FOOD AND FEEDING HABITS OF THE STRAIGHTFIN BARB BARBUS PALUDINOSUS (PETERS, 1852) (PISCES: CYPRINIDAE) IN LAKE ZIWAY, ETHIOPIA

Abstract

The feeding habits of the straightfin barb Barbus paludinosus  was studied in Lake Ziway, Ethiopia, from 504 gut samples collected from April to May (dry months) and July to August (wet months) of the year 2011. Gut contents were analyzed using the frequency of occurrence and volumetric analysis methods. Insects and detritus were the dominant food items and they occurred in 86.3% and 93.5%, and constituted 47.3% and 38.0%, of the total volume of food items, respectively. Macrophytes, phytoplankton, zooplankton and ostracods occurred in 36.1%, 40.3%, 32.7% and 15.5% of fish guts and volumetrically they constituted 4.8%, 4.7%, 3.9% and 1.3% of the food items, respectively. Insects, detritus and zooplankton were important food categories in the dry season while detritus, insects and phytoplankton dominated in the wet season. Insects were the dominant food items in all size classes followed by detritus. The proportion of macrophytes increased with size of fish while the importance of detritus and zooplankton declined with fish size. Based on these results, it was concluded that B. paludinosus in Lake Ziway has an omnivorous habit.  Keywords: B. paludinosus , Diet composition, Fish feeding habit, Lake Ziway, Ontogenetic diet shifts.