ecosystem engineer. ☛ • As the native oyster species, it was once abundant in European seas including the North Sea – and is now classifed as threatened with extinction on Germany’s Red List. ☛ • Current [...] fat oyster abundant in Europe? European fat oysters were once abundant in European seas, including the German North Sea. But due to human impacts such as overfshing, their numbers have steadily declined [...] are on the OSPAR List of threatened and/or declining species and habitats in the North-East Atlantic. In the German North Sea, the species has been considered to be nearly extinct since the 20th century and