134 SEA FISHERIES 



III 



This new piscatorial technique is as yet in the state of 

 a laboratory experiment ; but so far it has shown itself 

 extremely effectual and perfectly practicable. Do not let 

 us forget that it is in the open sea that it has succeeded. 

 It will be all the more valuable in the enclosed salt-water 

 lakes, lagoons, or pools of the coast. 



To the north of Jutland stretches a network of salt 

 lakes and channels, all connected, and all debouching to 

 the west in the North Sea and to the east in the Baltic. 

 They include an inland sea of more than 600 square 

 miles in area ; shallow, sandy, and rich in alimentary 

 matter. This inland sea is known as the Liimfjord. The 

 Lumfjord is a "nursery" of small plaice; perhaps the most 

 fruitful there is after that of Heligoland. The fish are 

 not hatched there ; they come from the North Sea during 

 their very first youth, and there grow up, but in a very 

 unequal fashion. Certain lakes are swarming with little 

 plaice which remain practically dwarfs. In certain others 

 the plaice are scarcer, but grow quickly ; here the struggle 

 for life is barely perceptible, there it is severe in the 

 extreme. Let us remember here that the prosperity of 

 the individuals of one single species is in an inverse ratio 

 to the severity of the fight for survival. A species being 

 in effect a harmonious whole, the factors of survival in a 

 region when nourishment is limited tend to level it to 

 a normal type. Consequently, the more numerous the 

 individuals of any given species concentrated at any one 

 point, the more will they hamper one another, and the 

 more debilitating will be the action of competition, 

 which, instead of resulting in a number of robust indi- 

 viduals, or the sacrifice of a large number of victims, will 

 produce only indifferent specimens. 



