Gill Damage and Recovery in Juvenile Black Sea Bream Acanthopagrus schlegelii Stressed by Uncontaminated Suspended Solids

Abstract

Studies on the responses of fish to suspended solids (SS) have focused on freshwater salmonid species, far less is about marine species. In this study, juveniles of black sea bream Acanthopagrus schlegelii were exposed continuously to various concentrations of uncontaminated SS for 10 days to detect gill damage, and then returned to clean seawater without SS for 10 days to detect gill recovery. The results showed that, no clear changes in chloride cells, Na+-K+-ATPase activity and DNA damage parameters (comet cell rate, tail length and tail moment) were observed after 10 days of exposure to 100 mg SS/L, while at 1000 mg SS/L these paramaters were significantly altered. After the 1000 mg/L SS-treated fish were transferred from water containing SS to clean seawater only, Na+-K+-ATPase activity, tail length and tail moment all indicated signs of recovery, but these kinds of recoveries were incomplete and did not return to the control levels. The rapid response and recovery observed in our study show that high concentration uncontaminated SS can induce gill damage of juveniles of A. schlegelii, and this kind of damage is difficult to recover completely.