Temperatures 



During the period of the investigation the temperatures at the various 

 levels shov/ed roughly similar readings. 



Surface 29.5 to 29.3 degrees; 25 meters 29.3 to 29.5 degrees; 50 

 meters 28.3 to 29.4- degrees; and 100 meters 2^.0 to 26.6 degrees. The 

 temperature dropped sharply at the 150-meter level, v/ith a range of 5.9 

 to 7.-4 degrees between 100 and 150 meters. The 200-metpr level shov/ed a 

 further drop^ with a range of difference of 10.3 to 10.7 degrees from the 

 100-meter level. The following tables give the temperatures at the 

 various stations. - 



■Vater Color and Clarity 



Water color was determined by using Forel's standard fluid. At all 

 seven stations in Woleai 'vaters the color was No.l, except for Station A 

 where it was No. 2. 



Clarity was measured by lowering a white plate 1 foot in diameter 

 into the sea. Visibilities recorded at the various stations were closely 

 similar, with a maximim of 33 meters. It is thought that the more notable 

 variations in visibility were due to variations in the brightness of the 

 sunlight. 



Disposition of the Catch 



After the fish were caught they were dry frozen in the Zuiho Maru's 

 freezer (2 tons freezing capacity) and held in that ves:el's cold storage. 



Concl'i-Sions 



Tne fishing situation turned out to be rather good, perhaps because 

 this investigation r^ay have coincided with the ti"^e of the schools' migra- 

 tion into these v/aters. It is, hov/ever, extremely doubtful whether the 

 schools como into these waters at all times of the year. At the time of 

 the last tuna fishing investigation at ?foleai the fishing situation was 

 very unfavorable, and skipjack schools, too, were rarely sighted. It is 

 therefore thought that the skipjack schools found in these waters are of a 

 migratory character, however, the period of this investigation was too 

 short to make it possible to determine whether they migrat- under the 

 influence of some oceanographic or other factors or v/hether they come at 

 regialar periods, and it is impossible to assess the value of the fishing 

 grounds solely on the basis of these experiments. It is hoped that with 

 the data from this investigation and with the accumulation of more data in 

 successive investigations we mil be able to evaluate these fishing grounds 

 and clarify the total aspect of the fishery so as to provide material for 

 reference in planning commercial operations. 



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