Cormac Walsh, Ommo Hüppop, Thiemo Karwinkel, Miriam Liedvogel, Oliver Lindecke, James D. McLaren, Heiko Schmaljohann, Bernd Siebenhüner

Human activity in the North Sea is intensifying, as emerging uses, such as offshore wind farms (OWFs) and liquid natural gas (LNG) terminals, are added to fishing, freight shipping and fossil fuel production as traditional forms of resource exploitation. The volume and scale of these additional installations are projected to increase substantially in the coming decades, which amplifies the need to understand better the biological implications of human activities in the ecoregion. Previous studies have identified that offshore wind turbines either pose a physical barrier to flying animals, leading to avoidance and displacements, or act as sensory traps attracting animals by interfering with the sensory input of natural cues, leading to increased collision risk and mortality. Here we aim to characterise impacts of artificial light pollution at night (ALAN) on offshore migratory birds and bats, and discuss implications for conservation policy and practice. Considering littoral states are aiming to multiply the OWF capacity by a factor of eight before the year 2050, a significant increase in the cumulative risk increase of ALAN can be expected. In light of these developments, we discuss the potential for scientifically informed, anticipatory and ecosystem-based marine governance.