RECON: Reef effect structures in the North Sea, islands or connections? : Summary report

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

“…Most studies investigating interconnectivity between offshore installations in the North Sea have been performed using larval dispersal models. To date, a limited number of studies have been published on the topic (Coolen et al, 2018a;Dannheim et al, 2018;Henry et al, 2018;Kamermans et al, 2018;van der Molen et al, 2018). Larval dispersal models use modelled water currents based on tidal currents and weather patterns from past years to hind-cast the path virtual larvae from a certain species travelled from their origin to their settlement location.…”

“…• Amphipod Jassa herdmani (Coolen et al, 2018a) • European flat oyster Ostrea edulis (Dannheim et al, 2018;Kamermans et al, 2018), The models help explain observed patterns. Questions to be answered: why are some species never observed far offshore while others are common; which locations are connected and which not; do species use locations in-between as stepping stone to reach locations further offshore; what would be the impact when installations are removed from these de-facto networks.…”

“…Some species may be found on every location, such as Metridium senile and Jassa herdmani. Other species, such as the blue mussel M. edulis, are common on offshore platforms and wind farms, but rare on subtidal reefs such as shipwrecks (Coolen et al, 2018a). In general, species with long pelagic larval stages, such as mussels (70 days), have interconnected populations on offshore installations (Coolen et al, 2018a;Henry et al, 2017).…”

“…Other species, such as the blue mussel M. edulis, are common on offshore platforms and wind farms, but rare on subtidal reefs such as shipwrecks (Coolen et al, 2018a). In general, species with long pelagic larval stages, such as mussels (70 days), have interconnected populations on offshore installations (Coolen et al, 2018a;Henry et al, 2017). Species with short pelagic stages have populations that are mostly isolated, or are even lacking from offshore installations, such as the European flat oyster (larval stage 10 days, absent offshore; Dannheim et al, 2018;Kamermans et al, 2018).…”

“…For example, while in one report a pelagic larval duration (PLD) of 22 days for M. senile is used (Henry et al, 2017), other authors state a duration of 180 days (van der Molen et al, 2018). For blue mussels PLD varies between 30 and 70 days (Coolen et al, 2018a;Henry et al, 2017;van der Molen et al, 2018).…”