216 BRITISH FISHERIES 



within the area assigned to it, and in the course of 

 these cruises the hydrographical observations are 

 made, and samples of the sea-water are taken for 

 analysis at the laboratories on shore. 



In reality these hydrographical observations form 

 the least part of the sea-going work, so far as time 

 is concerned, and very considerable attention is 

 being devoted to the several questions of very 

 great practical importance to the fisheries. These 

 are : (i) the migrations of the principal food-fishes 

 of the North Sea, especially herring, plaice, and cod ; 

 and (2) the important question of over-fishing by 

 trawlers in the North Sea and adjacent fishing 

 grounds. These two questions are treated co- 

 operatively by the vessels working in the areas 

 affected. Each question is entrusted to a com- 

 mittee, the conveners of which are Dr J. Hjort 

 (migrations) and Mr W. Garstang (over-fishing). 

 In addition to this co-operative biological work, 

 each State is, of course, free to make whatever 

 investigations are judged of importance. 



"The chief aim of the whole work is to increase 

 our knowledge of the conditions of the fisheries, 

 and thus to further the interests of a rational ex- 

 ploitation of the sea. It must be remembered, 

 however, that only those results are permanently 

 and really useful which will bear the test of severe 

 scientific criticism. The study of the sea is to 

 proceed orderly and as rapidly as possible, but it 

 would be unpractical to sacrifice the accuracy of 



