THE INVISIBLE FOOD OF FISH 241 



what was, until recently, thought to be their principal 

 food now appears to play only a limited part in their 

 maintenance, and the common fisherman's view, that 

 river fishes work hard for their living and subsist 

 mainly on worms and grubs, with a change to may- 

 fly in the season and occasional feasts of ground- 

 bait and paste, is almost as far removed from fact 

 as the showman's description of the elephant's diet 

 as consisting mainly of cakes and hay. 



But the case of the river fish did not settle the 

 obvious problem suggested by the question of the 

 food supply in the sea. The sea, except in the 

 shallow-water fringe along the shore, is devoid of 

 vegetables. It contains in general no growth of 

 weeds and plants to harbour swarms of possible food 

 creatures with their eggs and larvae, and where such 

 vegetable growths do occur, as in floating weeds 

 of the Sargasso Sea, a race of fish and crustaceans 

 at once appears, limited to that locality, and obviously 

 fed from that source alone. Neither does the sea, 

 except in certain areas, greatly abound in vertebrate 

 fish. You may catch large fish at any point on the 

 voyage in the narrow seas, from Gibraltar down 

 the Mediterranean to Aden. But the open seas are 

 not full of the fry of fish which might form a 

 good supply for others, and in the Atlantic, except 

 on the Newfoundland banks, there are no fish found 



Q 



