[5] THE FOOD OF MARINE ANIMALS. 489 



one year than in former times. The number of consumers of salt-water 

 fish in our inland provinces has, since the introduction of railroads, in- 

 creased so much that the quicker and larger sales of fish have induced 

 the fishermen to bring more small fish to market than formerly ; thereby 

 they of course reduce the productiveness of the food-fish in their waters. 

 They follow the same course as large fish of prey, and do their share in 

 reducing the maturing faculty of valuable fish. The invertebrates found 

 in such waters then serve as food for other worthless fish, or at best 

 they only serve to develop a larger number of young immature food-fish, 

 whose total weight has much less value than the same weight of fully 

 grown fish, which moreover could do something in the way of propaga- 

 ting the species before they were caught. If fishermen, therefore, wish 

 to permanently reap an average reward of their labor, the fish which 

 spawn in coast waters should not be caught at all ages, but should be 

 protected especially during the period of their youth and during the 

 spawning season. 



In no part of the sea has fish-food decreased, as has been the case in 

 many fresh waters of highly cultivated countries, causing a decrease of 

 fresh-water fish. In many countries our modern civilization has de- 

 stroyed the natural communities (Cenobitisms) of plants and animals, 

 and substituted those plants and animals which were most profitable to 

 man. But the natural communities of the sea human agencies can only 

 change to a certain degree in the coast waters. In the open sea the 

 natural communities of plants and animals will continue to live and 

 sustain each other as long as the waves of the eternal ocean continue 

 to roll. 



