SOME RESULTS OF THE INTERNATIONAL FISHERY INVESTIGATIONS. 471 



or winter and summer herring spawning has been explained by 

 assuming the existence of two " races " of fish, one spawning in the 

 spring and the other in the autumn. Whether or not such is also the 

 case with the cod must be left for future investigation. 



On the Lofoten cod fishing grounds, as in the North Sea, the cod 

 frequents the coastal shallow water when about to spawn. The striking 

 figures given by Hjort in the paper quoted show that the eggs were present 

 in extraordinary abundance on the surface of the sea over these banks. 

 In the waters of the channels between the banks much smaller numbers 

 of eggs were taken out at sea, and generally over the surface of the open 

 Norwegian sea the cod eggs were most scanty, or altogether absent. Just 

 where the spawning fish were present on the bottom, there the resulting 

 eggs were found. The eggs were very slowly distributed over the sea 

 area, so slowly that in the meantime incubation had proceeded and 

 resulted in the hatching of the pelagic fry. Many fishery experiments 

 were made by the Norwegians to determine the range of distribution 

 of the cod fry of different stages and at different seasons, and these 

 results are very interesting. Hjort's Fig, 6 in the paper referred to 

 shows this in a striking manner. The area over which the eggs were 



O CO 



distributed extended but little out to sea from the banks. Outside this 

 again, but a little later in the year (June and July), were to be found 

 the young cod, at this period up to about 1 inch in length. Then in 

 August to September the area over which the fry was distributed had 

 greatly increased. Young cod up to about 3| inches in length were 

 found in the Norwegian sea as far from land as 120 nautical miles. 

 During the interval between spawning in March and April and 

 September, the cod fry had slowly drifted off-shore and to the north. 

 All this time they were pelagic in habit — that is, they were found near 

 the surface of the sea — but when attaining this length they began to seek 

 the bottom. This habit differs greatly from that of the young cod in 

 the North Sea. There the pelagic mode of existence is abandoned, and 

 the little fish seek the bottom when little over 1 inch in length. 



Hydrograpiiic conditions in the sea are most probably the causes of 

 these differences in the habits of the cod. The dispersal of the eggs 

 and young fishes is due to surface-drifts and currents. The assumption 

 of tlie bottom-living habit of the young cod is no doubt also dependent 

 on the temperature, among other conditions. Thus over the greater 

 part of the northern North Sea area young cod are hardly ever found 

 at the sea bottom. There a bottom temperature of G"-?" 0. holds good 

 all the year round. With regard to the distribution of the cod in 

 its first year of life, a great amount of material has been collected 

 by the International exploring steamers, and when this is fully worked 

 out we may expect to possess a very complete knowledge of the manner 



