Seals and shipping : quantifying population risk and individual exposure to vessel noise

• Published in: Journal of Applied Ecology
• Main Authors: Jones, Esther L., Hastie, Gordon D., Smout, Sophie, Onoufriou, Joseph, Merchant, Nathan D., Brookes, Kate L., Thompson, David
• Other Authors: NERC, University of St Andrews. School of Mathematics and Statistics, University of St Andrews. School of Biology, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Marine Alliance for Science & Technology Scotland, University of St Andrews. Sea Mammal Research Unit, University of St Andrews. Centre for Research into Ecological & Environmental Modelling
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Halichoerus grypus; Phoca vitulina; Spatial overlap; AIS; Telemetry; Acoustic propagation; Marine stressor; MSFD; Noise pollution; Uncertainty; QH301 Biology; QL Zoology; DAS; NERC; BDC; R2C; SDG 14 - Life Below Water; QH301; QL; harbour seal
• Online Access: https://hdl.handle.net/10023/11459; https://doi.org/10.1111/1365-2664.12911; https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12911#footer-support-info

The work was funded under Scottish Government grant MMSS/001/11 and contract CR/2014/04, and supported by National Capability funding from NERC to SMRU (grant no. SMRU1001). Seal at-sea usage maps, location data for individual seals, locations and source levels for vessels, and SPLs from monitoring data used for acoustic validations are available from the Pure repository, https://doi.org/10.17630/89ac9345-240a-41bb-8f53-b3f14bb114c0. 1. Vessels can have acute and chronic impacts on marine species. The rate of increase in commercial shipping is accelerating, and there is a need to quantify and potentially manage the risk of these impacts. 2. Usage maps characterising densities of grey and harbour seals and ships around the British Isles were used to produce risk maps of seal co-occurrence with shipping traffic. Acoustic exposure to individual harbour seals was modelled in a study area using contemporaneous movement data from 28 animals fitted with UHF global positioning satellite telemetry tags and automatic identification system data from all ships during 2014 and 2015. Data from four acoustic recorders were used to validate sound exposure predictions. 3. Across the British Isles, rates of co-occurrence were highest within 50 km of the coast, close to seal haul-outs. Areas identified with high risk of exposure included 11 Special Areas of Conservation (SAC; from a possible 25). Risk to harbour seal populations was highest, affecting half of all SACs associated with the species. 4. Predicted cumulative sound exposure level, cSELs(Mpw), over all seals was 176·8 dB re 1 μPa2 s (95% CI 163·3–190·4), ranging from 170·2 dB re 1μPa2 s (95% CI 168·4–171·9) to 189·3 dB re 1 μPa2 s (95% CI 172·6–206·0) for individuals. This represented an increase in 28·3 dB re 1 μPa2 s over measured ambient noise. For 20 of 28 animals in the study, 95% CI for cSELs(Mpw) had upper bounds above levels known to induce temporary threshold shift. Predictions of broadband received sound pressure levels were underestimated on average by 0·7 ...