Itoh et al; Migration patterns of Thunnus orientolis determined with archival tags 



523 



130°E 



140°E 



40°N 



\ 

 '■ 270898 



30°N 



Figure 7 (continued) 



to the traveling phase were not included, that is to say, ten 

 days between the fourth and thirteenth days preceding 

 (or following) the onset (or end) of a traveling phase were 

 used. 



Among 12 features investigated, three differed between 

 the two phases (Table 2). The temperature difference be- 

 tween fish viscera and ambient water (thermal excess) was 

 more than 1.0°C higher during the traveling phase for four 



out of five fish. In the one remaining fish (no. 241), data 

 used for analysis were those from days at the end of the 

 traveling phase. The larger thermal excess during a trav- 

 eling phase was observed at both daytime and nighttime 

 (Fig. 10). The second significant feature was that all fish 

 dived to water deeper than 150 m more frequently during 

 the traveling phase. Except for one fish (no. 241), which 

 spent a long time in water deeper than 150 m, almost all 



