Figure 5
From: Wild harbour porpoises startle and flee at low received levels from acoustic harassment device
Behaviour around AHD exposure of HP6. See legend in Fig. 3 for general figure explanations. (a) This porpoise swam at the surface during the entire exposure period, but after about 1 min post exposure, it resumed to a dive pattern similar to the pre-exposure period. (b) This porpoise received moderate AHD levels (rms fast), and was not at risk of TTS. The decreasing received levels of pings indicates that the porpoise increased distance to the sound source. (c) The very high frequency echolocation clicks of the porpoise were not reliably detected because of the lower sampling rate of the audio recording on this specific mid-frequency dtag. (d) While remaining at the surface, swimming effort increased 3 min into the exposure period and was maintained at a high level for at least 15 min after the AHD exposure stopped. During the exposure, the porpoise was breathing at regular intervals.
