FACTORS OF DESTRUCTION 111 



and carried by the second current, except that the young 

 fish develop in the north. Pelagic eggs, in short, and 

 this is a general truth, are hatched in certain propitious 

 localities, often far distant from the spawning-place. 



The spawning-ground thus appears as a place of birth 

 and growth. It nearly always consists of sand, more or 

 less muddy, with here and there projecting rocks. Some- 

 times it is found close to the shore, in bays and estuaries, 

 where nourishment is abundant ; sometimes it is out in 

 the open sea, among the banks and shoals. Thus the 

 Dutch coast and the shores of Heligoland and Lumfjord 

 are the nurseries for nearly all the flat-fish of the North 

 Sea, the Danish coast for the haddock, and the slopes of 

 the Great Fisher Bank for the cod. A spawning-ground, 

 thus defined, is a reserve which assures the species of 

 perpetuity. It is evident that were this reserve exhausted 

 the future of the species would be endangered. But 

 it cannot be said that the trawl catches large and small 

 fish indifferently. 



Certain English experts have made conclusive inquiries 

 upon this point. They have refuted the argument that 

 the meshes of the otter-trawl, large as they may be, close 

 up under traction and prevent the immature fish from 

 escaping. The experiments made were simple and con- 

 vincing. " The pocket of a large regulation trawl with 

 meshes of 6 inches (that is, of ij inches wide from knot 

 to knot) was surrounded by another net of a much finer 

 mesh. The result, according to Mr. Wemyss Fulton, was 

 as follows : 5,906 fish of 25 species were taken in the 

 pocket of the trawl, while 32,237 escaped through the 

 meshes and were found in the finer net. In other words, 

 19 per cent, were taken and 81 per cent, escaped." It is 

 true, says Mr. Roy, that not all species of fish escape in 

 the same proportions ; for of 1,282 flounders which 



