International Research Conference of UWU-2020

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Browsing International Research Conference of UWU-2020 by Subject "Aquaculture"

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    Anesthetic Efficacy of Clove oil, Benzocaine and MS-222 under Simulated Long Transportation Conditions of Koi (Cyprinus carpio L.)
    (Uva Wellassa University of Sri Lanka, 2020) Silva, S.S.U.; Liyanage, N.P.P.; Mudalige, A.R.; Fernando, E.S.R.
    Koi (Cyprinus carpio) is one of the most popular temperate ornamental fish species. Growth of the Koi trade in Sri Lanka is hindered by poor packing strategies and mortalities during transport. Therefore, the study aimed at evaluating the anesthetic efficacy of Clove oil, Benzocaine, and MS-222 in simulated long transportation conditions on Koi. 75 d old Koi with standard length (6.025 ± 0.04 cm) and weight (6.153 ± 0.23 g) were selected for the experiments. These individuals were subjected to four different dosages of anesthetics, based on the results obtained at the range-finding test. Each sample consists of 10 individuals and dosages were triplicated. Samples were exposed to simulated transportation conditions for 10, 20, 30, 40 h, and effective dose for each anesthetic was determined by assessing the Sedation Induction Time (SIT), Recovery Achievement Time (RAT), Mortality Rate and Post-exposure Survival Rate of Koi. Changes in water quality parameters including pH, ammoniacal nitrogen, and dissolved oxygen in transport water were recorded. Results obtained were analyzed using one-way ANOVA followed by Tukey's’ method and General MANOVA using Minitab 17.0 version (p< 0.05). Among four different test concentrations used for clove oil, 145 µLL-l was recorded as the best concentration while 140 µLL-l and 70 mgL -1were obtained for Benzocaine and MS-222 respectively, based on the results obtained from statistical analysis of SIT and RAT (p<0.05). Further, there were 0% mortalities for the 40 h test period and 7 d after recovery for all the three anesthetics at effective concentrations (p<0.05). In conclusion, the present study indicates that all three anesthetics perform well in the above concentrations. However, clove oil can be used as a good substitute for synthetic anesthetics because of its efficacy at a lower dosage with higher safety at a low cost. Keywords: Sedation, Ornamental carp, Ornamental fish trade, Mortality rate, Packing density
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    Comparative Study on Growth Performance and Profitability of Shrimp Farming Industry in Sri Lanka: Native Penaeus monodon vs. Imported Specific Pathogen Free
    (Uva Wellassa University of Sri Lanka, 2020) Priyadarshana, S.D.A.M.; Athula, J.A.; Ranathunga, R.M.N.P.K.; Lakmal, J.A.S.; Adikari, A.M.L.W.
    Until 2018, Penaeus monodon was the main commercial-scale cultured shrimp species in Sri Lanka and the seed production industry depended on wild-caught native broodstock. Due to the high prevalence of White Spot Disease among the wild-collected brood shrimps, the farming industry has been affected by post larvae shortage and disease outbreaks. As a solution, National Aquaculture Development Authority has decided in 2016 to introduce Specific Pathogen Free (SPF) broodstock to the industry imported from Thailand and they are planning to encourage the SPF shrimp farming in the country. Therefore, this study was focused to compare the growth performance and profitability of farming these two varieties. During the period of 21st March 2019 to 28th February 2020, 14 ponds for each variety were selected from the Ambakandawila area in Puttalam District for the study. Data collection was initiated after the 8th week of the stocking and continued up to the harvest. Specific Growth Rate (SGR), Survival Rate (SR), Average Daily Gain (ADG) of the body weight, Feed Conversion Ratio (FCR), total cost, revenue, and net profit were calculated. SGR was recorded as 2.51 ± 0.1 & 2.13 ± 0.06 and ADG of the body weight was recorded as 0.31 ± 0.02 & 0.23 ± 0.01 g day-1 for SPF and native shrimp varieties respectively. SR was recorded as 70.1 ± 3.4% & 69.9 ± 3.2% and FCR was recorded as 1.51 ± 0.04 and 1.54 ± 0.07 for SPF and native shrimp varieties respectively. It recorded 1,482,311.62 ± 50,687.49 and 1,087,716.21 ± 72,449.54 LKR acre-1 as the total cost of the farming of SPF and native shrimp varieties respectively. Total revenue was recorded as 1,783,733 ± 102,197 and 1,535,122 ± 162,199 LKR acre-1 and estimated net profit was calculated as 301,421 ± 105,412 and 447,406 ± 101,576 LKR acre-1 for SPF and native shrimp culture systems respectively. Although the SGR, SR, ADG, FCR are better in SPF shrimps than native shrimps, profitability mainly depends on the total cost. Keywords: SPF Penaeus monodon, Shrimp farming, Growth performance, Profitability
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    Comparative Study on Ring Net and Bottom-Set Gillnet Fisheries in Thalaimannar Pier, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Kulas, J.A.J.F.; Wickramaratne, I.U.; Sosai, B.M.K.; Gayathry, L.D.
    Thalaimannar Pier, Sri Lanka was dominant with Ring net (Surukku) and Bottom-set gillnet fisheries. Details with those fisheries were lacking in the literature. A comparative study of both fisheries in Thalaimannar Pier was vital towards sustainable exploitation of fishery resources. The study aims at determining Catch-Per-Unit-Effort (CPUE), catch composition, and supply chain analysis of selected species from two fisheries last October (2019) to early January (2020). Total catch was recorded to the nearest kilogram and effort in-unit kilograms per square meter (kgm-2 ). The total catch of fish species in ring & gill nets was recorded. Results showed ring net catch mainly comprised of finfish (97.8%), crustaceans (1%), mollusk (1%); 1.2% were non-target species. Bottom-set gillnet catch comprises of crustaceans (50%), finfish (25%), mollusk (20%), and echinoderms (1%). Portunus pelagicus was the major target species, nearly 43% of the total catch. Out of the total, 29% of the bottom-set gillnet catch was discarded as nontarget species. Gillnet produced more non-target species. Mean CPUE (kgm-2 ) and standard deviation of ring & gill nets were 0.205 ± 0.062 and 0.0711 kgm-2 ± 0.018 respectively. CPUE for ring net increased from Late-November to Early-January; for gillnet, it decreased from mid November to early January. Sardinella gibbosa showed 71.11% of the price difference from wholesalers to outside retailers and Pampus argenteus (only exportable species) showed 47% of it from fishers to exporters in the supply chain. Ring net was harmful due to comparatively high catch per unit effort which may lead to overexploitation of commercially important fish populations. Gillnet was also harmful due to the high catch of non-target species. The current study provides baseline information that paves the way for sustainable exploitation of the aforementioned fisheries. Keywords: Ring net & Bottom-set gillnet fisheries, Catch per unit effort, By-catch
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    Development of Fish Feed Using Marigold Petals and Banana Peel to Enhance the Coloration of Koi Carp (Cyprinus carpio)
    (Uva Wellassa University of Sri Lanka, 2020) Sachintha, S.L.; Coswatte, A.C.W.W.M.C.L.K.; Bambaranda, B.V.A.S.M.
    Koi is an economically important fish variety because of the wide diversity of skin color patterns. Fishes are unable to synthesis carotenoids in their body. The culture of ornamental fish without supplementation of dietary carotenoids leads to fade coloration. But synthetic carotenoids are expensive. Marigold petals (Tagetes erecta) and banana peels (Musa acuminata) are inexpensive, abundant, rich in carotenoids, and discarded as wastes. The objective of this study was to develop a suitable color enhancing fish feed and enhance the skin color of Koi carp by using natural color pigments. An experiment was carried out for nine weeks to enhance the body coloration of Koi carp under laboratory conditions. Four weeks old, 252 Kohaku fish were randomly introduced into seven treatments with triplicates. Marigold petals and banana peels were sundried, ground into fine particles, and sieved. Color enhancing diets were prepared with different concentrations (5, 10, 15%) of sun-dried marigold petal powder and banana peel powder; with the control treatment; commercial fish feed. All seven feed types were analysed for crude protein, crude lipid, ash, and moisture. Feed samples were checked for changes in physical properties at room temperature and refrigerated conditions (4 ºC) for one month. The total carotenoid concentration of all diets was measured using a UV spectrophotometer. The color analysis of the fish skin was done by a photographic method using Image J software. After 9 weeks from feeding, maximum skin coloration of Kohaku fish was achieved by the feed incorporated with 15% Marigold petal powder and 15% banana peel powder with significantly different. (p<0.005). Marigold petal incorporated feed obtained high skin coloration than banana peels. The lowest skin coloration was achieved in commercial fish feed. The growth rate of fish did not show any significant difference among prepared feeds during the trial. This study showed that prepared diets using Marigold petals and banana peel with different concentrations provide adequate enhancement of coloration for Kohaku fish with a short time. Keywords: Kohaku Carp, Fish feed, Skin coloration, Marigold petals, Banana peels
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    Development of Quality Assessment Guideline for Litopenaeus Vannamei (Whiteleg Shrimp) Post Larvae
    (Uva Wellassa University of Sri Lanka, 2020) Premarathna, N.M.C.N.; Athula, J.A.; Soyza, W.A.D.; Lakmal, J.A.S.
    Penaeus monodon is the main brackish water aquaculture species in Sri Lanka which targets the production for the export market. Litopenaeus vannamei (Penaeus vannamei) was introduced in 2018 as a new species expecting a rapid increase in production in the country. As a management strategy implemented by the National Aquaculture Development Authority (NAQDA), the assessment of post larvae quality is a compulsory requirement to obtain a better harvest via better growth without disease infections. Quality assessment of the P. monodon is based on 10 criteria and a minimum of 80% marks are required to get the approval for stocking. Up to now, the same assessment method has been used for P. vannamei, and due to some morphological and anatomical deviations; it did not totally comply with the new species. Hence, this study aimed to develop a post larvae quality assessment guideline for Litopenaeus vannamei with a score allocation procedure for each quality assessment criterion. The characteristics of different post-larvae stages (PL 1 - PL 30) from three different culture cycles of Litopenaeus vannamei were evaluated under each criterion and performed microscopically and morphologically. The microscopic observations were Monodon baculoviruses and Baculovirus penaeid, condition of hepatopancreas and gut content, necrosis and deformities, epibiont fouling, muscle opaqueness, and gut to muscle ratio of post larvae. The average body length, rostral spines, and size variation of each PL stage were the morphological observations measured to apply as standard values. The obtained values for post larvae of P. vannamei differed from the values of P. monodon. This study reveals the incompatibility of using the same assessment method for both shrimp species. Revision of marks allocation procedure, validation of the quality assessment method, and introduction as a new guideline will contribute to the future development of the Litopenaeus vannamei farming industry in Sri Lanka. Keywords: Litopenaeus vannamei, Post larvae quality, Quality assessment guideline, Shrimp farming
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    Development of Seaweed Based Ready-to-Serve (RTS) Beverage using Elkhorn Sea Moss: Kappaphycus alvarezii - A Novel Approach in Value Addition to Seaweed Resources in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Karunarathne, K.M.C.S.; Kulasinghe, W.M.A.A.; Thushari, G.G.N.; Abeygunawardana, A.P.; Silva, A.P.R.; Jayarathne, D.S.W.N.; Liyanage, N.P.P.
    In Sri Lanka, the development of seaweed-based food products such as nutritious drinks still gained less attention. This study was focused on the identification of product processing potential with appropriate production technology for the RTS beverage using common red algae: Kappaphycus alvarezii having high culture potential in Sri Lanka. Preliminary trials were conducted to identify the composition of raw materials and ingredients for the development of RTS products. Then, final experiments were followed using 3 levels of Kappaphycus extracts (15, 20, and 25%) blended with 5% fresh lime juice. Final products were subjected to pasteurization at 90 ºC for 5 min and stored at room temperature. The selected final product was analyzed for organoleptic parameters, proximate composition, and keeping quality characters. Results indicated the production potential of value-added RTS beverage using red algae. Final treatment with 20% of K. alverazii recorded as the best product with the highest consumer preference. Based on the results, this RTS beverage contained a significant amount of minerals (2.05±0.01%) and high antioxidant potential (~70%) with 0.001% of carbohydrate level closer to zero (atkins drink) compared to the market available products. pH level (4.37±0.06 - 3.90±0.05), antioxidant property (70.98±1.7 - 53.3±2.0%), acidity (0.30 - 0.36%) and Total Plate Count (2.60 - 3.60 log CFU ml-1 ) of final product had a significant effect with storage time period (P <0.05). Total Soluble Solid level of the product (1.2 ºBrix) was constant during the storage period due to extremely low sugar content. According to physicochemical parameters and microbiological tests, this product was safer for consumption within 4 weeks of the period. Moreover, the production cost is relatively lower compared to the market available, common beverage products. In conclusion, this seaweed-based product can be introduced as a healthy, low-cost, atkins drink as an alternative to conventional beverages. Keywords: Nutritious beverage, Red algae, Atkins drink, Physico-chemical properties, Seaweed based product
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    Growth Performances of Tilapia (Oreochromis niloticus) Fed with Duckweed (Lemna minor)
    (Uva Wellassa University of Sri Lanka, 2020) Harshani, H.M.D.; Coswatte, A.C.W.W.M.C.L.K.; Jayamanne, S.C.
    Food fish is the most valuable protein source and highly enriched with many nutrients. The cost of feed is the major reason for decreasing food fish production. The present study was conducted to identify the effect of duckweed on the growth of Tilapia. Five different diets (experiment, 2, 3, 4, 5, 6) were prepared with 40% crude protein while control diet. Experiment 1 contained a 0% duckweed leaf meal. Fish meal in experiment 2-5 was partially replaced with 10, 20, 30, 40, and 50% of dried duckweed leaf meal. Tilapia fry (bodyweight 0.21± 0.007 g and standard length 0.73± 0.005 cm) reared in indoor glass tanks were used for each experiment's diets ensuring three replicates. Daily feed allowance (5% of body weight of fish) was offered at 0900 h. and 1500 h. Results showed that mean weight gain recorded in fish fed with the experimental diets 2, 3, 4, 5, and 6 were significantly different from that of fish fed with the control diet (p< 0.05). There was a significant difference in the Specific Growth Rate of fish fed with the control diet and the experimental diets. Survival Rate of the fish fed with the experimental diets 2, 3, 4 was not significantly different (p> 0.05) with a control diet, when diet 5 and 6 were significantly different (p<0.05) with a control diet at the end of the study period. The highest Feed Conversion Ratio was recorded in fish fed with a control diet (1.28) and the lowest ratio was recorded in diet 4 (0.98). Protein Efficiency Ratio of fish fed with every 5 experimental diets were significantly different from the control diet (p<0.05) at the end of the study period. The cost of production for 1 kg of feed was considerably low for diet 6 compared to the control diet. Present results showed that 30% of dried duckweed leaf meal in a formulated diet for Nile Tilapia fish is very effective and showed the highest growth rate. Keywords: Oreochromis niloticus, Duckweed, Crude protein, Growth performance, Fish feed
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    Illustration of Key Morphological Characteristics of Highly Demanded, Export Restricted and Export Prohibited Marine Ornamental Fish Species in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Dhananjaya, B.G.N.; Dias, P.C.B.; Herath, H.M.T.N.B.; Deyshappriya, N.P.R.; Liyanage, N.P.P.
    The marine ornamental fish export industry becomes a valuable foreign income generator over the past few years. However, illegal exporting of marine ornamental fishes has threatened the most marine species. Illegal exports continue, despite the available sufficient regulations including Fauna and Flora Protection Act No 49 of 1993 and Fisheries and Aquatic Resources Act No. 02 of 1996 of Sri Lanka. Illegal exporting of marine ornamental fishes also attributed to the misidentification of the marine species. Therefore, the present study aimed to develop a user-friendly marine ornamental fish identification guide based on a dichotomous key which aids to minimize the misidentification issues. Ten highly demanded marine ornamental species were selected from the Sri Lanka Customs database. In addition to that, 14 export restricted marine ornamental species and 17 export-prohibited species were chosen for preparation of the guide based on Fisheries and Aquatic Resources Act No. 02 of 1996. Secondary data were utilized to identify the morphometric and meristic characters that discriminate against the fish families. Morphological characters used to identify the species are included; body colour, body patterns, pectoral fin length, presence of stripes, number and position of the photophores, and head length. Fish species that live in the same area at the adult growth stage was used for collecting morphological characteristics among individuals of the same species. Forty-one species under the 16 families were included in the dichotomous key to find out from the study that Family Chaetodontidae has the highest number of restricted species (n=12). Under the prohibited species, family Haemulidae bears the highest number of species (n=4). The developed guide is important for fish divers, collectors, exporters as well as customs officers to identify the restricted and prohibited species. The dichotomous key developed in the present study will be utilized for the development of marine ornamental fish identification mobile application. Keywords: Dichotomous key, Marine ornamental fish, Sri Lanka, Mobile application
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    Occurrence of Microplastics in Gut and Muscles of Commerson's Anchovy in Madu-Ganga Estuary of Southern Province, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Praboda, M.W.K.; Egodauyana, K.P.U.T.; Wijethunga, H.N.S.; Abeygunawardana, A.P.; Senevirathna, J.D.M.; Thushari, G.G.N.
    Plastic pollution causes serious ecological risks on biodiversity with toxicological effects on the biota. The objective of this study was to assess microplastic accumulation in seasonally common fishery resource: Stolephorus commersonnii (Commerson's Anchovy) harvested from Madu-ganga estuarine ecosystem. Fifteen matured fish samples (n=15) were randomly collected from local fishermen from November 2019 to January 2020. Microplastic particles were extracted from the digestive tract and muscles of anchovies using the recommended protocol of 10% KOH digestion. Hot needle test and Fourier Transform Infrared Radiation (FTIR) analysis were used for the confirmation of microscopically observed microplastics in anchovy samples. Microscopically observed microplastics were counted and categorized according to the size, color, and shape of plastics. Results revealed the microplastic accumulation in both the digestive tract and muscles of anchovies. Microplastics accumulate into the muscles via translocation and different respiratory modes. The average microplastic accumulation rate of anchovy gut and muscles were recorded as 301.70±3.58 items/g and 29.33±1.19 items/g respectively. White/transparent microplastic particles were the most abundant type in both guts (145.50±2.18 items/g) and muscles (13.55±1.23 items/g) of fish. However, blue (71.33+0.83 items/g: gut, 9.85+1.13 items/g: muscle), black (37.85+1.07 items/g: gut, 2.49+0.44 items/g: muscle), red (28.31+0.60 items/g: gut, 2.31+0.3 items/g: muscle) and pink (15.31+0.34 items/g: gut 0.96+0.24 items/g: muscle) microplastic debris were also recorded from gut and muscle samples. The majority of accumulated plastics in both gut and muscles were at the size range of 0.50 -1.00 mm. Fiber shape microplastics were observed in all the samples. FTIR results revealed that polypropylene as the only polymer type of microplastics in fish muscles and gut. This polymer is a key component of fishing ropes, netting materials, bottle caps, and packaging materials that enter through tourism/recreational activities and fishery operations into the estuarine ecosystem. Therefore, the current study recommends sustainable, integrated fishery management and eco-tourism programs focusing on plastic pollution control and prevention activities in Madu-ganga estuarine ecosystem. In conclusion, this study highlights the occurrence of microplastic contamination in the estuarine biota and the urgent need for plastic wastes management programs. Keywords: Coastal fishery resources, Estuarine ecosystem, Integrated fishery management, Microplastic accumulation rate, Plastic pollution control programmes
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    Preliminary Study on Fishery of Gurunagar in Jaffna, Sri Lanka Penaeus monodon
    (Uva Wellassa University of Sri Lanka, 2020) Nishanthi, S.; Wickramaratne, I.U.
    Gurunagar is one of the major fishing centers and its production rate also high compared with other fishing villages in Jaffna west. Effective sustainable fisheries management measures were not highlighted in Gurunagar fishery previously. This study aimed at collecting information on fishing practices, species composition, fish production, catch per unit effort, supply chain and market structure, and the level of awareness of fisher community as baseline information on fishery sustainability to improve fishery management. This study was carried out from October 2019 to January 2020. Primary data were pre-tested and collected using a questionnaire from 60 individuals, personal interviews, and direct field observation. Secondary data were collected from the Fisheries Department at Jaffna, and journal articles. Data were analysed statistically. The study revealed that a total of 12 types of fishing gears and 5 types of fishing crafts used in Gurunagar fishery. A total number of 53 species, representing 32 families were identified in the Gurunagar fish landing site during the study period. Average fresh fish and dried fish production were found 606 Mt and 56 Mt from October to December, respectively. Fishers caught 8 to 19 kg/100 net square meter-hours, 1 to 2 kg/100 net square meterhours, 1 kg/100 net square meter-hours, and 3 to 4 kg/100 hook-hours using a trawl net, gill net, stake net, and long line on average, respectively. Gurunagar fishery supply chains represented both local and foreign market interventions. Average profit/kg for prawns, seer fish, and needle cuttlefish were 1700, 565, and 425 LKR respectively. Gurunagar fisher community has moderate awareness of the importance of fishery sustainability. Current study findings may pave the way to improve the fishery management system of the Gurunagar area. Keywords: Gurunagar, Supply chain, Fishery sustainability, Catch per unit effort, Awareness
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    A Preliminary Study on Potentials of Seaweed Culture as an Alternative Livelihood for Small Scale Fishing Community in Southern Coast of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Gayathry, L.D.; Silva, A.P.R.; Shanuke, D.S.; Wijethunge, H.N.S.; Egodauyana, K.P.U.T.; Dharmakeerthi, T.N.; Jayarathna, W.N.D.S.; Bambaranda, B.V.A.S.M.
    Large scale seaweed mariculture is widespread in many Asian countries for decades. But Sri Lanka is still in its infancy. Therefore, promoting seaweed mariculture as a commercialscale industry is an urged necessity. Seaweeds grow abundantly along the southern coast of Sri Lanka. Therefore, the study attempted to assess the socio-economic status of small-scale fishermen, the potentiality of using seaweed culture as an alternative livelihood, and awareness of fishermen regarding seaweed culture on the southern coast of Sri Lanka. Data were collected by key-informant interviews and questionnaire surveys from November 2019 to February 2020. Cluster sampling was used to draw a sample of 160 fishermen from 8 major landing sites. Results of the socio-economic analysis showed that 72% of fishermen were between the age group of 35 - 55 years. Due to the seasonality of fishing, 65% of fishermen are having below-average monthly income (LKR 12,000 - 15,000). In three landing sites, 25% of fishermen are seasonal fishers. But almost all fishers are active in other landing sites. In total, 90% of fishermen are interested in seaweed farming. Identified reasons for their interest in seaweed culture were, additional income (85%), manageable with fishing (65%), and women empowerment (58%). Results relevant to awareness on seaweed farming among fishermen 80 - 90% in four landing sites, 60 - 65% in two landing sites, and below 30% in the other two landing sites. Favorable environmental conditions, adequate workforce, and willingness to initiate seaweed culture were identified as potentials. Absence of proper mechanism to disseminate knowledge, financial support, and lack of knowledge on marketing were identified as constraints for the initiation of seaweed farming. Accordingly, knowledge regarding seaweed farming should be disseminated and effectively transferred. The overall results indicate greater potential to initiate seaweed mariculture as an alternative livelihood for small scale fishing communities in southern Sri Lanka. Keywords: Seaweed, Mariculture, Fishing community, Alternative livelihood, Southern coast
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    Present Status of the Marine Aquarium Fishery in the Eastern Coast of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Dhanasundara, I.P.T.P.; Thilakarathne, E.P.D.N.; Dias, P.C.B.; Egodauyana, K.P.U. T.; Malshani, P.K.T.
    Marine aquarium industry is a popular multimillionaire industry in the world and a considerable amount of global market is fulfilled by exporting from Sri Lanka since its beginning. Almost all marine ornamental species of Sri Lanka are collected from wild habitats which cause serious stock degradation of endemic and other marine species. The collection of marine ornaments has been establishing as a community-based industry on the Eastern coast of Sri Lanka due to high resource availability and accessibility compared to other regions; however, it is poorly documented. Therefore, a survey was designed to study the situation, threats, and issues of the industry on the East coast by using a questionnaire-based survey combined with field observations. Information was gathered from the collectors, suppliers, buyers, fisheries officers, and other relevant stakeholders. Almost 190 fish collectors and 15 suppliers are currently occupying during the southwestern monsoon period roughly from May to October in the Eastern coast. About 250 marine fish species (mainly butterflyfish, angelfish, damselfish, gobies, wrasses, surgeonfish, groupers, blennies & lionfish) and 50 marine invertebrate species (shrimps, Anemones, Sea Slugs & Sea lilies) are being collected mainly from Ottamavadi, Pasikudah, Kalkudah, Paul point, Adukkuparu, and Nilaweli reefs and rocky habitats. However, 01 - 05% of fish are discarding due to catching issues and 05 - 10% of caught fish are discarding due to improper handling, holding, and packing methods before reaching to local exporters. Dynamite fishing, overexploitation, fluctuations of price levels, mishandling of caught live forms, degradation of reef habitats due to natural and anthropogenic factors are the main identified threats so that the industry in the Eastern coast is certainly unsustainable. Therefore, it is highly recommended that a powerful management system should be rapidly established for the benefit of valuable marine ecosystems and the industry. Keywords: Marine ornamental fish, Reef fish, Color fish, Trincomalee, Batticaloa
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    Socio-economic and Livelihood Related Issues of Cast Net Users in Koggala Lagoon Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Hettiarachchi, H.K.R.; Wickramaratne, I.U.
    The study was conducted in the Koggala lagoon, Southern province in Sri Lanka to assess the basic socio-economic and livelihood related issues of cast net users. A cast net is one of the traditional, effective, environmentally friendly, fishing gear; the use of traditional fishing practices should be given priority to promoting sustainable fishing, better livelihood & socioeconomic wellbeing of fishers. Hence the current study of existing issues in cast net fishery provides baseline information that raises attention for appropriate management measures. The study has been carried out for four months. Sixtysix cast net fishermen were randomly selected as a sample and pre-tested and interviewed through a questionnaire survey. Variables related to socio-economics of the cast net users were collected and descriptive statistics employed to analyze the situation. Present cast net contributes 40% from total fish catch; 98% of male representation, 77% are old population & 73% have more than 33 years of experience among the laggon fishermen. 80% have only primary education and 82% are doing fishing as the primary income method along with other fishing practices. 45% of fishermen have 4 - 5 family members. To cover monthly expenditure fishermen, take loans from various sources. Their monthly harvest ranged from 0 to 15 kg with an average of 7 kg. Lagoon mouth was a highly productive area for cast netting. Six livelihood issues were identified; crocodile attacks – 27%, low harvest – 20%, illegal fishing activities – 19%, mixing of fuel with water – 15%, net damage by oysters – 13%, chemicals from the factories – 6%. Crocodile attacks, low harvest, illegal fishing activities were the main issues prevailing for fishermen in Koggala lagoon. The current preliminary study upraised the necessity of proper surveillance of cast net fishery in Koggala lagoon in enhancing fisher livelihood and sustainable fishing which aid in proper management; however adequate attention should be paid in future studies in this regard. Keywords: Cast net, Livelihood issues, Lagoon fishermen
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    Some Aspects of the Population Characteristics of Selected Marine Fish Species (Ambligaster sirm, Hyporhamphus dussumieri, Decapterus russelli and Atule mate) in Trincomalee District
    (Uva Wellassa University of Sri Lanka, 2020) Anushika, P.; Herath, H. M.T.N.B.; Dias, P.C.B.; Gayathry, L. D.
    Coastal fisheries of the eastern coast considerably contribute to the total marine fish production of Sri Lanka. Beach seining and gillnet fishing are renowned fishing practices in Trincomalee district and its catch mainly consisted of Ambligaster sirm, Hyporhamphus dussumieri, Decapterus russelli, and Atule mate. Fish population studies can determine the need for management measures to manage overexploiting fish stocks. However, detailed population studies on the above species are lacking. Therefore, the present study aimed at determining particular population parameters of selected fish species for evaluation of stock status. In total, 1187 individuals belong to four species were collected from four landing sites in Trincomalee district from October 2019 to January 2020. Samples were collected from gillnet catches. Total length and total body weight were measured to the nearest millimeter and nearest gram respectively. Total length ranges from 115 to 210 mm for A. sirm, 110 to 225 mm for D. russelli and 93 to 220 mm, and 200 to 274 mm for A. mate and H. dussumieri respectively. Results showed negative allometric growth (b<3) for A. sirm and D. russelli species. This concludes A. sirm and D. russelli in the study area can grow faster in length than in weight whereas positive allometric growth was recorded for A. mate and H. dussumieri (b>3). Stock status was determined using the Length Based Spawning Potential Ratio model. Result showed, Spawning Potential Ratio as 29% for D. russelli which signs status of the stock is above a limit reference point, stock status of H. dussumieri was determined as sustainably exploited with Spawning potential ratio of 33%. A. sirm and A. mate were determined as below limited reference point with spawning potential ratio of 12%. Accordingly, A. sirm and A. mate population in the study area is overexploited. In conclusion, A. sirm and A. mate population in Trincomalee district needs to be managed for a sustainable fishery. Keywords: Length-weight relationship, Barefoot ecologist toolbox, Condition factor, Spawning Potential Ratio
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    Status of the Marine Ornaments Export Industry in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Dhanasundara, I.P.T.P.; Thilakarathne, E.P.D.N.; Dias, P.C.B.; Egodauyana, K.P.U. T.; Malshani, P. K. T.
    The marine aquarium industry in Sri Lanka has become a popular industry during the past few years. Exporters have shown an increasing trend for marine ornamental species exporting due to globally increased demand. Therefore, a study was designed to assess the present situation of the marine ornamental industry in Sri Lanka. Pretested questionnairebased survey with visual observations of the exporting process was conducted by selecting 30 leading marine ornaments exporting companies to assess the situation of the industry. Export data that were gathered from Sri Lanka Customs were analyzed using descriptive analysis methods. The analysis figured that approximately 611,310 marine fish individuals in 2017 and 459,425 individuals in 2018 have been exported from Sri Lanka. Thus, 151,885 individuals of prominent decrease have been observed in exporting marine ornamental fish due to the reduction of fish catch from the wild. However, a prominent growth (49,468) has been observed in exporting marine invertebrates as 105,750 individuals in 2017 and 155,218 individuals in 2018. These ornamentals have the highest demand in the USA (336,452) followed by Japan (143,497) and UK (25,386). As per the regions, the North American region had the highest demand for marine fish approximately 406,470 individuals totally in both years and followed by the North Asian region by exporting 290,916 individuals. Family Gobidae (21.6%) was the most demanded fish family in the export market followed by family Serranidae (11.7%) Acanthuridae (10.7%), and Labridae (7.7%). Most demanded invertebrate family was Hippolitidae (83.9%) followed by family Rhynchocinedae (9.0%). However, these targeting particular species in wild capture fishery may highly affect to collapse the balance of Sri Lankan reef ecosystems. Therefore, suitable strategies should be immediately implemented to fulfill the huge demand in the exporting market while sustainably utilizing natural resources. Keywords: Marine aquarium fishery, Wild catch, Reef fish
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    Study on Illegal Fishing Practices Used for Exploitation of Fishery Resources in the Koggala Lagoon, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Guruge, S.H.; Herath, H.M.T.N.B.; Wickramaratne, I.U.
    Koggala lagoon is located in Galle district with a significant contribution to the fishery sector of Sri Lanka. The inevitability of illegal fishing practices causing a threat to the commercially important fish populations due to strengthened demand, higher prices, and emerging competition in the market, had also been a serious issue in the fishery of Koggala lagoon. The objectives of the present study were to, identify the illegal fishing methods practiced in the lagoon and quantify the approximate illegal production. A selfadministrated questionnaire survey was designed and pre-tested to collect sociodemographic details of the sixty fishermen and also average production data using illegal fishing gears over three months from October to December 2019. Catch data were collected to calculate the Catch per Unit Effort (CPUE) in common fishing gears. The Garret ranking technique was applied to assess the degree of severity of the fishing gears according to the lagoon fishermen’s perception. Results of the questionnaire survey indicated that gillnets (97%) with less than 3 ½” mesh size and monofilament nets (48%) were the most common illegal fishing gears used among the lagoon fishermen. Among the wide range of mesh sizes of the gillnets, 57.15 mm (2 ¼”) size was frequently (23.3%) used for fishing in the lagoon. According to the fishermen’s perception on the weight of the harvest and the size of the juveniles, the fixed purse net was found to be the most detrimental gear used in the lagoon (1.79 kg hour-1 ). However, considering the average catch data, the fixed purse net (7.64 kg) was also the most efficient gear used in the Koggala lagoon. The current study revealed that illegal fishing is very common in the lagoon violating government rules and regulations. Therefore, active legal enforcements and monitoring on illegal fishing practices such as usage of over-small mesh nets and monofilament nets are extremely important in preventing overexploitation of fish populations. Keywords: Koggala lagoon, Illegal fishing, Sustainable utilization, Garret’s ranking technique, Socio-demography
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    Trophic Status and Spatial Variation of Cyanobacterial Diversity in Lunugamwehera Reservoir, Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2020) Gunawardane, M.H.M.A.S.V.; Gamage, S.M.K. Widana; Wijesooriya, M.M.; Randima, G.W.A.P.; Masakorala, K.; Atapattu, K.S.S.; Sanjaya, K.
    Lunugamwehera is a large man-made reservoir located in the South Eastern dry zone of Sri Lanka. It is the main source of drinking water, irrigation, and fisheries for more than 5000 families in the area. The occurrence of cyanobacterial blooms or high population densities in water bodies results in various environmental and health issues. Population density and composition of cyanobacteria in a waterbody may vary with the trophic status of water. There is a high potential of contaminating the Lunugamwehera reservoir with mineral nutrients that come from agricultural lands. However, considerable attention has not been paid to study trophic status and cyanobacterial diversity of the Lunugamwehera reservoir. Therefore, our objective was to determine the spatial variation of cyanobacterial diversity in the Lunugamwehera reservoir along with trophic status. Sub-surface water samples collected from 28 sampling sites representing the whole waterbody were microscopically examined to identify cyanobacterial species. Total phosphorous concentration, total chlorophyll-a concentration, and Secchi depth were determined to assess trophic status using Carlson Trophic State Index. Also, water quality parameters were measured using a multiparameter water quality meter. Microscopic analysis revealed the presence of only two cyanobacterial species, Microcystis and Oscillatoria implying less cyanobacterial diversity in the reservoir. Microcystis spp. (~3.257 x 107 cells mL-1 ) dominated all sampling sites with significant difference (p<0.05) in cell densities among sites while Oscillatoria spp. (5 - 10 cells mL-1 ) occurred rarely. Apart from cyanobacteria, Pediastrum spp., Tribonema spp. and Nitzschia spp. (1 - 2 cells mL-1 ) were also identified scarcely. Water quality parameters were approximately similar in all sampling sites except increased turbidity near the inlet. According to the Carlson Trophic State Index (37.70), the water body was ‘slightly oligotrophic’. Therefore, the overall results infer the presence of less cyanobacterial diversity and significant spatial variation in Microcystis spp. as the dominant species in the slightly oligotrophic water of the Lunugamwehera reservoir. Keywords: Carlson trophic state index, Cyanobacteria, Oligotrophic, Spatial variation