ber of the plaice taken by the German and Dutch sailing vessels, which are fitted for 

 the capture of live fish. But in the case of the plaice fishery from larger sailing vessels 

 and steam trawlers, the method almost exclusively employed in England, and which is 

 responsible for by far the greatest part of all the plaice landed from the North Sea, the 

 great majority of undersized fish taken are already dead when brought to the surface, 

 and are in any case not capable of living when returned to the water. A legal size- 

 limit can thus not be effective here as a protection for the undersized plaice unless the 

 limit is set so high that it cannot pay to trawl on the grounds where they occur in 

 greatest quantities, so that the trawlers will avoid such plaicegrounds, and themselves 

 restrict their fishing in the interest of plaice protection. 



The governments of the various countries will scarcely be inclined to impose any 

 legal restrictions upon the fishery unless they are convinced i) that such measures are 

 absolutely necessary for the maintenance of a good stock of plaice, 2) that they are 

 practicable, 3) that they really ensure the attainment of the object in view, i. e., the 

 protection of the young plaice, and 4) that the inevitable loss which the fishing industry 

 will sufier thereby in the first years, will soon be compensated by an improvement in 

 the yield, especially in point of quality. 



The question of proper international protective measures for the plaice is therefore 

 a difficult and complicated one. A satisfactory solution of the same is only possible 

 when we are in possession of exact knowledge as to the distribution of the plaice, its 

 habits of life, its food, and its migrations. We must also know, how great a quantity 

 of plaice, both as regards number and weight, is annually landed from the North Sea, 

 and in what manner this quantity is composed with regard to the different age- and 

 size-classes. Ten years ago our knowledge on these points was almost nil. Since that 

 time however, the International Investigation of the Sea has increased and extended our 

 knowledge to such a degree that it is now possible to seriously consider the task of 

 arriving at a solution of the plaice question. 



The ''International Investigation of the Sea!' was founded on the idea "that a rational 

 exploitation of the sea must as far as possible rest upon a scientific basis, and that one 

 of the main objects of the work here to be carried out is the practical improvement of 

 the fishing industry". It has therefore from the commencement paid special attention 

 to the question of overfishing and the imprudent destruction of young fish by present 

 trawling methods. At the meetings of the Central Council for the International Investigation 

 of the Sea in Hamburg in February 1904, and in Copenhagen in July 1905, resolutions 

 were passed to the effect that the countries concerned should undertake to furnish exact 

 and reliable details as to the extent of the destruction of undersized fish, in particular 

 plaice, and also to supply regular fishery statistics for the purposes of a Statistical 

 Bulletin, to be published by the Central Bureau. These latter should in particular deal 

 with the monthly and yearly landings of the principal food-fishes at the different fisning 

 ports, as far as possible with regard to both number and weight, and with the closest 

 possible indication of the place of capture. F"or the plaice especially exact particulars 

 were further demanded as to the composition of the landings according to the various 

 market-classes (e. g. large, medium, small) and measurement of large samples of the 

 landings in order to determine the composition of same from centimetre to centimetre. 

 As a result, a very great quantity of material was collected during the following years, 



