SPACE USE OF FISH IN RELATION TO OFFSHORE RENEWABLE ENERGY
DEVICES (OREDS)

Populations of fish have complex spatial and temporal dynamics characterised by migrations, distinct habitat preferences, and age and sexual segregation. The processes structuring natural fish populations are not well known, even though a responsive management framework requires defined management units that represent the scales over which actual populations operate. An emerging issue in understanding fish spatial ecology is how and why fish select particular habitats at certain times, and linked to this is how human-made devices may modify space use compared to adjacent areas.

Offshore renewable energy devices (OREDs) are likely to have direct and indirect impacts on shelf and coastal ecology over a wide range of scales. Environmental effects may include: habitat change; increased water turbidity and contaminant remobilisation during construction and decommission; and increased habitat heterogeneity, noise, vibration and electromagnetic fields during operation.

Our research investigates the effects of the Wave Hub energy generating devices, to be located 13km off Hayle, North Cornwall by 2010, on the movements, behaviour and space use (before, during and after commissioning) of commercially important marine fish using data-logging tags in addition to the UK’s first large-scale, long-term monitoring acoustic array for fish tracking (available through a NERC Capital Award).

Commercially important species in the region such as thornback ray Raja clavata and Atlantic cod Gadus morhua are being investigated. Movement data are largely absent for these species in the Western English Channel and the Celtic Sea, which are valued fishing areas not only for the UK but also Ireland, France, Belgium, Spain and Denmark. Moreover, movements and habitat use of large fish have not been studied before, during and after an ORED installation anywhere in the world. Understanding their population movements, structure and habitat selection in relation to the Wave Hub will contribute to fundamental knowledge of how OREDs impact the sustainability of fish stocks, both locally and through dispersal effects (‘spillover’) into adjacent areas and the wider environment.

People involved: Dr Steve Cotterell, Professor David Sims (MBA & University of Plymouth), Matt McHugh, Nick Humphries (MBA).

Funding: NERC Oceans 2025, PRIMaRE (Universities of Exeter and Plymouth).