Analysis of Parasitic Infections in Oreochromis niloticus and Clarias gariepinus Obtained from Selected Fish Farms in Calabar, Nigeria

Freshwater fish species harbour parasitic organisms, serving as either intermediate or definitive hosts for parasites that can be harmful to humans and animals. This study was conducted to assess the prevalence of parasites in two fish species obtained from selected farms in Calabar, Nigeria. Collection, examination, sex determination, and identification were performed using the recommended procedures. A total of 300 fish samples from four fish farms were examined for parasites, and 88 (29.3%) were found to be infected. The highest prevalence of parasitic infection was observed at the Nyahansang fish farm (41.3%), whereas the lowest prevalence was recorded at the University of Calabar (UNICAL) fish farm (18.7%). Gyrodactylus sp. (8.3%) were the most prevalent parasites, followed by Trichodina spp. (6.7%); Dactylogyrus sp. (4.7%); Aeromonas sp. (3.0%); Eustrongylides sp. (2.3%); Henneguya pinnae (2.3%); Ergasilus labracis (1.3%); and Chilodonella sp. (0.7%). Oreochromis niloticus had the highest parasite prevalence (54 [36.0%] ) compared to that of Clarias gariepinus(34 [22.7%] ). The prevalence of parasites was higher in females (31.4 %) than males (27.2%). In O. niloticus, 25 males (34.2%) and 29 females (37.7%) harboured parasites, but the comparison between sexes showed no significant difference (p>0.05). Similarly, in C. gariepinus, 15 males (20.3%) and 19 females (25.0%) harboured parasites, with no significant difference observed between the sexes (p>0.05). This study revealed the considerable prevalence of parasitic infections in the two fish species used. The results of this study highlight the potential risks posed by parasites on aquaculture, fish health, and economic sustainability. A deeper understanding of these parasitic dynamics is crucial for enhancing fish health, improving aquaculture productivity, and fostering sustainable fish farming practices in Nigeria.