Opportunity Knocks: Leveraging Offshore Wind Development as a Natural Experiment to Address the Ecological Function of Artificial Reefs

Artificial structures deployed in marine environments as reefs are often presumed to increase fish production. However, our literature review found a lack of evidence, with only 12 studies empirically quantifying secondary production at artificial reefs, and only three studies using a control site. We propose the forthcoming large-scale construction of offshore wind (OSW) energy structures presents a natural experiment to examine the ecological function of artificial reefs, including their effects on fish production. To provide causal inferences of OSW effects, studies must obtain appropriate ‘before’ data, per before-after-control-impact and related designs. This requirement dictates that society must begin planning and collecting data now, prior to OSW deployment. We also highlight that responses beyond fish biomass measures, including life stage specific survival, site fidelity and trophic dynamics, must occur at appropriate spatial and temporal scales to maximise causal inference. By leveraging a timely opportunity and natural experiment with OSW development, the long-running ‘attraction–production debate’ about artificial reef ecological function may be addressed.