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The Atlantic horse mackerel ( Trachurus trachurus ) is a semi-pelagic fish species with a wide geographical distribution and commonly found on the continental shelf. In recent years, the species has received some attention due to its ecological role in pelagic food webs. Stable isotope of nitrogen and carbon (δ 15 N and δ 13 C) and Stomach Content Analysis (SCA) of T. trachurus were adopted as tools to provide necessary knowledge on its feeding habits in the Strait of Sicily. The strong correlation found between δ 15 N and δ 13 C values with body length, together with significant ontogenetic shift evidenced by SCA, could be associated to changes in food availability, which in turn is triggered by environmental conditions. Spatial distribution of T. trachurus in the study area, mainly for small and medium size specimens, is linked to lower temperature, salinity and Photosynthetically Active Radiation (PAR sat ) values with higher aggregations on the Adventure Bank (i.e., an area characterized by periodic upwelling events). Larger size specimens mostly inhabited shallower waters characterized by higher temperature, salinity and PAR values, typical of the central-eastern part of the study area. Our results support the hypothesis that feeding behavior of T. trachurus is strictly linked to environmental factors (i.e. chiefly oceanographic conditions of the water column and day duration) that in turn influences the distribution of its prey. Findings can supply knowledge needed for improving fish stock management and promoting plans able to take into account also local ecosystem analysis.

Trophic ecology of adults of European sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) was examined and compared among various regions of central Mediterranean Sea. Carbon and nitrogen stable isotope analyses (delta C-13 and delta N-15) were adopted as a tool to determine changes in feeding behaviour of adults of sardines and anchovies. In the study period (summer) a clear geographical pattern was recognized in the isotopic composition of both species, with an increasing trend northward. The highest variations in isotopic signal were linked to the geographical positions of the samples and, especially, between pairs of areas: South Sicily/South Campania and Gulf of Gaeta/South Elba. Higher isotope values were found in the anchovies and sardines caught in northern Tyrrhenian Sea, while lower values were mostly estimated in the southern region. Higher carbon and nitrogen isotopes may reflect a more coastal behaviour of both species, being C-13-enriched source from benthic primary producers in addition to phytoplankton. Variations in the nitrogen isotope ratio may reflect not only differences in the trophic level of prey species, but also variations in the baseline level of food webs. Our results support the hypothesis that feeding behaviour of both species is directly or indirectly influenced by local factors, or by resource partitioning based on zooplankton size. Findings can supply knowledge needed for improving fish stock management and promoting plans able to take into account also local ecosystem analysis. (C) 2016 Elsevier Ltd. All rights reserved.

The response of benthic foraminiferal assemblages to trace element pollution in the marine sediments of the Gulf of Milazzo (north-eastern Sicily) was investigated. Since the 1960s, this coastal area has been a preferred site for the development of two small marinas and a commercial harbour as well as for heavy industry. Forty samples collected in the uppermost 3-4 cm of an undisturbed layer of sediment in the littoral environment were used for this benthic foraminiferal analysis. The enrichment factors (EFs) of selected trace elements (As, Co, Cr, Cu, Mn, Ni, Pb and Zn) were also calculated. Changes both in benthic foraminiferal assemblages and in some trace elements concentrations have provided evidence that the gulf's littoral zone can be subdivided into three sectors characterised by environmental changes in the marine ecosystem. In the sector unpolluted, close to the Milazzo Cape, foraminiferal assemblages exhibit high values of species richness and foraminiferal density while trace element concentrations and their EFs are very low. Here, the highest densities of Miliolids and epiphytic species are present. On the contrary, in the sector polluted, from the marinas to the crude oil refinery, foraminiferal density and species diversity are low, and assemblages are dominated, albeit with very low densities, by species that tolerate stressed environmental conditions, such as LOFAs, agglutinants and Ammonia spp. Here, the highest trace elements concentrations of Pb, Zn and Cu and related EFs were detected. Eastwards, in the sector moderately polluted, foraminiferal populations are quite poor. They are characterised by low values of species richness and foraminiferal densities, nevertheless trace element concentrations become lower than in the other sectors and their EFs are often below 1. Deformed foraminifera, with percentages up to 7.14 %, were found in all three of the sectors. Differences in benthic foraminiferal assemblages, coupled with results from statistical analysis, indicate that anthropogenic trace element pollution could be considered as one of the most important causes of the modifications of foraminiferal assemblages in the study area.