Small-scale distribution of fish larvae around the Medes Islands marine protected area (NW Mediterranean)

Abstract

During the spring and summer of 2003, the small-scale spatial distribution of fish larvae was analysed in and around the Medes Islands marine protected area (MPA). High specific richness was found during both seasons, which is when most coastal fish species spawn in the NW Mediterranean. Despite the small dimensions of the area, well-defined larval fish patterns were found. Larvae from pelagic eggs were located farther from the adult habitat than those from demersal eggs; however, there were exceptions, which highlight the influence of larval behaviour and pelagic larval duration. Inside the reserve, there was both a high diversity index and a high abundance of shorefish larvae in relation to the high abundance of adults and a possible retention of larvae in the MPA. Although there was a great variability both in species composition and abundance between periods, the sampling station assemblages were similar. Factors such as habitat and spawning location of adults, and the role of the MPA seem to determine the stability of the larval distribution patterns in time. The importance of small-scale approaches is highlighted to understand the fish larval spatial distributions.