XI 



FISHES AND MAN 



Man's influence, which has so altered the face of the land, also reaches 

 out into the water. During the last half-million years or so fishing has 

 grown continually, until at the present time in fresh and shallow sea 

 waters man has become the most important source of mortality of fish. 

 However, he still leaves vast regions of the sea, as of the land, almost 

 untouched. It may be that methods of catching the fish that swim 

 above deep waters will eventually produce changes there too, pro- 

 viding a substantial extension of the food-supplies of man and 

 effecting great alteration in the population of the sea. 



Man has caught fish from his earliest times and he uses many parts 

 of their bodies. The skin, especially of elasmobranchs, makes a useful 

 leather and also a polishing material. The scales of the bleak (Alburnus) 

 yield a substance that when coated on to the inside of glass beads 

 makes artificial pearls. The lining of the air-bladder, especially of 

 sturgeons, makes isinglass, a shiny powder used for various purposes 

 as an adsorbent (i.e. in wine-making). Fish-glue is obtained from the 

 connective tissue of the skin and other parts. Fish oils are used as 

 food, and are also valuable in the manufacture of soap and other things. 

 Besides their direct use as human food, fish products may be fed to 

 animals, and the liver makes excellent manure. 



Fish therefore provide the raw material for many human activities, 

 but it is, of course, principally for food that they are caught. From a 

 fish diet one can obtain not only abundant calorific value, especially 

 if the fish be fat, but also various proteins, often the fat-soluble 

 vitamins A and D, and usually considerable amounts of combined 

 phosphorus and other elements. Herring and mackerel are probably 

 the cheapest source of protein available to many people in Britain. 

 Fish are undoubtedly good food, and what is perhaps even more 

 important they are esteemed as such; most people think that they 

 taste good. 



It is not possible to give an accurate estimate of the amount of fish 

 caught every year; 20 million tons, of value £200 million, is certainly 

 not an overestimate for the catch of the whole world in each of the 

 years between the Great Wars. An appreciable fraction of the nutri- 

 ment of the human race is derived from fish. The annual catch was 

 estimated at 26 million metric tons in 1951 . The greatest national 



