Many countries have set ambitious renewable energy targets with offshore sources anticipated to form an important part of this; for example, it is estimated that one fifth of the electrical supply in the UK could come from marine (wave and tidal stream) resources. However, the environmental impacts of tidal turbines on marine wildlife (particularly seals, whales, and dolphins) is largely unknown. One major concern is the potential for marine mammals to collide with the rotating turbine blades causing injury or death. It is critical to learn whether this concern is valid by collecting data on the underwater movements of marine mammals around operating tidal turbines. Collecting these data is extremely challenging and available methods for measuring movements of marine mammals underwater and interactions with tidal turbines are limited. However, a small number of cutting-edge technologies have the ability to detect and track marine mammals underwater; these are underwater video, and active- and passive-acoustic tracking. This project will design and build a standardised marine mammal detection and tracking system based on the integration of this suite of technologies for the tidal energy industry. The system will be designed to be standardised in terms of the data collected but will be flexible to ensure it can be integrated into a range of different tidal turbine designs and can be deployed in a variety of different tidal environments. Effectively, the system will be designed to be 'plug and play' so that it can be integrated easily with future tidal turbines, and can be deployed and retrieved with minimal impact to turbine operation. Further, to ensure that the data collected by the system is standardised and therefore comparable between future monitoring studies, a series of open source and freely available data archiving and analysis tools for the datasets will be provided. Overall, this project aims to deliver a unique monitoring tool that will provide the Tidal Energy Industry with a data collection system that may be required as part of their consent monitoring conditions, and will provide regulatory authorities with the evidence base upon which to make informed decisions about marine mammal collision risk during the consenting process for tidal energy developments. keywords: tidal stream energy, tidal turbines, marine mammals, collision risk, impact assessments, sonar, video, hydrophones, seals, dolphins, porpoises, behaviour, underwater tracking stakeholders: Regulators, Tidal Developers, Statutory Advisors, Scottish Government, Scottish Natural Heritage, Natural Resources Wales, Atlantis Resources Ltd