Table 2.

Estimated detection ranges of different prey items based on detection capabilities of a captive Pseudorca, and the source parameters derived in the present study

PredatorSL (dB re. 1 μPa, pp)f0 (kHz)Noise (dB re. 1 μPa2 Hz-1)PreyTS (dB)Detection range (m)
Pseudorca 2205035Tuna (1 m)—301210
Pseudorca 2205035Dolphin (Tursiops)—202320
Pseudorca 2205035Small squid (20 cm)—50380
Grampus 2207532Small squid (20 cm)—50385
Grampus 2207532Large squid (80 cm)—403130
  • 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.

  • 1 Bertrand et al. (1999)

  • 2 Au (1996)

  • 3 Medwin and Clay (1998)