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

Abstract

Long-term effects of the Horns Rev 1 offshore wind farm (OWF) on fish abundance, diversity and spatial distribution were studied. This OWF is situated on the Horns Reef sand bank in the North Sea. Surveys were conducted in September 2001, before the OWF was established in 2002, and again in September 2009, 7 yr post-establishment. The sampling surveys used a multimesh-size gillnet. The 3 most abundant species in the surveys were whiting Merlangius merlangus, dab Limanda limanda and sandeels Ammodytidae spp. Overall fish abundance increased slightly in the area where the OWF was established but declined in the control area 6 km away. None of the key fish species or functional fish groups showed signs of negative long-term effects due to the OWF. Whiting and the fish group associated with rocky habitats showed different distributions relative to the distance to the artificial reef structures introduced by the turbines. Rocky habitat fishes were most abundant close to the turbines while whiting was most abundant away from them. Species diversity was significantly higher close to the turbines. Overall, these results indicate that the artificial reef structures were large enough to attract fish species with a preference for rocky habitats, but not large enough to have adverse negative effects on species inhabiting the original sand bottom between the turbines.

The role of sand lances (Ammodytes sp.) in the Northwest Atlantic Ecosystem: A synthesis of current knowledge with implications for conservation and management

“…In the North Sea, the presence of A. marinus and A. tobianus was assessed before and after the construction of wind turbines. Short‐term effects of the facilities were either not observed (Lindeboom et al, 2011) or showed increases in density at wind development sites after construction (Degraer, Brabant, Rumes, & Vigin, 2016; Leonhard et al, 2011; Stenberg et al, 2015; van Deurs et al, 2012; Vandendriessche, Hostens, Courtens, & Stienen, 2011). Positive short‐term effects were attributed to increased or neutral effects on sediment quality, increases in juvenile abundance, associations of midwater feeding schools with structure and/or reductions in predators during construction (Leonhard et al, 2011; van Deurs et al, 2012).…”

“…Alternatively, these patterns could be due to, or in synergy with, the aggregation effects of the offshore structures through flow or shade effects. No long‐term effects on Ammodytes were seen in such areas, despite an increase in species diversity due to artificial reef effects (Degraer et al, 2016; Leonhard et al, 2011; Stenberg et al, 2015; van Deurs et al, 2012).…”

Offshore Wind Power for Marine Conservation

“…The spatial extent of this aforementioned attraction of fish is variable and not well established. However, monitoring programs from wind farms have indicated that the abundance of several species increases not only in the vicinity of foundations, as noted above, but also in the area in between turbines, compared to controls [50].…”

Mechanistic evidence of enhanced production on artificial reefs: A case study in a Bahamian seagrass ecosystem

“…In the case of artificial reefs, ecological thresholds have rarely been explored, limiting our understanding of the ecosystem processes associated with these reef structures. Because of the widespread and ever-expanding scope of artificial reef projects (Ajemian et al 2015, McLean et al 2015, Stenberg et al 2015, more attuned attention to ecosystem function on these structures is clearly needed. Even more broadly, artificial structures (e.g., seawalls, jetties, breakwaters) have become ubiquitous features of the coastal realm, and consideration of their role in fundamentally shifting ecosystem processes should be a primary focus of applied ecological studies in these systems (Bulleri and Chapman 2010).…”