Temporal and spatial structure in the suprabenthic community of a shallow estuary (western Portugal: Mondego river estuary)

The suprabenthic fauna of the Mondego river estuary (western Portugal) was sampled monthly between June 1996 and June 1997. Quantitative samples were taken, with a suprabenthic 500-mu m mesh size net, at regularly spaced stat ions covering the entire south arm of the estuary. The diversity of the sam ples and the distribution of the species were assessed. Suprabenthic commun ities were identified using a divisive multivariate statistical technique a nd species composition, density and biomass of the dominant species of each community were compared among communities. Diversity was highest in the mo uth of the estuary where density and biomass were lowest. Diversity decreas ed upstream and was lowest in the mid and inner estuary where density and b iomass reached maximal values. Suprabenthic animals, mainly the mysid Mesop odopsis slabberi, reached high densities in inner and upstream stations, wh ereas the more seaward stations had lower densities but a higher number of species. The spatial patterns dominated over the temporal patterns. (C) 199 9 Editions scientifiques et medicales Elsevier SAS.