Longitudinal Exploitation of the Transversal Gradient of Oreochromis niloticus Gill System by Four Monogeneans Species at Melen Fish Station (Yaounde, Cameroon)

Tombi Jeannette, Akoumba Jo

Abstract

From February 2012 to February 2013, 406 fish were caught in the Melen fish station, then fixed in 10% formalin and taken to the laboratory to be examined. Mounting of monogeneans carried out using binocular magnifying glass; the determination of the various species was further done using the optical microscope. The colonization of the four pairs of arches by C. thurstonae occurred in the anterio-posterior direction. The other three species showed non-specific model of occupation of the transversal gradient. These different patterns have undergone permanent modifications. The results obtained in this study could be explained based on the heterogeneity of the gill system, the ventilation of current flow, the model of gills colonization by the oncomiracidiums of the Monopisthocotylea. The low diversity values obtained within seasons indicate that this period is harmful for the parasites studied. The species C. halli has exploited the resource space better in all. The populating of arches II and III were the best organized.