Striking long-term change in subtidal epibenthos of the northern Wadden Sea

• Main Authors: Waser, Andreas M., Buschbaum, Christian, Reise, Karsten
• Format: Conference Object
• Language: unknown
• Published: 2021
• Subjects: Pacific; Crassostrea gigas
• Online Access: https://epic.awi.de/id/eprint/55076/; https://hdl.handle.net/10013/epic.99aaaf12-21af-4fca-b696-ad086f13f1cd

In the Wadden Sea, long-term dynamics of macrobenthic communities have been intensively studied on intertidal flats. Much less is known from subtidal bottoms and their habitat structuring organisms. However, first investigations date back to studies on commercial European oyster (Ostrea edulis) beds in the late 19th and early 20th century. Since the loss of these native oyster beds due to overexploitation, the subtidal epibenthos has been revisited at intervals from the 1980s onwards up to 2021. We present dredging data from surveys of shallow and deep subtidal bottoms in the List tidal basin in the northern Wadden Sea, using the historic type of a 1-m oyster dredge for comparison. Our study period comprises peak and termination of blue mussel (Mytilus edulis) exploitation in the area as well as the invasion of Pacific oysters (Magallana (Crassostrea) gigas). We illustrate what has followed the former biogenic formative structures in the subtidal zone, the European oyster beds and reefs of the colonial Ross worm (Sabellaria spinulosa) on the scale of a century. Change in the subtidal epibenthos has exceeded by far what has been observed on intertidal flats of the Wadden Sea.