Abstract
Marine renewable energy developments (MRED) will result in large quantities of infrastructure being deployed in coastal habitats, and the localised exclusion of fishing. The ecological consequences of this scale of deployment are largely unknown, particularly for benthic species. Infrastructure has the capacity to act as artificial reefs (ARs), providing novel habitat, and this may viewed as a benefit of MRED, or a means to mitigate the exclusion of fishing. At present, the functioning of AR ecosystems remains poorly understood. As a measure of ecosystem function, secondary productivity can be used to assess the implications of MRED. The lack of suitable methodology, deployable at relevant scales within time and/or cost constraints, has limited benthic secondary productivity (BSP) quantifications on ARs. Techniques to measure potential BSP and particle flux were developed and applied to the Loch Linnhe Artificial Reef (functionally similar to scour protection material). Variations in BSP and mobile epifaunal densities on, and between, structures in different environments were quantified. Reefs exposed to intermediate current had the highest potential productivity. The BSP on internal areas of structures contributed to the total productive output, but the relative contribution varied according to reef location and design. BSP was primarily determined by particle supply, but the response was not consistent among locations. Mobile epifaunal densities related to reef location, but not reef design, and were highest on reefs in the deepest water and exposed to the fastest currents. The evidence presented in this thesis highlights the need to account for the receiving environment when predicting the ecological consequences of MRED, or when modelling the productive capacity of structures. Such information can be used to suggest modifications to proposed or existing structures in order to maximise their benefit to coastal ecosystems.