Research Symposium-2016
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Browsing Research Symposium-2016 by Subject "Aquatic Resources"
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Item The Aspects on Reproductive Biology of Blue Swimming Crab Portunus pelagicus, (Linnaeus, 1758) in Mannar Area(Uva Wellassa University of Sri Lanka, 2016) Abeygunawardana, A.P.; Jayamanne, S.C.Blue swimming crab fishery is a newly emerging export oriented fishery in North and North-Eastern provinces of Sri Lanka. Since the exploitation is heavy in these areas establishment of management strategies are important for sustainability of the fisheries. Hence the aspects on reproductive biology such as maturity stages, pre-spawning and post spawning fecundity, size at first maturity and gonadosomatic index of the Blue swimming crab (Portunus pealagicus) in Mannar area were studied during the period, May to July, 2015. The fecundity was estimated using Gravimetric method. Six ovarian development stages, immature, developing, early Mature, late mature, ripe and spent were identified in non ovigerous crabs and five ovarian development stages, light yellow ovaries, pale yellow ovaries, pale orange ovaries, black colour ovaries and grey colour ovaries were identified in ovigerous female crabs. The size at first maturity was determined as 57.5 mm carapace length and carapace width 113.50 mm. The pre spawning fecundity estimates ranged from 105874 to 516000 in the crabs of 133 mm to 158 mm carapace width. The post spawning fecundity estimates ranged from 537600 to 1739000 in the crabs of 121 mm to161 mm carapace width. The pre spawning fecundity and the post spawning fecundity showed positive correlations with the carapace width, carapace length and the body weight (P<0.01). The Gonadosomatic Index of the female crabs varied from 0.94+0.0208 in immature crabs to 30.6 +0.8048 in matured crabs. More than 80 % of the catches contained immature crabs while percentage of ovigerous females was 8%. High exploitation of immature crabs and ovigerous crabs may have serious impacts on the sustainability of the Blue swimming crab fishery in future. Keywords: Carapace length, Pre spawning fecundity, Post spawning fecundity, Reproductive biology.Item Determination of a Suitable Hardening Medium for Micropropagated Anubias nana(Uva Wellassa University of Sri Lanka, 2016) Kumari, A.M.S.M.; Jayamanne, S.C.; Chandrarathna, W.P.R.Most of aquatic plant varieties are used in aquariums as ornamental plants due to their aesthetic and ecological value. The genus Anubias of the family Araceae is considered as one of the highly demanded plant types among other aquatic plant species. Among Anubias varieties, A. barteri var. nana is considered as a most cultivated and commercially important species. Micropropagation is currently applied to this plant as a tool for large scale multiplication of plants since the planting material has a very low multiplication rate. However, the high rate of mortality experienced by micro propagated plants during or following laboratory to outdoor transfer is still existing as a major limitation in large scale applications. Therefore, it is a requirement to develop an effective acclimatization procedure for a successful establishment and survival of plantlets. The present experiment was carried out in order to determine a suitable hardening medium for micropropagated Anubias nana using complete randomized design. The study was conducted at the Ornamental Fish Breeding and Training Centre, Rambadagalle. Four weeks old uniform sample of in vitro rooted Anubias nana plantlets were hardened by using five different potting media. Coir dust, coconut husks, clay brick shards, boggy soil and sand were used as different hardening media/treatments. Each treatment was replicated ten times. Every plantlet was provided with a constant amount (N: P: K-4:2: 1) of a commercial fertilizer in once a week. The performances of plantlets were measured by using survival rate and growth in each treatment. The measured growth parameters were number of roots and leaves, length of roots and leaves, fresh weight and dry weight of plantlets after 6 weeks of hardening period. Data were analyzed by using one way ANOVA and Tukey's test. The maximum survival percentage (100%) was obtained in coir dust, clay brick shards and sand. Out of five treatments of media, a significant difference (p<0.05) of root growth was shown by plantlets in coconut coir dust and sand. A significant difference (p<0.05) of leaf growth and weight was reported in plantlets in clay brick shards media. Keywords: Anubias nana, Micropropagation, HardeningItem Development of In-vitro and Conventional Propagation Protocols for Two Different Endemic Species of Aponogeton (Aponogeton rigidifolius and Aponogeton jacobsenii)(Uva Wellassa University of Sri Lanka, 2016) Weerasekara, W.N.V.; Bambaranda, B.V.A.S.M.; Jayamanne, S.C.; Krishnarajah, S.A.This research was focused on the development of successful propagation protocols for two different endangered and threaten aquatic plant species of A. rigidifolius and A. jacobsenii. Due to lack of effective propagation methods, Aponogeton species indiscriminately harvested from wild and leads to extinct. To overcome the problem of species loss and inadequate supply to the local and foreign market, in vitro and conventional propagation protocols were developed for both species. Rhizomes, seeds and leaf explants of both species were sterilized using NaOCI and 0.1 % HgC12 and established on full strength MS medium supplemented with combination of 6- benzylaminopurine (BAP) 2, 3, 5 mg/L with or without 0.1 mg/L indole acetic acid (IAA) for initiation. For shoot multiplication 2, 3, 5 mg/L BAP were used. Rhizome cuttings and seeds of both species were planted in pots, which contain sand, sand: top soil, top soil and boggy soil with water as conventional propagation method. Experiment was arranged in Complete Randomized Design method and data were analyzed using ANOVA and Tukey's Test. The presence of growth regulators had significant effect (p<0.05) on shoot initiation of A. rigidifolus rhizome. The highest shoots per replicate (2.4) were proliferated in 2 mg/L BAP medium. Application of hormones had a significant effect on number of leaves and seedling height of seed explants of both species. Maximum number of leaves (5) and seedling height (5.8cm) in A.rigidifolius obtained from the treatment which supplemented both 5 mg 1-' BAP and 0.1 mg IAA while the highest leaves (3.43) and height (1.92 cm) shown in 5 BAP alone medium in A. jacobsenii seedlings. The highest shoots per seedling (4.2) obtained from 2 mg BAP contain multiplication medium in A. rigidifolius seedling. Conventional growth media significantly influence on the shoot development from A. rigic4folius rhizome cuttings, seed germination, and in other seedling growth parameters of both species. Mean number of leaves, height of seedlings, and number of roots and length of roots were high in both plants which planted in boggy soil medium. The highest shoots ofA. rigidifolius obtained in sand medium. Keywords: Aponogeton rigidifolius, Aponogeton jacobsenii, in-vitroItem Development of micropropagation protocols for two different Cryptocoryne species in Sri Lanka (Cryptocoryne parva and Cryptocoryne xwillisii)(Uva Wellassa University of Sri Lanka, 2016) Boyagoda, D.T.K.; Jayamanne, S.C.; Herath, H.M.I.An efficient protocol was developed for the micropropagation of Cryptocoryne parva and Cryptocoryne xwillisiii, two endemic threatened aquatic herbs of Sri Lanka, which considered as highly valued aquarium plants. Rhizomes and leaves of two species were surface sterilized using Sodium Hypochlorite and 0.1 % Mercuric Chloride successfully and they were established on full strength Murashige and Skoog (MS) medium. Experiment was arranged in factorial Complete Randomized Design (CRD). Effects of basal MS medium supplementation with factorial combinations of BAP 6- benzylaminopurine (0, 1, 3, 5mg r') and NAA-Naphthalene Acetic Acid (0, 0.1, 0.3 mg 1') on shoot initiation from rhizome and leaf explants were determined after 42 days. Data were analyzed using ANOVA and Tukey's Test incorporated in MINITAB 16 software. The presence of growth regulators in MS medium had a significant (p<0.05) effect on shoot initiation in rhizomes of both species. Highest mean number of shoots initiated per single rhizome explant was observed in the combination of 5.0 mg 1-' BAPwith 0.1 mg V NAA in both species (C. parva 4.3, 3.7; C. xwillisii 4.1). Regenerated shoots of rhizome explants were cultured on MS medium supplemented with BAP 0, 1, 3 mg r' for shoot multiplication. The presence of growth regulators in MS medium had a highly significant (p<0.05) effect on shoot proliferation of both species. Highest mean number of shoots proliferated per shoot (C. parva? and C. xwillisii 5.6) was observed in 3 mg r' of BAP. Presence of growth regulators in MS medium had a highly significant (P<0.05) effect on embossing leaves of both species as a positive response. Best explant source for both species was rhizome. Optimum hormone combination for shoot initiation of both species is 5 mg of BAP with 0.1 mg r' of NAA and for shoot multiplication optimum hormone concentration is 3 mg 1-1ofBAP. Keywords: Cryptocoryne parva, Cryptocoryne xwillisii, BAP, NAA, Rhizomes and leaves, Shoot initiation, Shoot multiplicationItem 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.Item Effectiveness of Ultraviolet Filtration of Incoming Sea Water for Controlling Vibrio spp. in Shrimp Hatcheries in North Western Province(Uva Wellassa University of Sri Lanka, 2016) Pathirana, I.P.D.H.; Rajapakshe, R.M.G.N.; Jayamanne, S.C.; Ranathunga, R.M.N.P.K.Vibrio spp. are natural micro flora that presence in marine waters are one of the main factors which responsible for larval mortality of penaeid shrimp. To avoid bacteriological problems, shrimp hatcheries adopt extensive water treatments which include effective ultraviolet filtration. But there the effectiveness of UV filters is a considerable problem. Therefore effectiveness of UV filtration of incoming sea water for controlling the Vibrio spp. and the management procedures that can be implemented for improving the efficiency of UV filters were studied. Ten shrimp hatcheries out of forty seven hatcheries in north western province of the country were selected. Sea water samples were taken before and after the UV filtration and were subjected to the Total Vibrio Count (TVC) test. Thiosulfate Citrate Bile salt Sucrose (TCBS) agar was used as the culture medium and pH, salinity, Ammonium-N, Nitrate-N, Nitrite-N were checked. Questionnaire survey was also conducted for collecting information regarding water treatment systems, disinfection procedures and the factors affecting on the efficiency of UV filters. According to this study there is a significant difference by considering the TVC among hatcheries and between the TVC of sea water before and after UV filtering. It was observed that salinity and pH have no significant effect on the TVC. According to questionnaire survey, although each hatchery uses the UV bulb capacities which are relevant to the water flow rates by considering the water usage volume, the effectiveness of UV filtration is not in an efficient level when comparing the mean values of TVC of sea water before and after UV filtering. According to Chi square Goodness of fit test, availability of charcoal filters, maintaining the records of hours of UV filter operation, replacing UV bulbs after its life time and routine changing of filter media in sand, charcoal and cartridge filters have significant impact on the TVC of UV filtered water. Therefore productive maintaining of the filter system is very important for the effectiveness of UV filtration. Keywords: Water quality, Shrimp disease, Bacteriological problems, Water treatments, UV filtersItem Efficacy of Aloe vera Against Aeromonas hydrophila in Gold Fish (Crassius auratus)(Uva Wellassa University of Sri Lanka, 2016) Dissanayaka, D.M.S.G.; Jagoda, S.S.S de S; Wijesundera, R.R.M.K.K.Sri Lanka is a pioneer county of ornamental fish industry. Guppy, Goldfish, Swordtail, Moly are some fresh water fish species which have high export potential. Disease is one of the major constraints to the development of the ornamental fish industry and bacterial infections are very common in ornamental fish. Herbal medicines have become cheaper and better alternatives to antimicrobial drugs to treat bacterial infections in fish. Therefore, this experiment was conducted to determine the efficacy ofAloe vera for gold fish growth and against artificially injected A. hydrophila. A. hydrophila was isolated from a septicaemic fish and the identity was confirmed through conventional bio chemical tests and Polymerase Chain Reaction- Restriction Fragment Length Polymorphism (PCR¬RFLP). Fresh and mature A. vera leaves were used for the experiment. Antibacterial efficacy ofA. vera was tested in in- vitro by using A. vera supernatant. To examine in- vivo antibacterial efficacy, A. vera supernatant was combined with commercial fish feed and three different A. vera concentrations, i.e; 250 g/kg, 500 g/kg and 750 g/kg were used with a control. According to the results, there was a positive effect of A, vera against A. hydrophila in-vitro. Original A. vera supernatant had the highest inhibition zone in-vitro. Inhibition zone diameter was decreased with increased dilution. When consider about the in- vivo method, a noticeable increase in body weight and Feed Conversion Efficiency was observed as the A. vera concentration in feed goes up, though the values are not statistically significant. Different levels of mortalities were observed in all groups, but the highest mortality within the observed period was recorded in control group and the lowest in the group fed with highest A. vera concentration. Keywords: Bacterial infections, PCR- RFLP, Feed conversion efficiency, Antimicrobial drugs, Ornamental fish industry.Item Examine the Appropriate Ovulation Time to Determine Latency Period of Golden Tinfoil Barb (Barbonymus schwanenfeldii) Using OvaprimTM(Uva Wellassa University of Sri Lanka, 2016) Isharini, W.A.U.; Epasinghe, E.D.M.; Karunaratne, T.A.D.W.; Adikare, A.M.A.N.; Liyanage, N.P.P.Fertility of the Golden Tinfoil Barb is very low when they are subjected to induced breeding practices. The research was carried out to determine the appropriate ovulation time for maximizing the fertility rate of Golden Tinfoil Barb, Barbonymus schwanenfeldii. Induced spawning of Barbonyms schwanenfeldii was conducted at different Ovaprim (sGnRHa and Domperidone) dose and latency period combinations to observe the appropriate ovulation time to increase the fertility. For the purpose, three doses of Ovaprim (0.4, 0.6 and 0.8 mL/kg of body weight) and three latency periods (4, 6 and 8 hours) were considered in nine combinations. Males were injected with half of dosage from female. Induced of breeding was carried out in the hatchery and same water source was used for maintaining the equal condition. After the injection, biopsy tests were performed for all the females after 4, 6 and 8 hours from the injection to detect the moment of ovulation. After eight hours, mean egg diameter was 982.81 ± 48.49 vm, germinal vesicle had broken down, follicle had already removed and ovulation had occurred. When ovulation was observed, hand stripping and then artificial fertilization was carried out. One hour after fertilization, between 40 and 60 eggs of three samples were taken from the hatching jar for each dosage and eggs were counted to calculate percentage of fertilization. Although all ovulation times were recorded in approximately eight hours after the injection, the recorded fertility rates were different. 4% fertility rate was recorded with the 8 + 2.0 hours in 0.4 mL/kg, while it was 80% with the 8 ± 0.5 hours in 0.6 mL/kg of Ovaprim and fertility rate was 52% when 8 ± 0.5 hours in 0.8 mL/kg. The highest fertility rate was recorded in 0.6 mL/kg of dosage. Although 8 ± 0.5 hours ovulation time was recorded in 0.6 mL/kg and 0.8 mL/kg of body weight of female, their fertility rates were different. Keywords: Fish breeding, Egg diameter, Hand stripping, GnRH, Fertility rateItem Identification of Factors Affecting the Survival of Lobster Exports Industry in Sri Lanka with Special Reference to Spiny Lobster(Uva Wellassa University of Sri Lanka, 2016) Chamodika, L.P.S.; Jayamanne, S.C.; Duminda, T.G.A.At present there are five main species of Spiny Lobsters exported from Sri Lanka. There are controversial findings regarding lobster resource and it is required to know the current status of the lobster resource in Sri Lankan oceanic waters. Thereby the status of lobster fishery and exports industry as well as the factors affecting the survival of lobster exports industry in Sri Lanka are required to be identified. The present study was carried out to fulfill this requirement. Questionnaires and direct interview methods were used to obtain the relevant information from the exporters, lobster fishermen, lobster purchasing centers and collectors. Lobster export data and catch data were analyzed by using MS Excel. Information related to legal aspects and other stock assessment projects related to lobsters were obtained from Ministry of Fisheries and NARA. Currently, Panulirus longipes is the mostly exported lobster species and it accounts for 30.4% of total lobster exportation. Panulirus ornatus is nearly overexploited. Panulirus polyphagus has completely vanished from Sri Lanka. Panulirus ornatus fetch the highest price in the export market (US$ 701Rs. 8200 per Kilogram). Highest lobster production and export quantity as well as the highest export value were earned in 2013. Availability of the lobsters in the ocean around Sri Lanka, laws and regulations, political influence, Scuba divers & other recreational divers, problems faced by the lobster fishermen, problems faced by the exporters, illegal activities done by fishermen, collectors and exporters are the factors affecting the survival of lobster exports industry in Sri Lanka which were identified from the present study. Some of these factors affect positively on the survival of lobster exports industry while other factors affect negatively on the survival of this industry. Relevant authorities should take steps to protect this lobster resource while providing opportunities to the fishermen, exporters and local consumers to use the resource in a sustainable manner. Keywords: Lobster export industry, Lobster production, Stock assessmentItem An Investigation of the Economic Impact on Fishing Communities in Mannar District Caused by Illegal Fishing by Indian Trawlers in Sri Lankan Waters(Uva Wellassa University of Sri Lanka, 2016) Sosai, B.M.K.; Wickramaratne, I.U.; Jayamanne, S.C.Mannar district is located in the Northwestern Sri Lanka (8° 52' 0" N, 80° 4' 0" E). Thalaimannar, Pesalai, Vankalaipaadu, Erukkalampiddy, Pallimunai, Panankaddikoddil, Thalvupadu in Mananr District were selected for the study. Primary data were collected through a questionnaire survey and direct interviews with fishing community leaders, officials of department of fisheries, fishing agents and traders. Information on fishing season (charts), monthly income, the relative impact of Indian trawlers on village fishing activity, direct and indirect losses to the ancillary service sectors in each village, the quantities of fish and fish species caught by Indian trawlers and the number of Indian trawlers and their annual production were obtained. Secondary data was gathered through research papers, publications and internet. Gathered data were analysed with three approaches i.e. Approach A: Direct losses due to Indian trawlers harvesting Mannar's marine resources, (estimated daily and annual direct losses were Rs.54.4 million and Rs.6955.2 million, respectively) Approach B: Indirect loss due to Mannar fishermen by not being able to harvest Mannar's marine resources (estimated annual indirect losses were Rs.425.63 million), Approach C: Direct losses due to the destruction of fishing gears (Rs. 2, 56, 18,750), Approach D: Direct and indirect losses for ancillary service sector (Rs.24, 59,400 and Rs.24, 59,400 respectively). Data were analyzed using MS Excel 2010. Indian trawlers fish in the northern Palk Bay and south of Gulf of Mannarall year round, while they trawl Pesalai, Vankalaipadu, Erukkalampiddy and Pallimunai in northern coast of Mannar from May to October. Further, Panankaddu koddil and Thalvupadu, located in Southern Mannar were trawled from November to April. Mechanized trawling has been banned by Tamil Nadu State Government for 45 days a year, therefore illegal trawl fishing stops in between March to April (about 45 days). In this study it was found that Thalaimannar (with idela location for fishing), Peasalai and Vankalaipaadu villages were highly affected. Vankaalaipaadu fishery activities mainly depend on gill net. It was found gill net fishing activity was affected by trawler activity. Five other villages faced less loss due to the operation of trawlers, because fishery activities carried out only for six months using variety of fishing gears. Keywords: Mannar district, Indian Trawlers, Coastal fishery, Gill net, Economic Impacts.Item An Investigation on Total Catch, Catch Composition, Catch Quality Variation Based on Different Effort Levels in Multiday Boats in Kalutara District(Uva Wellassa University of Sri Lanka, 2016) Fernando, A.W.K.; Gunawardane, N.D.P.; Wickramarathna, I.U.; Jayamanne, S.C.Deep sea fisheries commenced in late 1980s and introduction of Multiday boats with modern technologies (GPS, SSB radio, Freezer unit, Fish detecting sonar) and synthetic nets increased the pelagic fish production. The multi-day boats in operation today are of several types, varying according to their length and the degree of sophistication. Those vessels use several types of fishing gears based on their preference and also fishing duration also differ with those boats. Fishermen have their own selections on those variables according to their knowledge, experience to maximize their catch with good quality by applying minimum effort.This study was carried out to identify the deep sea fishery trends and optimum efficiency levels in Kalutara fishery district using landing statistics (Catch) and fishing inputs (effort) and to give recommendation on management of Kalutara fishing fleet. In this study, total catch per fishing trip and species wise catches taken as output data and gear type, fishing trip duration, boat length, facility level, no. of crew and boat capacity are taken as input data. Parallel organoleptic survey of fish catch was conducted to measure the quality level of fish. The study found that only the gear type is significantly affecting total catch per trip and other five factors (Boat length, Boat capacity, No. of crew, Trip duration, and Facility level) do not affect the total catch per trip. Three types of fishing gear including longline, gillnet and ring net and combination of gears was used basically and the catch composition of the single species catch is not significantly affected by gear type. Longline, gillnet and ring net when taken individually, significantly affects the species catch variation. The fish quality is significantly affected by total catch, trip duration, and boat capacity while not significantly affected by gear type and facility level. So according to the study it can be recommend that gear combination (better to use Longline cum Gill net) is the most suitable fishing method as it gives high fish catch (2427 236) with medium quality (1.8571 0.1650) fish and more emphasis should be given on fish quality improvement in Beruwala fishery harbor. Keywords: Deep sea fishery, Multiday fishing vessels, Catch, Fishing effort, Fish quality, Fisheries managementItem Preliminary Study of Bioluminescence Species in the Southern Bay of Bengal(Uva Wellassa University of Sri Lanka, 2016) Wimalasiri, H.B.U.G.M.; Jinadasa, S.U.P.; Dissanayake, D.C.T.; Weidemann, A.; Wijesekera, H.Marine organisms ranging from bacteria to fish make their own chemically induced light called bioluminescence, it is used to hunt, frighten predators, attract mates, communicate, or camouflage them. The bioluminescence phenomenon was studied in the southern Bay of Bengal during August 2015 onboard R/V Roger Revelle operating from Colombo, Sri Lanka. The intensity of light produced by bioluminescence spices was measured using Recoverable Bathy Photometer (RBP). The RBP recorded light intensity while free falling at a speed of about 1-1.5 m/s. Several RBP profiles in the upper 200 m were collected at six different sites encompassing a region 5 - 8N, 85.5 - 88.5E. All samples were collected in the night time to minimize interferences from other light sources. Zooplankton samples were collected using 150 1.11T1 mesh size plankton net from each location to identify light producing zooplankton species. The RBP measurements showed the existence of bioluminescent organisms in all the sampling locations and high light intensity was found up to 150-200 m water depths. Sapphirina sp belonging to the family Sapphirinidae of phylum Arthropoda was identified as one of the light emitting zooplankton species. Studies are underway to examine the luminous substances, and vertical and spatial distribution of these species, especially around Sri Lankan coastal waters. Key words: Bioluminescence, Recoverable bathy photometer, Zooplankton, Bay of Bengal.Item A Preliminary Study on Absorption of Heavy Metal (Lead) From Synthetic Waste Water Using Mullet (Mugil spp.) Fish Scales(Uva Wellassa University of Sri Lanka, 2016) Herath, H.M.S.S.; Alakolanga, A.G.A.W.; Abeyrathne, E.D.N.S.Heavy metals are relative dense metals present in earth crust that are in high accumulation level in water bodies. Among several technologies to remove these heavy metals, biosorption is a novel concept that use in waste water facilities. This study was carried out tofind the feasibility of using mullet (Mugilidae spp.) fish scales as a biosorbant and find the best cost effective form of mullet fish scales to absorb heavy metal (Pb) in synthetic waste water.The effect of oven drying conditions, particle size, and dosage of fish scales and pH for the absorption of heavy metal (Pb) absorption were investigated by Atomic Absorption Spectrophotometer (AA240, 283.33 nm, Varian., Australia). The reusability was investigated with the use of nitric and hydrochloric acids. The highest mean absorption results were obtained for 3 g (98.70 0.73) of damaged 1-2 cm2 size (92.03 ± 0.51) with oven drying conditions of 80°C (99.10 ± 0.52) for 24 hours (93.93 ± 2.38). All parameters were indicated that there was a significant difference among the treatments (P < 0.05). In addition to that, absorption was not depended on pH and reusable ability was high with the nitric (19.83 ± 5.66) compared to hydrochloric acid (3.09 ± 0.37). But in cost effective manner new fish scales were more applicable. The observed reason for the efficient biosorption from the fish scales were the crystal structure, chemical composition of hydroxyapatite with porous structure and the highly ordered three dimensional structure of collagen. This research revealed that, there is a high potential to use mullet fish scales as a biosorbant for treat waste water in wastewater treatment facilities and it is a rapid, cost effective and high efficient biosorbant among other biosorbants. Keywords: Heavy metal, Biosorption, Cost effective, Hydroxyapatite, CollagenItem Strategies to Reduce Larval Cannibalism of Pangasius stitch!(Uva Wellassa University of Sri Lanka, 2016) Thilakarathna, W.M.W.S.; Epasinghe, E.D.M.; Karunaratne, T.A.D.W.; Adikari, A.M.A.N.; Liyanage, N.P.P.Ornamental fish industry is the most significance income earning approach in Sri Lankan economy. Pangasius sutchi (Thai pangus) is considered as the most popular ornamental fish species. In their early larval stage, they show cannibalistic behaviour which leads reduction of population. Then experiment was conducted to reduce the larval cannibalism of larvae within first 72 hours because it has been identified as the critical period of their cannibalistic behaviour. Therefore several types of feed, feeding frequencies and stocking densities were tested. We investigated the effect of two different types of feed(Artemia and Moina),three different feeding frequencies (3hr,4hr,5hr)and three different stocking densities(60.90.120)one square feet can hold 80 larvae and 22"x 10x 10glass tank can hold approximately 94 P.sukhi larvae. Each tank was randomly assigned to one of the treatment. At the end of the experiment numbers of survivals were calculated to determine the cannibalism rate. Five fish from each tank were sampled to measure body length. Then numbers of average body length were recorded. Data were statistically analized by using MINITAB 17 software. Significance levels were calculated to determine whether there is any relationship or not. Results showed that the feed types were not significantly (p>0.05) affect the survival rate and it only affected the body length. Feeding frequency was significantly (p<0.05) affected the survival rate and not affected the body length. And also results showed that stocking density affected the survival rate significantly (p<0.05) and not affected significantly for body length of larvae. Final results indicated that highest mean survival rate was recorded with 60 stocking density whereas lowest survival rate was recorded in 120.highest mean body length was recorded with the Artemia feeding with 3hour feeding frequency. Keywords: Cannibalism, Feeding frequency, Stocking density, Artemia, MoinaItem Study of the Diversity of Benthic Macro-Invertebrates at Panadura Estuary in Sri Lanka(Uva Wellassa University of Sri Lanka, 2016) Weerasooriyagedara, M.S.; Hettige, N.D.; Amarathunga, A.A.D.; Rajapaksha, R.M.G.N.; Jayamanne, S.C.; Weerasekara, K.A.W.S.; Maddumage, M.D.S.R.; Azmy, S.A.M.; Wickramaarachchi, W.D.N.; Jayawardane, J.K.P.C.; Narangoda, S.R.C.N.K.Panadura estuary situated in the western province in Sri Lanka where Bolgoda lake opens into Indian Ocean harbours a lot of aquatic biodiversity. Therefore, main objective of this study was to identify the diversity of benthic macro-invertebrates, to assess the correlation between physico-chemical parameters and macro-benthic invertebrate diversity and to evaluate the pollution level in the estuary with respect to the diversity of benthic macro-invertebrates in Panadyra estuary. Both sediment and bottom water samples were obtained from 19 randomly selected sampling locations in Panadura estuary. Collected Benthic macro-invertebrate samples were wet sieved and identified using standard identification keys. The diversity of benthic macro — invertebrates was determined by using Shannon —Weiner index, richness was calculated using Margalef s index and the health status of the estuary was determined by using Pollution Tolerance Index. Similarities among macro-benthic communities at different locations were determined by using Bray — Curtis similarity coefficient. This study also attempted to determine the physico — chemical determinants that govern the spatial variation. Individuals of 1708 species of macro benthos belonging to 14 families were identified. Planobidae, Haminoidae and Veneridae were the most abundant families. The lowest species richness and diversity was reported at PE6 while highest species richness and diversity was reported at PE7. The sampling locations were separated into several clusters based on the diversity of macro benthos. The major physico-chemical parameters which had effect on the diversity of macro benthos were Biochemical oxygen demand and nitrate nitrogen concentration. Shannon Weiner diversity index in each location at Panadura estuary was in between 2 — 3 and Pollution Tolerance Index in each location was lower than 20. Both these indices confirmed that the aquatic health of Panadyra estuary was in poor condition. Key words: Benthic macro- invertebrates, Diversity, Pollution Acknowledgements: The authors are thankful to the National Aquatic Resources Research and Development Agency for providing funds to carry out this research project