Diel feeding habits of juveniles of Mullus surmuletus (Linneo, 1758) in the lagoon of the Stagnone di Marsala (Western Sicily, Italy)

Diet composition, feeding rhythm, gastric evacuation rate and daily ration were investigated in juvenile Mullus surmuletus (Linneo, 1758). Fish were c ollected in the lagoon of the Stagnone di Marsala in western Sicily, in Jul y 1995, during a 24 h sampling period. Copepoda, Polychaeta, Amphipoda and Tanaidacea were shown to be the most frequent prey items. The feeding index values showed two different daily feeding rimes. A unimodal trend in the d aily rhythm of food consumption was derived, with a peak in feeding between 1200 and 2000 h. Gastric evacuation in juvenile M. surmuletus is best desc ribed by an exponential model, with a gastric evacuation rate R = 0.66 g h( -1) (r = 0.88) (T = 24.45 +/- 0.64 degrees C). The amount of food consumed daily, calculated according to the Elliott and Persson model, was 0.079 g, equal to about 8% of the average dry weight of the fish.