Tidal, wave and offshore wind resources will be important for meeting an increasing proportion of society's future energy needs. However, marine renewable energy devices are likely to have direct impacts and indirect effects on shelf and coastal environments and biota across a range of spatio-temporal scales. These potential effects (both positive and negative) have implications for pelagic, demersal and benthic fish and invertebrate (shellfish) populations, their essential habitats and the fisheries they support. Globally, there is at present a very limited understanding of how large-scale development of marine renewable energy installations (MREI) will affect fish and shellfish populations and the fisheries that exploit them.

Whilst some research to date has considered fish sensory responses to probable noise and electromagnetic fields associated with MREIs, the major gaps in knowledge that will have particular socio-economic importance lie in understanding the longer term behavioural and ecological responses, including habitat use by fish and shellfish, arising from marine renewable devices themselves and the areas immediately surrounding areas that exclude fishing. Hence, there is a need to quantify whether fisheries in areas adjacent to fishery exclusion zones around MREI sites in temperate regions are enhanced by the hypothesised biological 'spillover' effect, how MREI areas may be connected biologically, and the biological and socio-economic effects of displacing exploitation pressure from MREI sites to adjacent areas.

In the proposed research we will use a novel combination of behavioural tracking, density estimations and modelling approaches to address whether 'spillover' of species abundance (fish, shellfish) as a consequence of the no-fishing area around MREIs enhance adjacent areas. We propose to conduct research at a small-spatial scale, wave energy test site (the Wave Hub, off Hayle, Cornwall) and a Round 1 (R1) 30-turbine offshore wind farm (North Hoyle, off Rhyl, North Wales) and the area north of this towards the R2 Gwynt-y-Mor wind farm currently under construction. Our approach in these locations will be to quantify where large numbers of fish and shellfish of several species (e.g. edible crab, lobster, Atlantic cod, thornback ray) are located in relation to MREI, adjacent and more distant areas, and how much time they spend in those locations over annual cycles. We will then use this precise spatial information for several hundred individuals to scale up to potential population levels using relative abundance data from surveys for these focal species in those areas. From this, empirical estimates of the magnitude of spillover and its spatio-temporal dynamics will be made. These will be compared with spatial fishery models, to assess how rates of exchange of animals between areas accessible and inaccessible to fishing determine outcomes in terms of both spawning potential and fishery yield. We will use an individual-based modelling approach to identify how patterns of space use by fish/shellfish determine these outcomes when MREIs are introduced into stock areas. This research will also undertake a socio-economic analysis of the impacts and benefits to fisheries of MREIs that exclude fishing, and the effects of displacement of fishing exploitation to adjacent areas.

These data will be contextualised with the relative abundance of predators of fish (seabirds, marine mammals) in MREI and adjacent areas together with how fish and shellfish movements and space use change in response to variations in the physical environment (wave height, current velocity) will allow a deeper understanding of the drivers of distributional change in target species in MREI and adjacent areas. The proposed research will benefit from using novel tracking technologies, including an acoustic monitoring array that is unique to the UK, to obtain the first long-term movement data for multiple species around MREI sites.

Potential Impact:
See main proposal document.