Underwater noise levels of pile-driving in a New Zealand harbour, and the potential impacts on endangered Hector's dolphins

Eva M Leunissen; Stephen M Dawson

doi:10.1016/j.marpolbul.2018.07.024

Underwater noise levels of pile-driving in a New Zealand harbour, and the potential impacts on endangered Hector's dolphins

Mar Pollut Bull. 2018 Oct:135:195-204. doi: 10.1016/j.marpolbul.2018.07.024. Epub 2018 Jul 14.

Authors

Eva M Leunissen¹, Stephen M Dawson²

Affiliations

¹ Marine Science Department, University of Otago, P.O. Box 56, Dunedin, New Zealand. Electronic address: eva.leunissen@gmail.com.
² Marine Science Department, University of Otago, P.O. Box 56, Dunedin, New Zealand. Electronic address: steve.dawson@otago.ac.nz.

PMID: 30301031
DOI: 10.1016/j.marpolbul.2018.07.024

Abstract

Impact pile-driving generates loud underwater anthropogenic sounds, and is routinely conducted in harbours around the world. Surprisingly few studies of these sounds and their propagation are published in the primary literature. To partially redress this we studied pile-driving sounds in Lyttelton Harbour, New Zealand, during wharf reconstruction after earthquake damage. That Lyttelton harbour is routinely used by Hector's dolphins (Cephalorhynchus hectori), an endangered species found only in New Zealand, provided further context for this study. Steel piles of 0.61 or 0.71 m diameter were driven using three different pile-drivers. Maximum calculated source SEL was 192 dB re 1 μPa²s @ 1 m (SPL_0-p of 213 dB re 1 μPa @ 1 m). Propagation of piling noise was strongly influenced by harbour bathymetry and a rock breakwater near the piling operation. We calculated range estimates at which Hector's dolphins may suffer temporary hearing threshold shift and behavioural change.

Keywords: Hector's dolphin; Marine protected area; Noise impacts; Pile-driving.

MeSH terms

Acoustics
Animals
Dolphins / physiology*
Endangered Species
Environment
New Zealand
Noise / adverse effects*
Transportation Facilities