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Abstract: Time series (1825–1973) of the Atlantic bluefin tuna, Thunnus thynnus, landings from the trap fishery of Sardinia (W. Mediterranean) were analyzed to identify (i) patterns of catch variability in the historical traps of Isola Piana, Portoscuso and Porto Paglia, and (ii) effects of three local environmental variables: Mining, Run-off and Sea Surface Temperature. We applied different time series analysis techniques: auto-correlation functions, spectral analysis and Dynamic Factor Analysis (DFA). Moreover, an asymmetrical design using a Before/After and Control/Impact location approach was used to test the perturbations due to mining processes that have characterized the fishery area. A sharp decreasing trend of Porto Paglia trap landings beginning in 1880, coincided with mechanized mining. This result was confirmed by the ANOVAs contrasting Before vs. After (P <0.01) and Controls vs. Impact location (P <0.01). We found a slight cyclical behaviour in the same time series. Spectral analysis highlighted that pattern synchronized with the Run-off cycles with periods corresponding to 7 years. We hypothesized that the effect of Run-off from watershed mine tailing dams creates a pulsing boundary ‘reflective’ effect for tuna migration schools on the in-shore trap of Porto Paglia, resulting in a periodic oscillation of captures. We have identified (i) a reversal of trends in captures between Portoscuso and Isola Piana traps and (ii) significant differences of the monthly distribution of capture events and timing of landings (P <0.01) with a higher proportion now in May, rather than in June as in the past. We assume there is a relationship with climatic changes because warmer waters can induce precocity in gonad maturation. DFA did not show any significant differences among environmental factors and landings probably because the cyclical component in Run-off is masked. We emphasize the importance of Mediterranean traditional traps as ‘sentinels’ of the homing reproductive behaviour of bluefin tuna and we argue the case for a plan to link the remaining traps in a common monitoring network. [Copyright &y& Elsevier]

The present investigation was carried out on the bluefin tuna (Thunnus thynnus) collected during the month of April 2003 from the Straits of Messina. The aim of this study is to determine heavy metal levels (Cd, Cu, Hg, Mn, Pb and Zn) in liver and muscle tissues of 14 Thunnus thynnus of different age and sex and to investigate the relationships between fish sex and size (length and weight and metal concentrations in the tissues. The concentrations of the various metals were determined by a Varian atomic absorption spectroscopy instrument. The results showsignificant variations ( p < 0.01) for Hg and Zn concentrations in muscle than in liver samples. Concentrations of Cd and Pb are below the instrumental detection limits in almost all muscle samples. Levels of Hg (3.03 + 0.55 μg/g) are above the MRLs only in muscle (1μg/g) establishing toxicological risks for the consumer. Regression analysis shows a negative correlation between mercury level and weight and length in samples from both female and male. No significant difference between mean heavy metals concentrations and male or female tuna is seen. For greater food safety, it would be advisable to reduce the mercury intake by selecting safer fish, species and size and by the avoidance of tuna fish consumption by pregnant women, young children and old people, who are more sensitive to mercury exposure. [ABSTRACT FROM AUTHOR]

The article discusses the detection of higher tumors among fishes. The author cited some of these tumors including the mesenchymal tumors which are present among teleosts and tumors with an endodermal or ectodermal origin in higher vertebrates. Another newly discovered bluefin tuna disease named lithognathus mormyrus and hippoglossus have been found in a marine fish farm in Southern Italy. The tumor is said to consist of adipose cells with large fat vacuoles and flat nuclei.