Influence of Environmental Drivers on Settlement and Recruitment of Diplodus Sargus in Minorca (NW Mediterranean)

In this study we analyse the influence of environmental factors on settlement and recruitment of Diplodus sargus in shallow rocky habitats of Minorca. We compare the variability in settlement and post-settler population dynamics in two areas, north and south, with different wind regimes and ocean dynamics. During 2012, settlement was measured by direct visual census of fish juveniles throughout the settlement and recruitment period (April-July) at three coves located in each area. The settlement pattern was similar at the three nearby coves but notable differences were observed among areas, which were attributed to differences in environmental forcing. A decline in settlement was observed in the north coves in response to a storm with winds exceeding 10 m/s, waves above 3 m and alongshore flow enhancement. We did not observe significant variations in post-settler growth between the two areas. Thus, population dynamics were mainly regulated by variations in juvenile mortality. Mortality rates were observed to decrease along the settlement period and increase in response to wind forced processes with remarkable differences in recruitment between two areas. Our results suggest that environmental forcing at nursery areas may be as important as initial settlement variations in the regulation of recruitment in Diplodus sargus.