Mass mortality in endangered fan mussels (Linnaeus 1758) caused by co-infection of and multiple infection in Çanakkale Strait, Turkey.

Purpose: (fan mussel) is one of the most important endemic bivalve molluscs in the Mediterranean and mass mortality events were observed in these mussels in recent years. In this study, we report mass mortalities caused by , which has been spreading in the Mediterranean for 3 years, and reached the Çanakkale Strait, which is the entrance of the Marmara and the Black Sea.

Material And Methods: Field observations during sampling and subsequent histopathological, biochemical, genetic, and microbiological analyses were carried out.

Results: These analyses showed that infection spread among the natural beds of , causing severe tissue damage and oxidative stress. Our phylogenetic analyses suggested that the parasite spread through the Mediterranean much faster than thought. The results showed that vibriosis originating from , , , and , acted together with in infected individuals and caused death.

Conclusion: It is highly probable that the spread of to the Sea of Marmara and the Black Sea may occur earlier than expected, and it was concluded that mass deaths were caused by co-infection with and a geographically specific marine pathogen that can infect populations.