Schaefer and Fuller Movements, behavior, and habitat selection of Thiinnus obesus 



775 



Time (CTZ) 

 12 00 12 00 12 00 12 00 12 00 12 00 12 

 I   — ' — ' — ' — ^^ —  — ■— ' — ' — ' — ' — ' — ' — ' — ■-^ — ' — ' —  — ' —  — ' — 129 



oT 22 00 02 04 06 08 10 12 14 16 18 20 22 00 02 ^ 



Figure 6 



Depth and temperature records for a bigeye tuna carrying an archival tag 

 (99-792), exhibiting behavior associated with a floating object. Approximate 

 area, 1°N 97°W, is based on geolocation estimates from the archival tag. 

 CTZ = central time zone. 



of time at liberty. The fish traveled a considerable distance 

 west and southwest to about 5°S and 110°W, before mov- 

 ing back toward the east. It was recaptured only 82 nmi 

 east of its release location (Fig. 9C, Tables 1, 2, and 4). The 

 fish with tag 99-787 was released at the same FAD where 

 the fish with tag 99-792 was also released. It was at liberty 

 for 129 d and exhibited behavior associated with floating 

 objects for 12.8'^^f of time at liberty. In contrast to the fish 

 with tag 99-792, the fish with tag 99-787 traveled in the 

 opposite direction, toward the east, moving fairly rapidly 

 to around 82°W, and then moving north and south between 

 about 3°N and 3°S. This fish was recaptured 843 nmi east 

 of its release location (Fig. 9C, Tables 1, 2, and 4). 



The fish with tag 99-889 was at liberty 76 d and exhib- 

 ited behavior associated with floating objects for 10.0% of 

 time at liberty. This fish traveled a considerable distance 

 south to about 7°S, before moving back northward, and 



was subsequently recaptured only 100 nmi southwest of 

 its release location (Fig. 9D, Tables 1, 2, and 4). The fish 

 with tag 99-869 that was released at the same FAD where 

 fish 99-889 was released, was at liberty 112 d and exhib- 

 ited behavior associated with floating objects for 19.2% 

 of time at liberty. The fish initially traveled in a similar 

 direction as that of fish 99-889 before moving westward. 

 It showed extensive latitudinal movements from about 

 5°S to 5°N, and was recaptured 430 nmi northwest of its 

 release location (Fig. 9D, Tables 1, 2, and 4). 



Habitat selection 



The habitat selected by bigeye tuna is presented by month 

 in Figure 11, for days with unassociated type-1 behavior 

 only. The nighttime and daytime depth distributions were 

 very similar for April, May, and June. Most of the time 



