Publication Date:
2022-05-25
Description:
Author Posting. © Inter-Research, 2009. This article is posted here by permission of Inter-Research for personal use, not for redistribution. The definitive version was published in Marine Ecology Progress Series 395 (2009): 161-175, doi:10.3354/meps08204.
Description:
Increasing numbers and speeds of vessels in areas with populations of cetaceans may have the cumulative effect of reducing habitat quality by increasing the underwater noise level. Here, we first use digital acoustic tags to demonstrate that free-ranging delphinids in a coastal deep-water habitat are subjected to varying and occasionally intense levels of vessel noise. Vessel noise and sound propagation measurements from a shallow-water habitat are then used to model the potential impact of high sound levels from small vessels on delphinid communication in both shallow and deep habitats, with bottlenose dolphins Tursiops sp. and short-finned pilot whales Globicephala macrorhynchus as model organisms. We find that small vessels travelling at 5 knots in shallow water can reduce the communication range of bottlenose dolphins within 50 m by 26%. Pilot whales in a quieter deep-water habitat could suffer a reduction in their communication range of 58% caused by a vessel at similar range and speed. Increased cavitation noise at higher speeds drastically increases the impact on the communication range. Gear shifts generate high-level transient sounds (peak– peak source levels of up to 200 dB re 1 µPa) that may be audible over many kilometres and may disturb close-range animals. We conclude that noise from small vessels can significantly mask acoustically mediated communication in delphinids and contribute to the documented negative impacts on animal fitness.
Description:
This work was supported by the PhD
School of Aquatic Sciences (SOAS), Aarhus University, DK,
WWF Verdensnaturfonden and Aase & Ejnar Danielsens
Foundation, the Siemens Foundation, a research agreement
between La Laguna University and Woods Hole Oceanographic
Institution, the Faculty of Science at the University of
Aarhus, Denmark, and the Danish Natural Science Foundation
via a Steno scholarship and frame grants to P.T.M. M.J.
and N.A. were funded by the National Oceanographic Partnership
Program.
Keywords:
Acoustic communication
;
Vessel noise
;
Masking
;
Bottlenose dolphins
;
Pilot whales
;
Recreational vessels
;
Whale watching
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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