Copepod feeding in the Westerschelde and the Gironde

As in most European estuaries, the mesoplankton of the Westerschelde and the Gironde is dominated by calanoid copepods. In the Westerschelde, Eurytemora affinis dominates the brackish water area between station 7 and 10 in winter and spring while Acartia tonsa is dominant in summer. Maximum abundance of A. tonsa is located slightly more seawards than that of E. affinis. Acartia bifilosa occurs in winter and spring in lower abundances than A. tonsa and its maximum abundance is located between the brackish and the marine area. In the Gironde, E. affinis dominates in winter and spring between station J and K, with its maximum around station K. The second important species in the Gironde is Acartia bifilosa with a maximum abundance in summer, located around station E and J. In the Gironde, A. tonsa occurs in the same area as A. bifilosa only in late summer and early autumn