Potential feeding and spawning habitats of Atlantic bluefin tuna in the Mediterranean Sea

Atlantic bluefin tuna Thunnus thynnus (ABFT) is a fish of high market value which recently become strongly overexploited, notably in the Mediterranean Sea. This area is an habitat for ABFT reproduction and growth. We present here an approach for deriving the mapping of potential ABFT feeding and spawning habitats based on satellite-derived sea temperature (SST) and chl a concentration. The feeding habitat was mainly derived from simultaneous occurrence of oceanic fronts of temperature and chl a content while the spawning was mostly inferred from the heating of surface waters. Generally, higher chl a contents found to be preferred for the feeding habitat and a minimum SST value was found for spawning habitat. Both habitats were defined by the presence of relevant oceanographic features are therefore potential and functionally-linked habitats. This approach provides, for the time, a synoptic view of the potential ABFT habitats in the Mediterranean Sea. The model well in areas where both satellite data and ABFT observations are available, as 80% of data are in the vicinity of potential habitats. The computed monthly, seasonal and annual of potential feeding and spawning habitat of ABFT from 2003 to 2009 are in good agreement current knowledge on ABFT. Overall, the habitat size of ABFT is about 6% of the Medi - Sea surface. The results displayed a strong seasonality in habitat size and locations as as high year-to-year variations (30 to 60%), particularly for the potential spawning habitat, is key information for evaluating the utility of ABFT Marine Protected Areas in the Medi - Sea.