Seasonal Variation in Parasitic Prevalence of Oreochromis niloticus from Upper River Benue, Mutum Biu, Taraba State, Nigeria

Abstract

Seasonal variation in parasitic prevalence of Oreochromis niloticus from Upper River Benue, Mutum Biu, Taraba State, Nigeria was conducted using standard parasitological methods. 400 samples of varied sizes of Oreochromis niloticus consisting of 200 samples each in dry and rainy seasons were bought from fishermen at the Upper River Benue, Mutum Biu, Taraba State for a period of ten months and transported fresh to the Parasitology Laboratory, College of Veterinary Medicine, Joseph Sarwuan Tarka University, Makurdi (formerly called University of Agriculture, Makurdi) where they were sorted out into different sizes and sexes. Out of the 400 samples comprising of 200 samples each of Oreochromis niloticus collected in dry and rainy seasons, 211 (52.75%) samples were infested with 605 parasites. Out of the 200 samples collected in dry season, while 105 (52.50%) were infested with 327 parasites, in rainy season, 106 (53.00%) samples were infested with 278 parasites out of the 200 samples. Prevalence of infection (53.00%) was higher in rainy season than dry season with prevalence of infection of 52.50% whereas, percentage parasite load (54.05%) was higher in dry season than rainy season with the percentage parasite load of 45.95%. Among the parasite species in dry season, while Camallanus spp. was the most prevalent (22.02%) Ichthyopthirius multifilis was the least (3.67%). In rainy season, while Diphillobothrium latum was the most prevalent (19.07%), Ichthyopthirius multifilis was the least (1.44%). Among the external parts, while the gill had the highest percentage parasite load in both seasons, the least was recorded for fin and skin, respectively. Percentage parasite load was higher in the intestine than the stomach in both seasons though, there was no significant difference (p>0.05) recorded for percentage parasite load of both external and internal parts of the fish samples in both seasons. Male Oreochromis niloticus had higher prevalence of infection and percentage parasite load than the female though, there was no significant difference (p>0.05) in the prevalence of infection and percentage parasite load and the sexes in both seasons. Samples of Oreochromis niloticus with longer lengths and greater weight had higher percentage parasite load than the samples with shorter lengths and smaller weight.