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Fishery and Sea ResourcesSpecies Survey 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 AverageMerlMer MEDITS 112 137 89 125 114 128 119 89 122 119 113 115GRUND 119* 151* 95 140 107 108 137 104 120 131 118Mullbar GRUND 97 83 80 81 107 104 85 76 85 90 89Phyible MEDITS 156 129 144 141 157 131 148 130 168 153 139 145Papelon MEDITS 24 20 17 16 18 14 15 17 20 18 15* 18GRUND 11* 17 16 19 19 16 16 18 17 20 17Arisfol MEDITS 28 26 27 27 31 28 28 25 30 33* 29 28Neprnor MEDITS 27 21 32 26 27 28 24 23 30 33 32 27GRUND 29 16 23 26 31 21 21 21 16 24 23Eledcir MEDITS - 31 29 28 28 25 32 29 39 42 40 32Table 1: Cut-off length (mm) of each species for each year/season. When splitting of theLFD components was difficult (marked by an asterisk), the estimated value was replacedwith the average of the cut-off lengths of the corresponding series.ranged between 129 and 168 mm TL witha mean value equal to 145 mm TL (Table1). The recruits were present in the epibathialgrounds between 200 and 500 mand showed a concentration peak between400 and 500 m depth. The spatial distributionof greater forkbeard recruits showed avery stable pattern over time. Two persistentnurseries were identified in the westernand eastern margins of the AdventureBank at depths between 200 and 400 m(Figure 2e). The LFDs of the Norway lobsterallowed the identification of recruits inboth spring and autumn surveys. The meancut-off length was equal to 27 mm CL inspring and 23 mm CL in autumn (Table1). Recruits were distributed on the upperslope between 250 and 500 m depth,with a peak of abundance between 400 and500 m. The density maps of Norway lobsterrecruits showed a well defined spatialpattern in both seasons with the presenceof two stable hot spots . They were locatedwest and east of the Adventure Bank between200 and 400 m depth (Figure 2f),and they overlapped the nurseries of thegreater forkbeard. The recruitment of thegiant red shrimp takes place in spring [18],allowing the easy identification of the firstmodal component in the LFDs of springsurveys. The mean cut-off length was 28mm CL (Table 1). Recruits were widelydistributed over the bathyal grounds (500-700 m) of the central area of the Strait ofSicily. The analysis of persistence, onlyperformed on five years, showed the presenceof two areas of stability (Figure 2g).5 DiscussionThe nurseries of a pool of species with significantcommercial value in the Strait ofSicily were identified in this paper. Theanalysis was performed by following threesteps:1) estimating the juvenile fraction ofthe population (i.e. recruit density indices);2) mapping the yearly recruit density indexand delineating the areas showing the highestconcentrations of juveniles (i.e. recruit1984