Browsing by Author "Guruge, K.P.G.K.P."

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    Abundance and Diversity of Ichthyoplankton in the West Coast of Sri Lanka, from Kelani River Estuary to Maha Oya Estuary
    (Uva Wellassa University of Sri Lanka, 2019-02) Silva, A.P.R.; Rathnasuriya, M.I.G.; Guruge, K.P.G.K.P.; Jayasinghe, R.P.P.K.
    Fundamental understanding of fish resources has become an urgent need in Sri Lanka for the sustainable management of fish stocks. As studies on ichthyoplankton (fish eggs and larvae) in Sri Lankan coastal waters are scarce, a preliminary study was carried out with the aim to find the abundance, distribution and composition of ichthyoplankton in the west coast. Samples were collected in five stations bordering Kelani river estuary, Negombo lagoon and Maha Oya estuary in the west coast where human interactions are relatively high. Horizontal surface sample and a vertical sample were collected from each station using Working Party 2 (WP2) plankton net (180 µm mesh size) for three months in 2018: March, September and October representing 1st inter-monsoon, Southwest monsoon and 2nd inter-monsoon respectively. Fish eggs and larvae were separated from plankton and identified to the lowest possible taxonomic level under the stereo microscope using the standard keys. A total of 4095 fish eggs and 465 fish larvae belonging to 23 families were collected from the study area. An average abundance of 8772 eggs and 996 larvae per 1000 m3 were recorded. Most abundant taxonomic level in each month were, Family Siganidae in March, Family Blennidae in September and Order Clupeiformes in October. The highest abundance of fish eggs was found in Station 3 (22158 per 1000 m3 in vertical sample and 13934 per 1000 m3 in horizontal surface sample) and larvae was found in Station 4 (1196 per 1000 m3 in vertical sample and 2537 per 1000 m3 in horizontal surface sample) which is located adjacent to Maha Oya estuary, showing estuaries’ ecological services as nursery grounds for early stages of fish. This study infers that there is a high pelagic and demersal fish diversity and abundance in the west coast of Sri Lanka. Since this is a preliminary study, comprehensive studies on the spatial and temporal variation of abundance and diversity of ichthyoplankton in Sri Lankan waters are recommended.
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    Development of an Edible Coating Using Crude Sodium Alginate from Sargassum ilicifolium Incorporated with Ascorbic Acid for Minimally Processed Artocarpus Heterophyllus Lam
    (Uva Wellassa University of Sri Lanka, 2019) Chandanee, M.R.; Bogahawaththa, B.R.S.; Ranasingha, M.K.; Guruge, K.P.G.K.P.; Abeyrathne, E.D.N.S.
    Jackfruit (Artocarpus heterophyllus) lam is a highly available and demanded tropical food because its’ sensory attributes are similar to meat. Many processes involved in minimally processing of Jackfruit lam. However, the challenge is the browning. Therefore, processors are in need of healthy, cost effective ways to minimize the browning. Hence, this study was conducted to minimize the browning in Jackfruit lam using an edible coating from seaweed hydrocolloid. Seaweed hydrocolloid was extracted from highly abundant, locally available, underutilized brown algae species, Sargassum ilicifolium by using sequential biorefinery extraction process. The extracted yield of crude alginate was 31.4% of alga (w/w). Sliced lam was coated using dipping method. Extracted crude alginate, commercial food grade alginate, gelatin with and without ascorbic acid were coated at the room temperature. Citric acid, ascorbic acid treated and uncoated samples were served as the control. Coated samples were stored separately at room temperature (27C) and refrigeration conditions (4C) for evaluate the physiochemical (Browning index, Radical Scavenging Activity, Thiobarbituric Acid Reactive Substances, Color and Texture) microbiological and sensory properties. Sensory analysis was conducted by serving boiled lam without adding any ingredients for 30 untrained panelists with 9-point hedonic scale. The UV spectrophotometric readings were indicated that the coating significantly reduce the browning compared to uncoated lam (p<0.05). Besides that, crude alginate with ascorbic acid were recorded as highest radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl assay, overall sensory quality, lowest microbial count in total plate count and extend the shelf life for 3 days at room temperature and 2 days under refrigerated conditions. Hence, ascorbic acid enhances the effectiveness of the coating. Then, Jackfruit lam coated with crude sodium alginate with ascorbic acid reduced the browning.
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    Effect of Diets Incorporated with Dried and Autolyzed Shrimp Waste on Growth Performance of Goldfish (Carassius auratus)
    (Uva Wellassa University of Sri Lanka, 2016) Rathnayake, R.M.C.P.; Liyanage, N.P.P.; Athula, J.A.; Guruge, K.P.G.K.P.; Senaarachchi, W.A.R.K.
    The shrimp processing industry turns out tons of head, tail and shell waste every year and this is a rich source of protein that could be used to prepare aquaculture feeds. The efficiency of different methods for extracting protein from shrimp waste were observed. This study has been designed to assess the possibility of partial replacement of fish meal with shrimp waste in diets formulated for goldfish. Known amount of shrimp waste samples were subjected to autolysis and subsequently subjected to oven drying and make fine powder. Crude protein, crude lipid, ash and moisture were estimated for both autolysed and powdered dried shrimp waste (purchased from Agri-Star Compost private limited). Two different diets were prepared by incorporating autolysed shrimp waste powder and dried shrimp waste powder as supplementary source of protein. Commercial feed that contains 42% protein was used as the control diet. Uniform sized glass tanks were stocked with twenty individuals with an initial mean weight of 0.13 f 0.00 g per tank. Fishes were hand-fed daily three times per day for 30 days with three diets. Wet weight of the fish were measured weekly. Feed Conversion Ratio (FCR), Specific Growth Rate (SGR), Protein Efficiency Ratio (PER) and Condition Factor (K) were calculated for each diet. The highest protein level (65.55%± 0.60) and lowest ash level was observed (11.35% ± 0.03) in autolysed shrimp waste. Significantly higher SGR, PER and survival rate (91.25% + 3.15) were observed in individuals fed with diet incorporated with autolysed shrimp waste while significantly low FCR was observed in the same (P<0.05). Condition Factor was not significantly changed among the test diets (P>0.05). The findings of this study indicate that autolysis is the best method to extract protein form shrimp waste. During the process of autolysing meat part was detached from the shell and extracted to the aqueous medium. This process will facilitate to collect comparatively pure source of protein with compared to the dried shrimp meal. Therefore, autolyzed shrimp waste powder that contains significantly higher protein percentage can effectively enhance the growth parameters while use as protein supplement in the diet of goldfish. Keywords: FCR, SGR, Fish feed, Fish nutrition, Ornamental fish.
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    Effect of Nitrogen Sources on Growth Performance of Marine Microalgae Nannochloropsis sp.
    (Uva Wellassa University of Sri Lanka, 2019-02) Kondasinghe, K.P.R.S.; Jayasiri, H.B.; Mallawaarachchi, J.; Guruge, K.P.G.K.P.; Thilakarathna, E.P.D.N.
    Nannochloropsis sp. is a marine micro alga immensely valuable for aquaculture and food industry as they are rich sources of essential fatty acids, pigments, amino acids and vitamins. Present study was conducted to identify the effect of nitrogen sources on their growth and nutrient content in the cells. For the study, F/2 culture media was used as media in control culture which contains NaNO3 as the source of nitrogen. The F/2 culture media was prepared by using KNO3 (9 g l-1), CH4N2O (Urea) (27 g l-1) and NH4Cl (47.3 g l-1) as the sources of nitrogen in the culture media. Algae cultures were prepared in triplicates for all treatments and cultivated under indoor condition, maintaining the 27 oC of constant temperature and 25ppt of salinity with a continuous aeration. The results of ten days culture revealed that there was no significant difference for cell density with the time for all treatments (Two-way ANOVA: p>0.05). However, significant difference was found for chlorophyll-a nitrate and nitrite content which are produced by Nannochloropsis sp. (p<0.05). The significantly highest chlorophyll-a, nitrate and nitrite content were reported in the F/2 culture media with urea than that of other culture media treated with potassium nitrate and ammonium chloride. The Urea can be recommended as a more effective source of nitrogen for F/2 culture media to obtain high chlorophyll-a, nitrate and nitrite content for Nannochloropsis sp. culture. This study provides baseline information about the appropriate nitrogen sources which can elevate the higher productivity of Nannochloropsis sp.
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    Impact of Thermocline Variability on Yellowfin Tuna Catch Rates of Sri Lankan Long-Liners
    (Uva Wellassa University of Sri Lanka, 2018) Sinhakula, S.M.B.; Rajapaksha, J.; Thushari, G.G.N.; Guruge, K.P.G.K.P.
    Tuna fishery is an important source of income to Sri Lanka, having a greater potential for development. Yellowfin tuna: Thunnus albacares is a major species, exported to Japan and EU countries. Vertical migration of fish with changes in temperature is considered as an important parameter to ensure fishing efficiency, thus harvest of yellowfin tuna is associated with the thermocline layer and its seasonal changes. The objective of the present study was to investigate the influence of vertical structure of temperature on catch rates of longline fishery. Temperaturedepth recording sensors were used to understand the depth penetration level of hooks and associated temperatures, during the period from July 2012 to February 2014. Based on sensor data and catch records, fishing depth was determined by means of sag caused by slack of the main line in between two buoys. Thermocline variability was analyzed using oceanographic datasets obtained from Copernicus Marine Environmental Monitoring Service. Temperature vertical profiles were extracted from those datasets at each fishing positions and a 5-parameter sigmoid model was used to determine the thermocline properties. Most commonly, 6-9 hooks per basket have been used in longlines, while total number of hooks was 8001000. Buoy-lines and branch-lines were ranged between 20-30 m and 45-50 m, respectively. Based on the hooks per basket, the depth penetration level closer to buoy-line is -70 m and -100 In at the center of a basket. Sagging variability of hooks in a basket have shown a linear relationship (r2=0.9992) with the distance between branch lines starting from buoy-line to the middle of a basket. Catch per unit effort was ranged between 15-70 kg / 1000 hooks. Thermocline depths altered between 100125 m with variations of corresponding temperatures at 21-23 °C. The developed model is capable of predicting hooking depths, thus the longline configuration can be adjusted with thermocline information for successful fishing operations.
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    Study of Manganese Accumulation and Temporal Variation of Water Quality in Badulu Oya
    (Uva Wellassa University of Sri Lanka, 2019-02) Wijesinghe, N.H.; Thilakarathne, E.P.D.N.; Guruge, K.P.G.K.P.
    Demand of safe drinking water is gradually increasing with rising of population in Sri Lanka as a basic need of human. Badulu oya is the main water source for drinking water in Badulla District, Uva province. Recently manganese (Mn) concentration in Demodara reservoir which was made for the purpose of water treatment facility year-round has increased unsteadily from the Sri Lankan Standards for drinking water (0.1 ppm). Therefore, the present study was conducted to determine Mn accumulation in the reservoir and to identify temporal variation of physico-chemical parameters of water. Sixteen locations from disparate upper tributaries and the reservoir were selected for sampling and that was carried out from October 2018 to December 2018. Manganese concentration of water samples were determined using Atomic Absorption Spectrometer and other water quality parameters; Turbidity, TDS, Alkalinity, Hardness were measured using standards methods. Data were statistically analyzed using SPSS 23.0 package. There was a significant difference of Mn concentration in the reservoir (06°54'47.0016" N, 081°03'38.0016" E) with the time (p<0.05) and with the location (p<0.05). Average Mn concentration in the reservoir (0.12 ppm) was significantly higher than the average Mn concentration of all other sampling sites (0.02 ppm). Average turbidity of the reservoir was correlated with average turbidity of all other sampling sites (r=0.855). Average TDS (53.25 ppm), Alkalinity (36.40 ppm), and Hardness (44.22 ppm) of reservoir were lower than the average value of all other sampling sites (60.96 ppm, 51.22 ppm, 49.77 ppm respectively). The results of this study will be helpful to take necessary actions to mitigate accumulated manganese of reservoir. Agricultural and industrial activities as mining of quarries may cause to adversely change the water quality parameters of Demodara reservoir. But more studies are needed to find out reason(s) for reservoir has higher Mn concentration.
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    Zooplankton Studies in East Coast of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2019-02) Koshika, K.; Wimalasiri, H.B.U.G.M.; Jayasinghe, R.P.P.K.; Guruge, K.P.G.K.P.
    Zooplankton plays a vital role in marine environment by transferring the energy to higher trophic levels through the food web. However, the studies on zooplankton in the coastal water of Sri Lanka especially in the East coast are deficient. The present study was conducted to investigate zooplankton abundance in East coast of Sri Lanka in marine resources survey using the Research Vessel: Dr. Fridtjof Nansen during June to July 2018. Twenty-five samples were obtained from five transects using WP2 plankton net with 180µm mesh size. The samples were collected vertically from 30 m, 100 m and 200 m depths. In the laboratory; zooplankton was identified to the lowest possible taxonomic groups using standard keys and counted. The results revealed that zooplankton are dominated by the Phylum Arthropoda (63%), followed by Chordata (20.6%), Sarcomastigophora (7.4%), Chaetohnatha (4%), Cnidaria (2.5%), Annelida (1%), Echinodermata (0.4%), Mollusca (0.4%) and Ciliophora (0.2%). The highest (13053.57 m-3) and lowest (5747.43 m-3) abundance were recorded at transects near Mullaitivu and Batticaloa respectively. The study showed that there was no significant difference (p>0.05) of the abundance of zooplankton among the sampling stations. However, abundance of the zooplankton between shallow and offshore sampling stations were significantly different (p <0.05). The abundance of zooplankton at the depth of 100 m indicated an increasing trend towards Batticaloa. Offshore (100 m and 200 m) zooplankton abundance (2697 m-3) at 30 m depth was higher than the abundance of nearshore samples (1298 m-3). This study revealed that there are spatial variations of zooplankton in East coast of Sri Lanka and it may affect the fish production in the area. Therefore, further comprehensive studies on zooplankton are recommended to find out the possible reasons for such variations which could be useful in managing the marine environment.