Long-term comparison of macrobenthos within the soft bottoms of the Bay ofBanyuls-sur-mer (northwestern Mediterranean Sea)

The macrofauna present at seven of the stations within the Bay of Banyuls-s ur-mer (northwestern Mediterranean) initially sampled by Guille during the late 1960s was reassessed in 1994, using the same gear and techniques as th ose used during the reference study. Results showed an increase both in the number of species and of individuals (all species pooled) per unit of surf ace area at nearly all stations. This trend was not significant for total b iomass. The most important changes were linked to the increase of the polyc haete Ditrupa arietina (both within the Spisula subtruncata and the Nephtys hombergii community) and the decrease of the polychaetes Scoloplos armiger and Notomastus latericeus within the Scoloplos armiger community. The poss ible causes underlying these changes are discussed. The most probable cause is considered to be a slight modification of sediment composition (decreas e of fine material in the sediment) within the Spisula subtruncata, the Nep htys hombergii and the Scoloplos armiger communities. Temporal changes in ( 1) Rhone river input, (2) small coastal river inputs, and (3) frequency of easterly storms may all have contributed to such a decrease. (C) 1998 Elsev ier Science B.V. All rights reserved.