Biomarkers and metal content in white seabream (Diplodus sargus) and its relationship with the occurrence of the Abnormal Tough Syndrome

There is still controversy on the cause of the incidence of abnormal tough syndrome (ATS) in some fish species, mainly the white seabream ( Diplodus sargus ). This work analyses the incidence of the ATS in white seabream in areas with a different extent of heavy metal pollution and its possible relationship with fish health. Muscular cholinesterase (ChE) activities were selected to assess their potential as biomarkers of ATS occurrence. Among the trace elements Zn, Cu, Pb, and As in muscle and Cu in liver were significantly higher in the fish from the most polluted marina location. ATS incidence (33 %) was also recorded in this site with individuals showing a significantly lower body condition but ChE activities did not reflect any neurotoxic impact on the fish, neither did detoxification and oxidative stress damage. However, a significant negative association was seen between AChE activity and muscle body burden of Hg, Cu, and Se in fish from the less impacted sites, which suggests a certain neurotoxic modulation by these metals. It also alerts for the consumption of fish from recreational activities that do not follow any regulatory measures. • Abnormal tough syndrome is not reflected in muscular cholinesterases. • White seabream near marinas accumulates high levels of toxic metals. • First time characterisation of white seabream cholinesterases.