Comparative survey of helminth parasites of Clarias gariepinus (Burchell, 1822) and Clarias pachynema (Boulenger, 1903) from the Ogun River and Asejire Dam in south-west Nigeria

摘要

A total of 250 randomly selected fish specimens consisting of 72?Clarias gariepinus?and 51Clarias?pachynema?from Ogun River around the cattle market, Isheri, Ogun State. 73?C. pachynema?and 54?C.?gariepinus?from Asejire Dam (which has not been reported to be polluted) in south-west Nigeria were sampled for helminth infection between September 2008 and February 2009. All helminthic infections observed and recorded were restricted to the stomach, intestine and gill chamber. The helminths recovered included three cestodes,Wenyonia?sp.,?Polyonchobothrium?sp.?and Pleurocercoid larva,?a nematode,?Procamallanussp.?and one digenean,?Clinostomum?sp.?Prevalence and mean?intensity of?parasitic?infectionwere higher in specimens from the Ogun River than those from the Asejire Dam. Overall, parasite prevalence of 75 and 45.1% were recorded for?C. gariepinus?and?C. pachynema?from the Ogun River, respectively, while 25.9 and 31.5% were recorded for?C. gariepinus?and?C. pachynema, respectively, for the Asejire Dam. Male?C.?gariepinus?from the Ogun River had the highest infection rate (76.5%), while those from Asejire Dam had the lowest (21.43%). No significant?difference in the?prevalence?of parasitic infection in relation to?the host sizes?(P > 0.05) was recorded; however, largest size fishes had no parasitic infection.?Clinostomum?sp.was found only in?C.?gariepinus?and?C.?pachynema?from Ogun River.