2. Methods RHIBs (Fig. 1) were recorded at three sites:(1) Juan de Fuca Strait, outside of
Victoria Harbour, British Columbia, Canada,(2) Haro Strait, British Columbia, Canada, and
(3) Cockburn Sound, south of Perth, Western Australia (Table 1). In Canada, two omni-
directional hydrophones [International Transducer Corp.(CA, USA) 4123, bandwidth 50 Hz–
25 kHz, sensitivity− 145 dB re 1 V/μPa] were lowered to depths of 5, 10, 15, or 25 m from a
Canadian Coast Guard vessel that was drifting with the main engines switched off. Sound …