From the progress of the density it is clear that one would hav« 

 to continue at the same rate for only a few years to fish the North 

 Sea actually "dead'*o It is also apparent that the density whereby 

 the stock could deliver the optimum catch (llOa or 1,068 million 

 kilograms) was reached already in 1923| that is, only 4 years after 

 the first World Waro 



Approximate calculations, published elsewhere (Baerends, 1946), show 

 that in 1946 the stock had reached about the same density as it had 

 in 1919o If the fishing intensity is given unlimited opportunity 

 to increase, the threat exists that within 5 years a state of overfishing 

 will have appeared. It is clearly most urgent to introduce a 

 stringent regulation of the fishing intensity in the North Seao 



It is appropriate, if not more than a certain quantity of fish 

 may be taken from the sea, that this fish will bring in as much as 

 possible o That is to say, the quantity of fish which has to be 

 thrown overboard because the fish are too small for human consumption 

 or the quantity which would bring very low prices on the market 

 because of their small size, will have to be kept at a minimumc For 

 economical reasons it is, therefore, desirable, in addition to the 

 quota regulations, to take measures for the protection of the small 

 fish. 



We have already given an estimation of the weight of undersized 

 fish which were destroyedo The number also interests us because each 

 fish which was caught small would have been able to bring a better 

 price latere Destroying of an important part of the year class at 

 an early age causes the older year groups to be represented weakly« 

 These are exactly the year groups which bring in the highest returns 

 and consist of sexually mature fish producing the eggs necessary to 

 retain the stock at a steady levelo 



A fair amount of literature has been published about the quantities 

 of non-marketable fish which are destroyed. We have said already that 

 the quantity of small haddock thrown overboard by English trawlers was 

 about 14 percent of the total haddock catch in 1932 (Russell, 1932), 

 whereas in the areas where much young haddock are present this amount 

 may rise to 51 percent. 



Bftckmann (1933) shows that during 1930 about 65 million small 

 plaice were landed by shrimp fishers and converted into fish meal. 

 He' estimates this to be about 6 percent of the available stock of 

 plaice under 23 centimeters « More than half of these 65 million 

 plaice consist of individuals which have not yet reached the age of 

 two years. The destroying of these is thought to be far less harm- 

 ful, as will be explained. 



8S 



