Short- and long-term effects of an offshore wind farm on three species of sandeel and their sand habitat

Abstract

Offshore wind farms (OWFs) are being constructed at a high rate due to a high demand, both economically and politically, for sources of renewable energy. We investigated the short-term and long-term effects of an OWF situated in the North Sea off western Denmark (Horn Rev I; global position: 7.84°E, 55.48°N) on 3 ecologically important species of sandeel. Since sandeels display a distinct preference for sand habitats with a weight fraction of silt+clay < 2%, we expected changes in habitat quality to provide a causal explanation for the potential effect of the OWF on the sandeel community. A Before-After-Control-Impact (BACI) analysis was applied. A baseline survey from March 2002 (prior to construction) was combined with surveys conducted in March 2004 (short-term effects) and March 2010 (long-term effects) plus an additional survey in September 2009. Sandeels were collected using a modified scallop dredge and sediment samples using a van Veen grab. The results from an analysis on all species combined revealed a positive short-term effect on the densities of both juveniles and adults, which was consistent with a reduction in the fraction of silt+clay. In the long term, a negative effect on juveniles was found; however, this effect was neither consistent with the additional survey in 2009 nor the silt+clay fraction. Subsequent analysis at the species level revealed that the effects detected were driven by Hyperoplus lanceolatus, which dominated the study area in all years. Habitat quality was high in both the affected and control area throughout the study period.

Long-term effects of an offshore wind farm in the North Sea on fish communities

“…sediment composition) were too low to influence their abundance. Impact assessments on sand-dwelling fish fauna from other OWF studies generally report similar results (Lindeboom et al 2011, van Deurs et al 2012, van Hal et al 2012) with the exception of 2 studies indicating a positive effect on flounder Pla tichtys flesus (Bergstrom et al 2013), turbot Psetta maximus and sole Solea solea (Vandendriessche et al 2014) The DEM group remained at a low level throughout the study but its large decrease in the Control area resembled that seen for whiting. The shift in the DEM group from flat-to round fishes (such as cod and dragonet) could be interpreted as the introduction of new habitat favoring species capable of benefiting from the new shelter and prey opportunities without having any serious negative effect on the former.…”

“…The long-term impact on local fish abundance of introducing OWFs into sand habitats has so far been investigated only for species of sandeel (van Deurs et al 2012). However, fish attraction to underwater constructions at OWFs has been reported for different gobiid species (Wilhelmsson et al 2006, Andersson & Öhman 2010 and for the gadoids, such as cod Gadus morhua (Winter et al 2010, Reubens et al 2013a and pouting Tri sopte rus luscus (Reubens et al 2011(Reubens et al , 2013a.…”

Effects of an offshore wind farm on temporal and spatial patterns in the demersal fish community

“…For fish, population-and community-level effects are poorly known, as available studies are typically short term or relate to individual fish species (e.g. Wahlberg & Westerberg 2005, Wilhelmsson et al 2006a, Reubens et al 2011, 2013, van Deurs et al 2012.…”

On the potential benefits of marine spatial planning for herring spawning conditions—An example from the western Baltic Sea

“…While several scientific studies highlighted the strong relation between fisheries and MSP (e.g. Gray et al, 2005;Crowder and Norse, 2008;Berkenhagen et al, 2010;van Deurs et al, 2012;Lamp, 2012), as well as ways in which fisheries could be included in MSP (e.g. Douvere et al, 2007;Fock, 2008;Stelzenmüller et al, 2008), so far fisheries are rarely considered in current marine spatial plans in Europe; exceptions are the Norwegian Integrated Management Plan for the Barents Sea-Lofoten area (Norwegian Ministry of the Environment (NME), 2011) and the English East Inshore and East Offshore Marine Plans (HM Government, 2012).…”