Coastal man-made habitats: Potential nurseries for an exploited fish species, Diplodus sargus (Linnaeus, 1758)

Abstract

Human pressure on seashores has induced the installation of many seawalls. Artificial coastal defence structures may be providential for the juveniles of fish species exploited by artisanal fisheries. Focusing on Diplodus sargus, the number of settling juveniles was estimated on artificial structures and on natural rocky shores. The aim is to know if these artificial areas can have a nursery function. Densities of juveniles are from 30 to 109 times greater than those in natural habitats. Artificial coastal defence structures can be regarded as artificial nurseries. However, in the studied case, they also cause the loss of the nursery function of the nearby lagoon. The artificial seawalls at the entrance to the lagoon receive almost all the larvae that would normally enter the lagoon. This study underlines the important role of these artificial habitats in the life cycle of white seabream. They may have a positive impact on maintaining other species exploited by artisanal fisheries.