Title: First record of the calanoid copepod Acartia omorii (Copepoda: Calanoida: Acartiidae) in the southern bight of the North Sea
Abstract: The occurrence of the calanoid copepod, Acartia omorii, is reported for the first time in the coastal waters of the Southern bight of the North Sea, off Calais harbour. Acartia omorii males and females were consistently found in four plankton samples. The collected specimens were compared with A. omorii individuals collected from the type locality (Tokyo Bay, Japan). The capture of A. omorii, a species native to Japanese coastal waters, is in agreement with the recent observation of the Japanese macroalgae Undaria pinnatifida within Calais harbor and the hypothesis of passive transport in ship's ballast water.