Refining Estimates of Collision Risk for Harbour Seals and Tidal Turbines

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Refining Estimates of Collision Risk for Harbour Seals and Tidal Turbines

We’re excited to announce the release of a new report which updates how we can assess the potential impacts of collisions between marine mammals and tidal energy devices!

As the marine renewable energy industry grows, understanding the way that marine mammals may interact with devices is really important to understand. This is especially true of tidal energy devices, in relation to the potential risk of collision between marine wildlife and rotating turbine blades below the sea surface. For harbour seals (Phoca vitulina) in the Pentland Firth and Orkney Waters region where populations of this species are in decline locally – this is potentially an important issue!

SMRU Consulting has carried out a new piece of research to try to improve assessments of the risk of collision between harbour seals and tidal turbines using the most up to date information available on how harbour seals use tidally active areas. This research, commissioned by Marine Scotland and Scottish Natural Heritage, was carried out with the Sea Mammal Research Unit, in collaboration with Dr Bill Band, an independent expert in collision risk modelling, and APBmer, a marine consultancy. Building on work undertaken in previous projects, this research has further developed the approach to modelling risk utilising additional information on observed seal behaviour patterns derived from tagged wild seals in the Pentland Firth, such as dive depth profiles and transit speeds. It also incorporates the relationships between tidal current, rotor speed and the risk of a collision being fatal.

Including these kinds of data and this type of approach can really improve how we robustly assess the potential for impacts. The report can be found here. One of the things that this work has highlighted is that any prediction of collision risk is very sensitive to the estimates of the likely density of animals at tidal turbine sites and on the assumptions made about seals ability to avoid collisions. Unfortunately these are the two factors which we know least about therefore any estimates of collision rates are currently highly uncertain.

In order to solve this problem, as part of its Demonstration Strategy for tidal energy, Marine Scotland is funding SMRU to carry out further research in this area, deploying sophisticated combinations of underwater instruments (active sonar devices, acoustic monitoring, video cameras and seal tagging) to observe the interactions between tidal turbines and a range of animals, including harbour seals and other marine mammals, at an operational tidal array. We’re really hoping this will shed light on how animals might behave around these devices. Check out the project summary and the phase 1 report here.

SMRU Consulting with partners SMRU are working on a number of similar monitoring projects globally and are at the forefront of developing the means to detect and track marine mammals underwater around marine energy projects and to provide understanding of the real risks posed by the developing industry on these animals.

 

About the Author:

Rachael is an Associate Scientist at SMRU Consulting Europe. Check out her bio under the "About Us" tab.

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