The Role of Fish Aggregating Devices (FADs) in Juvenile Fish Dispersal along the North-Western Coast of Sicily

Abstract

Fish aggregating devices (FADs) are used worldwide to attract fish. Previous studies revealed that FADs affect the distribution and dispersal patterns of juvenile fish species during their life stage under floating objects. In this study, we hypothesised that a system of FADs arranged along an inshore–offshore gradient could favour the approach of young fish associated with FADs towards coastal habitats, using individual FADs as stepping stones. Our findings suggest that FAD systems might exert two different effects on juvenile fish distribution: (a) offshore FADs tend to retain associated fish for longer periods of time compared with coastal FADs, (b) coastal FADs favour the transition of fishes from the pelagic to the benthic domain. Furthermore, in order to obtain more information on the dynamic and movement patterns of the young-of-the-year (YOY) Seriola dumerili and Caranx crysos associated with FADs, tagging experiments and underwater visual censuses were conducted. The two juvenile species tagged and released under FADs placed at different distances from the coast showed different movement patterns. S. dumerili exhibited low FAD fidelity and large movements, while C. crysos showed high fidelity to the site. The results of the two research approaches confirm that FADs affect the dispersal of species toward the coast and their correct use could help to improve the sustainable management of these coastal fish resources.

Keywords

• fish aggregating devices (FADs)
• tagging
• visual census
• juvenile post larvae fish