Preface 



In the past this Station has published reports ofj among 

 other things, the progress of its Trork on the relationship 

 between sea conditions and skipjack fishing grounds in the 

 Northeastern Sea Areao The plan in the present case is to 

 select from these reports only the material of a basic charac- 

 ter andg adding to it data abstracted from the reports of the 

 National Fishei'ies Experiment Stations, to present it as a 

 summary for the use of the fishermen of this prefecture. It 

 is hoped that this paper may be of some use to persons actually 

 engaged in the skipjack fishery o 



Ihis opportunity is also taken to express the hope that 

 all persons in the industry iiill ungrudgingly proffer the data 

 which they have obtained, not only in this fishery alone but in 

 all departments of the industry^ in order to assist the Station 

 in projects of this sort and to work for the improvement and 

 development of Miyagi fisheries o 



(1) Surface water temperatures and the distribution 

 of skipjack-fishing grounds in the Northeastern 

 Sea Area 



According to studies made in the Northeastern Sea Area since 

 1929— 



ao Suitable temperatures are 20° = 2i|.° Co IK.thin this 

 range, the greatest number of schools appeared at 

 22° - 23°. 



bo As the areas of suitable water temperatures shifty 

 the skipjack fishing grounds within them shift o CSee 

 the chart of the movements of the center of gravity 

 of the fishing grounds) o 



