Meals on Wheels? A Decade of Megafaunal Visual and Acoustic Observations from Offshore Oil & Gas Rigs and Platforms in the North and Irish Seas

• Published in: PloS one Vol. 11; no. 4; p. e0153320
• Main Authors: Todd, Victoria Louise Georgia, Warley, Jane Clare, Todd, Ian Boyer
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.04.2016; Public Library of Science (PLoS)
• Subjects: Acoustic noise; Acoustics; Analysis; Animals; Artificial reefs; Biology and Life Sciences; Breweries; Cetacea; Cetorhinus maximus; Climate change; Computer programs; Conservation; Conservation of Natural Resources - methods; Conservation of Natural Resources - statistics & numerical data; Dolphins; Dolphins & porpoises; Drilling; Drilling platforms; Drilling rigs; Earth Sciences; Economic aspects; Ecosystem; Environment; Environmental assessment; Environmental impact; Environmental impact assessment; Environmental monitoring; Hydrophones; Mammals; Mammals - classification; Mammals - physiology; Marine Biology - methods; Marine Biology - statistics & numerical data; Marine mammals; Meals; Megafauna; Minke Whale - physiology; Mitigation; Natural gas; Nature conservation; North Sea; Oceans and Seas; Offshore drilling rigs; Oil and Gas Fields; Phoca - physiology; Phocoena phocoena; Physical Sciences; Platforms; Population Dynamics; Porpoises; Real time; Science; Seals, Earless - physiology; Sharks - physiology; Social Sciences; Studies; Underwater; Visual observation; Visual search behavior; Weather forecasting; North Sea; Ireland; Denmark; Netherlands; United Kingdom > UK; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0153320

A decade of visual and acoustic detections of marine megafauna around offshore Oil & Gas (O&G) installations in the North and Irish Seas are presented. Marine megafauna activity was monitored visually and acoustically by Joint Nature Conservation Committee (JNCC) qualified and experienced Marine Mammal Observers (MMO) and Passive Acoustic Monitoring (PAM) Operators respectively, with real-time towed PAM in combination with industry standard software, PAMGuard. Monitoring was performed during routine O&G industrial operations for underwater noise mitigation purposes, and to ensure adherence to regulatory guidelines. Incidental sightings by off-effort MMOs and installation crew were also reported. Visual and acoustic monitoring spanned 55 non-consecutive days between 2004 and 2014. A total of 47 marine mammal sightings were recorded by MMOs on dedicated watch, and 10 incidental sightings of marine megafauna were reported over 10 years. Species included: harbour porpoise (Phocoena phocoena), Atlantic white-sided dolphin (Lagenorhynchus acutus), white beaked dolphin (Lagenorhynchus albirostris), common dolphin (Delphinus delphis), minke whale (Balaenoptera acutorostrata), common seal (Phoca vitulina), grey seal (Halichoerus grypus) and, basking shark (Cetorhinus maximus). Passive Acoustic Monitoring was conducted on two occasions in 2014; 160 PAM hours over 12 days recorded a total of 308 individual clicks identified as harbour porpoises. These appear to be the first such acoustic detections obtained from a North Sea drilling rig whilst using a typically configured hydrophone array designed for towing in combination with real-time PAMGuard software. This study provides evidence that marine megafauna are present around mobile and stationary offshore O&G installations during routine operational activities. On this basis, Environmental Impact Assessments (EIAs) for decommissioning O&G platforms should be carried-out on a case-by-case basis, and must include provisions for hitherto overlooked marine megafauna.