As of July 2019, there are 8.5 GW of UK offshore wind installed capacity, and the UK Government has estimated 20% of current UK electricity demand could be met with wave and tidal stream sources. Scotland is targeting the equivalent of 100% of gross annual electricity consumption from renewable sources by 2020, having achieved 74% as of 2018. However, with rapid development of marine renewable energy (MRE) including wind, wave and tidal stream energy devices, uncertainty remains surrounding the environmental and ecological effects of installing and operating devices and arrays. Concerns include disruption of migratory and foraging behavior, direct mortality from animal collision with underwater turbines, attraction of animals to structures or to prey attracted to or aggregating around structures, or conversely displacement from preferred habitat. Changes in behavior of fish species, in particular those which are common prey of seabirds and marine mammals, could lead to changes in foraging behavior of their predators as observed at offshore wind turbines. Regulators, developers and operators need to understand the environmental effects of installing and operating devices and arrays in the marine environment.