. Bulletin. Science; Natural history; Natural history. ANGEL SHARK BEHAVIOR 197 q; 1000 CO Z) crO 750 UJ I tLcr ^°° ^^ 250 SPEED3 - CLASS 2 - ANGEL SHARK SWIMMING RATES sunset- _ ^^rate of \ / \ / \ \ / / 750 ^1000 crO LlJ X I- 500 UJ LL- S^ 250 0 4 - SPEED 3 : CLASS I -. O OOODOOOOO 19 20 21 ~i—'—I—'—I—'—r- 22 23 24 01 —1—I—I 02 03 OCXJOOOOOOO OOOOOOI -1—--n—I—I—>—I—'—I—'—|— 03 04 05 06 07 08 09 ~i— 10 II n— 13 14 15 1 16 TIME Fig. 4. Swimming speed data obtained at lO-min intervals from one 5. catifornica tagged with a single-channel transmitter. Speed class 1. 0-15 cm/sec; 2, 15-50 cmyse
. Bulletin. Science; Natural history; Natural history. ANGEL SHARK BEHAVIOR 197 q; 1000 CO Z) crO 750 UJ I tLcr ^°° ^^ 250 SPEED3 - CLASS 2 - ANGEL SHARK SWIMMING RATES sunset- _ ^^rate of \ / \ / \ \ / / 750 ^1000 crO LlJ X I- 500 UJ LL- S^ 250 0 4 - SPEED 3 : CLASS I -. O OOODOOOOO 19 20 21 ~i—'—I—'—I—'—r- 22 23 24 01 —1—I—I 02 03 OCXJOOOOOOO OOOOOOI -1—--n—I—I—>—I—'—I—'—|— 03 04 05 06 07 08 09 ~i— 10 II n— 13 14 15 1 16 TIME Fig. 4. Swimming speed data obtained at lO-min intervals from one 5. catifornica tagged with a single-channel transmitter. Speed class 1. 0-15 cm/sec; 2, 15-50 cmysec: 3. 50-75 cm/sec; 4, >75 cm/sec. When two points are plotted they represent and minimum speeds during the one minute sampling period. "Atypical Behavior'"). None of tiie sharks showed maximum mean rate of move- ment during the day (sunrise to sunset). There was no indication that a properly-placed transmitter affected the move- ment of the sharks, except for a brief burst of swimming immediately after tag application. One shark, however, was tagged improperly, too far posteriorly, resulting in the unit actually trailing beyond the body. This probably impaired the shark's swimming ability, as this individual moved the least of any of the tagged sharks (less than 600 m during the 20-h tracking session). Home range.—One significant finding of this study was that the angel sharks at Ship Rock appeared to confine their movements to a distinct, limited area (Fig. 3). Although the durations of the individual trackings were not sufficient for accurate determinations of individual home ranges, the data collectively indicated a com- mon area preference. The telemetered sharks, excluding the improperly tagged one, moved an average of 4 km (range, 2-9 km) during the tracking sessions, but nearly all movements were in an area of approximately 150 ha ( by km). This area includes a narrow circular region around Ship
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