Figure 1. Controlled exposure experimental design to measure behavioural responses of humpback whales to different vessel noise levels.

(A) Schematic showing simulated whale-watch approaches of resting mother-calf pairs in the during phase, at the same distance and speed, with different vessel noise playback levels (control/low 124/148 dB re 1 μPa, medium 160 dB re 1 μPa, high 172 dB re 1 μPa; not to scale). (B) Set up of the vessel and underwater acoustic transducer (circled). (C) Aerial photograph of a mother-calf pair resting on the surface, from the view of the unmanned aerial vehicle during data collection.

Figure 1—figure supplement 1. Study area in Exmouth Gulf, Western Australia, and research effort tracks.

Figure 1—figure supplement 2. Spectral signatures of whale-watch vessel noise and research vessel noise.

Figure 1—figure supplement 3. Spectral components of the vessel noise recording compared to playback noise.