Using Artificial-Reef Knowledge to Enhance the Ecological Function of Offshore Wind Turbine Foundations: Implications for Fish Abundance and Diversity

Abstract

As the development of large-scale offshore wind farms (OWFs) amplifies due to technological progress and a growing demand for renewable energy, associated footprints on the seabed are becoming increasingly common within soft-bottom environments. A large part of the footprint is the scour protection, often consisting of rocks that are positioned on the seabed to prevent erosion. As such, scour protection may resemble a marine rocky reef and could have important ecosystem functions. While acknowledging that OWFs disrupt the marine environment, the aim of this systematic review was to examine the effects of scour protection on fish assemblages, relate them to the effects of designated artificial reefs (ARs) and, ultimately, reveal how future scour protection may be tailored to support abundance and diversity of marine species. The results revealed frequent increases in abundances of species associated with hard substrata after the establishment of artificial structures (i.e., both OWFs and ARs) in the marine environment. Literature indicated that scour protection meets the requirements to function as an AR, often providing shelter, nursery, reproduction, and/or feeding opportunities. Using knowledge from AR models, this review suggests methodology for ecological improvements of future scour protections, aiming towards a more successful integration into the marine environment.

Temporal and spatial variation in adult and juvenile mobile fauna associated with natural and artificial coastal habitats

“…Early work on the mobile fauna associated with subtidal artificial structures focussed on artificial reefs (reviewed by Baine 2001) and more recent studies have considered the impact of renewable energy installations (Wilhelmsson et al 2006;Reubens et al 2013;Krone et al 2013;Langhamer et al 2016;Bender et al 2020;Glarou et al 2020;Sheehan et al 2020) and decommissioned oil rigs (Claisse et al 2014(Claisse et al , 2015. Yet work on other types of artificial structures in temperate regions, such as pipeline infrastructure and subtidal coastal defences, is lacking.…”

The Effects of Offshore Wind Farms on Hydrodynamics and Implications for Fishes

“…The construction, operation, and decommissioning phases of offshore wind farms all exert pressures on marine environmental receptors (i.e., plankton, benthos, fish, turtles, birds, marine mammals, and bats; see reviews by Gill, 2005;Boehlert and Gill, 2010;Thomsen et al, 2015). In this regard, the attraction of benthos and fishes to newly introduced hard substrates, called the artificial reef effect (see Mineur et al, 2012;Degraer et al, 2020, in this issue;Glarou et al, 2020), has been a focus of impact analysis, but offshore wind development effects on hydrodynamics and their possible secondary effects on fishes have received less attention. Plans to expand OWF development and the evident role hydrodynamics plays in the life cycles of fishes suggest that a systematic review of the current state of knowledge regarding these potential impacts is warranted.…”

Offshore Wind Farm Artificial Reefs Affect Ecosystem Structure and Functioning: A Synthesis

“…To that end, a proper understanding of mechanisms behind the impacts is needed (Dannheim et al, 2020) in order to develop effective nature-inclusive designs that are, for example, mandatory for the development of new OWFs in the Netherlands (Ministerie van Economische Zaken, 2019). Requirements may include eco-designing scour protection layers to enhance fish habitat or restore oyster beds (Glarou et al, 2020) and deploying add-on structures such as fish hotels (Hermans et al, 2020). To avoid contributing to ocean sprawl, the use of add-on structures (i.e., artificial structures away from the turbines) may be questionable and deemed undesirable (Firth et al, 2020).…”