Prey items of 0-and 1-group plaice Pleuronectes platessa, sole Solea solea, brill Scophthalmus rhombus, turbot S. maximus and dab Limanda limanda of the surf zone of a Belgian sandy beach, included hyperbenthic (e.g. mysids), endobenthic (e.g. polychaetes) and epibenthic (e.g. shrimps) species. Little dietary overlap was observed. If diet overlap did occur, it mainly involved prey species that are dominant in the surf zone of Belgian beaches, such as shrimps and mysids. These results suggest an opportunistic utilization by flatfish of the available food resources in surf zone ecosystems. Also, two strategically different feeding habits could be distinguished between the five flatfish species. Turbot and brill mainly fed on large, highly mobile prey (e.g. fish, mysids) and had a rather narrow prey spectrum, whereas plaice, dab and sole ate more benthic prey (e.g. polychaetes) and had a broader prey spectrum. 1999 The Fisheries Society of the British Isles

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Macrocrustaceans and juvenile demersal fish were sampled in spring of 1997 in the surf zone of an exposed sandy beach on the Belgian coast. Three consecutive 24 h cycles were sampled to investigate tidal, diurnal and semi-lunar distribution patterns within the epibenthic community. Multivariate statistical techniques and 3-way ANOVA were used to evaluate the effects of the environmental variables measured. The most important variable correlated with the variation in epibenthic catch density was the state of the tide (ebb and flood), but light intensity (day and night) was also important. The individual catch density of several species differed significantly over the three 24 h cycles. Despite the strong turbulent conditions of the site studied, clear tidal (e.g. the brown shrimp Crangon crangon, juvenile plaice Pleuronectes platessa) and diurnal (e.g. juvenile sole Solea solea and clupeids, caught mainly during the night/day respectively) periodicities of many macrocrustacean and demersal fish species were observed. Nevertheless, the extremely turbulent conditions of the surf zone possibly affect the behaviour of many species (e.g. juvenile brown shrimp are not able to bury themselves as the water retreats). To investigate whether the high dynamics of the surf zone suppress the ability of juvenile plaice to actively search for food, stomach contents were analysed. Also, the interaction with potential prey was investigated: the hyperbenthic fauna was sampled simultaneously and macrobenthic data were available from the literature. Clearly, the Belgian sandy beaches are used as a feeding ground by I-group plaice. An opportunistic utilisation of available food resources is suggested. I-group plaice migrate high up the beach during the flood tide to profit from the rich macrobenthic intertidal area, while the 0-group feeds mainly on the most abundant hyperand macrobenthic organisms from somewhat deeper water. The presence of the 0-group in the intertidal area is possibly linked to refuge for predators or influenced by the strong surf zone currents.

An inventory of fish and epibenthic macrocrustaceans of the surf zones of sandy beaches along the Belgian coast was constructed. The surf zones were sampled intensively with a 2-m beam trawl in April May 1996 (12 stations) and 26 species were recorded belonging to caridean shrimps (4), brachyuran crabs (5), cephalopods (1) arid fish (16). The brown shrimp Crangon crangon dominated almost all samples (>80%). Total densities exceeded several times 250 ind 100 m(-2) and 10 ind 100 m(-2) if C. crangon was excluded. An east - west distinction as found in other (epi)benthic studies in deeper waters of the Belgian coast, was not found in the surf zone during this study. Spatial variation was mainly correlated with local characteristics such as turbidity of the water and the morphodynamic features of both the beach and the adjacent subtidal area