Helminth Endo-Parasites of Mochokids in a Tropical Rainforest River System

Abstract

A study of the helminth endo-parasites of Brachysynodontis batensoda, Hemisynodontis membranaceous, Synodontis gobroni, S. clarias, S. sorex, S. budgetti, S. xiphias, S. nigrita, S. filamentosus, S. eupterus, S. schall, and S. ocel ifer randomly sampled from commercial fishers was made in the lower reaches of Anambra river from March 2001 to February 2002. The helminth endo-parasites recovered were Sandon a sudanens s (Trematoda) Wenyon a synodont s, W youdeoweii, W. kainji (Cestoda) and Procamallanus laeviconchus (Nematoda). B. batensoda, S. clarias, S. eupterus, S. gobroni and S. ocellifer are new geographical records for W. synodontis, which appeared to be the most important endo-parasite of mochokids in terms of fishery management in the Anambra river. It infected more hosts than the other Wenyonia species put together or the other parasite species. The prevalence of all the endo-parasites was low (≤ 20 %). There were cases of mixed infection involving S. sudanensis and P. laeviconchus as well as Wenyonia species and P. laeviconchus but never between Wenyonia congeners. The habitat most preferred by S. sudanensis and Wenyonia species was the small intestine, whereas P. laeviconchus was found only in the stomach. Prevalence, mean intensity and abundance of all the endo-parasites were generally higher in the dry than in the rainy season. No visible damage or injury resulting from the endo-parasites was evident on parasitized fish.