Persistent organic pollutants (PCBs and DDTs) in European conger eel, Conger conger L., from the Ionian Sea (Mediterranean Sea).

The present study provides novel data regarding levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (DDTs) in muscle tissue of European conger eel (Conger conger) from Ionian Sea (Mediterranean Sea). The mean concentration of PCBs (891 ng g(-1) lipid weight) was higher than those of DDTs (543 ng g(-1) lipid weight). PCB pattern was dominated by higher chlorinated congeners (hexa-CBs: 69.

A histological investigation of the occurrence of non-reproductive female bluefin tuna Thunnus thynnus in the Mediterranean Sea.

The presence of non-reproductive Atlantic bluefin tuna Thunnus thynnus females in the Mediterranean Sea was investigated through histological analysis of the gonads. Three hundred and twenty-six ovary samples were collected from adults captured at different locations in the Mediterranean Sea during the reproductive seasons between 1998 and 2008. Only three specimens were considered to be in a non-reproductive state: two of them were in a reabsorbing state showing ovaries with early vitellogenic oocytes and extensive alpha and beta atresia of vitellogenic follicles; the third showed gonads with perinucleolar oocytes and was considered to be in a resting state.

Brain morphology and immunohistochemical localization of the gonadotropin-releasing hormone in the bluefin tuna, Thunnus thynnus.

The present study was focused on the morphology of the diencephalic nuclei (likely involved in reproductive functions) as well as on the distribution of GnRH (gonadotropin-releasing hormone) in the rhinencephalon, telencephalon and the diencephalon of the brain of bluefin tuna (Thunnus thynnus) by means of immunohistochemistry. Bluefin tuna has an encephalization quotient (QE) similar to that of other large pelagic fish. Its brain exhibits well-developed optic tecta and corpus cerebelli.