International Research Conference of UWU-2019

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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.
Assessing the Ecological Impact of the Bottom-set Crab Net Fishery for Portunus pelagicus on Non-Target Species at Thuraiyoor, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Subaha, V.; Wickramaratne, I.U.; Herath, H.M.T.N.B.
The bottom-set crab net Portunus pelagicus fishery has been recently developed and is now one of the top livelihoods of Thuraiyoor fishermen, which is located in Jaffna District inside the Palk Bay. The crab net fishery seems to be ecosystem friendly when compared with trawling. However, a better understanding of the ecological impact is lacking in the Sri Lankan context. This study aimed to quantify the total bycatch, determine the catch composition of non-target species and examine the likely impact of the fishery on nontarget species. Data were collected using a fishery dependent survey. From the total catch observed from the 152 net-sets, 45% of the catch was targeted catch and 55% was bycatch. The resulted proportion of bycatch as valuable bycatch (i.e. retained) and discarded bycatch were 40% and 15% respectively. Based on fishery dependent surveys, a total number of 84 non-target species were observed in the bycatch. The bycatch included 32 species of fish, 23 species of crustaceans, 18 species of mollusks, 9 species of echinoderms and 2 species of cnidaria. Among the total bycatch, spider conch (Lambis lambis) comprised 30% of the total catch by weight and identified as a main species. The remaining 25% included all other non-targeted species and the majority were mollusks and crustaceans. The automated Marine Stewardship Council (MSC) vulnerability score and MSC overall score for spider conch were as 2.35 and 89 respectively, which is equivalent to an Unconditional Pass of the MSC Fishery Standard for Sustainable Fisheries. Consequently, this study at Thuraiyoor supports earlier studies in the Palk Bay, which indicate that the ecological impact on the non-target species by bottom-set crab net P. pelagicus fisheries in the Palk Bay is a low conservation concern at present.
Comparative Analysis on Morphological Variation of Three Populations of Saccostrea cucullata (Rock Oysters) and Crassostrea madrasensis (Indian Backwater Oyster) (Bivalve: Mollusca) in Selected Coastal Regions of Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Peiris, M.S.D; Prasadika, H.K.A.E; Thushari, G.G.N; Pitawala, J.C
Crassostrea madrasensis (Indian backwater oyster) and Saccostrea cucullata (Rock oyster) are abundant shellfish varieties with higher culture potential along coastline of Sri Lanka. Limited research studies are available on population clustering and distribution patterns of Oysters in Sri Lankan coast. This study was focused to analyze intra-specific morphological variation among 03 populations of C. madrasensis and S. cucullata in Sri Lanka. C. madrasensis samples were collected from Panadura, Trincomalee and Kalpitiya coasts, while S. cucullata samples were collected from Dickwella, Jaffna and Mt’Lavinia during August-December 2018. Ten morphometric parameters were measured using 190 samples and standardized morphometric measurements were subjected to Discriminant Function Analysis (DFA). Two discriminant functions were derived by predicted two models for populations of S. cucullata (Function 1: Wilks’ƛ=0.005/Function 2: Wilks’ƛ=0.81, P<0.05) and C. madrasensis (Function 1: Wilks’ƛ=0.35/Function 2: Wilks’ƛ=0.82, P<0.05). Derived first Discriminant functions were identified as strongest factors by highly accounting for models of S. cucullata and C. madrasensis with of 99.9% and 85.8% of total variances respectively (Eigen values: 164.55 and 1.34). The ratio between Adductor Muscle Scar Height of Right Valve/Adductor Muscle Scar Area {AMSH(R)/Area} was selected as the highly contributing parameter on strongest function in extracted models of S. cucullata (0.68) and C. madrasensis (0.52). The group plots derived for S. cucullata indicated overlapping between two populations in Colombo and Jaffna, while population of Dickwella illustrates a clear separation from other two groups with intra-specific variation. Group plots of C. madrasensis records overlapping of populations with morphological similarity and three groups consider as one population. This study provides basic information on population structure of S. cucullata and C. madrasensis in Sri Lanka. Population genetic studies are recommended to confirm the findings of this study.
A Comparative Study on Ancient and Contemporary Fisheries Management Systems in Inland Reservoirs of Anuradhapura District in Sri Lanka: A Review
(Uva Wellassa University of Sri Lanka, 2019-02) Lakpawan, W.M.P.; Liyanage, N.P.P.; Tennakoon, T.M.P.S.I.; Herath, H.M.T.N.B.; Kulathilaka, C.J.P.
Archaeological evidences prove that fishery activities were initiated during pre-historic era. According to historical evidences, inland fishery was one of the important economic activities in ancient Sri Lanka and it was regularized after introduction of freshwater fish species during British period. This study was focused on investigation of ancient and contemporary fisheries management systems under four criteria such as, decision making, fishing gears, fish varieties, fish selling and revenue process in Anuradhapura District. 220 fishermen were selected using stratified sampling and data were collected using selfadministrated questionnaire, interviews with key persons and group discussions with fishermen. Secondary information was collected from National Aquaculture Development Authority (NAQDA), Department of Fisheries and Aquatic Resources and library survey. Results of the present study revealed that current fishery practices were managed through community based organizations, NAQDA officers and strong legal framework. As recorded in literature, ancient inland fishery activities were managed by Welwidane with the support of set of norms. In ancient time karaka, Kemana, Iratiya, Athnagu were used as fishing gears to catch native fishes such as Heteropneustes sp, Anabas sp, Channa sp, Wallago sp. At present, pole & line and gill nets were used as legally accepted gears to catch exotic food fishes such as Indian/ Chinese carps and Tilapia. Mainly barter system was applied during the ancient period and Machchabaga & Diyabeduma taxes were applied for harvest & usage of tank. Currently, organized fish selling system is practicing at landing sites and in well managed fishery systems, toll collection was observed. However, no direct taxes were applied in contemporary systems. Both pros and cons were identified in two systems. Abiding nature of villagers, dissemination of harvest and community services practiced can be taken as positive examples from ancient system
Comparative Study on Total Chlorophyll, Carotenoid, Fucoxanthin in Seaweeds Ulva reticulata, Sargassum ilicifolium and Gracilaria multipartita and Colour Enhancing Commercial Ornamental Fish Feeds
(Uva Wellassa University of Sri Lanka, 2019-02) Samarakoon, S.M.N.U.; De Silva, M.P.K.S.K.; Senaarachchi, W.A.R.K.; Liyanage, N.P.P.
Seaweeds are photosynthetic marine macro algae, contain various natural colour pigments. Considering high bioavailability and low cost of processing, this study aimed on evaluating the potential of using seaweeds as a feed additive for colour enhancement of ornamental fish compared to commercial colour enhancing ornamental fish feeds by assessing three types of pigments. Three algae species (green algae-Ulva reticulata, brown algae-Sargassum ilicifolium and red algae-Gracilaria multipartita) were collected from Dickwella area. Pigments were extracted into 10 ml of 99% acetone from sun-dried algae and from 3 types of commercial feeds having green, brown and red colours. Total chlorophyll, carotenoid and fucoxanthin content of seaweeds and commercial feeds were quantified using UV spectrophotometer. Non-normally distributed data were analyzed by Kruskal Wallis test in Minitab version 17 at 0.05 significant level. Highest total chlorophyll content was observed in U. reticulata (70.50±0.39 µg g-1) & S. ilicifolium (59.53±4.34 µg g-1) and it was significantly different from their respective colour feeds (green 4.57±1.63 µg g-1 and brown 7.69±5.56 µg g-1). Similarly, U. reticulata and S. ilicifolium had significantly different carotenoid content (1.44±0.16, 2.11±0.07 µg g-1) compared to their respective colour feeds (green 0.22±0.09 µg g-1 & brown 0.21±0.07 µg g-1). Chlorophyll & carotenoid content had no significant difference between G. multipartita and its respective red colour feed. Fucoxanthin content was also higher in seaweeds (U. reticulata 2.12±0.89 µg g-1, S. ilicifolium 4.69±3.05 µg g-1 and G. multipartita 1.52±0.82 µg g-1) than three commercial feeds (green 1.82±1.81 µg g-1, brown 0.53±0.33 µg g-1 & red 0.49±0.06 µg g-1) with no significant difference. Results indicate that sun-dried seaweeds contained comparatively high level of pigments studied; the selected sea weeds may be taken as an effective feed additive for the colour enhancement of ornamental fish.
Development of Low Cost Mass Culture Media for Spirulina platensis
(Uva Wellassa University of Sri Lanka, 2019-02) Munirathna, K.S.P.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
Spirulina platensis is an algae popular as a food supplement with high protein content. The pure cultures of Spirulina are maintained using Zarrouk medium, which cannot be used for mass culture as the medium is highly expensive. The present study aims to develop a low cost mass culture media suitable for commercial scale culture of S. platensis in Sri Lanka. Three culture media [T1 (w/w)-NaHCO3:73.68%, NaCl:8.77%, Urea :10.96%, Albert solution:4.38%, T2 (w/w)-NaHCO3:75.4%, NaCl:7.18%, Muriate of Potash:4.39%, Triple Supper Phosphate:1.79%, Urea:11.22%, T3 (w/w) -Triple Supper Phosphate:0.95%, NaNO3:7.18%, Muriate of Potash:4.96%, NaCl:47.91%, MgSO4 :0.71%, CaCl2:0.19%, NaHCO3:38.33%] were formulated by incorporating selected fertilizers and other cost-effective alternative chemicals, while Zarrouk medium was used as the control. Three media were tested in triplicates for growth performance of Spirulina. One-unit volume was used from a pure culture with 1100 cells ml-1 and inoculated in to all the treatments. Cultures were initiated in an axenic batch culture method in the formulated media and maintained under the illumination of 4000 lux and at 35oC temperature. The growth rate of culture was measured by counting the number of cells under light microscope and cell ratio was calculated. Data were collected once in three days for 15 days and data were statistically analyzed by one-way analysis of variance (ANOVA) Results revealed the significantly high numbers of cells (186.24±25.76 cells ml-1) in T3 followed by control 123.21±3.10 cells ml-1, T1 114.80±27.97 cells ml-1, T2 96.92±3.69 cells ml-1 (P<0.05). Hence, T3 medium was identified as the most favorable media for the growth of S. platensis. The highest growth rate was also observed in T3 medium during the 15 days culture period. According to the cost analysis, T3 medium was three times cheaper than the Zarrouk’s medium and can be recommended for initiating mass culture of S. platensis in Sri Lanka.
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.
Effect of Sesame Seed Cake Meal as an Alternative Protein Source in the Diets of Juvenile Guppy Fish Reared in Outdoor Farming Conditions
(Uva Wellassa University of Sri Lanka, 2019-02) Nishshanka, K.M.; Radampola, K.
Replacing expensive fish meal component in fish feeds using alternative protein sources is necessary for sustainable aquaculture industry. A six week feeding trial was carried out to evaluate the effects of inclusion levels of sesame seed cake meal (SS) to replace commercial fish meal (FM) in diets for Guppy (Poecilia reticulata) reared in outdoor tanks. Four experimental diets were prepared and control diet (CD) contained 18% FM and 0% SS. The other three diets were 10SD (10% SS + 8% FM), 15SD (15% SS + 3% FM) and 20SD (20% SS + 0% FM). Additionally, a commercial diet (ED) was also used as one treatment to compare growth, feed performance and survival of fish. Fish (0.06 + 0.01 g and 1.80 + 0.11 cm) were randomly allocated across 15 cement tanks (120 x 90 x 40 cm) at a stocking density of 80 fish m-3 with three replicates per treatment and fed adlibitum three times per day for 6 weeks period. Final total length was significantly higher in fish fed on 10SD (3.18 + 0.18 cm), 15SD (3.12 + 0.23 cm) and 20SD (3.14 + 0.24 cm) diets compared to fish in CD (2.92 + 0.22 cm) and ED (3.00 + 0.19 cm) treatments. Percentage SGR of fish were significantly higher in all SD treatments and ED treatment compared to control treatment. Feed consumption (% Body weight day-1) and FCR were ranged from 5.31± 3.08 to 5.67 ± 3.51 and 1.29 ± 0.06 to 1.41± 0.12 for SS included diets respectively. Fish fed on CD and ED diets showed higher feed consumption (% Body weight day-1) and FCR values than SS included diets. Fish in SD treatments showed better growth performances and feed utilization without any negative effects on their survival compared to fish fed on commercial feed. Total cost (1 kg) of ED was Rs 250 while cost for the other four diets were Rs 176, 149, 136, 127 for CD, 10SD, 15SD and 20SD respectively. Present study indicates that sesame seed cake meal can be successfully included up to 10-20% as a low cost alternative protein source in practical diets for guppy reared in farm conditions.
Evaluation of Sensory Qualities of Catla Fish (Catla Catla) in Three Selected Reservoirs of Badulla District, Uva Province, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Leshika, D.L.; Ediriweera, T.K.; Abeygunawardana, A.P; Siriwardana, E.M.C.; Thushari, G.G.N; Liyanage, N.P.P.; Jayamanne, S.C.
Catla (Catla catla) is one of the common exotic Indian carp species in inland fishery sector of Uva province in Sri Lanka. There is a high potential to develop Catla fish production and introduce value added products from the excess fish harvest. Environmental factors can significantly affect the physico-chemical and organoleptic quality of fish meat. Current study was focused on investigating Organoleptic properties of Catla fish flesh from 03 reservoirs selected (Ulhitiya, Rathkinda, Sorabora reservoir) with higher fish production in Badulla district. The fish samples with weight of 6.0 -12.5 kg and length of 65cm-95 cm were collected from the landing sites of three selected reservoirs. Prepared fish fillets were subjected to steam cooking for 10 minutes without adding spices at temperature of 1000C. The sensory evaluation was conducted using 05point hedonic scale to assess the sensory characters; color, texture, aroma, mouth feel, taste, overall acceptance of the steamed fish fillets by 30 untrained panelists. Sensory scores were statistically assessed through Friedman non parametric test. As results revealed, all the sensory parameters of flesh samples are significantly different according to the type of reservoir (p<0.05). Highest estimated median for all the organoleptic parameters (color/texture/aroma/mouth feel/taste=4, overall acceptance=5)were recorded for Catla flesh samples of Ulhitiya reservoir showing that, Catla fish from Ulhitiya reservoir has highest consumer preference. Sensory qualities of fish flesh depend on different kind of factors such as characteristics of living environment, fertility of water, availability of food and climatic condition. In conclusion, consumer acceptability also depends on organoleptic properties of fish samples. Detailed study on biochemical and physical quality changes of Catla fish samples in different reservoirs is recommended improve knowledge on fish quality.
Extraction of Protein from Discarded Shellfish Waste; Value Added Shrimp By-products for fish Feeds
(Uva Wellassa University of Sri Lanka, 2019-02) Senaarachchi, W.W.A.R.K.; De Silva, M.P.K.S.K.
Shrimp head and shell waste is a rich protein source having the possibility to use in fish feed formulation. Extraction of these valuable proteins from shrimp waste is restricted due to strong covalent bonds ß (1-4) found in chitin-protein. Present study aimed to extract the proteins in high percentages by breaking the chitino-protein bonds in shrimp shells, combining the activity of proteolytic endoenzymes in crab shell waste and temperature activated autolysis. Two tests were conducted. Test I-pressure cooked ground shrimp waste was mixed with ground crab waste at crab: shrimp ratios of 0:1, 1:1, 1:2, 1:3, 1:4 and, 1:9. Tests II: using the same crab: shrimp ratios in Test I without pressure cooking. All the samples in triplicates were heated with continuous stirring at 55 0C for 15 minutes. Each hydrolysate was dried at 60 0C and weighed. Crude protein percentage was determined by Kjeldhal Analysis. Data were analysed by one-way ANOVA using SPSS 17 version. No significant difference in crude protein percentage (p > 0.05) between pressure cooked and uncooked samples with the same ingredient ratios. Highest crude protein content was recorded in crab: shrimp 1:2 (69.00 ± 12.66%) in cooked samples and in 1:9 (68.66 ± 9.45%) of uncooked samples. In contrast crab: shrimp ratio of 1:9 of cooked samples had comparatively low protein percentage (55.00 ±7.54%). Lowest crude protein percentage recorded in crab: shrimp 0:1 in both uncooked (41.56 ± 5.56%) and cooked samples (42.00 ± 23.38%) as there is no crab wastes are added. Present study reveals that incorporation of crab shell wastes to uncooked shrimp waste and temperature induced autolysis is an efficient method to extract higher amount of protein from shellfish wastes.
Growth Performance of Holothuria scabra (Sand Fish) with Different Stocking Density in Open Sea Pen Culture in Jaffna, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Mahishalini, V.; Athula, J.M.; Nirooparaj, B.
Sea cucumber, Holothuria scabra is over exploited species in worldwide due to the high fishing intensity from the wild stocks. Sea cucumber pen culture practices are being expanded in Northern Province of Sri Lanka and presently operated more than 57 pen culture farms in the region. This research is intended to investigate the growth performance of H. scabra pen culture with different stocking densities to find out the most appropriate stocking density to introduce the farmers. This research was carried out in coast of Mankumpan village in Jaffna district, Sri Lanka. Early matured H. Scabra with average weight 49.78 g and average length 11.28 cm were collected from the Sea cucumber farmers. Four pens were constructed by using 5 mm mesh size high density polyethylene nets and wooden planks. The size of each pen was 25 m2. Early matured H. scabra was reared with stocking densities of 1, 2, 3 and 4 individual m2. Thirty percentage sample size was randomly collected in each pens to measure the growth parameter. Average length, weight and water quality parameters were measured twice a month and finally, survival rate was calculated. After 60 days of the culture period average specific growth rates were calculated twice a month and it shows 2.53 + 0.56 gday-1, 1.98 + 0.20 gday-1, 1.95 + 0.21 gday-1 and 1.08 + 0.27 gday-1 for pen 1, pen 2, pen 3 and pen 4 respectively. Data was analyzed using Minitab17 version by one-way ANOVA test. Average survival rates for pen 1 and pen 2 were recorded as 100% and for pen 3 and pen 4 were recorded as 85.33% and 85% respectively. Temperature, Salinity, PH, Nitrate and Phosphate were ranged 27−31oC, 35−40 ppt, 7.3−8.8, 0.25−2.5 mgL-1 and 0.38−0.44 mgL-1 respectively. The results show that, there were significant difference (p > 0.05) between Specific growth rate and stocking density. The result indicated that the specific growth rate and survival rate were higher in pen 1 and pen 2 than pen 3 and pen 4 and applicable for the implementation.
Molecular Identification of Fresh and Cooked Tuna Samples Using Triplex-Polymerase Chain Reaction Assay
(Uva Wellassa University of Sri Lanka, 2019-02) Efrem, S.M.; Rodrigo, W.W.P.; Lukshman, S.M.P.
During trade and processing of tuna products, it is very important to detect commercial frauds regarding substitution of species. As a consequence, a guarantee can be given to the consumers about the safety and origin of the tuna product. Identification of the correct tuna species is important to detect and prevent food adulterations. The main objective of this project is to differentiate most available tuna species of yellowfin, bigeye and skipjack tuna from other fish species in fresh and cooked samples using triplex PCR method. DNA was extracted from fresh samples by salt method and from cooked samples by DNeasy mericon food kit (Qiagen). Fish specific PCR was carried out to confirm that the samples are actually belonging to a fish species and to check the quality of the DNA for the amplification purpose due to the presence of PCR inhibiters especially in the cooked samples. Band size of 251 bp was obtained for all fish samples as expected and band sizes of 284 bp, 140 bp and 242 bp were obtained for yellowfin, bigeye and skipjack tuna respectively in triplex PCR. Out of 10 fresh tuna samples five were identified as adulterated samples and no PCR product was obtained for non tuna samples as expected. Cooked tuna samples labeled as yellowfin and skipjack produced expected bands, and the product labeled as “tuna ambulthiyal” detected as skipjack. Product labeled as “fish ambulthiyal” and the rest of the cooked fish samples were not obtained any band which demonstrated the tested samples not belongs to the yellowfin, bigeye or skipjack. Therefore, this assay can be used successfully for the identification of adulterated fresh and cooked tuna samples and did not get any band for other fish samples which confirm that this assay was specific for above mentioned tuna species.
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.
A Review on Export Trade of Freshwater Ornamental Fish Species in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Rathnamurthi, T.D.N.K.S.; Dias, P.C.B.; Jayawardana, J.M.D.R.; Senevirathne, J.D.M.; Liyanage, N.P.P.
Freshwater Ornamental Fish industry of Sri Lanka has developed rapidly during the last few decades due to high export demand. Industry sustains with culture of exotic species rather than a wild collection of ornamental fish including endemics. Hence, a review on the present status of the export industry of Freshwater Ornamental Fish and identification of the existing gaps are important for further development in the industry. Secondary information on exporting levels, species and countries were collected from Sri Lanka Customs. Further, 32 registered exporters were identified using NAQDA registry and pretested questionnaire was used to collect information on knowledge of exporters, productivity and export details. Results revealed that majority of export fish varieties were Guppy (87%) followed by Platy (3.3%), Molly (2.2%), Tetra (2%), Zebrafish (1.7%) and Barb (0.9%). According to the results, demand for the exporting fish is changed with the quarters of the year and majority of the species (Guppy, Platy, Molly, Tetra) have high demand in 1st quarter. Demand for Zebra fish and Barb fish has high demand in 4th and 2nd quarter of the year respectively. Results of the survey indicated that 80% of companies target only the export market rather than local trade. Majority (55%) of the exporters depended on local farmers to fulfill their requirement of export market. This vast export demand still cannot be achieved due to the communication barriers (67%) among farmers and exporters. The major constrains were identified as difficulties of recognise the actual market demand (87%), lack of adequate knowledge and technical approach regarding disease control (73%) and water quality management (87%). “Ceylon Fish Guide” a userfriendly android tool was developed to enhance the knowledge and communication of farmers and exporters. Therefore, improving the ornamental fish industry with novel technologies is important to compete with global market.
Sea Urchin Abundance and Diversity at Selected Locations in Southern and Eastern Coasts of Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Wimalasiri, H.B.U.G.M.; Balawardhana, D.G.T.C.; Haputhanthri, S.S.K.
Sea urchins are a vital group of herbivores in both temperate and tropical food webs because they control macroalgal cover, and consequently influence primary productivity and phase shifts on reefs. Sea urchin gonads is a delicacy in many countries. Due to the commercial value, sea urchin has identified as a cultivable marine invertebrate species. This study aims to identify the abundance and diversity of sea urchin at five selected sites in the southern (Midigama, Kottegoda, andNilwella) and eastern coasts (Pulmudei and Trincomalee) of Sri Lanka. The study was carried out using Random transect sampling method and transects were vertical to shoreline with the length varying from 5m -20m at the selected sites to estimate the sea urchin abundance during January to August, 2018. At the field, a quadrate of 0.5m x 0.5m was laid along transects all the sea urchin species were counted within the plot. Density and diversity of Sea urchin in two regions were estimated, and their means were compared.According to the results, a total of 12 sea urchin species were detected among the five sampling sites. On the Southern and Eastern coast, sea urchin abundance is recorded as 18individuals m-2, and 10 individuals m-2 respectively. Shannon Weinner index of diversity is highest in Midigama in Southern coast than other locations. Dominant species was Stomopneustes variolaris(Black sea Urchin) both in eastern and southern regional coasts. The abundance of S. variolaris was significantly higher in the Southern Coast compared to Eastern coast (P<0.05). If Sri Lanka initiated commercial catching of sea urchins, special management measures would be needed to prevent overexploitation of sea urchins. It is recommended to study other aspects of sea urchins including reproductive biology and stock size estimation. This study would provide some baseline information for the management of sea urchin population around Sri Lanka .
Social Relationships of Dried Fish Producers in Trincomalee District, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Yuganthan, A.; Wickramaratne, I.U.; Koralagama, D.N.; Herath, H.M.T.N.B.
Being a traditional source of animal protein in local diet, dried fish accounts for 4% in Sri Lankan average monthly household expenditure. Although, 70% of local dried fish products come from North & East Provinces, a production oriented dried fish studies are lacking. This study aims to investigate producer based intra & inter relationships & social & cultural influences on dried fish production. A mixed method approach was adapted to glean data from Kinniya & Muthur in Trincomalee District in Eastern Sri Lanka. A questionnaire survey (n=60) & in-depth interviews (n=10) were conducted to gather quantitative & qualitative data respectively. The snowball sampling method was employed. Gathered data were analyzed descriptively. Findings unravel multiple intra & inter relationships of dried fish producers particularly on knowledge sharing, fresh fish supply, supporters & buyers. Awareness on dried fish processing descends from parents (53%). Fresh fish sources are; boat owners (35%), fishermen (31%) & fish traders (25%). Intra relationships are prominent among supporters such as family & siblings (44%), friends (21%) & relatives (16%). Almost all producers (100%) sell through wholesaler demonstrating an external relationship with outsiders. Albeit, there are multi-faceted intra & inter relationships, an institutional arrangement is lacking. Muslims culture in both sites allows only men to engage in dried fish processing minimizing women involvement. Social & cultural analysis indicated that intra & inter relationships are converged toward family, siblings & relatives representing inner most tier of the community. Religion & cultural taboos further restrict expansion of the industry. Establishment of dried fish producers, association would be worthwhile by giving equal opportunities for both men & women producers that broaden their social networks & relationships to expand production
Some Aspects of the Reproductive Biology of Dasyatis zugei (Paleedged stingray) in the Gulf of Mannar, Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Gayathry, L.D.; Abeygunawardana, A.P.; Jayawardana, J.M.D.R.; Jayamanne, S.C.
Dasyatis zugei is one of the major non-target species caught in the bottom-set crab nets used for catching blue swimming crab (Portunus pelagicus) in Gulf of Mannar. This study aims to determine the length–weight relationship, size at first maturity and fecundity of D. zugei. In total of 1,404 individuals were collected from crab nets in two landing sites; Vankalai and Thalvupadu in Gulf of Mannar during the period of September - November, 2018. Disc Width-WD of all the individuals were measured to the nearest mm, body weight was weighed to the nearest gram and sex was determined. The state of maturity of gonads of females was identified through dissection and macroscopic examination of ovaries. Mean ova diameter significantly varied among females according to the different maturity stages (P<0.05). Sex ratio in the catch was 1:1.35 (M: F). Disc width of males ranged from 85-260 mm with a mean of 175.43±22.42 and females ranged from 110-220 mm with a mean of 167.27±17.55. The Disc width-weight relationship was analyzed by Simple Linear Regression using log transformed data and it showed Log W = -0.5923 + 2.364 log WD for male and Log W = -3.497 + 2.599 log WD for female. The results show negative allometric growth (b<3) for D. zugei. There was no significant statistical difference (P>0.05) in the male and female regression co-efficient. The size at first maturity was 166.5 mm for female D. zugei. Embryos were found only in females ≥ 160 mm of WD. The maximum fecundity was three embryos per female which is varied with the size of the female. This study reports the first findings on length- weight relationship and size at maturity of D. zugei in Sri Lankan waters.
A Study on the Potential of Extraction of Roe Oil from Thunnus albacares, Katsuwonus pelamis, Canthidermis maculata and Lepidocybium flavobrunneum
(Uva Wellassa University of Sri Lanka, 2019-02) Shanuke, D.S.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
Fish oil contains essential polyunsaturated long chain fatty acids which are crucial for normal growth and survival of the fish. Food fish roe and fish waste contain oils in different levels. Even though roe of food fish has a lower demand in Sri Lanka, there is a potential of extracting edible fish roe oil and fatty acids. In this study, five different oil producing methods; heat and salt extraction, enzymatic hydrolysis, mechanical pressing and solvent extraction were tested with selected four fish species (Thunnus albacares, Katsuwonus pelamis, Canthidermis maculata and Lepidocybium flavobrunneum) to identify the best method and best fish roe type for edible roe oil production. Solvent extraction with 2-propanol was found to be the best method of producing roe oil considering oil yields (1.48±0.70 g: T. albacares, 1.33±0.10 g: K. pelamis, 1.27±0.25 g: C. maculata and 1.01±0.01 g: F. flavobrunneum). Hence, solvent extraction method was carried out for the selected matured roe of four species using four types of solvents: (50ml) 2-propanol, hexane, acetone and mixture of hexane and 2-propanol (70:30). Oil yields of roe in different maturation stages were (using 2-propanol) measured and compared. Highest oil yields were recorded by matured roe of (K. pelamis: 1.18±0.14 g, T. albacares: 1.03±0.32 g, L. flavobrunneum: 1.01±0.01 g and C. maculata: 0.94±0.52 g). Oil yields of immature roe in all four fish species were negligible. The results showed a significant difference between oil yields and solvents used for extraction (P<0.05). Highest oil yield was obtained (25 g of matured roe) as 1.60±0.26 g with acetone extraction for T. albacares followed by 2-propanol: hexane mixture, 2-propanol and hexane solvents were recorded oil yields of 1.43±0.89 g & 1.18±0.14 g for K. pelamis and 0.64±0.17 g for T. albacares respectively. It was revealed that roe of T. albacares is the most suitable for extraction of roe oil.
Suitability of Plant Based Ingredients: Rice Bran, Coconut Poonac and Maize as Binders for Quality Improvement of Fish Feed Additive Made from Autolyzed Shrimp Waste
(Uva Wellassa University of Sri Lanka, 2019-02) Jayasundara, J.M.S.K.; De Silva, M.P.K.S.K.; Senaarachchi, W.A.R.K.; Liyanage, N.P.P.
Discarded shrimp shells, a good source of natural astaxanthin, proteins and lipids can be used as a feed additive to enhance colouration and growth of ornamental fish. Temperature-induced autolysis of shrimp waste breaks the chitin-protein bonds and releases these nutrients. Hydrolysate extracted by autolysis is sticky and perishable at room temperature (30 °C). The main Objective of this study was to improve quality and shelf life of shellfish waste extract using plant-based ingredients as binders. Shellfish waste (100 g) was subjected to thermal autolysis at 55 0C for 15 minutes with continuous stirring. Resultant Hydrolysate was mixed with powdered rice bran, coconut poonac and maize separately in different ratios of hydrolysate: plant ingredient (1:1, 1:2 and 1:3) each in triplicates. Protein and moisture content were determined in oven-dried samples. Samples at room temperature were checked for changes in physical properties (colour, stickiness, odour) and fungal formation (clotting) once a week for one-month period. Highest crude protein percentage was observed in samples of 1:1 hydrolysate: plant ingredient ratio (rice bran: 38.13±8.20%, coconut poonac: 47.83±3.75% and maize: 36.76±5.74%) with significant differences (P=0.002) of treatments among three binders. Protein content and stickiness reduced with increasing binder content. Rancid odour, colour change and clotting were minimal during this time period with highest binder content (1:3). Moisture percentage was significantly different (P<0.05) among samples of 1:1, 1:2 and 1:3 ratios and lowest (9.54±1.79) in samples with 1:2 ratio prepared using coconut poonac. Coconut poonac with highest protein and lowest moisture content is advantageous than other two binders. As there is no difference observed in physical properties in three ingredients, maize and rice bran are also suitable as binders. Selection of plant ingredient and suitable ratio depend on protein level and storing period of additive as required by farmer.

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