Case history and persistence of the non-indigenous diatom Coscinodiscus wailesii in the north-east Atlantic

The introduction of non-indigenous marine plankton species can have a consi derable ecological and economic effect on regional systems. Their presence. however, can go unnoticed until they reach nuisance status and as a conseq uence fe case histories exist containing information on their initial appea rance and their spatio-temporal patterns. Here we report on the occurrence of the non-indigenousdiatom Coscinodiscus wailesii in 1977 in the English C hannel, its subsequent geographical spread into European shelf seas, and it s persistence as a significant member of the diatom community in the north- east Atlantic from 1977-1995.