1895 • ^O. 9. IIYDR.-BIOL. STUDIES OF THE XORW. FISHERIES. 6^ 



the Inspector, Captain Knap ^ reports that the fishing only took place 

 on the, so called, edge (on the 100 fathom curve), where, therefore, the 

 fishing ceased in water of a temperature of 5 degrees. Several of the 

 chief boatmen who then used the thermomètre during the fishing affirmed 

 that the}- had only caught fish in water of 5 ", and that the\- had done 

 better than any of their companions. 



In 1 89 1 and 1892, the measurements of temperature were continued 

 on a large scale by Lieutenant Gade. He says in his Report 2; »At 

 those times when there has been a sharp boundary between the cold 

 and warm waters, I cannot indicate one single instance in which the fish 

 have kept to the cold water ^^ (under 4 to 5 degrees). 



If one now examines the charts of those places where the Cod 

 fishing takes place, for instance Chart of Depths IV, of the Lofotens, 

 and Xo. \ , of Vigten, one will see that channels will be found every- 

 where running up towards land. These channels, which, therefore, are 

 valleys on the bottom of the »Norwegian Coastal Banks« (see Chart of 

 Depths i) lead up towards the shallows, the shoals near land (in the 

 Depth Charts, coloured light or dark brown). Wliilst the bottom of the 

 channels is covered with ooze, the shallows are covered with shell-sand 

 and sand »banks«. In warm years the cod come up to these shoals, 

 often up to a height of but a few fathoms from the surface, and there 

 spawn their floating roe. If cold layers cover the shallows the fish lie 

 further out, and the fishermen must proceed as far out as they can find 

 deep water, in order to reach them. 



From all these experiences I may, I think, say, that one ot the 

 reasons, possibly one of the most important causes of the great varia- 

 tions in the Winter fishery must be sought in the great changes in the 

 hydrographical conditions produced by the variable coastal currents 

 during the influx of the fish. 



From the investigations made by the Northern Ocean Expedition 

 and Sars, we know that both the Herring as well as the Cod, keep to 

 the open sea during the greater part of the year, the Herring far out 

 to sea in the surface layers, the cod on the edge of the Coastal Banks, 

 and thence possibly far out in the Northern Ocean at a similar depth. 

 In both these resorts, the water, during the Winter, is salt, Atlantic 

 Water,; and the temperature at both places is probably from 6 to 7 

 degrees ^. When, then, the large shoals approach the coast for the 



1 Loc. cit. 

 - Loc. cit. 

 3 Sec Mohn (Loc. cit.) Pl. XVI. and Pl. XVII. 



