Traditional and experimental floating fish aggregating devices in the Gulfof Castellammare (NW Sicily): Results from catches and visual observations

Floating fish aggregating devices (FADs) have long been used to attract fis h in NW Sicily since antiquity. Recently, a number of changes have been mad e to the type of material employed to construct FADs, with the aim of incre asing their effectiveness. In this paper we compare the catches made at eig ht experimental floating FADs (polypropylene ropes frayed at the ends) with those obtained at eight traditional FADs in the Gulf of Castellammare. A t otal of 672 samples were collected during summer and autumn in 1995 and 199 6 at the 16 FADs using a surrounding net. Visual observations of fishes ass ociated with the FADs were also conducted to obtain qualitative information about the spatial distribution of species. A total of 1632 specimens weigh ing 144 kg and belonging to eight species were caught during the survey. Se riola dumerili, Caranx crysos, C. rhonchus and Coryphaena hippurus were the most frequent and abundant species accounting for 96% of the total catch. Average fish abundance and weight, characterised by high variance, were sig nificantly higher at the sites with experimental FADs than at the sites wit h traditional FADs. S. dumerili was the only species with higher catches ar ound the experimental FADs. Some spatial and temporal variations in fish ab undance and size were also detected. Younger individuals of S. dumerili wer e observed to show high affinity for the experimental FAD tufts.