Base line pathological data of the wedge clam Donax trunculus from the coasts of Tyrrhenum (Mediterranean Sea)

In the recent years, a collapse in Donax trunculus fishing yields has been experienced in the Tyrrhenian sea of the Mediterranean Basin. Unfortunately, few data are available on the impact of D. trunculus diseases on the above condition. For the first time, a pathological survey on the natural beds of the bivalve on the Campania and Latium coasts was performed. Detected pathogens and related diseases were analysed, and their prevalence and mean intensity values were calculated. Viral particles, rickettsia-like organisms (RLO), ciliates, coccidians, microcells and trematodes were observed. An unknown ciliate was linked to severe inflammatory and necrotic lesions in the digestive gland. Metacercariae of the trematode Postmonorchis sp. were also strongly represented in almost all samples, reaching high levels of infection. None of the pathogens described were OIE (World Organisation for Animal health) notifiable. The initial results indicate that further surveys related to environmental data are necessary in order to assess the relevance of these early observations in managing the declining D. trunculus population in the Tyrrhenian Sea.