Harbour porpoise distribution can vary at small spatiotemporal scales in energetic habitats

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Benjamins, Steven, van Geel, Nienke, Hastie, Gordon, Elliott, Jim, Wilson, Ben
• Other Authors: NERC, University of St Andrews. School of Biology, University of St Andrews. Sea Mammal Research Unit
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Monitoring; Arrays - Marine mammals; Tidal currents; Water waves - Marine renewable energy development (MRED) - Passive acoustics; QH301 Biology; GC Oceanography; NDAS; NERC; SDG 7 - Affordable and Clean Energy; SDG 14 - Life Below Water; QH301; GC; Harbour porpoise; Phocoena phocoena
• Online Access: http://hdl.handle.net/10023/11068; https://doi.org/10.1016/j.dsr2.2016.07.002; http://www.sciencedirect.com/science/article/pii/S0967064516301849?_rdoc=1&_fmt=high&_origin=gateway&_docanchor=&md5=b8429449ccfc9c30159a5f9aeaa92ffb#s0065

The authors acknowledge support received from the Scottish Funding Council, Highlands & Islands Enterprise, Scottish Power Renewables and E.ON under the Hebridean Marine Energy Futures (HMEF) programme (Grant reference number 1R042 (HFU) SPIRIT , Project Ref. HR10012), a research initiative led by the University of the Highlands and Islands (UHI) and Aquamarine Power. Scarba C-POD data were collected under the UK Natural Environment Research Council (DEFRA/NERC) grant NE/J004367/1 (RESPONSE). Marine habitat heterogeneity underpins species distribution and can be generated through interactions between physical and biological drivers at multiple spatiotemporal scales. Passive acoustic monitoring (PAM) is used worldwide to study potential impacts of marine industrial activities on cetaceans, but understanding of animals’ site use at small spatiotemporal scales (<1 km, <1 day) remains limited. Small-scale variability in vocalising harbour porpoise (Phocoena phocoena) distribution within two Scottish marine renewable energy development (MRED) sites was investigated by deploying dense arrays of C-POD passive acoustic detectors at a wave energy test site (the European Marine Energy Centre [Billia Croo, Orkney]) and by a minor tidal-stream site (Scarba [Inner Hebrides]). Respective arrays consisted of 7 & 11 moorings containing two C-PODs each and were deployed for up to 55 days. Minimum inter-mooring distances varied between ~300–600 m. All C-POD data were analysed at a temporal resolution of whole minutes, with each minute classified as 1 or 0 on the basis of presence/absence of porpoise click trains (Porpoise-Positive Minutes/PPMs). Porpoise detection rates were analysed using Generalised Additive Models (GAMs) with Generalised Estimation Equations (GEEs). Although there were many porpoise detections (wave test site: N = 3,432; tidal-stream site: N = 17,366), daily detection rates varied significantly within both arrays. Within the wave site array (<1 km diameter), average daily detection rates ...