Upscaling positive effects of scour protection in offshore wind farms : Quick scan of the potential to upscale positive effects of scour protection on benthic macrofauna and associated fish species

Ecology of the brown crab (Cancer pagurus) : and production potential for passive fisheries in Dutch offshore wind farms

“…In addition Helgoland and the numerous OWF's in this area (see Fig. S2 (Steenbergen et al, 2012) a quick scan calculation resulted in an estimated increase of 4.5 times, or even 8.8 times in population growth when assuming larger scour protections (Coolen et al, 2019). Using a similar approach as Coolen the 60 turbines at the Prinses Amalia park could provide substrate for approximately 100,000 brown crabs which is a 73 times increase assuming a background population of 100 crabs per km 2 .…”

“…A clear outlier in the BTS data of 2010 was found in the German Bight (n=618, see Fig. 5) A rough estimate of approximately 100 edible crabs per km 2 (1 per hectare) in the Dutch part of the Netherlands(or 0.01 km 2 per crab) was based on an assessment of the potential for targeted fisheries on edible crab using pots (Coolen et al, 2019) (Steenbergen et al, 2012). These data originated from the SNS and BTS beam trawl surveys of mostly soft substrate along the Dutch coast in 2010.…”

“…In a quick scan of the potential to upscale positive effects of scour protection on benthic macrofauna and associated fish species edible crab was used as an example to estimate density (Coolen et al, 2019). With an average of 5,080 brown crabs on 1,013 m 2 (equals 5.01 crabs per m 2 ) around a monopile foundation, Krone et al (2017) extrapolated to 5,000 monopile foundations in the German North Sea (assuming installations identical to the monopile studied) amounting to 25.4 million brown crabs.…”

“…calculated that, with the introduction of 5,000 monopile foundations of 1,013 m 2 , the population of edible crabs in the Dutch North Sea would increase 4.5 times (approximately 350% additional brown crabs) compared to the background population (25.4 million/5.7 million= 4.46). When assuming scour protections of 2,000 m 2 , the estimate may even increase to 50 million, which is 8.8 times that of the background population(Coolen et al, 2019). The scour protection around the 60 turbines in Prinses Amalia park cover a total area of approximately 20,790 m 2 (346.5 m 2 x 60 turbines).…”

“…7 million Coolen et al (2019). calculated that, with the introduction of 5,000 monopile foundations of 1,013 m 2 , the population of edible crabs in the Dutch North Sea would increase 4.5 times (approximately 350% additional brown crabs) compared to the background population (25.4 million/5.7 million= 4.46).…”