6 FISHERIES OF THE NORTH SEA 



particularly round the British Isles and 

 the Iceland banks. They were making 

 their periodic migrations when Caesar 

 landed and conquered Britain ; uninter- 

 rupted by the devasting wars of European 

 Powers and the ravages of the human race, 

 they have continued their evolution. But 

 it is only within the last few decades that 

 mankind has in any large measure taken 

 advantage of these splendid sea prairies 

 with their teeming life. Unlike meat, 

 cereals, and other foods, fish supplies are 

 not diminished but increased by a great 

 war. The best fishing areas are neglected 

 in war-time, and no toll is taken of vast 

 supplies of marine life. Consequently they 

 go on from increase to increase, and num- 

 bers are only limited by the fertility of the 

 ocean. In considering the possibilities of 

 development of our fisheries, one should 

 realize that the ocean covers five-sevenths 

 of the earth's surface, its average depth 

 is 11,000 feet, the volume of water in this 

 space is 3,000,000,000 cubic miles. This 

 water contains a quantity of living matter 

 far exceeding that on the land-surface of the 

 earth. The problem for man's future con- 



