138 STUDIES IN INSECT LIFE, ETC. 



longer period, and considering the flat fishes, we 

 find that the numbers of plaice and lemon sole 

 taken sank from 29,869 for the five years 1885-90 

 to 28,044 for the five years 1891-95. On the other 

 hand, the dabs, a comparatively worthless fish, 

 had increased from 19,825 to 29,483 during the 

 same two periods. These figures, it is true, have 

 not been generally accepted as an exact measure 

 of the changes which took place during the period 

 investigated, but independent criticism has cor- 

 roborated their general tendency. 



In Norway elaborate experiments have been 

 made to test the utility of fish hatcheries as a 

 means of artificially increasing the supply of fish. 

 For many years Captain Dannevig has carried on 

 operations of this kind at his hatchery at Arendal, 

 and there are many stories of English visitors 

 to his establishment who have dined upon cod 

 artificially hatched and reared in the Arendal 

 tanks. The practice, however, at this and at 

 other hatcheries has hitherto been to plant the 

 fry out at sea immediately after hatching, and 

 many experts have doubted whether such pro- 

 ceedings could materially influence the supply, 

 since the cod, like other sea fish, is enormously 

 prolific, and the ordinary fish hatchery cannot 



