Population Biology of the Metazoan Parasites Infecting Fishes from Lakes Uba and Ruwe, Lower Rufiji Floodplain, Tanzania

Abstract

Out of the 48 fishes examined, 40 (83.3%) were infected by 759 parasites, which comprise of trematodes, monogeneans, crustaceans and acanthocephalans. Acanthocephalans and strigeid trematodes were the majority, 23 (47.9%) of all the parasites, while crustaceans, Ergasilus was the minority (20.8%). Fish with length size greater than 160 mm were infected (prevalence 100%). Strigeids showed the highest prevalence (83.3%) and mean intensity (24.7) in fish of total length 160 - 189 mm while those greater than 219 mm had the least prevalence (20%) and mean intensity (2). Acanthocephalan showed the highest prevalence (87.5%) and mean intensity (15.7) in fish of total length 190 - 219 mm and least prevalence (30.4%) and mean intensity (5.6) in those with 130 - 159 mm in total length. Generally male fish had higher prevalence (88.5%) and mean intensity (21.6) than female fish. However, statistically these were not significant (P > 0.05). A total of 9 parasite taxa were recovered; 5 from Oreochromis urolepis, 4 from Citharinus congicus, 2 from Clarias gariepinus and Synodontis maculipinna. Three groups of parasites were common in Oreochromis urolepis, these include Dactylogyrus, Acanthocephala, and strigid. Ergersilus lamelifer was common in Citharinus congicus and Clarias gariepinus. Nematodes, Procamalanus laevionchus and Oxyuridae were common in Synodontis maculipinna and Citharinus congicus respectively.