124 THE STORY OF LIFE IN THE SEAS. 



destroys the validity of many theories which 

 were prevalent among fishermen and others before 

 the days of the more exact scientific treatment 

 of fishery questions. 



It is well known that from the end of the 

 month of June to December immense shoals of 

 Heriings are found in the North Sea. It is quite 

 impossible to estimate the numbers of Fish in 

 these shoals, but they are so great that if they 

 could be counted it would probably be found 

 that the Fish that are annually caught by all the 

 fishing boats, form but an insignificant fraction 

 of the whole. All of these Fish are in such a 

 condition that it is evident their spawning time 

 is close at hand. When they are ready they 

 approach the coasts, the exact time varying 

 according to the race of Herrings, and the spawn 

 is deposited on or close to the ground, the eggs 

 becoming attached to stones and other objects on 

 the bottom. After the Herrings have spawned, 

 they seem to disperse, or, at any rate, to dis- 

 appear from the surface-waters of the North Sea. 

 What actually becomes of these shoals of spent 

 Herrings is not known, but it is a fact that in 

 the spring there are so few Herrings to be found 

 in the narrower part of the North Sea that it 

 does not pay the fishing boats to go after them. 

 It is possible, however, that, after the spawning 

 process, the Herrings migrate to the deeper 

 water of the Norwegian coasts, in order to feed 

 on the Crustaceans and other forms of life that 

 are to be found there in abundance. 



The Mackerel do not apparently make such 

 extensive migrations as the Herrings. They 



