Zooplankton Communities in the Bristol Channel and Severn Estuary

Abstract

The basic distribution and composition of the zooplankton in the Bristol Channel and Severn Estuary is now understood. The communities, or associations of species, described in this report are normal for estuaries in northern latitudes both in their abundance and species composition. Multi-demensional scaling analysis gave similar results to the classification method and confirmed the relationship between the distributions of the plankton and salinity. The four assemblages or associations of species derived from the dendrograms conformed to the generalized classification of plankton according to their tolerance of salinity ranges in estuaries that is, (a) true-estuarine, (b) estuarine and marine. The assemblages were characterized in this study by the four copepods Eurytemora affinis (Poppe), Acartia bifilosa var. inermis (Rose), Centropages hamatus (Lilljeborg) and Calanus helgolandicus, Claus respectively.