Régime alimentaire de Distichodus rostratus (Characiformes, Distichodontidae) dans un bassin Ouest africain (fleuve Bandama, Côte d\'Ivoire)

Abstract

La morphologie du tube digestif et le régime alimentaire en fonction du stade de maturité et de la saison de Distichodus rostratus (Günther, 1864) ont été étudiés en milieu naturel entre deux barrages hydroélectriques du fleuve Bandama (Kossou et Taabo). L\'analyse a porté sur 220 individus de longueur standard comprise entre 131 et 610 mm. La
description du tube digestif a révélé la présence d\'un estomac peu développé et un intestin long (2,34 < CI < 5,16), rapprochant ainsi l\'espèce de la catégorie des poissons phytophages. D. rostratus consomme essentiellement des macrophytes (Ip = 99,98%) surtout de Cymodecea sp. (Ip = 57,8 %) et de débris végétaux (Ip = 41,4 %). L\'indice de Schoener ( ) montre de façon générale une grande similitude du régime alimentaire des poissons en fonction de la taille et des saisons.
Studies of the digestive tract morphology and the feeding habits of Distichodus rostratus from the hydrosystem located between the hydroelectric dams of Kossou and Taabo (Bandama river) is undertaken for the first time. About 220 individuals of measuring between 131 and 610 mm length were examined. The digestive tract morphology had less developed stomach with a relatively long intestine (2,34 < CI < 5,16) allowing the classification this species as a micro/ macrophytophagous fish. The identification of the items found the stomach contents revealed that the dominants food items were the Cymodocea sp. (Ip = 57,8 %) and macrophyte fragments (Ip = 41,4 %) in general. Young specimens food fed on mainly macrophyte fragments (Ip = 61,5 %) and Cymodocea sp. (Ip = 38,4 %). Or while adults were concern with the Cymodocea sp. (Ip = 66,5 %) and macrophyte fragments (Ip = 31,2 %). The macrophyte fragments (Ip = 52,18%) was mainly eaten during the dry season whereas Cymodocea sp. (Ip = 64,3 %) was mainly eaten during the rainy season.
Schoener overlap index showed the similary in the diet composition in relation with size of the fishes and with the season.
Keywords: Distichodus rostratus- Diet - Bandama River - Côte d\'Ivoire.

Sciences & Nature Vol. 5 (2) 2008: pp. 167-176