Structural Alterations in Scales of Capoeta capoeta (Güldenstädt, 1773) from Heavy Metal-Contaminated River Water

Heavy metal pollution, especially in freshwater, is a

serious problem for aquatic organisms and human health. In this study, the

scales of Capoeta capoeta living in the Karasu River (Turkey), which is

estimated to be contaminated with pollutants, especially heavy metals, were

examined for structural anomalies. Two stations on the river were selected for

this purpose. Fish and surface water samples were taken at the stations. The

heavy metal analyses were carried out in the water and the fish tissue. Heavy

metal pollution was detected in the surface water. It was also observed that

some heavy metals (As, Cu, Cd, Cr, Mn, Pb, Ni, Zn) accumulate in the fish

tissue. Significant structural differences were observed on the dorsal surface

of the scales, such as interrupted primary radii, damaged circuli, damaged

focus, damaged anterior scale margin, broken focus, deformed scale structure,

scattered chromatophores, dilatation of primary radii, loss of focus, damaged

annuli, symmetry shift in the lateral line canal, eroded circuli, damaged

posterior scale margin, double focus, branching in the primary radii,

asymmetric circuli, incomplete annuli and interrupted secondary radii in each

of the fish collected from the contaminated site. Heavy metals are suspected to

be responsible for the structural anomalies in the scales. Based on these

observations, it can be said that fish scales can be used as an effective

indicator of water quality.<o:p></o:p>