Incidence of nematode parasites in snakehead, Parachanna obscura of the lower Cross river system, Nigeria

Abstract

The incidence of nematode parasites in African snakehead, Parachanna obscura of the lower Cross River system was investigated. The objective was to determine the prevalence and intensity of the infection with size, gender and season of the fish species. A total of 510 specimens of Parachanna obscura was sampled from July 2009 to January 2010. The fish were processed through standard parasitological manipulations. There was 53.9% prevalence of infection and mean intensity of 8 nematodes per fish in the Great Kwa River. In the Cross River 96 fishes were infected with a total of prevalence and mean intensity was highest in the lower length-classes. Mean intensity was lower inrnfemales than in males due to their reproductive requirement. Generally, there was no significant difference in prevalence by size and gender at p > 0.05. Mean intensity and nematode abundance, were higher in Great Kwa River than the Cross River. There was no correlation between the total numbers of nematodes and the infected P. obscura by size and gender. The prevalence of infection by season in Great Kwa River was variable; with a mean intensity of 12 worms per fish in dry season and 6 worms per fish in wet season. The low level of helminthes infection in Parachanna obscura means that it is safe as aquaculture candidate and this should be vigorously pursued.