of tho population can be solved satisfactorily only by a quantita^ 

 tive analysis o It is understandable that only a very few quanti=» 

 tative treatments have been given^ since the statistics to be used 

 as a basis often were not reliable.. I have persuaded myself into 

 a quantitative treatment becausej, in the first place j, the basis 

 of the necessary information now is not too unreliable^ and in the 

 second placej, I hoped to show what information is necessary to 

 arrive at a workable plan for future researcho In the third 

 place, I was of the opinion that I could best give the reader an 

 illustration of the relation between the various factors by the 

 use of statistics© Although the statistics may not be accepted 

 as finalj I believe that their doubtfulness is not of sufficient 

 magnitude to change the prec^icted effect of the proposed measure- 

 ments to an essential degree o By execution of the plans the 

 results will have to be controlledj, of course, so that possible 

 mistakes may be amended o 



In the above study it has not been taken into account that 

 changes in the hydrographic conditions may change the fertility 

 and thereby the productive power in the North Seao We have worked 

 with a constant fertility=-an average over several de cades ^^^ind 

 wo have determined how, with this constant quantity of food, the 

 productive power was changed by variations in the fishing intensityo 

 I think this is a responsible working method because it does not 

 appear that important changes have taken place in the environment 

 during this century© However, in the future this possibility 

 will have to be consideredo 



To increase a rational fishing in the North Sea our conolu-' 

 sions have led us to propose? 



lo That the fishing intensity must be regulated in such a 

 way that each year not more than 390 million kilograms of bottom 

 fish be taken from the North Seao 



2» That the minimum sizes and the width of the meshes be 

 regulated in order to insure that these 390 million kilograms will 

 bring as high a price as possibleo 



The first proposal is sweeping© It is a serious encroachment 

 upon the traditional freedom of the sea and there will be many 

 difficulties involved in the practical application of such a 

 "quota system** o It will be asked if it is not possible to prevent 

 overfishing exclusively by the protection of the small fisho We 

 will, therefore, re=examine this possibilityo 



Looking at the proirress of the fishing during this century 

 it is clear that the state of overfishing did not occur because 

 too many small fish were caught© On the contrary, it was impossible 

 to sell small fish at the beginning of this century because no 



