Annotated checklist and biodiversity analysis of benthic fauna at Sylt Outer Reef and Borkum Reef Ground (North Sea)

Abstract

Benthic fauna caught by ring dredge and 2 m beam trawl at the NATURA 2000 Sylt Outer Reef (SAR) and Borkum Reef Ground (BRG) sites in the North Sea are examined in relation to the intensity of mobile bottom-trawling fisheries. Samples were taken from 33 stations in the two areas, and the collected benthic fauna, consisting of infauna, epifauna, and demersal fish was determined. A total of 123 species were found, consisting of the phyla Chordata, Mollusca, Arthropoda, Echinodermata, Annelida, Cnidaria, and Bryozoa, with Chordata and Mollusca being the most species-rich phyla. The species compositions of BRG and SAR are relatively clearly separated. There was greater species diversity at BRG, likely due to lower fishing pressure from mobile bottom trawling than at SAR. Long-term data acquisition and analysis will be needed to visualize past and future changes in biodiversity.