Histopathological lesions in the selected tissues of Cirrhinus mrigala (Ham.) fingerlings exposed to a sublethal concentration of mercury

In the present investigation histopathological lesions in the selected tissues such as gills, kidney and eye of the fingerlings of Cirrhinus mrigala exposed to a sublethal concentration of mercury, i.e. 240 μg/l from static bioassay have been studied. The primary gill lamellae showed degeneration in the middle and distal region. In distal region, spherical structure showing complete degeneration and fusion of pillar, epithelial, mucus producing gland and blood cells in the secondary gill lamellae. Degeneration and necrosis in glomerulus, interstitium tissue and epithelium lining of renal tubules in kidney have also been seen in mercury treated fingerlings. Whereas periorbital region of eye showed exudation in choroids layer and degeneration in oedematous tissue or adjacent sclera. The results have been discussed in relation to respiratory and excretory physiology and probable cause of fish death due to mercury poisoning.