Diel feeding periodicity, daily ration and relative food consumption in some fish populations in three reservoirs of Sri Lanka

Abstract

Twelve diel surveys were carried out in three reservoirs of Sri Lanka viz. Minneriya, Udawalawe and Victoria, to investigate diel feeding patterns, daily ration and relative food consumption in fish populations. Stomach content weights of different size classes of various fish species in the three reservoirs in 12 diel surveys were analysed using an iterative method, MAXIMS. Predominantly herbivorous or detritivorous fish species such as Amblypharyngodon melettinus and Oreochromis niloticus exhibited one peak in the diel feeding pattern. Two peak feeding periods were evident in predominantly insectivores and/or zooplanktivores (e.g., Puntius chola and Rasbora daniconius) and interestingly in macrophyte feeders (i.e., Etroplus suratensis, Puntius filamentosus and Tilapia rendalli). It might be possible that all species with two feeding peaks in diel feeding patterns rely on vision for feeding. Food consumption per biomass (Q/B ratio) defined as amount of food consumed per unit weight of an age-structured population of fish was estimated on the basis of the average quantities of food consumed over a long period of time by various size classes in order to minimize the bias of estimates.Résumé -Périodicité nycthémérale d'alimentation, ration journalière et consommation relative chez des poissons de trois lacs artificiels du Sri Lanka. Douze séries d'échantillonnage ont été effectuées dans trois lacs-réservoirs du Sri Lanka : Minneriya, Udawalawe et Victoria, afin d'étudier le modèle journalier d'alimentation, les rations journalières et à la consommation relative des populations de poissons. Les poids des contenus stomacaux de différentes classes de taille ont ainsi été analysés en utilisant une méthode itérative, MAXIMS. Les espèces herbivores ou détritivores telles que Amblypharyngodon melettinus et Oreochromis niloticus montrent un pic dans l'activité de nutrition. Tandis que les espèces détrivores et/ou zooplanctivores en présentent deux (ex., Puntius chola et Rasbora daniconius) de même que des espèces se nourrissant de macrophytes (ex., Etroplus suratensis, Puntius filamentosus et Tilapia rendalli). Il est possible que la vision joue un rôle chez ces espèces présentant deux pics journaliers d'alimentation. La consommation de nourriture par rapport à la biomasse (le rapport Q/B) est défini comme la quantité d'aliment consommé par unité de poids d'une population de poissons structurée en âge, sur la base de quantités moyennes de nourriture consommée sur une longue période de temps et par diverses classes de taille, afin de minimiser les biais dans les estimations.

Application of Ecopath model on trophic interactions and energy flows of impounded Manwan reservoir ecosystem in Lancang River, southwest China

“…Approximately 70% of river systems are regulated by large reservoirs around the world and 20% of the water flows are altered (Hooper et al 2001). The main aims of dam construction are hydroelectricity generation, water supply, flood control, aquaculture, and agricultural irrigation (Weliange et al 2006;Ol ıas et al 2011). Because of their high productivity, reservoir ecosystems are considered an important habitat for numerous aquatic organisms.…”

Postprandial changes in pH and enzyme activity from the stomach and intestines ofTilapia rendalli(Boulenger, 1897), Oreochromis mossambicus(Peters, 1852) andClarias gariepinus(Burchell, 1822)

“…Warmwater aquaculture in South Africa is dominated by three species: Tilapia rendalli, which predominantly feeds on macrophytes (Weliange et al., ; Hlophe and Moyo, ); Oreochromis mossambicus, an algal feeder (El‐Sayed, ; Doupé et al., ); and Clarias gariepinus , with well documented omnivorous/carnivorous feeding habits (Rad et al., ; Kadye and Booth, ). The digestive tracts of T. rendalli and O. mossambicus are largely similar, being characterised by a small sac‐like stomach and long coiled intestines (El‐Sayed, ).…”

A comparative analysis on the effects of river discharge on trophic interactions in two tropical streams

“…References for daily ration (DRR) are; a − De Silva et al (); b − Weliange et al (); and Amarasinghe et al (); c − Weliange and Amarasinghe, unpublished data; d − approximations on the basis of freshwater species from the tropical region of similar size and food habits (Froese & Pauly, ). Abbreviations used: EO‐WZ = Eswathu Oya in Wet‐Zone, YO‐DZ = Yan Oya in Dry‐Zone, LDR = Low discharge regime, HDR = High discharge regime, nf = not found; na = not available.…”

“…Relative abundance is the total number of fish caught in the sampling area from electro‐fishing trials, because the duration of a fishing run (20 min) and the length of sampling stretch (25 m) were consistent in each sampling campaign. Values of daily ration of fish were obtained from the literature (Amarasinghe et al, ; De Silva, Amarasinghe, & Wijegoonawardena, ; Weliange, Amarasinghe, Moreau, & Villanueva, ). As daily rations of some species were not available, they were approximated on the basis of data from other tropical freshwater species of similar size and food habits (Froese & Pauly, ).…”

“…In Sri Lankan reservoirs, various aspects such as food resource partitioning among fish (Weliange & Amarasinghe, ), seasonality and ontogeny of dietary habits of fish (Weliange & Amarasinghe, ), trophic patterns of fish (Weliange, Amarasinghe, Kakkaeo, et al, ), diel feeding periodicity, daily ration and relative food consumption of fish (Weliange, Amarasinghe, Moreau, & Villanueva, ), ecomorphological patterns of fish (Weliange, Amarasinghe, & Schiemer, ), food consumption of fish (Amarasinghe, Weliange, Kakkaeo, Villanueva, & Moreau, ) and food webs (Amarasinghe, Vijverberg, Weliange, & Vos, ; Villanueva, Moreau, Amarasinghe, & Schiemer, ) have been studied. However, studies on stream ecology in Sri Lanka are restricted to hydrobiological surveys (Geisler, ), food and feeding habits of stream fish species (Costa & Fernando, ), and niche segregation within stream fish communities in the wet zone (De Silva, Cumaranatunga, & De Silva, ; Moyle & Senanayake, ; Wikramanayake & Moyle, ).…”