Persistence and co-occurrence of demersal nurseries in the Strait of Sicily (central Mediterranean): Implications for fishery management

This study investigated the nurseries of seven commercially important demersal species of the northern sector of the Strait of Sicily (central Mediterranean): red mullet, European hake, horned octopus, deep-water rose shrimp, greater forkbeard, Norway lobster and giant red shrimp. An eleven-year series of data collected through experimental trawling in the Strait of Sicily during spring and autumn was analyzed. The spatio-temporal persistence of the high-density aggregations (hot spots) of juvenile individuals in their first year of life was investigated to identify habitats that serve as nurseries. The density of recruits within the persistent nurseries was used as a proxy of the unit area contribution of individuals which recruit to the adult population. The spatial distribution patterns of the recruits of most the species were well defined and very stable in the long term. Persistent and potentially highly productive nurseries of European hake, deep-water rose shrimp and greater forkbeard were identified off the southern coast of Sicily. Persistent areas of recruits concentration were also observed for the other species investigated, but their specific potential contribution of individuals to the adult population was not substantial compared to adjacent grounds. The close or overlapped localization of sites which regularly host vulnerable life stages of different exploited species, revealed an area of great ecological significance which probably plays a major role in the dynamics of the fishery resources in the Strait of Sicily. Appropriate spatial protection measures of this area, including marine protected area designation, could complement conventional management approach for ensuring the long-term sustainability of these fisheries and stocks conservation.