THE CULTIVATION OF SEA FISH 301 



one barrel of medicinal cod liver oil, whereas in an average 

 year four hundred fish will supply the same quantity. 



It would be out of place to give a life-history of the cod 

 here; the discovery, in 1864, of Professor G. O. Sars that 

 the eggs float on the surface of the sea gave the first impulse 

 to the artificial cultivation of the cod and other sea fish. 

 In 1864 Sars found that one could take the ripe ova of a 

 female fish and impregnate it by introducing a few drops of the 

 milt of the male fish into the water. There is no difficulty in 

 keeping the impregnated eggs alive until the young fish hatches 

 out, nor the young fish itself as long as it feeds on the yolk- 

 sac ; but once that is absorbed, all man's efforts to rear the 

 young cod beyond this stage have been practically useless, 

 and in Norway and America and elsewhere, where cod are 

 artificially hatched, all that can be done is to turn the young 

 fish into the sea almost as soon as they are hatched. In 

 Norway Captain Dannevig and others have taken great 

 interest in cod-fish culture, and at the Flodevigen Hatching 

 Establishment since 1884 many millions of cod fry have been 

 released annually. In 1896 the number was 327 millions, 

 and the average every year for seventeen years has been over 

 100 millions. This seems to be an enormous quantity ; but, 

 as compared with the natural fecundity and natural supply 

 of the cod, it is only a drop in the ocean. 



A cod of 10 lb. has a million eggs, so that a very few 

 fish will produce naturally all that the hatchery can do artifi- 

 cially, and with far greater chance of success. What a drop 

 in the ocean 100 million cod-fish eggs are will be seen from 

 the fact that on July 26th, 1895, Professor Hensen calculated 

 that there must be over 278 billions of impregnated cod eggs 

 in each square Norwegian geographical mile of the surface 

 of the Skagerrak. 



As Professors Hjort and Dahl point out, to expect to 

 increase the supply of cod by artificial means in the face of 

 these figures can only result in disappointment. " As a 



