Effects of natural environmental drivers and different mobile bottom-contact fishing intensity on infauna communities in NATURA 2000 sites in the German Exclusive Economic Zone of the North Sea

Three marine protected areas, i.e., Borkum Reef Ground, Sylt Outer Reef, and Dogger Bank, have been established within the European NATURA 2000 program in the German Exclusive Economic Zone of the North Sea. Within them, we analysed the effect of the varying impact of mobile bottom-contact fishing on infauna communities in selected focus areas as a baseline study prior to the exclusion of mobile bottom-contact fishing since 2023. The three focus areas varied significantly in sediment composition and depth. The mobile bottom-contact fishing intensity was lowest at Borkum Reef Ground, but revealed decreasing gradients at Sylt Outer Reef and Dogger Bank. The infauna communities in the three focus areas were significantly different. Gradients in sediment composition, e.g. sand, mud, gravel and shell contents, revealed significant relationships with the infauna communities in the three areas. But on a small spatial scale also the gradients of mobile bottom-contact fishing intensity correlated significantly with the variations of the infauna communities at Sylt Outer Reef and Dogger Bank. The common agreement of the European Commission for the exclusion of mobile bottom-contact fishing in parts of Borkum Reef Ground and Sylt Outer Reef since 2023 and of Dogger Bank since 2025 will provide the opportunity to study the recovery of the infauna communities in these areas from mobile bottom-contact fishing in future.