Analysis of the Relationship Between Chemical Elements and Neural Necrosis Virus in Mugilids from the Southern Caspian Sea

Abstract

For years, the Caspian Sea has been affected by chemical pollution resulting from human activities. More recently, Viral Nervous Necrosis (VNN) has emerged as a new threat, severely impacting fish populations in this aquatic ecosystem. The aim of this study was to evaluate differences between healthy and VNN-infected mullets along the southwestern coast of the Caspian Sea. A total of 63 individuals were randomly sampled, including 34 Chelon auratus and 29 Chelon saliens. Viral prevalence was higher in C. saliens. Statistical test revealed clear differences between healthy and infected individuals based on their elemental profiles. Infection with NNV was associated with significantly elevated concentrations of several metals, particularly Hg, Pb, Mo, V, and Cu, with Hg showing up to a tenfold increase in infected fish. These findings confirm that the southern Caspian Sea is contaminated with multiple trace elements, which not only compromise ecosystem health but may also predispose fish to viral infections such as VNN.