Food and Feeding Habits of the African Big Barb Labeobarbus Intermedius (Rüppell, 1836) in Ethiopian Water Bodies: a Review
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Academic Journal of Nutrition 6 (2): 28-33, 2017 ISSN 2309-8902 © IDOSI Publications, 2017 DOI: 10.5829/idosi.ajn.2017.28.33 Food and Feeding Habits of the African Big Barb Labeobarbus intermedius (Rüppell, 1836) in Ethiopian Water Bodies: A Review Agumassie Tesfahun and Mathewos Temesgen Ambo University College of Natural and Computational Science, Department of Biology, Ethiopia Abstract: The food and feeding habits of the African big barb Labeobarbus intermedius (Rüpell, 1836) was reviewed in Ethiopian water bodies systems. Data sources were collected from June, 2017 through November, 2017 from different sources of information. The results from difference study indicated that macrophytes, detritus, insects and phytoplankton are the most important food items in the diet of L. intermedius, whereas the contributions of zooplankton, fish scales and ostracods are relatively low in the diet. Macrophytes and detritus are the important food items reported in the diet of fish during the wet months, whereas phytoplankton and zooplankton are the dominant food items in dry season. The fish showed different ontogenetic shift in different Ethiopian water bodies as it increases in size, except in Lake Tana, where no visible ontogenetic dietary shift was reported. Based on the review, L.intermedius is omnivorous and the dietary pattern of L.intermedius in Ethiopian water bodies shifts with prey availability, season, habitat difference and size of the fish, aspects that might warrant further study in view of aquaculture applications as well as climate change. Key words: Ethiopia Feeding Habits L. intermedius Ontogenetic Diet Shift INTRODUCTION Persson and Crowder [9] the major factors that influence diet composition of L. intermedius are fish size, maturity, The African big barb Labeobarbus intermedius is a environmental condition, season (Water level), depth, widely distributed fish species in Northern Kenya and in latitude and habitat types. In aquatic systems, where the most parts of Ethiopian drainage basin [1]. They are found water level in lakes and reservoirs have been known to widely distributed in Ethiopian rift valley basin, Abay fluctuate, the quality and abundance of the food items basin and Baro-Akobo basin part of Ethiopia, where Lake vary significantly through a time [8]. A particular Tana harbored the largest number of big barb species characteristic of L. intermedius is that the increase in size [2, 3]. It is one of the most commercially important fish during their ontogeny is correlated with changes in species in the country [4-6]. The total annual yield of L. food quality and quantity in aquatic systems and intermedius from the total inland water bodies is growth varies according to the food availability in the estimated to be about 365 tonnes per year [4]. However, environment [8, 9]. recently the need for consumption of L. intermedius The study of food and feeding habits of freshwater mainly the catch from rift valley lakes (Lake Hawassa fish species is a subject of continuous research. This is and Lake Koka) declined, because it was found to be because it makes up a basis for the development of a unsafe for human consumption due to high mercury successful management program on fish capture and concentration [7]. In addition, the declining of the fish culture [10]. Moreover, studies on natural feeding of fish species in natural environments due to overfishing and enable to identify the trophic relationships present in parasitic infection has result the less accessibility of the aquatic ecosystems, identifying feeding composition, fish on the local markets [1, 6, 7]. structure and stability of food webs [11, 12]. In addition, The diet composition of the fish is varying the information is vital for management of the fish in the considerably within a wide range of temporal, spatial controlled environment and for formulation of the conditions and environmental factors [8]. According to appropriate dietary given for the fish in the aquaculture Corresponding Author: Agumassie Tesfahun, Ambo University College of Natural and Computational Science, Department of Biology, Ethiopia. E-mail: [email protected]. 28 Acad. J. Nutr., 6 (2): 28-33, 2017 [10]. However, the information on African big barb is very aquatic macrophytes, zooplankton, phytoplankton, limited to use it for aquaculture in Africa in general and in detritus, insects, fish scales and nematodes [1]. However, Ethiopia in particular. the type of food items consumed by L. intermedius Various authors have studied the food and feeding depends on prey availability, season, habitat differences habits of L. intermedius in Ethiopian water bodies and size of the fish [6, 13, 18]. For instance, Admassu and [6, 7, 13-17]. All of them reported that L. intermedius is Dadebo [13] reported that the diet composition of the fish feed on different types of food based in natural in Lake Hawassa encompasses phytoplankton, insects, environment on the environment in which they live. detritus, macrophytes, gastropods and fish, respectively. However, there is no compiled information on the food However, Desta et al. [6] reported that food items in the and feeding habit of L. intermedius in different Ethiopian diet of the fish is dominated by mollusks (Gastropods), water bodies, which give the general insight on food and aquatic insects, macrophytes, detritus, fish fry and fish feeding habit of the fish. Therefore, this review paper is eggs, respectively in the same lake. In other words, the aimed to assess the food and feeding habits of the diet of the same species in Lake Tana is mainly dominated African big barb Labeobarbus intermedius in Ethiopian by benthic invertebrates followed by insect larvae, water bodies. detritus, Zooplankton, Macrophyte and nematode, respectively [14, 15, 19]. According to Dadebo et al. [1], MATERIALS AND METHODS macrophytes, detritus and insects are the most important in the lake. In similar manner, macrophytes, zooplankton Data sources were collected from June 2017 through and aquatic insects accounted for 81.50 % volumetric November 2017. A range of literature sources were used contribution of the prey items consumed in the diet of for this review including journal articles, books and book L. intermedius in Gilgel Gibe Reservoir [20]. However, chapters, workshop proceedings, FAO reports, bulletins, Engdaw [19] reported the dominance of detritus in the diet legal documents and unpublished reports including PhD of L. intermedius, which accounted for 43.12% of the total dissertations. The documents were collected from Addis volume followed by insects (17.89%), phytoplankton Ababa University library, Hawassa University library, (14.57%) and gastropods (12.02%), respectively in Lake Ethiopian Ministry of Livestock and fishery, from the Tana (Figure 1). individual researchers and from Internet. Generally, the dietary studies on big barbs in different water bodies showed that the ingestion of detritus, sand Food and Feeding Habit of African Big Barbs in Ethiopian particles and benthic food items indicated the ability of Water Bodies the species to live in benthic habitats [13, 19]. However, Diet Composition of African Big Barbs in Different several studies have considered that an increased Water Bodies of Ethiopia: Different authors have reported consumption of detritus is a prime response to a decline that L. intermedius feed on variety of food items including of higher valued primary food resources in the water [21]. Fig. 1: The mean volume (%) of different food items in the diet of L. intermedius from some of the Ethiopian freshwater systems (MAC- Macrophytes, DET-Detritus, INS-Insects, PHY-Phytoplankton, OST-Ostracods, FSC-Fishscales, MOL-Molluscs, FG-Fish egg, FPR-Fish prey and ZPK-Zooplankton) [1, 6, 19, 20]. 29 Acad. J. Nutr., 6 (2): 28-33, 2017 This is because detritus is low in its nutritional value in the diet of L. intermedius in Ethiopia. For instance, a [22, 23]. In addition, the importance of insects mainly considerable variation was reported in the type of diet and Dipterans in the diet of different Barbus species was the proportions of food consumed by L. intermedius in reported by various authors [1, 6, 19, 20]. This could be Lake Koka, where detritus (34.0%) and insects (32.5%) are due to the dense stand of aquatic weeds that support the most important food items during the dry period significant biofilm assemblage of benthic prey production volumetrically followed by macrophytes (12.7%), [24]. phytoplankton (5.8%), Ostracods (4.4%), fish scales (4.6%) and zooplankton (6.1%), respectively [1]. Fish Preys in the Diet of African Big Barbs in Ethiopian According to Dadebo et al. [1] the source of detritus Water Bodies: Pisces, mainly, small pisces are using as could be probably floods that introduced fragments of source of food for many of the larger fish species. plant materials in the lake. However, macrophytes are the However, there was no pisces observed in the diet of most important food items accounting for 66.1% of the L.intermedius in different water bodies of Ethiopia, for total volume food items in wet season of the year. The instance, in Lake Koka [1], Lake Tana [19] and Gilgel Gibe increase of ingestion of macrophytes during the wet Reservoir [20] (Figure1). This may be due to the presence season can be explained by the fish moving to shallow of a top predator, such as Clarias gariepinus, which parts of the lake for reproduction. They stay there for a feeds on Cyprinus carpio, Oreochromis niloticus and long period by feeding on macrophytes and vegetations Barbus spp. [1]. Studies indicated that piscivory is not in the wet season [31]. This show that, the contributions common in Cyprinidae due to the absence of oral teeth, of foods of plant origin during the wet month is very high, lack of stomach and shortage of stomach acidity for while the contribution of animal prey is low. In other way, digesting of large preys [6, 25, 26].