First in situ passive acoustic monitoring for marine mammals during operation of a tidal turbine in Ramsey Sound, Wales

Abstract

The development of marine renewables has raised concerns regarding impacts on wildlife, and environmental monitoring is often required. We examined 3 mo of continuous passive acoustic monitoring (PAM) data collected at the Tidal Energy Ltd. DeltaStream turbine deployment in Ramsey Sound, UK. We aimed to assess the performance of the PAM system at an operational turbine, describe the 3D movements and behaviours of small cetaceans in the vicinity of the turbine, and model changes in detection rates against temporal and environmental variables. The PAM system was designed to acoustically detect, classify and track porpoises and dolphins via their vocalisations within a ~100 m radius of the turbine. In total, 247 small cetacean encounters were identified from click detections, which were also used to reconstruct the spatial movements of porpoises and dolphins, including close approaches to the turbine. Not all hydrophones were functional, which limited the ability to localise porpoise clicks; the probability of detecting and localising a click decreased by 50% at a range of ~20 m. Mechanical sounds on the turbine may have alerted cetaceans of its presence. In models examining acoustic detection patterns, the tidal state, time of day, low low-frequency noise levels and moon phase best explained the acoustic presence of porpoises. The limited duration of turbine operation yielded insufficient data to understand the effect of turbine rotation on animal presence and movement near the turbine. This is the first description of how small cetaceans behave and move around a tidal turbine, and we present recommendations regarding how PAM can be used to improve environmental monitoring at future tidal energy sites.

Oceanographic drivers of marine mammal and seabird habitat-use across shelf-seas: A guide to key features and recommendations for future research and conservation management

“…However, achieving this will require novel methodological techniques. Adaptive survey designs (Embling et al, 2012;Suberg et al, 2014;Waggitt and Scott, 2014;Waggitt et al, 2016a;Benjamins et al, 2017) that incorporate active and passive acoustics (Williamson et al, 2015;Benoit-Bird and Lawson, 2016;Macaulay et al, 2017;Malinka et al, 2018) alongside underwater videography (Machovsky-Capuska et al, 2011;Crook and Davoren, 2014) may prove particularly useful, as will animal borne biologging via the attachment of accelerometers (Viviant et al, 2010;Watanabe and Takahashi, 2013), cameras (Votier et al, 2013;Watanabe and Takahashi, 2013;Tremblay et al, 2014), GPS loggers (Yoda et al, 2014), oceanographic sensors (Charrassin et al, 2008) and satellite relay systems (e.g. the Argos satellite system; Photopoulou et al, 2015;CLS, 2016;Cox et al, 2018).…”

Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system

“…However, there are a number of limitations that should be considered. Specifically, the maximum depth that seals were detected using the system was a ~35 m, and although this would be sufficient to monitor the full water column in many of the existing tidal developments (Malinka, Gillespie, Macaulay, Joy, & Sparling, ; Sparling, Lonergan, & McConell, ), the industry is likely to exploit deeper water locations in future (Lewis et al, ).…”

Adaptable Monitoring Package Development and Deployment: Lessons Learned for Integrated Instrumentation at Marine Energy Sites

“…In addition to our experience with the AMP, in one recent tidal turbine deployment, hydrophone nodes were dispersed on a turbine's support structure, which provided sufficient baseline separation for source localization. However, even with redundant hydrophones at each node, instrumentation failures rendered portions of the array inoperable, as the elements could not be serviced without recovering the entire turbine [35].…”

“…Furthermore, if a MEC-integrated strategy is employed (Section 5.2), the interface specification for an integrated package on a turbine or wave energy converter can be as simple as a bolt pattern and a cable for power and data. Distributing instrumentation across a wider area can have benefits for passive acoustic tracking [35] and stand-off distance, but significantly increases integration cost and precludes the evidenced requirement for independent maintenance of sub-surface instrumentation. Phase 1 integration also allows multiple fields of view to be observed from a single platform and make concurrent observations of marine animals with different sensing modalities (Figure 9 and 13).…”