Extension of distribution of Pseudodiaptomus marinus, an introduced copepod, in the North Sea

Pseudodiaptomus marinus was described from eastern Asian waters and has subsequently been spread in the Indo-Pacific region, but has only been found in European waters since 2007. The presence of the species in inshore waters of the Southern Bight of the North Sea, in Calais Harbour and off Gravelines was noted in 2010 and 2011. The present records from the Continuous Plankton Recorder survey extend the known distribution northwards and across the Southern Bight between The Netherlands and British coasts. Net hauls for biological monitoring in the German exclusive economic zone add a location further north and east in the German Bight. Spread of the species to inshore waters of the eastern North Sea and to the Baltic is predicted.