Finally, the demand for small plaice increased after 1929 so 

 that a large proportion of the catches could be landed. 



The catches declined very much after 1929, and we can safely say 

 that a state of overfishing had appeared. Overfishing was not the 

 result of only the intense fishing for marketable plaice, but was 

 also caused, to a considerable degree, by the increasing trash 

 fishery. This can he shown by some data obtained from Bttckmann 

 (1939), considering the plaice landings of German draggers. 

 Bfickmann shows that the year classes 1926 and 1927 delivered 13.1 

 million fish to the German draggers, while the approximately equally- 

 strong classes of 1932 and 1933 delivered only, respectively, 5.8 

 million and 6.2 million fish. It may be expected that when no fish 

 are being destroyed, equally strong year classes deliver equal amounts 

 of fisho Therefore, we must asstime that a very large part of the 

 1932 and 1933 year classes was destroyed undersized and that this 

 caused the very large decline in productive power of those year classes o 



Before 1914, when there was no trash fishing, a state of over- 

 fishing had also appeared. This shows that the trash fishery is not 

 the only cause for the overfishing. 



ddo Sole 



The catches of sole declined during the period 1903-14, 

 apparently since more fishing was done in deeper water as the 

 number of steam trawlers increased. After 1918, the catches 

 increased continuously. This is no doubt due to the increase of 

 the fishery for sole and the growing ntnnber of draggers. The 

 smaller ships spend more time looking for sole. 



Although the intensive fishing is noticeable by the increase 

 of the percentage of "small** (see table 7), a state of overfishing 

 did not appear. While, in 1934, Bftckmann thought that the sole stock 

 had remained constant; Schmidt believed in 1942, that the stock 

 definitely had increased in density. This is extraordinary compared 

 with what happened to cod and haddock. Obviously there is a connec- 

 tion between the increase of sole and descrease of plaice, since both 

 fish use, for an important part, the same kind of food. 



The progress of fishing, therefore, varies from species to 

 species. The haddock stock appeared to be the first and most 

 overfished species and the overfishing of plaice appeared somewhat 

 later, about 1930} while for the cod we could discover only a limited 

 amount of overfishing. The stock of sole increosed in size, but 

 colirain 6 of table 5 shows that the increased sole catches did not 

 make good the other losses in fish. 



24^, 



