Collision Risk
Assessing the collision risk between marine vertebrates and offshore renewable energy devices has been identified as a potential ‘show-stopper’ for the wet-renewables industry by a variety of marine vertebrates (mammals, fish and diving birds) (e.g. Regulators meeting, EMEC 2008).
To determine the risk of collision of an underwater device, SAMS first find it necessary to characterise the background acoustic environment (see above). This will quantify the existing acoustic context into which any future device will be placed. When combined with in-situ device acoustic outputs, the level of audibility to marine mammals and other acoustically sensitive species will be calculable.
Encounter models have been used extensively in ecology to estimate predator-prey interactions of marine animals and to assess risk of predation mortality. As part of the ongoing 7th Framework Equimar Project, SAMS is developing a series of encounter (long range) and evasion (close range) models to determine underwater collision risks for large fish, mammals and birds with marine renewable devices:
Our models consider the many factors that can influence collision risk, for example depth of deployment, velocity of moving parts, the forming of traps (e.g. ducts) water turbidity, time of day/night and the summative effect of many devices in deployed in arrays.
Our modelling tools can be used to directly compare potentially harmful collision risks for different device types, deployment locations and species. Our model also enables us to provide mitigation advice, ranging from predictive modelling to enhancement advice.
