The number of trips made by steam trawlers decreased;, especially 

 in the southern part of the North Seao For instance, in 1910 the 

 German steam trawlers made 1,933 trips to the southern part of the 

 North Sea, but during the years igsS^S?, they made an average of 

 only 7 trips a yearo During the same period, the trips made by 

 German trawlers to the northern North Sea were respectively 2,901 

 and 742 o 



The number of trips made by English trawlers to the southern 

 part of the North Sea declined from 21, 650 to 16,830, while their 

 trips in the northern North Sea rose from 984 to l,252o Moreover, 

 only the less pcwerful trawlers remained in the southern North Sea© 



Offsetting the decreased fishing intensity as a result of the 

 above factors, an increase in fishing intensity resulted from the 

 acceptance of the Vi gne ron=>Dahl trawlo This increase amounted to 

 25 percent for plaice (Thursby Pelham, 1939) and 50 percent for 

 haddock (Bowman, 1932) » 



It is not likely, however, that this increase in the fishing 

 technique compensated for the very large decline in the number of 

 trips of the steam trawlers „ As is shown in table 4, the number 

 of motor vessels increased very much since World War lo 



These motor vessels fished mostly in the southern North Sea| 

 and although their average individual fishing capacity is probably 

 somewhat less than that of the steam trawlers which used to fish 

 the North Sea, they are numerically so strong that it is our opinion 

 that they have compensated for the decrease in steam trawler activity, 

 and that through their use the fishing intensity must have increased 

 in the southern North Sea during the period 1914-40o 



In the northern North Sea, the decline in the steam trawler 

 activity is not so greato Here, haddock is fished chiefly with the 

 Vi gne ron-'Dahl net and the resulting increase in fishing capacity 

 undoubtedly must have erased the influence of the decrease in the 

 number of days at sea, and also must have increased the fishing 

 intensityo 



The above conclusion is supported by the fact that a greater 

 percentage of tagged plaice was caught yearly during the period 

 1918'=40 than during the period 1903°14i, and that in the former period 

 the percentage of the category "small* in the catches reached a 

 higher value than it did before the first World War (see table 7) o 



bo Landings 



Table 5 and figures 2a and 2b show the progress of the total 

 catches and of the catches of the major species » The value in 

 guilders is also showno It is now apparent that the values reached 

 a peak in the first 3 years after the first World War, then showed 

 a small decline and later decreased more rapidly «. 



14 I 



i 



