Seasonal dynamics of macroinfaunal key species inhabiting shallow soft - bottoms in the Bay of Blanes ( NW Mediterranean )

Within the frame of a wider research project on the littoral ecosystem of the Bay of Blanes (NW Mediterranean), the dynamics of shallow soft-bottom macroinfaunal assemblages of medium-to-fine-sand sediment communities of Spisula subtruncata have been followed since March 1992. These assemblages exhibited a very predictive annual cycle. Abundance and biomass rose sharply during spring, followed by a striking drop through summer showing lower values during autumn and winter. These cycles were consistent with the temporal variation of key macroinfaunal species in these shallow habitats: Spisula subtruncata, Owenia fusiformis, Ditrupa arietina, Lucinella divaricata, Echinocardium mediterraneum, Spio decoratus, Chone infundibuliformis, Paradoneis armata, Mediomastus fragilis, Protodorvillea kefersteini, Branchiostoma lanceolatum, Glycera cf. capitata and Callista chione. These species were included in ecological groups based on the trends observed during the 4 years of seasonal dynamics which are presented.