From: Autonomous underwater videography and tracking of basking sharks
 | Mission 1 | Mission 2 | Mission 3 |
---|---|---|---|
Date | 11-Jul-19 | 14-Jul-19 | 16-Jul-19 |
Shark sex | Female | Female | Male |
Shark total length | 7–8 m | 6–7 m | 4–5 m |
Mission start | 12:32 | 09:56 | 13:47 |
Mission end | 16:42 | 12:05 | 18:23 |
Mission duration | 250Â min | 129Â min | 276Â min |
AUV speed; mean (± 1 S.D.) | 1.5 m s−1 (0.5) | 0.9 m s−1 (0.6) | 1.5 m s−1 (0.4) |
Shark depth; mean (± 1 S.D.) | 15.6 m (6.5) | 15.3 m (12.8) | 31.8 m (21.9) |
Shark depth (maximum) | 25.0Â m | 59.7Â m | 63.7Â m |
Water temperature; mean (± 1 S.D.; range) | 11.3 °C (0.2; 11.1–12.0) | 11.1 °C (0.7; 10.3–13.1) | 11.2 °C (1.0; 9.2–12.3) |
Chl-α concentration; median (IQR) | 1.2 mg m3 (1.06–1.43) | 0.7 mg m3 (0.46–0.83) | 0.8 mg m3 (0.59–1.17) |
AUV-retag tracking offsets | |||
 Forward–aft | 3 m aft | 1 m aft | 1 m aft |
 Port–starboard | 0 m | 2 m port | 2.5 m port |
 Above–below | 1 m below | 1 m above | 1.5 m above |
Minimum AUV altitude | 6Â m | 2Â m | 3Â m |
Minimum AUV depth | 1Â m | 1Â m | 3Â m |
Maximum permitted AUV depth | 80Â m | 90Â m | 90Â m |
Cumulative duration shark observed (% of mission duration) | 36Â min (14%) | 20Â min (16%) | 90Â min (33%) |
Number of contacts events with shark | 2 | 6 | 3 |
Horizontal visibility (% tracking duration) | Mission 1 (%) | Mission 2 (%) | Mission 3 (%) |
---|---|---|---|
≤ 5 m | 12 | – | – |
5 to 7 | 23 | – | – |
7 to 10 | 65 | 19 | 48 |
10 to 15 | – | 81 | 29 |
15 to 20 | – | – | 23 |