Propagule dispersal and larval patch cohesiveness in a Mediterranean coastal fish

Abstract

The assessment of fish dispersal is fundamental for both conservation and management of fishery resources as it provides crucial information for the establishment of more effective marine protected areas (MPAs) and networks of MPAs. In this study, we investigated the ele - mental composition of otoliths in early life stages of the saddled sea bream Oblada melanura (Linnaeus, 1758) (Perciformes: Sparidae) in order to obtain information on its propagule (egg and larva) dispersal in the south-western Mediterranean Sea. Specifically, using pre-settlement individuals we investigated (1) larval patch cohesiveness during the last phase of larval life; and with early post-settlement individuals we investigated (2) the number of potential natal sources, and (3) propagule dispersal distances. Results indicated that different larval patches can merge in the pelagic environment after having travelled separately for some days. In total, 7 natal sources were found to replenish, with different proportions, almost all sampling sites along a stretch of coastline of ~180 km, suggesting that propagule dispersal can extend at least up to ~90 km. This information provides important insights for understanding fish dispersal processes and supports the appropriate establishment of spatially explicit conservation strategies such as MPAs and MPA networks in the south-western Mediterranean Sea.