Report on the presence of Acartia tonsa Dana (Copepoda) in the harbour of Dunkirk (France) and its geographical distribution in Europe

Abstract

Acartia tonsa is an important copepod in the zooplankton of the harbour of Dunkirk. The author completes the morphological description and draws a map of the European places in which the bibliography mentions the presence of the species. The reported sites, which are of an estuarine type, show a salinity less than 33‰ and a higher temperature than the neighbouring off-shore waters. The addition of A. tonsa to the European fauna is considered as permanent.