— 83 — COUNCIL-MARCH 1920-APPENDIX 



In view thereof it was urged that, immediately after the war, it would be ne- 

 cessary to resume international scientific investigations in the North Sea and adjacent 

 waters. A proposition to this eiïect was unanimously adopted by the meeting, and 

 it was resolved to send copies of this proposition to all Delegates of the Council, 

 requesting a reply after consultation with their respective Governments. 



From Holland and Denmark replies have been received to the effect that these 

 countries are prepared to continue the said investigations during and after the war. 



The aforesaid view as to the reduction of the stock of fish in the North Sea 

 was based upon elaborate investigations carried on during several years by the par- 

 ticipating countries, and in particular by those bordering on the North Sea. 



The results were laid down in reports from the various countries interested in 

 the Plaice fishery in the North Sea, and were assembled in a "General Report" by 

 Professor Heincke, of which, until now, a "prehminary brief summary" and the "first 

 part" of the main report have appeared (in Vol. XVI. and Vol. XVII. A, respectively, 

 of Rapports et Procès-Verbaux. Cons. perm, internat, pour l'exploration de la mer). 



Heincke sums up the main results of the plaice investigations in the following 

 way: (Rapports et Procès-Verb. Vol. XVI., 1913, p. 56). 



"1. It is very probable that the density of the plaice shoals of the North 

 Sea has, with the introduction of intensive trawl fishing, remarkably decreased, 

 the absolute size of the plaice stock being also thereby reduced. 



"2. The reduction in the stock of plaice has not affected all size-classes in 

 equal degree, but chiefly the larger and older plaice. This is shown in the catches 

 and landings by a relative decrease in weight and number of the large plaice and 

 increase of the small, as well as in the reduced average size of the plaice. The larger 

 and older males especially have decreased greatly in numbers, and the point of 

 intersection of the curves of frequency of the sexes has fallen to a lower length." 



Regarding the question of international protective measures, Prof. Heincke 

 arrives at the following conclusion (Rapports et Procès-Verb. Vol. XVI. p. 67): 



"These results of our investigations seem to indicate that a really effective 

 protection against the enormous, and for the most part useless destruction of the 

 young of the plaice by the large steam and sailing trawlers can only be attained by 

 means of an international size-limit of 25 to 26 cm. Such size-limit is therefore 

 extremely desirable, and an endeavour must in any case be made 

 to introduce same. On the other hand, it is impossible to overlook the fact that 

 the introduction of so high a size-limit to be enforced in all the North Sea countries, 

 would in the first instance be productive of so heavy a loss to the plaice fishery of 

 certain countries, e. g., Germany and Holland, that these fisheries would be danger- 

 ously injured, and their very existence, upon present lines, seriously threatened. 

 In the interest of these fisheries it would be desirable, in the general opinion, to fix 

 for them at first — during a certain period of transition' — a lower size-limit. As the 



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