Webinar #2 in Annex IV Environmental Webinar Series
Sponsored by Ocean Energy Systems (OES)
May 19, 2014 @ 16:30 - 18:00 UTC
Marine Mammals and Tidal Turbines: What are the Issues of Concern and how are they being Resolved?
Ben Wilson, Scottish Association for Marine Science (SAMS)
The potential risks of marine mammals being injured by being hit by tidal-stream turbines, or of vacating significant areas in an attempt to avoid them, are among the most pressing environmental consenting issues facing this emerging family of technologies. Unfortunately, due to the inherent difficulties of studying marine mammal distribution and behaviour underwater, as well as the novelty of the machines themselves, information upon which to base robust impact assessments is extremely limited. Consequently, a variety of research projects in several countries are underway to address these data gaps and investigate different components of these questions. In this presentation we review potential marine mammal-related issues including collision and injury risks, acoustic impacts, displacement, barrier effects and attraction. We then outline what research approaches are being applied and how they relate to one another. The novelty of these challenges, especially working in waters flowing at velocities approaching research vessel speed, has prompted the development of several innovative scientific tools as well as focussing effort onto a previously little studied habitat. These efforts may also tell us much about how marine mammals use such sites, which due to increased density through geographical bottleneck effects, can be perceived as being disproportionately important. There are, however, challenges for the research community to keep pace with the industrial developments themselves, to learn from the many globally dispersed initiatives and to continue research on potential impacts once initial funded consent-to-operate licences have been issued.
Using the FLOWBEC Seabed Frame to Understand Underwater Interactions Between Diving Seabirds, Prey, Hydrodynamics and Tidal and Wave Energy Structures.
Benjamin Williamson, University of Aberdeen
The NERC/Defra collaboration FLOWBEC-4D is investigating the environmental and ecological effects of installing and operating arrays of wave and tidal energy devices. The FLOWBEC seabed platform combines a number of instruments to record information at a range of physical and multi-trophic levels at a resolution of several measurements per second, for a duration of 2 weeks to capture an entire spring-neap tidal cycle. An upward-facing multifrequency echosounder is synchronised with an upward-facing multibeam sonar aligned with the tidal flow. An ADV is used for local current measurements and a fluorometer is used to measure chlorophyll (as a proxy for plankton) and turbidity. The platform is self-contained, facilitating rapid deployment and recovery in high-energy sites. Five 2-week deployments have been completed at wave and tidal energy sites at EMEC in Orkney (UK), both in the presence and absence of renewable energy structures. Using multifrequency target identification and multibeam target tracking, the depth preference and interactions of birds, fish schools and marine mammals with renewable energy structures can be tracked. Seabird and mammal dive profiles, predator-prey interactions and the effect of hydrodynamic processes during foraging events throughout the water column can also be analysed. These datasets offer insights into how fish, seabirds and marine mammals successfully forage within dynamic marine habitats and also whether individuals face collision risks with tidal stream turbines. Measurements from the subsea platform are complemented by 3D hydrodynamic model data, concurrent shore-based marine X-band radar and shore-based seabird observations. This range of concurrent fine-scale information across physical and trophic levels will improve our understanding of how the fine-scale physical influence of currents, waves and turbulence at tidal and wave energy sites affect the behaviour of marine wildlife, and how tidal and wave energy devices might alter the behaviour of such wildlife. These results can be used to guide marine spatial planning, device design, licensing and operation, as these individual devices are scaled up to arrays and new sites are considered.
A Combination of Empirical and Modelled Datasets Reveals Associations between Deep Diving Seabirds and Oceanographical Processes at Fine Spatiotemporal Scales in a High Energy Habitat.
Beth Scott, University of Aberdeen
It remains unknown how tidal stream turbines could impact deep diving seabird populations such as auks Alcidae sp and cormorants Phalacrocorax sp. Predicting whether and how devices could affect populations is hampered by poor knowledge of what influences seabird foraging distributions in the tidal pass habitats favoured for installations. Here distributions of foraging seabirds are compared with a suite of concurrent environmental variables within the Fall of Warness, Orkney, UK to investigate associations between auks, cormorants and oceanographical processes. Results are presented for Atlantic puffins Fratercula arctica, black guillemots Cepphus grylle, common guillemots Uria algaa and European shags Phalacrocorax aristotelis. These studies provide the information that is needed to predict auk and cormorant distributions within tidal pass over different scenarios, revealing which and when species may interact with devices within these habitats.
A video recording of the webinar has been posted below: