Browsing by Author "Athawuda, A.M.G.A.D"

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    Preliminary Investigation on Current Status of Freshwater Fishery Sector and Sensory Qualities of Selected Food Fish in Three Selected Reservoirs of Badulla District in Uva Province of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2019-02) Weerasignghe, K.B.S; Athawuda, A.M.G.A.D; Gamage, S.; Abeygunawardana, A.P; Thushari, G.G.N; Liyanage, N.P.P.; Jayamanne, S.C.
    Sri Lanka is rich with large number of reservoirs which are highly useful for irrigational activities and inland fisheries. In Uva province, there is a high potential in expansion of freshwater fish production in reservoirs. Current status of inland fishery sector needs to be evaluated, prior to implement appropriate fishery management measures Also, assessment of organoleptic properties of food fish are useful to identify consumer acceptance for freshwater fish varieties. This study focused on 02 objectives: investigation of present situation of inland fishery sector and identification of organoleptic aspects of major fishery resources in 3 selected reservoirs of Badulla District. Sorabora, Ulhitiya, Rathkinda reservoirs were selected for the study considering production levels based on secondary data. A survey was conducted using pretested structured questionnaire to collect the data on fish production, harvesting methods, fishing gears, and food fish varieties focusing on 122 fishermen in 3 reservoirs. Food fish sources with highest demand and production were subjected to sensory assessment. Gill net (3.5” mesh) was the prominent fishing gear, while “manna” (kind of harpoon) and “karaka” (cover pot) was used into lesser extent for harvesting fishes. All fishermen used nonmechanized fiberglass canoes (length 15.5ft-18ft) as most common fishing craft during fishing operations. Fish yields in reservoirs were affected by climatic variation. Nile Tilapia: Oreochromis niloticus accounts for >80% of total fish production with high demand (80%) in 3 reservoirs. Thus, sensory assessment was conducted for Nile Tilapia samples only. Mozambique Tilapia: Oreochromis mossambicus, Malkorali: Etroplus suratensis, Catla: Catla catla, Rohu: Labeo rohita, Mrigal: Cirrhinus mrigala and freshwater prawn: Macrobachium rosenbergii were minor contributors to the total harvest. Based on sensory evaluation, Nile Tilapia samples from Sorabora reservoir recorded highest consumer acceptance as complying with survey results. At present, more than 60% of fishing community in 3 reservoirs has not engaged with processing of value added products. Current study revealed the organoleptic aspects of Nile Tilapia flesh and data on freshwater fishery is useful as baseline information in fishery management programmes of Uva province.
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    Screening the Effects of Microplastics on Selected Invertebrates along Southern Coastal Belt in Sri Lanka: A Preliminary Approach to Coastal Pollution Control
    (Uva Wellassa University of Sri Lanka, 2019-02) Wijethunga, H.N.S.; Athawuda, A.M.G.A.D; Dias, P.C.B; Abeygunawardana, A.P.; Senevirathna, J.D.M.; Thushari, G.G.N.; Liyanage, N.P.P.; Jayamanne, S.C.
    Primary and secondary microplastics entering into coastal and marine environment are potentially harmful to the health of aquatic organisms. Current study intended to assess plastic pollution effects on sessile invertebrates along the Southern coastal belt of Sri Lanka during July-December 2018. Twelve sampling sites (Hambantota, Godawaya, Rekawa, Tangalle, Dickwella, Polhena, Mirissa, Weligama, Unawatuna, Gallefort, Dodanduwa and Hikkaduwa) with different anthropogenic activities were selected as representing 03 districts (Hambantota, Matara, Galle) of Southern province. Biodiversity survey was conducted to identify prevalence of natural inhabitants in selected regional coasts and 03 dominant coastal mollusks: Saccostrea cucullata (Rock Oyster), Littorina sp. (Periwinkle) and Patella sp. (Limpets) were selected for screening microplastics accumulation level. Alkaline digestion protocol was identified as the most suitable procedure for microplastics extraction considering plastics recovery rate and digestion efficiency of flesh. Randomly collected, pooled biological samples (N=20-2) were subjected to KOH digestion and resultant microplastics were verified using hot needle test. As results revealed, all 03 invertebrates were contaminated with microplastics accumulation at average rates of 7.2-2.8counts/g in all sampling sites. Majority of contaminated microplastics were filamentous types (>90%) followed by rod shapes (1%). Microplastic accumulation rate varied significantly according to the type of species (p<0.05) due to differences of their feeding mechanism. Further, filter feeding organisms (Rock Oysters) were highly susceptible in accumulation of microplastics (7.24.1counts/g) in their bodies, while plastic accumulation rate was highest in oysters from Hambantota. Microplastic accumulation rate of mollusks was not significantly different according to the sampling site due to closer proximity (p>0.05). Tourism, unsustainable coastal fishery and harbor operational activities were identified as key factors affecting on higher plastic pollution level on Southern coast. Current study reflects negative aspect of plastic pollution on intertidal organisms.