Research Journal of Biological Sciences 7 (8): 320-326, 2012 ISSN: 1815-8846 © Medwell Journals, 2012 Corresponig Author: Elie Montchowui, Laboratory of Hydrobiology and Aquaculture, Faculty of Agricultural Science, Universite of Abomey-Calavi, 01BP 526 Cotonou, Republic of Benin 320 Cutaneous and Gastrointestinal Helminth Parasites of the Fish Synodontis schall and Synodontis nigrita (Siluriformes: Mochokidae) from the Lower Ouémé Valley in South Benin Jacques Dougnon, Elie Montchowui, Florian Dadjo Daga, 1 2,3 4 Jédirfort Houessionon, Philippe Laléyé and Nestor Sakiti 1 3 5 Departement de Production et Santé Animales, Ecole Polytechnique d’Abomey-Calavi, 1 Université d’Abomey-Calavi, 01BP 2009 Cotonou, Republique du Benin Ecole Nationale Supérieure des Sciences et Techniques Agronomiques de Ketou, 2 Université d’Abomey-Calavi, BP 95 Ketou, République du Benin Laboratory of Hydrobiology and Aquaculture, Faculty of Agricultural Science, 3 Universite of Abomey-Calavi, 01BP 526 Cotonou, Republic of Benin Département de Productions Animales, Faculté des Sciences Agronomiques, 4 Departement de Zoologie et Genetiqué, Faculté des Sciences et Techniques, 5 Universite d’Abomey-Calavi, 01BP 526 Cotonou, Republique du Benin Abstract: Since, approximately 2 decades, there has been a regression of fish captures in Benin and particularly in the Basin of Ouémé river. A high parasitic infestation which would affect negatively the dynamics of the halieutic population, would be one of the probable causes of this regression. The present study aims to inventory helminth parasites in Synodontis schall and Synodontis nigrita from the lower Ouémé valley in South Benin and to estimate their prevalence. A sample of 75 specimens of the 2 fish species was examined at the laboratory between September and October, 2011. The results revealed high parasitic prevalence in the two species: 82.14 and 78.72%, respectively. Six helminth genus were identified of which one digenean trematode (Clinostomum sp.), three nematodes (Cithariniella petterae, Procamallanus laeviconchus, Synodontisia thelastomoides) and two cestodes Stoeksia pujehuni and Lytocestus sp. Of the three parasites groups, nematodes are most abundant in both Mochokidae examined; they are 66.53 and 90.58% of parasites counted, respectively in S. schall and S. nigrita. Synodontisia thelastomoides has the highest prevalence: 46.43% in Synodontis schall and 42.55% in Synodontis nigrita. Key words: Prevalence, helminth, parasite, Synodontis schall, Synodontis nigrita, lower Ouémé valley, Benin INTRODUCTION halieutic resources by the use of prohibited fishnets, Synodontis schall and Synodontis nigrita are two by deforestation and hydro-agricultural substructures are catfishes species which, by their abundance in the lower the principal causes of this regression but bacteriological Ouémé valley, contribute significantly to subsistence and/or parasitic diseases can be also considered as fishing (Laléyé et al., 2004; Laléyé, 2006). They breed secondary cause. annually in flooded plains when the river is in spate Among diseases which affect fishes in natural (Laléyé, 2006). In Benin, catfishes are very appreciated for environment, parasitic occur mostly. Parasitic diseases food (Laléyé et al., 2004). They are the second most can affect growth, reproduction and other elements of the exploited fish group by artisanal fishing after Tilapias in dynamics of natural host populations (Hudson and Benin. Dobson, 1989; Begon et al., 1992; Gbankoto et al., 1999, Since, approximately 2 decades, there has been a 2003; Simkova et al., 2001) but moreover they can regression of fish captures in Beninese rivers and sometimes lead to public health problems by means of particularly in the basin of Ouémé river (Laléyé et al., zoonoses (Collier and Burk, 2002). Researches must thus 2007; Montchowui et al., 2008). Overexploitation of be done in order to better control the parasitic diseases in river’s pollution and the damage of aquatic environments