RAPPORTS. XIV: MASTERMAN 



— 26 — 



It will be noticed that there is considerable divergence of result largely due to the 

 employment of different kinds of gear and different meshes of net. 



The author's results for the two species may be compared at a glance by the 

 following figures derived from his curves. 



The experiments give the impression that, with a little further investigation on the 

 same lines, it should be possible to reduce the whole subject to a definite statistical problem 

 capable of mathemical treatment. 



PART II. 



RECOMMENDATIONS AND SUGGESTIONS. 



The appearance this year of a report upon a Pleuronectid other than the plaice is very 

 welcome. It is to be hoped that the attention of the International investigators may be 

 directed towards other flat fish, such as turbot, brill, and halibut, all of which present 

 their special problems. 



The results obtained by Wallace from a study of a series of trawl samples along 

 a selected line give a valuable practical indication of the great possibilities of this particular 

 line of investigation. In the earliest years of the International co-operation it soon became 

 evident that the all-important plaice had a definite distribution in the North Sea according 

 to size or age in relation to either depth or distance from shore. Later researches have 

 shown that the most intimate relation is that of size to distance from shore and less 

 indirectly that of age to distance from shore. 



This fundamental fact being accepted, it follows that the migrations producing 

 this condition render it impossible to determine any specific character of an age- 

 group such as relative growth or abundance, except by a quantitative sample taken 

 approximately in the direction of migration or at right angles to the general direction of 

 the shore. Such a line has been already selected, from the Texel to the Leman and the 

 results, so far as they go, justify the expectations which were made. 



