104 THE SEA-FISHERIES [PART I 



rivers of Britain if the value of this fish to the sportsman had not 

 been prolific of legislation for its protection. Eagles, ravens and 

 other birds have yielded to man's destructive instincts, and in other 

 countries the larger flightless birds such as the ostrich, cassowary, 

 emu and kiwi, are slowly disappearing or require to be culti- 

 vated or protected by legislation. The moa, great auk and dodo 

 have become extinct, but these were probably species which were 

 passing away from natural causes before man came on the scene. 

 In our own country many wild birds are the objects of protective 

 legislation, mainly in the interests of sport. Numbers of birds and 

 mammals which are useful or indispensable to man are now bred 

 and domesticated. Thus man's influence has been very powerful 

 in the case of the larger terrestrial creatures, and to some extent 

 this is the case in regard to some marine species. Steller's sea-cow 

 {Rhytina) has become extinct since 1786^ and the manatee and 

 dugong are becoming rare. It is likely too that the whales 

 and seals will in the future become very scarce if protection is not 

 invoked in their behalf But in the sea the area to be exploited 

 is so vastly greater than on the land that the influence of man is 

 only just appreciable. The fact that he is still the hunter of marine 

 animals shews that this is still the case. Fishes are not bred or 

 domesticated because these measures are necessary in order to 

 preserve them in sufficient numbers to afford food or ornament. 

 With few exceptions the sea is exploited in the twentieth century 

 essentially as it was in post-tertiary geological times. If we now 

 cultivate oysters and a few other truly marine animals it is for 

 convenience, or because greater commercial gain is so obtained, and 

 not because it is necessary to do so in order that these animals may 

 be preserved in sufficient numbers to form the material of a fishery. 

 The " Harvest of the sea " is a metaphor that appeals only to the 

 uninstructed. In the ocean nature sows the seed and man reaps 

 where he has not sown. 



But nevertheless the fishing industry has undergone very 

 much the same degree of elaboration and specialisation that some 



^ Rhytina was discovered on Behring and Copper Islands, in the North Pacific, 

 by Behring and Steller in 1741. Forty years afterwards the last individuals of the 

 species were extirpated by the hunters and traders who followed on the track of the 

 explorers. 



