Effects of oral exposure to inorganic mercury on the feeding behaviour and biochemical markers in yellowfin bream (Acanthopagrus australis)

Mercury is a known toxic metal but studies on the effects of inorganic mercury ingestion in aquatic organisms are scarce. The present study aimed to investigate changes in feeding behaviour and biomarkers (lipid peroxidation, acetylcholinesterase, glutathione S-transferase and catalase activities) of yellowfin bream (Acanthopagrus australis) after ingestion of inorganic mercury (control: 0.2 mg kg−1, low: 0.7 mg kg−1, medium: 2.4 mg kg−1and high: 6 mg kg−1) over 16 days. After 4 days, exposed fish attempted feeding more often, and showed a significantly lower eating success than controls. However, these differences became less notable with longer exposure periods. Most biochemical markers varied over time, regardless of mercury treatment. However, biomarker responses to mercury were also observed, mostly with increased exposure period and were dependant on the tissue analysed. This study showed that fish can recover from initial feeding behaviour effects of inorganic mercury, but showed delayed response in tissue biomarkers.