Ecology and ecophysiology of invasive and native decapod crabs in the southern North Sea

The Asian shore crab Hemigrapsus sanguineus is native to the coasts of China, Korea and Japan. It first invaded the U.S. east coast in the late 1980s and its present range extends from North Carolina to Maine. It was detected in France and the Netherlands in 1999. Nowadays, H. sanguineus is fully established at the European Atlantic coast. It can be found from the Contentin Peninsula, France to the German Wadden Sea, including the rocky island of Helgoland. In the U.S. and in Europe, H. sanguineus shares habitats with the native European green crab Carcinus maenas and competitive interactions between both are suggested. Thus, the main aims of this thesis were 1) to evaluate the status of H. sanguineus and C. maenas around Helgoland in relation to wave action, 2) to compare the respiratory metabolism and energy demand of both species, and 3) to assess their energy storage capacities and dietary preferences.