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The Atlantic bluefin tuna (ABFT), Thunnus thynnus (Linnaeus, 1758), is an important commercial species managed as two different stocks, western and eastern Atlantic, with their spawning grounds in the Gulf of Mexico and in the Mediterranean Sea, respectively. The eastern Atlantic stock has been overexploited in the last decades, leading to the application of specific management measures introduced by the International Commission for the Atlantic Tuna (ICCAT). A clear understanding of the genetic structure of ABFT Mediterranean population should be pursued in order to support management decisions. To date the genetic studies on the Mediterranean ABFT, carried out with different molecular markers and sampling procedures, have produced unclear results. Here, we analysed ABFT samples from central and western Mediterranean Sea with mitochondrial sequences and 11 microsatellite loci to investigate, among the others, the area of the Strait of Messina, where environmental conditions seem to support a resident population of ABFT. Furthermore, genetic analyses of mitochondrial sequences were carried out including nucleotide sequences of Adriatic ABFT wild larvae retrieved from GenBank. Among the investigated areas a genetic differentiation was detected between the Strait of Messina and the Tyrrhenian Sea with microsatellite loci according to the exact G test, but not to the Bayesian analyses carried out with STRUCTURE. The analyses with mitochondrial sequences do not reveal any differentiation among sampled areas, however, a highly significant genetic divergence was observed between the Adriatic mitochondrial sequences retrieved from GenBank and the central‐western Mediterranean sequences obtained in the present work. Our results provide some evidence of population structure of Mediterranean ABFT adding pieces to a still unclear picture.

Summary This study tested the hypothesis that the fish assemblage associated with a wreck can vary according to two factors: the vertical distribution and the level of wreck complexity. In the Southern Tyrrhenian Sea in September 2009, the composition and density of fishes were ascertained, coupling the detailed architectural reconstruction of a wreck with videos recorded by remotely operated underwater vehicles. A total of nine fish species were found. Anthias anthias followed by Clupeiformes dominated the upper zone of wreck, while in the lower zone a significant decrease in numbers of all fish species was recorded The study shows that vertical distribution is the factor most influencing the allocation of species, probably due to a greater exposure to the energy flows. In contrast, the complexity of the wreck appears to play a less important role, one that is in any case less clear. To clarify this point, further investigation with a higher resolution and a comparison with other wrecks should be performed.

Summary The objective of this study was to examine the space and environment variables that contributed to the presence of swordfish in the Strait of Messina during the 2003 and 2004 harpoon fishing activity. The relationships between catches per location and environmental factors (current, moon phase and sea surface temperature) were analyzed using a generalized linear model (GLM). The GLM analysis showed differences in CPUE (catch per unit effort) values in terms of swordfish numbers per location over the 2-year period. The central locations of the Strait were found to be teeming with fish; the CPUE was also higher in these areas during the new and rising moon phases.

Summary This paper provides data on age, growth and diet of the bluemouth rockfish, Helicolenus dactylopterus dactylopterus (Scorpaenidae), central Mediterranean Sea. Estimated by otolith readings, ages ranged from 0 to 21 years. Parameters of the von Bertalanffy growth curves were Linf = 26.1 cm, k = 0.14 year−1, t0 = −1.92 years and the growth performance index was Φ = 1.98. The weight-length relationship, W = 0.016 TL2.99; R2 = 0.99, described an isometric growth of the species. This species is a carnivore focusing mainly on the crustaceans Goneplax rhomboides and Lophogaster typicus. Statistical analysis showed an ontogenetic shift between small (4.0–6.3 cm) and larger fishes. Significant differences were also found in relation to the sampling depth.

Summary Age and growth of pearly razorfish Xyrichtys novacula (Labridae) were determined in specimens caught on sandy bottoms by surrounding nets and lines (depth range 5–30 m) between January 2000 and December 2002. The study location was in the central Mediterranean Sea. For this purpose the annual growth increments (annuli) in sagittae were analysed. A total of 470 individuals of X. novacula, ranging from 49 to 200 mm TL (total length), were examined. Conversion between total length and standard length was calculated and represented by the relationship: . Edge analysis on otoliths was carried out to validate seasonality deposition. Seven age-classes were determined from 0+ to 6+. The linear relationship between maximum otolith length (OL) and TL was summarized in the equation . The estimated parameters of the von Bertalanffy growth function were L = 175.05 mm, k = 0.80 year−1, t0 =−0.73 years and the growth performance index calculated as (Φ = 2.39). The length–weight relationship W = 0.0139 TL2.9326 described an isometric growth for the species in this area.

Summary A study on fish assemblage associated with fish aggregating devices (FADs) in Sicily was carried out between January 2000 and January 2001. With a fortnightly periodicity, 156 experimental hauls were carried out by means of a purse seine in a FAD-containing marine section banned to commercial fishing. A total of 14 229 fish specimens belonging to six families and 10 species was found. These species were Balistes carolinensis, Caranx crysos, Naucrates ductor, Seriola dumerili, Seriola fasciata, Tachurus picturatus, Coryphaena hippurus, Schedophilus ovalis, Thunnus thynnus, Polyprion americanus and showed all young-of-the-year undergoing a rapid growth. The applied ordination technique highlighted the existence of four assemblage periods describing the annual trend. The results confirm that fish assemblages associated with FADs are related to season, following a fish colonization tied to natural recruitment. Comparison of the ecological indices across the four periods showed that the assemblages in the periods from summer to winter were more structured than those in spring. The quantity of individuals also showed a strong variation peaking in the summer period. The results of this study reveal that FADs represent a particular nursery area for the associated species that could influence their survival.

Summary Illegal, unreported, and unregulated fishing for swordfish, mainly of immature specimens, are known to be the highest threats for this resource. This study provide a simple and useful tool for the maritime security service to recognize illegal landing sizes (

Wild Seriola dumerilii were collected in the South Mediterranean Sea during the 1990, 1991 and 1992 spawning seasons. Macroscopic and cytological characteristics of ovary and testis were analysed. Depending on the presence and the number of oocytes at different stages, a five point maturity scale was proposed for ovarian maturity. Nine maturity stages of the oocytes are described. Oocyte size-frequency distribution has shown a group synchronous ovarian development type. The testes have a typical lobular-type structure. Depending on lobules and sperm duct development and on the abundance of germ cells, testis maturity was classified in four stages. Maturity rate according to age and size was also determined. 100% of 1-year-old fish show immature gonads. The proportion of females with mature ovaries was 0, 12.5, 84.6 and 100% at the age of 2, 3, 4 and 5 years respectively. The proportion of males with mature testes was 14.3, 40, 80 and 100 at the same age. The median standard length at which 50% of the fish attained maturity is 109 and 113 cm SL in males and females respectively.