III. THE NATURAL HISTORY OF THE COD 



From the most ancient historical accounts (Sagas), we know that the cod fisheries have 

 played a most important role in the region of the Norwegian Sea for hundred of years. They 

 represented there the true great fishery, in comparison with which aU others were in the shade- 

 In the southern part of the ocean, in the North Sea, the cod also played an important part 

 certainly in the products of the fishery, hut it entered more as an additional catch along- 

 side of other economically more important fishes. Of the various cod fisheries again, those 

 fisheries which were carried on during the spawning season had a special character. In Norway 

 the spawning cod was thus given a special name ("Skrei") and the skrei-flshery was spoken 

 of in contradistinction to the others. 



Both the fisheries as well as the natural history of the spawning cod, have accordingly 

 had a prominent place in the fishery investigations for a long time, and we shall begin the 

 following description with this section of the life of the cod. 



1. The spawning- period 



a. In the Norwegian Sea as in the North Sea, the cod collect in shoals at certain 

 spawning places during the spawning time. In the Norwegian Sea the spawning period em- 

 braces especially the months February — April; at that time it is almost exclusively the cod 

 that is found on the spawning grounds, and they press together in great quantities on a narrow 

 spot. In the North Sea, on the other hand, the conditions are of a more complex nature ; the 

 cod spawns here at various periods of the year and many other fishes, especially the haddock, 

 also spawn at the same place and in the same quantity. It was advisable accordingly, to 

 undertake the important task of gaining a view over all the banks where spawning cod can 

 be caught in the different regions, by means of scientific investigations of various kinds. 



As mentioned before, it is well-known tliat Hen s en has endeavoured to determine the 

 amount of the spawning cod in the North Sea by quantitative investigations of the pelagic 

 eggs. The circumstance however, that pelagic eggs of many species occur in the North Sea 

 at the same time, makes such investigations so to speak, very difficult or impossible. One is 

 obliged therefore, altogether or in any case for the most part, to determine the amount of tlie 

 spawning cod themselves. This can be done either by special fishery experiments or by study- 

 ing the journals of the catches of the fishermen. 



In the Norwegian Sea, it has proved that, in addition to the fishery experiments, the in- 

 vestigation of the pelagic eggs is a valuable aid in the search for the shoals of spa\Mi- 

 ing cod. We shall therefore consider here the investigations in the Norwegian Sea first of all, 



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