Disturbance from whale-watching can cause significant behavioural changes with fitness consequences for targeted whale populations. However, the sensory stimuli triggering these responses are unknown, preventing effective mitigation. Here, we test the hypothesis that vessel noise level is a driver of disturbance, using humpback whales (Megaptera novaeangliae) as a model species. We conducted controlled exposure experiments (n= 42) on resting mother-calf pairs on a resting ground off Australia, by simulating whale-watch scenarios with a research vessel (range 100 m, speed 1.5 knts) playing back vessel noise at control/low (124/148 dB), medium (160 dB) or high (172 dB) LF-weighted source levels (re 1 μPa RMS@1m). Compared to control/low treatments, during high noise playbacks the mother's proportion of time resting decreased by 30%, respiration rate doubled and swim speed increased by 37%. We therefore conclude that vessel noise is an adequate driver of behavioural disturbance in whales and that regulations to mitigate the impact of whale-watching should include noise emission standards.
Data available from Dryad
Data from: Vessel noise levels drive behavioural responses of humpback whales with implications for whale-watchingDryad Digital Repository, doi:10.5061/dryad.9kd51c5dq.
- Kate R Sprogis
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Rosalyn Gloag, University of Sidney, Australia
© 2020, Sprogis et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.