Pierantonio Addis

Analyses of Nuclear ldhA Gene and mtDNA Control Region Sequences of Atlantic Northern Bluefin Tuna Populations

There has been considerable debate about whether the Atlantic northern bluefin tuna exist as a single panmictic unit. We have addressed this issue by examining both mitochondrial DNA control region nucleotide sequences and nuclear gene ldhA allele frequencies in replicate size or year class samples of northern bluefin tuna from the Mediterranean Sea and the northwestern Atlantic Ocean. Pairwise comparisons of multiple year class samples from the 2 regions provided no evidence for population subdivision. Similarly, analyses of molecular variance of both mitochondrial and ldhA data revealed no significant differences among or between samples from the 2 regions. These results demonstrate the importance of analyzing multiple year classes and large sample sizes to obtain accurate estimates when using allele frequencies to characterize a population. It is important to note that the absence of genetic evidence for population substructure does not unilaterally constitute evidence of a single panmictic population, as genetic differentiation can be prevented by large population sizes and by migration.

Characterization of the Lipid Fraction of Wild Sea Urchin from the Sardinian Sea (Western Mediterranean)

The fatty acid (FA) composition of Spatangus purpureus, Echinus melo, Sphaerechinus granularis, and Paracentrotus lividus, sea urchins, has been studied. Sea urchins were collected at different depth along Sardinia coast in the Mediterranean sea, and their gonad was measured, separated, and analyzed for FA composition by gas chromatography-mass spectrometry. A total of 53 FAs were detected, 16 saturated (SFA), 10 monounsaturated (MUFA), 9 polyunsaturated (PUFA), and 13 highly unsaturated (HUFA). Moreover, 5 furan FAs (FFAs) were revealed for the first time in sea urchin. The HUFA and PUFA classes were the most represented accounting for almost 80% of total FAs. Among these compounds, C20:4 n6 (19.64, 20.52, 23.37, and 8.48 mg/g, respectively) and C22:6 n3 (19.68, 20.05, 3.83, and 1.78 mg/g, respectively) were the most abundant. The results of principal component analysis indicated that the sea urchin samples could be clearly discriminated with respect to their FAs composition.

GC-ITMS analysis of PAH contamination levels in the marine sea urchin Paracentrotus lividus in Sardinia.

This paper describes the results of a two-year monitoring study examining the pollution of the sea urchin Paracentrotus lividus by polycyclic aromatic hydrocarbons (PAHs) in Sardinia. GC-ITMS analysis of sea urchin gonads showed the presence of 11 and 12 PAHs in the samples of Capo Pecora, and Capitana, respectively. Fluorene, naphthalene and its two degradation products, 1-methyl-naphthalene, and 2-methyl-naphthalene, were detected in all samples analyzed. The ΣPAH residues showed a similar trend over the two-year sampling period. Furthermore, the residues in the first year were slightly higher than in the second year. The information obtained by the multivariate statistical analysis PLS-DA allowed for the determination of samples based on field site and varying habitat types (rocky reef, and Posidonia seabed). The results of this study showed that Posidonia sea urchins are contaminated by high molecular weight PAHs and that Capitana samples are more contaminated due to a higher level of human activity in the area.

First record of the alien polychaete Naineris setosa (Scolecida; Orbiniidae) in Tyrrhenian Sea (Western Mediterranean)

During a survey in Santa Gilla, a Tyrrhenian lagoon located in southern Sardinia, several specimens of the alien polychaete Naineris setosa were found. 1) A brief description of the specimens is presented; they possess the rounded prostomium and the crenulated capillary chaetae typical of the genus, but they are characterized by the absolute lacking of uncini or subuluncini in thoracic neuropodia, which is unique trait within Naineris; 2) some environmental characteristics of the collection site are measured; 3) the description and the distribution of the specimens are also provided.