Surface Ultrastructural Changes in the Gill and Liver Tissue of Asian Sea Bass Lates calcarifer (Bloch) Exposed to Copper.

Surface ultrastructure of the gill and liver of 3-month-old Asian sea bass, Lates calcarifer, after copper exposure, was investigated by scanning electron microscopy (SEM). Fish samples were exposed to copper concentrations of 6.83 and 13.66 ppm (sublethal) for 28 days with parallel untreated control. These structures showed structural modifications in both low and high concentrations of copper exposure. Oedema, hyperplasia, desquamation, necrosis, epithelial lifting, lamellar fusion, collapsed secondary lamellae, curling of secondary lamellae and aneurism in the secondary lamellae were observed in gill tissues exposed to copper. Hepatic lesions related to cloudy swelling of hepatocytes, congestion, vacuolar degeneration, dilation of sinusoids and nuclear hypertrophy were evident in the exposed sea bass liver tissue.