Estimated detection ranges of different prey items based on detection capabilities of a captive Pseudorca, and the source parameters derived in the present study
| Predator . | SL (dB re. 1 μPa, pp) . | f0 (kHz) . | Noise (dB re. 1 μPa2 Hz-1) . | Prey . | TS (dB) . | Detection range (m) . |
|---|---|---|---|---|---|---|
| Pseudorca | 220 | 50 | 35 | Tuna (1 m) | —301 | 210 |
| Pseudorca | 220 | 50 | 35 | Dolphin (Tursiops) | —202 | 320 |
| Pseudorca | 220 | 50 | 35 | Small squid (20 cm) | —503 | 80 |
| Grampus | 220 | 75 | 32 | Small squid (20 cm) | —503 | 85 |
| Grampus | 220 | 75 | 32 | Large squid (80 cm) | —403 | 130 |
| Predator . | SL (dB re. 1 μPa, pp) . | f0 (kHz) . | Noise (dB re. 1 μPa2 Hz-1) . | Prey . | TS (dB) . | Detection range (m) . |
|---|---|---|---|---|---|---|
| Pseudorca | 220 | 50 | 35 | Tuna (1 m) | —301 | 210 |
| Pseudorca | 220 | 50 | 35 | Dolphin (Tursiops) | —202 | 320 |
| Pseudorca | 220 | 50 | 35 | Small squid (20 cm) | —503 | 80 |
| Grampus | 220 | 75 | 32 | Small squid (20 cm) | —503 | 85 |
| Grampus | 220 | 75 | 32 | Large squid (80 cm) | —403 | 130 |
SL, source level; f0, centroid frequency; TS, target strength.
It is assumed that detection is limited by ambient noise, and that the receiving system of a Grampus performs like that of a Pseudorca.
TS for a Tursiops may not represent TS for smaller delphinids preyed upon by Pseudorca, but it is the only available TS for a dolphin.
Bertrand et al. (1999)
Au (1996)
Medwin and Clay (1998)