A Survey of Gill Histopathology of Thirteen Common Fish Species in the Sanyati Basin, Lake Kariba, Zimbabwe/ Badania Histopatologiczne Skrzeli Trzynastu Pospolitych Gatunków Ryb W Zlewni Sanyati, Jezioro Kariba, Zimbabwe

Abstract Following a study of gill pathology in African catfish (Clarias gariepinus) and Nile Tilapia (Oreochromis niloticus) from the Sanyati Basin of Lake Kariba, Zimbabwe, a similar survey was carried out in thirteen other common fishes of Lake Kariba. Gill tissues were dissected from the fish, preserved and prepared for histology. The prepared tissue sections were observed under a light microscope. Six histopathological lesions were observed, namely epithelial lifting, hyperplasia, lamellae fusion, parasitic cysts, oedema, and aneurysm. Epithelial lifting was prevalent in all fish species whilst aneurysm was only observed in two fish species. Synodontis zambezensis had the highest prevalence of gill lesions whilst Marcusenius microlepidotus, Brycinus imberi and Micralestes acutidens had the least prevalence of lesions. Most of these histopathological lesions were mild to moderate, and this is suggestive of good health of the fish species investigated. Seventy seven percent of the fish species were infected with monogenean ectoparasites. More research on fish health in Lake Kariba is recommended and future studies should aim to quantify these histological changes in relation to environmental conditions of the lake. This will enable histopathology to be used as a biomarker or predictor of water quality.