The Pathology of Nematode Infection in Parachanna obscura (Pisces: Channidae Gunther, 1886) of the Cross River System, Nigeria

Study was conducted on the pathology of nematode infection in Parachanna obscura of the lower Cross River system, Nigeria. The objective was to find out specific pathological damages in Parachanna obscura caused by nematode infection. A total of five hundred and seventeen specimens of Parachanna obscura were sampled from artisanal fishers from January 2007 to August 2008. The infected fish were processed through the standard parasitological and histopathological procedures. Damages caused by nematode included black spots on the muscle fillet, muscle disintegration, gastrointestinal occlusion, exfoliation of intestinal mucosa, haemorrhage and distortion of the blood tissue. Infected fish had slightly lower health performance as revealed by the low condition factor compared to the non-infected. A one-way ANOVA however showed that there was no significant difference in the health index (P > .05) between the infected and the non-infected. There are potentials that the culture of nematode infected Parachanna obscura will lead to economic loss to aqua culturists, in terms of poor fillet quality and reduction in growth due to blood loss and poor nutritional activities. If P. obscura is to be used in aquaculture, anti-helminthes treatment must be applied before stocking. Further research would be needed in insitu detection of nematodes. This will boost food security and a turnaround in the economic fortune of the people of the lower Cross River basin.