Davis and Stanley: Movements of Thunnus maccoyii in the Great Australian Bight 



457 



ra 20^ 



t " 



Water 



liiffrirrnTTTr^''^^ 



1 1 1 r 



W=30 W=10 W=30 



-1 1 1 r 



W=40 W==30 



W=15 



"I 1 r 



80 

 100 



n 1 1 1 r 



12 15 18 



Local time (hours) 



21 



24 



16 



18 20 22 



Local time (hours) 



24 



02 



04 



Figure 7 



(A) Track southern bluefin tuna 10 on 16 January 1994. (B) Track of southern bluefin tuna 11 on 

 17-18 January 1994. See Figure 6 for legend details of upper and lower graphs. In the middle graph, 

 stomach temperature and water temperature (interpolated from the depth of the fish and data 

 logger temperature profiles) are plotted against time. 



Tuna 13 was released 15 km west of Labatt Point at 

 1226 h on 19 January with a temperature-pressure tag 

 in the stomach (Figs. 1 and 2E). This fish remained close 

 to the surface during the day and deeper at the night, 

 frequently staying just above the thermochne and some- 



times diving through it. It made an extended dive after 

 dusk and another just before dawn (Fig. 8B). It was associ- 

 ated with schools of tuna throughout the track. Although 

 tuna schools did not appear on the echosounder during 

 the afternoon, extensive bird activity and surface schools 



