CAREY and ROBISON: DAILY PATTERNS IN ACTIVITIES OF SWORDFISH 



loe-'so' loe'is' loe^so' 



2400 



109°15' 



6 Hours 



15' 



10' 



05' 



'23° 



Figure 2. — Ti-ack of swordfish no. 2, Baja California, separated into four panels for clarity. Each day this fish moved inshore to the 

 50-fathom ( 91 m) curve on a bank then moved out over deep vtater at night. The turn inshore began about 1 h before dawn; the offshore 

 movement began several hours before sunset. Compare with the depth record in Figure 9. Dots represent sunset; circles represent 

 sunrise. Ticks at 1-h intervals, bottom contours in fathoms. 



moving 9 km in 5 h, then turned to the south at 

 sunset and moved down the axis of San Jose 

 Canyon. It continued in a southwest direction 

 when it reached deep (2,000 m) water, and by 

 dawn on 6 May when we abandoned it, it had gone 

 88 km in 44 h. 



No. 6 showed the now-famihar pattern of verti- 

 cal movements, staying near the surface at night 

 and going deep during the day (Figure 5). Like no. 

 5 it made excursions to the surface during day- 

 Hght hours, coming up five times to spend periods 



of 0.5-1.5 h on the surface, then returning to 

 depths which averaged 75-100 m, but included 

 much deeper excursions. 



While on the surface during the day, no. 5 and 6 

 swam about actively. No. 6 moved at an estimated 

 1.6-3.2 km/h (1-2 kn) in a haphazard pattern with 

 much turning, so that progression along its course 

 was considerably slower than its swimming speed. 

 It appeared to be responsive and moved after a live 

 Pacific mackerel. Scomber japonicus, which was 

 thrown to it. On one occasion we attempted to 



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