species on the continental shelf itself may be 

 referred to elsewhere.* 



The northern limit of possibility of commercial trawling is 

 uncertain. Already, as stated above, the south coast of Iceland 

 and the banks off the Murman Coast (Barents Sea) are fished 

 by British trawlers. 



From 50 down to 300 fathoms on the northern edge of the 

 North Sea plateau saithe, ling, tusk, and halibut are captured. 

 Ail along the edge of the continental shelf from Spitsbergen 

 and Bear Island along the coasts of Norway, the North Sea 

 plateau, the Faroes, and the Faroe Iceland ridge, the following 

 are taken : Norway haddock, blue ling, black halibut, and 

 other species. 



Probably edible species may be captured in depths up to 

 300 fathoms in the Norwegian Sea. Below that depth the 

 water is certainly too cold to support edible fish and their food 

 in quantity. Even above that depth there may be large areas 

 without abundance of fish life. 



Large halibut are known to occur ofï the west of Bear 

 Island, round the North Sea plateau, the Faroes, and on to 

 Iceland. 



Hjort divides the northern pelagic communities into three 

 groups — (i) the Arctic, (2) the Boréal, and (3) the temperate 

 Atlantic. 



In the Norwegian Sea the Arctic water is found in the 

 Greenland Sea in the west, in Spitsbergen in the north, and 

 even close to the banks of Norway and the North Sea, and 

 this water excludes fish of the second and third groups 

 above. 



Since the first group, the Arctic, comprises only a few 

 forms, of which the Polar cod and the capelan {Mallotus 

 villosus) ave alone présent in quantity, it may be assumed that 

 the prospect of any northern extension of the présent com- 

 mercial irawling areas is extremely unlikely. 



* See " The Sea Fisheries," by J. T. Jenkins. London : Constable,' 

 1920. 



