Exposure of individual harbour seals (Phoca vitulina) and waters surrounding protected habitats to acoustic deterrent noise from aquaculture

• Published in: Aquatic Conservation: Marine and Freshwater Ecosystems
• Main Authors: Findlay, Charlotte R., Hastie, Gordon D., Farcas, Adrian, Merchant, Nathan D., Risch, Denise, Wilson, Ben
• Other Authors: NERC, University of St Andrews. School of Biology, University of St Andrews. Centre for Energy Ethics, University of St Andrews. Sea Mammal Research Unit
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Acoustic deterrent device (ADD); Aquaculture; Depredation; Harbour seals; Marine protected areas; Noise pollution; Pinnipeds; GC Oceanography; QH301 Biology; SH Aquaculture. Fisheries. Angling; NDAS; SDG 14 - Life Below Water; GC; QH301; SH; Phoca vitulina
• Online Access: http://hdl.handle.net/10023/25073; https://doi.org/10.1002/aqc.3800

This work was funded by the European Social Fund and Scottish Funding Council as part of Developing Scotland's Workforce in the Scotland 2014–2020 European Structural and Investment Fund Programme. NDM and AF were funded by the Centre for Environment, Fisheries and Aquaculture Science (Cefas). Funding for the seal tagging was provided by the Scottish Government to the Sea Mammal Research Unit (SMRU) as part of the Marine Mammal Scientific Support Program MMSS/002/15, with additional resources from the Natural Environment Research Council (grant numbers NE/J004251/1 and SMRU1001). 1. Pinniped depredation at aquaculture sites is a globally recognized problem. To mitigate depredation, the aquaculture sector uses acoustic deterrent devices (ADDs) as a non-lethal alternative to shooting pinnipeds interacting with caged finfish. However, it is unclear whether sound emissions from ADDs have the potential to also impact non-target pinnipeds at spatial scales relevant to populations. 2. Global Positioning System (GPS) tracking data from seven harbour seals tagged in a non-aquaculture context, on the west coast of Scotland, in 2017 were combined with modelled maps of ADD noise to quantify sound exposure and estimate the potential for auditory impairment. The acoustic model applied an energy flux approach across the main frequency range of ADDs (2–40 kHz). Predictions of temporary and permanent auditory threshold shifts were made using seal location data and published noise exposure criteria. The acoustic exposure of waters (10-km buffers) surrounding protected habitats (i.e. designated haul outs and Special Areas of Conservation (SACs)) on the west coast of Scotland was also assessed. 3. All tagged seals and waters surrounding 51 of 56 protected sites were predicted to be exposed to ADD noise exceeding median ambient sound levels. Temporary auditory impairment was predicted to occur in one of the seven tagged harbour seals and across 1.7% of waters surrounding protected habitats over a 24-hour period, when assuming a ...