Site and species dependent effects of offshore wind farms on fish populations
Anthony W. J. Bicknell, Samuel Gierhart, Matthew J. Witt
Abstract
The expansion of offshore wind energy capacity is changing the seascape with the large-scale introduction of turbines and associated infrastructure. Subsurface structures can influence the abundance, distribution and behaviour of some marine fish species by providing artificial habitat and food resources that supplements natural occurrence. At two of the highest latitude operational wind farms the abundance, biomass and size of haddock and flatfish was higher close to jacket turbine foundations, with the effect larger at the older and more complex foundations. The results provide further evidence of the fine-scale impacts of offshore wind turbines on demersal fish and illustrate their species and site-specific nature. Quantifying how these changes may have positive or negative effects on local ecosystems and scale up to networks of wind farms is a challenge, but will be required if potential future wind farm consenting policies are to be addressed. • Offshore wind energy infrastructure will change the marine seascape below water. • The impact of these large-scale developments on marine fish is still to be fully understood. • In this study, demersal fish abundance, biomass and size were greater around wind farm foundations compared to references. • The effect being larger at the wind farm with older and more complex structures. • The ∼2–3 fold increase in biomass at turbine structures may influence energy fluxes and change the foraging topography for predators.