17 - 19° water had moved southward about 3° of latitude to the vici"it:.' 

 of ^0°N. 



The 50-metpr level had temperatures of from 2^ to 5 lower then 

 those at the surface, and those at the 100-meter level were 1-4-° below 

 those at 50 meters. At the 200-meter level the temperatures Tiere 1° to 

 2° below those of the 100-meter level. At all levels the specific 

 gravities were directly proportional to the temperatures with low 

 chlorinities in the north and high values in the south, however, no 

 chlorinities of more than 2600 were found. 



In conclusion, a comparison of the surface temperature distribution 

 during this year's operatin;: period from May to October VTith the dis- 

 tribution shown for the same area on the North Pacific Oceanographic 

 Charts published by the Navy Hydro^raphic Office shc:-3 a tendency toward 

 roughly the same distribution, however, various localized differences due 

 to conditions at the tim.e are apparent, /n examination of the vertical 

 distribution of temperatures at the 50-meter and 100-meter levels indicates 

 that the temperature difference between the surface and the 100-meter 

 level gradually increases from "fey to September, but that fmm October on 

 it decreases at a comparatively rapid rate. The rate of increase and 

 decrease of the difference between the temperature at the 50-meter level 

 and the 100-meter level was net very marked this year. 



A grouping by areas of the cases in ^Thich albacore were taken and 

 the cases in vrtiich no albacore were taken is shovTn in Table 7A "Cases in 

 v3iich Albacore Were Taken" and B "Cases in "liich No .\lbacore Tl-ere Taken", 



(B) Water Temperatures and Catch Ratios 



In order to aid the consideration of the level at which the albacore 

 swim in the operating area of this investigation, the relationship 

 between catch rates and the temperatures at the surface, 50 meters, and 

 100 meters has been shown in tables 3, 9, and 10. The catch rates used 

 in these tables are the number of fish taken per 100 hocks fished, rnd the 

 temperatures have been rounded off by discarding fracti'"^ns belor .5 (for 

 example a temperature recorded as 15° m.eans from 14.. 5^ t. 15.4°). 



155 



