In the Dutch part of the North Sea, some Common spider crabs (Maja brachydactyla) have been spotted. This occurred during biodiversity monitoring with an underwater drone (ROV) around the base of wind turbines in Borssele IV, a wind farm of Blauwwind. Some individuals of this species have been found in Dutch waters before, but these reports are from almost 50 years ago.
This Atlantic species is found in the area between Morocco and Scotland. Fossil remains show that this species also used to occur in the Zeeland region.
The Common spider crab is an omnivore, likes to camouflage itself and lives in areas with both sand and stones. This probably explains why it is not readily spotted on the sandy Dutch North Sea floor. In Borssele IV wind farm, scour protection and wind turbines have been installed in the past year. This could provide a safe habitat for the Common spider crab. In this wind farm we are investigating whether flat oysters that have been released will be able to establish themselves permanently in the wind farm and whether this will attract new nature.
Publication in magazine 'Het Zeepaard', published by the Strandwerk community (2021) [Dutch]