524 



Fishery Bulletin 101(3) 



130°E 



140°E 



40°N 



30°N 



Figure 7 (continued) 



records of excursions below 150 m were due to spikes of 

 deep diving of short duration, less than 10 minutes. Fi- 

 nally the frequency of daily feeding events, detected by a 

 change of visceral temperature, was slightly higher dur- 

 ing a traveling phase (1.6 ±0.6) than a residency phase 

 (1.1 ±0.4). 



Records of surface temperature from the summary file 

 were examined to answer three questions regarding the re- 



lation of water temperature to traveling. The first question 

 was whether any water temperature change, an increase in 

 spring and summer or a decrease in winter, was observed 

 several days prior to the onset of the traveling phase. Such 

 a temperature change was observed in 10 out of 12 cases 

 ( Table 3, Fig. 11). In those 10 cases, the water temperature 

 increased in spring and summer to 19-26''C (average of 

 22°C), and decreased in winter to 15-17°C (16°C). 



