The Marine Renewable Energy Strategic Framework for Wales (MRESF) is seeking to provide for the sustainable development of marine renewable energy in Welsh waters. As one of the recommendations from the Stage 1 study, a requirement for further evaluation of fish collision risk with wave and tidal stream energy devices was identified.
This report seeks to provide an objective assessment of the potential for fish to collide with wave or tidal devices, including a review of existing impact prediction and monitoring data where available. The study has been progressed as a desk-based review of existing information together with targeted consultation with device developers and relevant research organisations. A conceptual model of fish collision risk was developed at the start of the study and has been used to focus the review and consultation exercises.
The conceptual model has been developed based around a standard environmental risk assessment model and focuses on four key factors contributing to collision risk:
- Exposure - based on whether a fish has ecological traits which will influence exposure to wet renewable (wave and tidal) devices which could cause a behavioural avoidance response;
- Long range avoidance - based on operational underwater noise characteristics of devices and fish hearing and responses to underwater noise;
- Close range evasion - based on relevant device characteristics and fish visual acuity, fish swimming speeds and traits; and
- Collision damage – based on likely consequences of collision between a fish and a device.
The study has collated available information on the characteristics of wave and tidal devices that influence the magnitude of risks to fish (Section 3) and also considers environmental characteristics of potential deployment locations in Wales and how this might influence the composition and abundance of fish exposed to collision risk (Section 4).
Detailed evaluations of the three key factors contributing to collision risk are provided in Sections 5 to 7 taking account of specific information relating to wave and tidal devices where available and making use of more generic information from other comparable activities. Significant information gaps highlighted by this review are described in Section 8. An assessment of overall collision risk for different types of fish and different wave and tidal devices is presented in Section 9 together with a discussion of the limitations of existing scientific knowledge and priorities for additional research. Potential mitigation and monitoring options are described in Section 10. Key conclustions of the study are described in Section 11.
The Approach to Sustainable Development Report presents the final outputs of the Marine Renewable Energy Strategic Framework (MRESF). The MRESF will be an essential management tool for the sustainable development of wave and tidal energy in Wales.