Contents lists available at ScienceDirect Journal of Sea Research journal homepage: www.elsevier.com/locate/seares Oil and gas platforms as artificial substrates for epibenthic North Sea fauna: Effects of location and depth Miriam Schutter a, ⁎ , Martijn Dorenbosch a , Floor M.F. Driessen a , Wouter Lengkeek a , Oscar G. Bos b , Joop W.P. Coolen b,c a Bureau Waardenburg, P.O. Box 365, 4100 AJ, Culemborg, the Netherlands b Wageningen Marine Research, P.O. Box 57, 1780 AB, Den Helder, the Netherlands c Wageningen University, Aquatic Ecology and Water Quality Management Group, Droevendaalsesteeg 3a, 6708, PD, Wageningen, the Netherlands. ARTICLE INFO Keywords: Hard substrate Benthos Species richness ROV videos Offshore constructions ABSTRACT Offshore oil and gas platforms, shipwrecks and wind farms are known to act as artificial reefs, attracting a broad range of marine species such as algae, invertebrate species and fish. Using Remotely Operated Vehicle (ROV) videos made for technical inspection of eight Dutch and nine Danish oil and gas platforms, we characterize the abundance and diversity of invertebrates and fish species found on or around these artificial hard substrates. Dutch platforms located in the southern part of the North Sea were at depths ranging from 26 to 46 m, whereas Danish platforms located about 400 km further north were deeper (40–66 m). A total of 38 taxa were identified. The most common species were Mytilus edulis (Mollusca), Metridium senile (Cnidaria) and Asterias rubens (Echinodermata). One non-indigenous species was identified: Mnemiopsis leidyi (Ctenophora). A significant clustering of species communities was found based on geographical location: a southern cluster close to the Dutch shoreline and a northern cluster near Denmark (p = .01). Species diversity was not significantly different between geographical clusters; however, average Braun-Blanquet abundance was significantly higher on in the northern cluster (p < .05). Invertebrate and fish communities did not change significantly with depth. However, depth zone was a significant clustering factor (p = .01): communities closer to the seafloor (maximum depth minus 5 m) were characterized by higher species diversity and species richness compared to communities found closer to the surface (< 10 m). Future research should focus on the potential role of habitat complexity, substrate orientation and type, and inter-specific relations in explaining the different communities on offshore platforms. 1. Introduction Offshore oil and gas platforms, shipwrecks and wind farms are known to act as artificial reefs that attract a diverse community of marine species by providing habitat for algae, invertebrate species and fish (offshore oil and gas platforms: Forteath et al., 1982, Lewbel et al., 1987, Ponti et al., 2002, Whomersley and Picken, 2003, Yan et al., 2006, Van der Molen et al., 2018; wind farms: Bouma and Lengkeek, 2013, Ashley et al., 2014, De Mesel et al., 2015, Coolen et al., 2018; shipwrecks: Leewis et al., 2000, Mallefet et al., 2008, Church et al., 2009; Lengkeek et al., 2013, Jimenez et al., 2017, González-Duarte et al., 2018). In the southeastern bight of the North Sea, natural hard substrates such as pebbles and boulders are rare, but nevertheless characterized by an epibenthic community with a high biodiversity that strongly differs from the community in soft benthic habitat (Bos et al., 2011; Coolen et al., 2015). Historically, approximately 27,000 km 2 of the southeastern bight of the North Sea was covered with natural reefs such as oyster reefs, coarse peat banks and glacial erratics (Olsen, 1883; Whitehead and Goodchild, 1909; De Vooys et al., 2004; Coolen, 2017), most likely providing habitat for many species associated with hard substrates. However, natural erosion, destructive fishing practices (mainly trawling), overexploitation and oyster diseases have led to the decline of natural hard substrate habitat (Donovan and Dingle, 1965; De Groot, 1984; De Vooys et al., 2004). Compared to the North Sea around the late 19th century, large parts of the seabed are nowadays characterized by sandy or silty soft substrate. Although efforts are un- dertaken to restore natural hard substrates (Smaal et al., 2015), re- covery of these systems by natural (re)colonization of species is a slow process and will most likely take decades. However, artificial structures such as offshore oil and gas platforms provide additional hard substrate, which may partly compensate for the loss of natural hard substrate habitat (Coolen et al., 2018). This may contribute to the persistence and https://doi.org/10.1016/j.seares.2019.101782 Received 9 October 2018; Received in revised form 29 July 2019; Accepted 19 August 2019 ⁎ Corresponding author at: P.O. Box 365, 4100 AJ, Culemborg, the Netherlands. E-mail address: info@buwa.nl (M. Schutter). Journal of Sea Research 153 (2019) 101782 Available online 21 August 2019 1385-1101/ © 2019 Elsevier B.V. All rights reserved. T