Untitled - CNR

Marine research at CNRdensity hot spots); 3) quantifying the persistenceover space and time of the recruitdensity hot spots (i.e. persistent nursery).Analysis of the decadal time series datafrom trawl surveys revealed the occurrenceof very stable nurseries in the Strait ofSicily for European hake, deep-water roseshrimp, greater forkbeard and Norway lobster.The distribution of red mullet recruitsresulted in a degree of spread across spaceand variable throughout time. Whilst asmall area of stability was identified on thesouth-western coast of Sicily, there werealso several sites along the whole southernSicilian coast where local densities ofrecruits varied substantially from year toyear. Finally, small persistent nurserieswere identified for horned octopus and giantred shrimp even if their stability wasonly evaluated for a few years.Recently, many studies have highlightedthe role of quite stationary mesoscalehydrological features of the Strait ofSicily in controlling abundance, spawning,eggs/larval dispersal and recruitment processesof different demersal and pelagicspecies [19, 20, 21, 22, 23, 24]. Inthe Strait of Sicily, cyclonic vortices andthermal fronts were considered responsiblefor the temporal persistence of nurserygrounds of European hake and greater forkbeard[10, 25]. According to [12], youngof-the-yearand mature females of deep waterrose-shrimp in the Strait of Sicily aggregatewhere retention and enrichment processesoccur. Most of the nurseries identifiedin this study, are located along theexternal western and eastern edges of theAdventure Bank. The topography of theAdventure Bank plays an important role inthe pattern of currents in the area, particularlyof the Atlantic Ionian Stream (AIS),a fresh water surface current of Atlanticorigin [26]. It enters the Strait of Sicilywest of the Adventure Bank and meanderseastward along the southern coast of Sicily.Its interaction with the complex topographyand the dominant northwesterly windsin the area generates a number of semipermanentfeatures such as upwellings, eddiesand fronts [26], which enhance andconcentrate marine productivity [27]. Thiscould ultimately favour reproduction andrecruitment of marine species and couldplay a key role in maintaining the spatialstructure and the stock unity of local populations.Identifying fish nursery grounds,highlighting the role of oceanographic featuresin the dynamic and connectivity betweenspawning and nursery grounds is importantto understand the ecology of earlylife history stages of fish and the processesthat determine their survival. The supplyof juveniles to the adult stocks forms thebasis of the sustainability of a populationto commercial exploitation and need to beconsidered in effective fisheries and habitatmanagement strategies. Marine areas ofcritical importance to the life-cycle of thecommercial species need to be managedfrom a spatial and temporal perspectivewith such measures as spatial/seasonal closuresor Marine Protected Areas. The spatialplanning of marine areas becomes evenmore important in those regions where fishingresources are shared, as in the Straits ofSicily [28, 29]. Indeed, all of the nurseriesidentified in this work fall in offshore areasbeyond the Italian national jurisdictionexcept for the red mullet nursery whichis located in shallow inshore waters. Accordingly,the enforcement of any managementactions could be achieved through enhancedcooperation and coordination betweenrelevant national and internationalfishery management bodies.1985