Parasites of african catfish clarias gariepinus and oreochromis niloticus polycultured in earthen ponds

Abstract

The prevalence, abundance and mean intensity of parasites of Clarias gariepinus and Oreochromis niloticus polycultured in three large earthen ponds in Nigeria were analyze in this paper. The ponds receive both water and fish from a dam fed by Anya River and Amaoba streams. The major ectoparasite of both fish was Trichodina heterodentata. There were no significant differences (P>0.05) in the prevalence of Trichodina heterodentata on both O. niloticus (34.71±0.01%) and C. gariepinus (34.5±0.04%). Abundance and mean intensity of T. heterodentata were significantly (P<0.05) were higher for O. niloticus than C. gariepinus. Camallanus polypteri was the major endoparasite associated with C. gariepinus and O. niloticus. There was higher prevalence, abundance and mean intensity of C. polypteri in O. niloticus (34.71±0.93%, 118.6±0.56 and 18.57±0.77) than C. gariepinus (22.5±0.33%, 9.6±0.11 and 11±0.21) (P<0.05). The feeding pattern of the fish seems to influence the type of parasite harboured. The infestation of Lernaea cyprinacea was more prevalent on O. niloticus (42.86±0.07%) compared to C. gariepinus (25.5±0.08%) (P<0.05). Nevertheless, the abundance and mean density of Lernea cyprinacea was significantly higher for C. gariepinus (5.1±1.03, 8.2±0.44) than O. niloticus (3.1±0.67,7.33±0.56) (P<0.05). Dactylogyrus extensus was more prevalent on the O. niloticus (42.86±0.31%) than C. gariepinus (25.5±0.66%) (P<0.05). Gyrodactylus limnonephrotus was more prevalent on O. niloticus1 (14.29±.34%) than C. gariepinus (12.5±0.56%) (P<0.05). There were no leeches found on O. niloticus but there was 25±0.67% leech on the C. gariepinus. The absence of leeches on the tilapia maybe due to their pelagic life style compared to catfish.