Distribution spatiale de deux monogènes du genre Protoancylodiscoides Paperna, 1969 (Dactylogyridea, Ancyrocephalidae) parasites branchiaux de Chrysichthys auratus (Geoffroy Saint-Hilaire, 1808) (Siluriformes, Claroteidae) dans le Lac Ossa (Littoral -Came

Abstract

Objectives: The aim of this study was to investigate the distribution of Protoancylodiscoides combesi and P. auratum monogeneans gill parasites of Chrysichthys auratus (Siluriformes, Claroteidae), commonly called machoiron is a widely exploited fish throughout the Sanaga Basin, and determine the mechanisms that influence their fixation. Methodology and Results: fish were caught using gillnets from April to June 2016, stored in jars containing formalin and dissected in the laboratory to isolate, mount and identify monogeneans species. Both species of monogeneans were found to be frequent and less frequent, respectively (prevalence = 71.4% and 28.60), their abundances are low and very low (mean intensity = 34, 14 and 16, 37 respectively). The two monogeneans show an aggregative distribution. They exploited the left and right sides, male and female individuals in the same way. Their fixation gradient on the gill arches is in the antero-posterior direction, from arch I to the arch IV. The two worms mainly attend the median sector, although their loads are similar in the three gill arch sectors. Conclusion and application of results: this work suggests once again that Protoancylodiscoides species have an antero-posterior fixation model on gill arches and, in a low intensity situation; their fixation on gill arches sectors is random. In general, parasite loads are very low or low suggesting that C. auratus breeding should be done in a poorly modified environment