Feeding pattern of the African big barb Labeobarbus intermedius (Rüppel, 1836) (Pisces: Cyprinidae) in Ribb Reservoir, Lake Tana Sub-basin, Ethiopia

Abstract

The purpose of this study was to investigate the feeding patten of Labeobarbus intermedius at Ribb Reservoir (Lake Tana Sub-basin, Ethiopia). A total of 498 specimens were collected using gillnets. Of these, 302 (60.6%) fish had different foods, while 196 (39.4%) were empty. The fish were dissected, their stomachs were removed, and stomach contents were preserved in a 5% formalin solution. Frequency of occurrence, volumetric method, index of preponderance, and geometric importance index were used to study the feeding pattern. Detritus was the primary food, accounting for 61.6% of the guts by volume. Mud, zooplankton, and phytoplankton were the second most important food items comprising 24.4%, 3.9%, and 2.8% by volume respectively. Feeding pattern differed with the size classes of fish. The smallest fish (<16.5 cm Fork length) consumed detritus, mud, and insects comprised 64.2%, 18.7%, and 7.3% by volume, respectively. The adult fish (>17.0 cm FL) majorly consumed detritus followed by mud. The importance of mud increases when the fish grows more except (>31.5 cm FL) size class. The proportions of food items of L. intermedius significantly varied with respect to the dry and wet seasons. Detritus and mud were mostly consumed in the dry season, contributing to 47.8% and 32.4% by volume, respectively. Detritus was the most preferred food item during the wet season, contributing 97.2% of the total guts and 75.6% by volume. Generally, L. intermedius feeding pattern depending on size classes and seasonal variations this may be linked to food availability in the reservoir.

Public Interest Statement

Lake Tana supports nine migratory spawner large cyprinid fishes. Of these, Labeobarbus intermedius migrates up to 60 km distance to reproduce. Ribb River is one of the breeding sites of this fish species. The African big barb Labeobarbus intermedius (family Cyprinidae) is the most commercially important fish species. Knowledge of their food and feeding profile is important to the establishment of aquaculture and for continuing fisheries management. The Ribb Reservoir is the basin with very important habitats of the endemic cyprinids fish fauna of the country. Knowledge of the diets and feeding habits of those fish species of the reservoir has not been systematically studied and explored. The necessity of conducting this study was to fill gaps in such biologically essential scientific information for the management and conservation of this dominant fish species in the reservoir.

Keywords:

• Feeding pattern
• frequency occurrence
• Labeobarbus intermedius
• Lake Tana sub-basin
• volumetric method

Reviewing Editor:

• Pedro González-Redondo, Associate Professor, University of Seville, Seville, Spain

Subjects:

• Agriculture & Environmental Sciences; Zoology; Marine & Aquatic Science

Acknowledgments

The authors highly acknowledged the research directorate and research vice president’s office of Debre Tabor University for their financial support. We are also very thankful to the Guna Tana Integrated Field Research Development Centre Debre Tabor University for helping with the financial provision and vehicle support.

Author’s contribution

Agumassie Tesfahun: Conceptualization, Methodology, Software: Agumassie Tesfahun. Data curation, writing-original draft preparation. Agumassie Tesfahun Visualization and Investigation. Sale Alebachew, Supervision.: Agumassie Tesfahun Software, Validation.: Sale Alebachew and Agumassie Tesfahun: Writing- Reviewing and Editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Availability of data

All the data sets used in this manuscript are accessible to the corresponding author via a reasonable request.

Additional information

Notes on contributors

Agumassie Tesfahun

Agumassie Tesfahun pursued his MSc Degree in Fisheries, Limnology, and Aquatic-eco-toxicology from Hawassa University, Ethiopia. Now, he is the Assistant Professor at the Department of Biology, Debre Tabor University, Ethiopia. In addition, he has been working in community service and research on fisheries biology of the most commercially important fish species from Ribb Reservoir Tana basin, Ethiopia, and aquaculture establishment (earthen pond system) from Fogera District, South Gondar, Ethiopia.

Sale Alebachew

Sale Alebachew was received his MSc Degree in Animal Production from Debre Markos University, Ethiopia. Nowadays, he is a lecturer and researcher at the Department of Animal Sciences, Debre Tabor University, Ethiopia. Moreover, he has been working on fisheries biology of the most commercially important fish species from Ribb Reservoir Tana basin, Ethiopia, and aquaculture establishment (earthen pond system) from Fogera District, South Gondar, Ethiopia.