No. 647] PROGRESSION OF LIFE IN THE SEA 503 



normal food. Destructive enemies appeared later in tlie 

 form of whales and seals and sea-birds, which had devel- 

 oped on the land and in the air. 



And now in these last days a new attack is made on the 

 fishes of the sea, for man has entered into the struggle. 

 He came first with a spear in his hand; then, sitting on a 

 rock, he dangled a baited hook, a hook perhaps made 

 from a twig of thorn bush, such as is used to this day in 

 villages on our own east coast. Afterwards, greatly dar- 

 ing, he sat astride a log, with his legs paddled further 

 from the shore, and got more fish. He made nets and 

 surrounded the shoals. Were there time we might trace 

 step by step the evolution of the art of fishing and of the 

 art of seamanship, for the two were bound up together 

 till the day when the trawlers and drifters kept the seas 

 for the battle fleet. 



There can be little doubt that in European seas the at- 

 tack on the fishes in the narrow strip of coastal water 

 where they congregate has become serious. A consider- 

 able proportion of the fish population is removed each 

 year, and human activity contributes little or nothing to 

 compensate the loss. We have not, however, to fear the 

 practical extinction of any species of fish, the kind of 

 extinction that has taken place with seals and whales. 

 Fishing is subject to many natural limitations, and when 

 fishing is suspended recovery will be rapid. There is evi- 

 dence that such recovery took place in the North Sea 

 when fishing was restricted by the War, though the in- 

 crease which was noted is perhaps not certainly outside 

 the range of natural fluctuations. Until the natural fluc- 

 tuations in fish population are adequately understood, 

 their limits determined, and the causes which give rise 

 to them discovered, a reliable verdict as to the effect of 

 fishing is difficult to obtain. 



If such problems as these are to be solved, the investi- 

 gation of the sea must proceed on broadly conceived linos, 

 and a comprehensive knowledge must be built up, not 

 only of the natural history of the fishes, but also of the 

 many and varied conditions which influence their lives. 

 The life of the sea must be studied as a whole. 



