Browsing by Author "Weliange, W.S."

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Abuse Potentials of the University Students
(University of Kelaniya, 2005) Weliange, W.S.; Kularatne, M.G.
Lack of facilities for various extra-curricular activities for all the students in the university community is one of the major reasons for student unrest in Sri Lanka. According to the investigation carried out in 1988, 20% and 80% students involved in competitive and non-competitive extra-curricular activities respectively, before they enter the university. 75% and 23% students expect jobs in the government sector and private sector respectively, only 5% prefers self-employment. Sports and aesthetic activities are most important for the well-being of the body and the mind. Involvement in different kinds of extra-curricular activities and continuation of activities that they have been doing since their childhood would probably help students 1) learn more about various challenges; 2) meet different people from prospective job markets and interests; 3) for capacity building; 4) in imagining about future prospective jobs; 5) develop the self-confident in facing the private sector and involve in self-employment. Therefore, the university education system should be reformed in a productive way to produce better graduates who can face any challenging situation in the country. Therefore, university as a learning organization should improve various activities to develop active participation of students in developing their skills in addition to academic activities. Thus, ongoing research should be carried out encompassing extra- curricular activities of the students in order to enhance active participation in the university environment.
Accounting for Diel Feeding Periodicity in Quantifying Food Resource Partitioning in Fish Assemblages in Three Reservoirs of Sri Lanka
(Asian Fisheries Society, 2003) Weliange, W.S.; Amarasinghe, U.S.
Most investigations on food resource partitioning in fish along the temporal dimension are based on the diet composition of constituent species in fish assemblages, pooled over a longer time lapse, but variation within 24-hour cycle is not considered. In the present study, an attempt was made to account for diel feeding periodicity in fish species in quantifying dietary overlaps among constituent species in fish assemblages in three reservoirs of Sri Lanka. The dietary overlap of fish species estimated as a mean for short time intervals in three reservoirs is significantly lower than that is based on the sum of all time intervals, especially for pairs with moderate and high overlaps. Furthermore, the dietary overlaps estimated for short time intervals, which indicate moderate and high dietary overlaps between pairs, exhibit negligible overlaps of peak feeding period indicating the necessity to account for diel feeding periodicity in quantification of food resource partitioning.
Butchering Practices of Veddah; the Indigenous People of Sri Lanka
(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Weliange, W.S.; Dandeniya, A.S.; Dewage, D.; Algiriya, A.K.P.P.
The Veddah are an ethnic group of people living in Sri Lanka whose population is limited to around 5000 people according to cense carried out in 2011. They live in several villagers adjacent to their original homeland forests. Seligman brothers have reported in 1911 that Veddah have used the arrow head for butchering. In this study state of art of butchering of the modern day Veddah was studied. The study was done in Rathugala in Batticaloa District where a Veddah community lives in Rathugala village adjacent to their original homeland; Nilgala forest. A monthly field visits were done to Rathugala village during 2010 and 2011. Totally 10 field visits were made and 45 days and nights were spent in the forest with Veddah ascertaining the practices related to the hunting. The interviews were done while in the forest, figures and illustrations of the muscular anatomy and skeletal anatomy of common animals were shown initially to familiarise and to acclimatise Veddah for a long run of study. Observations were made on how a monkey was butchered to produces 13 major meat portions and 8 byproducts. Each major meat portions and byproducts have terminologies in their language. Obtaining primal cuts are exactly similar to the modern method of butchering. The Veddah are still skillful butchers. One specific tool with a sharpen edge and a point is sufficient for successful butchering. During prehistoric period people have used similar methods in butchering. The findings are useful in re-creating prehistoric life style of people. Purpose driven ethnographic studies help gather information, deepen the understanding about the indigenous groups like Veddah, increase the weight of the cultural identity and help understand the lifestyle of prehistoric man.
Changes in feeding habits of Puntius filamentosus (Valenciennes) with body size, in Minneriya reservoir, Sri Lanka, during high water level
(Sri Lanka Association for Fisheries and Aquatic Resources, 2000) Weliange, W.S.; Amarasinghe, U.S.
A comparative analysis on the effects of river discharge on trophic interactions in two tropical streams.
(International Review of Hydrobiology, 2017) Weliange, W.S.; Amarasinghe, U.S.; Vijverberg, J.; Leichtfried, M.; Füreder, L .
Discharge-mediated seasonal patterns of food web interactions were investigated in two streams in Sri Lanka; Eswathu Oya (a perennial wet-zone stream) and Yan Oya (a seasonal dry-zone stream). Based on volumetric proportions of diet composition, relative abundance of fish species and their daily food rations, the mean cumulative consumption of each prey taxon was estimated for each fish population. Food web diagrams were prepared using trophic index of fish, trophic class of prey and feeding interactions between fish and prey. Both streams showed seasonal patterns of discharge due to rainfall, but no significant effect was evident in the trophic index of most fish species. In both streams, cumulative consumption of prey taxa was highest during low discharge regime due to increased abundance of both prey taxa and consumers. In Eswathu Oya, diversity of prey taxa was higher during the low discharge regime, but in Yan Oya, high diversity occurred during the high discharge regime. Herbivorous and/or detritivorous fish species were rare in Eswathu Oya but dominant in Yan Oya. Complex food web structure in Yan Oya due to high fish species richness and high diversity of prey categories made it less sensitive to discharge extremes in contrast to relatively simple food web structure in Eswathu Oya. This study, therefore, highlights the importance of maintaining the quality of riparian environments for conservation of biodiversity.
Comparison of trophic structure of fish assemblages in two tropical steams in Sri Lanka: a seasonal dry zone stream and a perennial wet zone stream
(International Review of Hydrobiology, 2019) Weliange, W.S.; Amarasinghe, U.S.; Vijverberg, J.; Leichtfried, M.; Füreder, L.
Most tropical rivers especially in the Asian region, are severely impacted by various human perturbations, and the diverse habitats in streams support rich invertebrate and vertebrate communities. It is hypothesized that the fish assemblages and their dietary structure in two tropical streams differ because they flow through different terrains and are exposed to different climatic conditions. In the wet zone stream, which is geomorphological more complex, fish faunal diversity showed significant longitudinal variations, and sustains endemic fish species. In the diets of fish, taxonomic composition was different along the longitudinal gradients, but dietary taxa richness in the two streams was virtually similar having 32 dietary taxa in wet zone stream and 36 taxa in dry zone stream. In the wet zone stream, we observed a lower proportion of specialist feeding species than those in the dry zone stream. Trophic indices of individual species in fish assemblages ranging from herbivory to carnivory also indicate structuring of fish communities along the longitudinal gradients of the two streams based on dietary structure. The main differences between the fish assemblages in the wet zone compared to the dry zone were the higher number of endemic species and the lower percentage of specialist feeders with higher trophic indices. The outcome of this study hopefully contributes to plan future biodiversity conservation management schemes under various river basin development strategies.
Diel feeding pattern and food consumption of selected fish populations in Asian reservoirs, Journal Aquatic Ecosystem and Development: Comparative Asian Perspectives
(Backhuys Publishers, 2008) Amarasinghe, U.S.; Weliange, W.S.; Kakkaeo, M.; Villanueva, M.C.; Moreau, J.
Diel feeding periodicity, daily ration and relative food consumption in some fish populations in three reservoirs of Sri Lanka
(Aquatic Living Resources, 2006) Weliange, W.S.; Amarasinghe, U.S.; Moreau, J.; Villanueva, M.C.
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.
Discovery of an iron smelting site in Waakare, Batticaloa district in Sri Lanka
(12th Annual Research Symposium, University of Kelaniya, 2011) Algiriya, P.; Dandeniya, A.S.; Alahakoon, A.M.D.; Weliange, W.S.
Steel was being produced in Sri Lanka since 300 BC by furnaces blown by the monsoon winds, and the protohistoric Early Iron Age in Sri Lanka lasted from 1000 to 600 BC. In March 2010, a group of researchers from the Postgraduate Institute of Archaeology of the University of Kelaniya, discovered a mound of iron slag in the flood prone area of the Kunjalkalkulam Reservoir in Batticaloa District in Sri Lanka. The GPS location of the particular site is obtained as (08°13'1.3'' N: 081° 24'20.4'' E) which is situated 39ft amsl. This particular site is about 10x10m2 in size and located between the Second Singha Regiment in Maankerny in Kunjalkalkulam and the Kunjalkalkulam Reservoir. Other than iron slag, pieces of a furnace were also discovered. The sizes of iron slag were less than 50cm. Pieces of iron slag were brought to the laboratory and tested for magnetism, which was proved. Also found were iron ore along the jeep track which extends from Madurankuliya to Omaliyamadu village. It was also discovered that for the construction of this particular jeep track, materials had been brought from another place close to this village. According to the visual inspections those iron ore were similar to Magnetite (FeO3). This preliminary investigation shows evidence of an iron smelting industry in this particular area. Further investigations would be needed.
Ecomorphology and feeding habits of fish assemblages in three reservoirs of Sri Lanka
(Sri Lanka Association for Fisheries and Aquatic Resources, 2002) Weliange, W.S.; Amarasinghe, U.S.
Ethno-eththo of Sri Lanka, the Vanneale: Ornithology of the Veddah
(University of Kelaniya, 2011) Weliange, W.S.; Dandeniya, A.S.; Algiriya, P.; Alahakoon, A.M.D.; Dewage, D.
Interviews were conducted with Veddah; the aboriginal people in Sri Lanka, during fieldwork in 2010 and 2011. Joint observations of birds in the wild, examination of illustrations and bird calls helped generate 25 Veddah names of bird species in two Veddah homelands; Dambana and Nilgala in the Ampaara district, in Sri Lanka. Vernacular names, practical uses, food and other behavioural patterns, and folk beliefs concerning the birds were recorded. Local names dese neei erew on the behaviour; particularly their feeding pattern, place of living and colour patterns in the body. While the birds occupy almost a negligible position in the diet and subsistence activities of the Veddah, birds have important meanings in folk beliefs, spiritual and cultural life. Bird names are also found in several poems and songs. The birds are believed to convey information on unpredictable distribution of animals and their behaviour in the forest. Veddah knowledge of birds is not limited to economically important species, as is often assumed. Veddah are familiar with most discernible species. Ethno-ornithology serves as a platform for studying specific relationships between indigenous culture and endemic birds to help increase local awareness of traditional knowledge. Increasing concerns on sustainable-use and community-based strategies also emphasize the importance of ethno-ornithology, and its implications for biodiversity conservation.
Food resource partitioning and diel feeding pattern of two herbivorous fish species in Udawalawe reservoir, Sri Lanka
(Sri Lanka Association for Fisheries and Aquatic Resources, 1999) Weliange, W.S.; Amarasinghe, U.S.
Food web: an interactive software for quantifying Wine miller’s trophic networks in fish communities
(Sri Lanka Association for Fisheries and Aquatic Resources, 2004) Weliange, W.S.; Wickramasinghe, R.I.P.; Kumara, K.H.; de Silva, C.; Amarasinghe, U.S.; Vijverberg, J.
Observed properties of aquatic food webs have important management implications as well as important theoretical implications in the subjects of fisheries science and aquatic ecology. The food web approach is useful to understand pathways of energy and material transfer and the structure of the hierarchy of species trophic interactions in aquatic ecosystems. Winemiller (1990) presented a graphical method to investigate spatial and temporal variation in trophic networks in tropical fish communities. A computer programme was developed to produce graphic illustrations of trophic networks in the fish communities and associated food web parameters namely number of nodes, compartmentalization, connectance, average number of prey per node, average number of predators per node and ratio of consumer nodes to total nodes. The input data for this software are relative importance of food items of constituent species in the fish community and the tropic levels of prey items. The graphic illustrations and associated food web parameters mentioned above can be used for spatial and temporal comparison of trophic relationships in fish communities.
Food‐web patterns and diversity in tropical fish communities
(Journal of Lakes & Reservoirs, 2014) Amarasinghe, U.S.; Vijverberg, J.; Weliange, W.S.; Vos, M.
IRESA – Initiative of river ecology in Sri Lanka: from Science to application
(Sri Lanka Association for Fisheries and Aquatic Resources, 2005) Fureder, L.; Leichtfried, M.; Amarasinghe, U.S.; Weliange, W.S.
Longitudinal variation of benthic macroinvertebrate communities in two contrasting tropical streams in Sri Lanka.
(International Review of Hydrobiology, 2017) Weliange, W.S.; Leichtfried, M.; Amarasinghe, U.S.; Füreder, L.
The benthic macroinvertebrate fauna and main abiotic parameters were studied to understandthe patterns of diversity and structure along the temporal and longitudinal gradients in twotropical lotic ecosystems in the wet and dry zones of Sri Lanka. Invertebrate abundance (annualmeans) was in the same magnitude in the two streams (2,520 ind. m−2in the wet zone streamand 2,940 ind. m−2in the dry zone stream). Both streams had similar annual mean diversity levelsmeasured as Shannon diversity (Eswathu Oya (wet zone) = 2.11; Yan Oya (dry zone) = 2.07),with a mean annual evenness (Pielou evenness) of 0.56 ± 0.14 for Eswathu Oya and 0.60 ± 0.09for Yan Oya. Along the longitudinal gradient, abundance and taxa richness increased toward thelower reaches in the wet zone stream but decreased in the dry zone stream. Composition offunctional feeding groups was greatly influenced by abiotic factors in the temporal gradient thanin the longitudinal gradient. This was possibly due to the seasonal patterns of flow regimes, andallochthonous nutrient inputs into the streams. Hence, resource management and conservationas well as attempts of ecological assessment in tropical streams should be based not only on thein-stream characteristics but also on the catchment properties.
Population Dynamics of Vermiculated Rabbit Fish Siganus vermiculatus (Valenciennes)in the Negombo Estuary,Sri Lanka.
(Sri Lanka Association for Fisheries and Aquatic Resources, 1996) Wijeyaratne, M.J.S.; Weliange, W.S.; Amarasinghe, U.S.
Present status of coastal Veddahs in Wakare, Sri Lanka
(University of Kelaniya, 2011) Weliange, W.S.; Dandeniya, A.S.; Alahakoon, A.M.D.; Algiriya, P.
The Coast Veddas or Vedar or Veda Vellalar are Tamilized indigenous Veddah people, who have adopted a dialect of the Tamil language and some of the Tamil social customs, while some original language and customs are still followed. In March 2010 Kunjalkalkulam, Thunaadi and Madurankulam areas were visited and their livelihood was observed. After the Tsunami struck in 2004, coastal Veddahs who lived in Batticaloa, Kalkuda, Maankerny, Panichchankerni, Kadiraweli, Werugal were resettled in inland areas such as Kirimichchiya, Kunjalkalkulam, Thunaadi, Kattamuvikulam, Aandankulam and Madurankulam. These Tamil speaking, resettled Veddahs belong to three caste systems such as Singhawanniyan Kudi, Ilasingha Wanniya and Warda Wellalam. They worship about 10 different gods and spirits. Presently, they live in concrete houses in small land plots and utilize the resources of the reservoirs and the surrounding dry forests. Fishing is done by men in the reservoir from August till February by gill nets and the rest of the year, women are involved in angling in the reservoir. From January to May fishing is done in Upaar Lagoon in Panichchankerny mainly for crabs and prawns and their marketplace is in Walachchane. Fishing was also done with plant ichthyotoxics. Karonkodiwel, Kukuru, Kalliya, Kokatiya and Kayan plants were used for fish stupefying. They have their own names for freshwater fishes which were analogous of Tamil language. Spatial transformation has caused them to start new survival techniques. Traditional knowledge and practices related to the coastal environment could be soon obsolete and disappear. Hence, further detailed investigations would be essential and timely in order to document their traditional knowledge and practices.
Relationship between Body Shape and Food Habits of Fish from Three Reservoirs of Sri Lanka
(Asian Fisheries Society, 2007) Weliange, W.S.; Amarasinghe, U.S.
In the present paper, an attempt is made to investigate whether the body shape indices can be used to predict food habits of fish species in three reservoir fish communities of Sri Lanka. The present analysis is based on the studies on food and feeding habits of fish species and their body shape indices in three Sri Lankan reservoirs, namely Minneriya, Udawalawe and Victoria. Body proportions of individual fish species were determined as P1 (= Maximum height of the body/ Maximum width of the body) and P2 (= Total length/ Maximum height of the body), which were found to be negative curvilinearly related. Trophic indices (Ti) of individual fish species were determined on the basis of trophic level of each food item and the fractions of all food items consumed by fish species, which ranged from 1 for exclusively herbivorous species to 3 for carnivorous species. A negative logarithmic relationship between P1 and Ti indicates that laterally compressed fish species with deep bodies feed on lower trophic levels in the food web. On the other hand, dorso-ventrally flattened species with low P1 have higher trophic indices than those with high P1. The positive logarithmic relationship between P2 and Ti also indicates that short, deep-bodied fish species representing low P2 values feed on lower trophic levels whereas slender, long-bodied species with high P2 values feed on higher trophic levels. The body shapes, measured as simple body proportions of the definitions of P1 and P2, can therefore be used to predict feeding habits of fish.
Seasonality in Dietary Shifts in Size-Structured Freshwater Fish Assemblages in Three Reservoirs of Sri Lanka
(Environmental Biology of Fishes, 2003) Weliange, W.S.; Amarasinghe, U.S.
We studied seasonal changes in feeding habits of size-structured fish assemblages in three freshwater reservoirs in Sri Lanka. We obtained fish samples for diet analysis from three reservoirs during the months of rising water level (RIWL) and receding water level (REWL). During RIWL, peripheral areas with terrestrial/semi-terrestrial macrophytes get inundated, which resulted in increased food availability for macrophyte feeding fish. During REWL, detrital food sources increase due to decaying terrestrial plant material, which has inundated. Based on the dietary habits of individual species in the three reservoirs during RIWL and REWL, it is evident that detritivorous and phytoplanktivorous fish species, which belong to low trophic levels do not show significant variation in dietary habits between the two seasons (e.g. Oreochromis mossambicus, Oreochromis niloticus and Amblypharyngodon melettinus). Stenophagous species such as benthic invertebrate predators (Puntius chola and Puntius dorsalis), macrophytophagous species (Etroplus suratensis and Tilapia rendalli) and zooplanktivorous Hemirhamphus limbatus do not exhibit significant variation in dietary habits between seasons. Also their feeding habits do not vary with body size. Euryphagous species such as Puntius filamentosus on the other hand, exhibit variations in dietary habits between seasons as well as with body size. Stenophagous species, which feed on detritus and phytoplankton and euryphagous species, which exhibit temporal dietary plasticity, are therefore abundant in fish assemblages of these reservoirs.