Assessing the effects of offshore wind turbine facilities on fish early life stages

Funding agency: The Institute of Marine Research, North Sea Program.
Project period: 2020-2023
Project leader: Howard Browman
Co-investigators: Anne Berit Skiftesvik, Caroline Durif, Alessandro Cresci
Project summary
The need to reduce fossil fuel emissions to combat global climate change has motivated a rapid development and expansion of sources of renewable energy, including large offshore wind farms (OWFs). To date, assessments of the potential effects of OWFs on marine organisms – needed to inform stakeholders and managers – have focused mainly on the construction phase – that is, on pile-driving. Very few studies have assessed lethal or sublethal effects of operational noise from OWFs, or electromagnetic fields (EMFs) from the subsea power cables that carry the energy produced from offshore to land. Besides a very small number of studies on the effects of simulated operational noise and static magnetic fields on fish embryos and hatching larvae, there is no information at all on the impacts of OWFs on the early life history stages of fish that either reside in or pass through OWFs. More effort is needed to investigate the possible impacts of OWFs on ichthyoplankton, particularly larval migratory behaviour or dispersal ecology.
Recruitment in commercially important fish is related, at least in part, to whether the early life stages disperse to areas that are suitable for survival. Dispersal of ichthyoplankton is determined by the combined effect of oceanographic features, active swimming, and directed orientation behavior. Active and directed orientation has recently been reported in the larvae of several commercially important species such as Atlantic haddock, Atlantic herring, saithe and European glass eel. Larvae use this ability to orient during their long-distance migrations and during dispersal from spawning grounds to nursery areas. We have also observed that exposure to very low levels of oil residues reduces the swimming speed and disrupts the orientation of Atlantic haddock larvae, demonstrating that sub-lethal effects of anthropogenic stressors can be subtle.
Objectives
Measure and model the sound and EMFs associated with OWFs, and at various distances from the wind turbines, to establish realistic exposure levels for experimental and field work.
Assess the potential impacts of sound and EMFs associated with OWFs on the ability of the early life stages of fish to disperse, orient, and navigate in their environment.
Apply the information produced to develop a first-order risk assessment.