Research Symposium-2013

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Antibacterial Efficacy of Mangrove Rhizophora mucronata Extracts on Aquatic Bacterial Pathogens
(Uva Wellassa University of Sri Lanka, 2013) Bokalawella, S.H.K.; De Silva, D.P.N.; Jayamanne, S.C.; Gunasekara, A. J. M.; Piyadasa, H.T.N.I.
Medicinal plants contain components of therapeutic value and are used as remedies for human/animal diseases. They are environmentally friendly due to less toxicity and have minimal health hazards (Opara and Wokocha, 2008). Mangrove plant extracts and its major chemical classes displayed various levels of antibacterial, antifungal, antifouling, antiviral and free radical scavenging effects due to their bioactive compounds (Bandaranayake, 2002). Bacterial infections cause severe economic losses to the aquaculture industry which increased the use of antimicrobial agents significantly as a treatment (Alderman and Michel, 1992). Improper usage and presence of drug residues lead to the development of resistant strains of pathogenic bacteria. Therefore, novel antibacterial compounds of natural products which degrade easily need to be synthesized to overcome above consequences. Aim of this study was to find out the antibacterial efficacy of Mangrove Rhizophora mucronata extracts on aquatic bacterial pathogens, to be used as a remedy to treat fish diseases. Methodology Fresh matured leaves of six mangrove plant species (Avicennia marina, Lumnitzera racemosa, Bruguiera sexangula, Acanthus ilicifolius, Excoecaria agallocha and Rhizophora mucronata) were collected from mangrove reserve at Kadolkele, Negombo and were brought to the laboratory for making extractions. Initially, preliminary trials were conducted for identification of most suitable species with antibacterial properties against four aquatic pathogens Listeria monocytogenes) in vitro by well diffusion method. Upon identification of Rhizophora mucronata having the highest inhibitory zone for tested bacteria, further analysis were performed using various parts such as roots, barks, flowers and fruits of R. mucronata. The solvent was extracted by mixing 8 g of each part of mangrove in powder form, with 125 ml of 95% methanol and evaporating methanol using rotary flash evaporator (model 519-00000-00- 3). Antibacterial efficacy was assessed against all four species of fish pathogens, using was used as the positive control against Rhizophora mucronata extractions of 350 mgml each. After 24 hour incubation at 25 o C, the diameters of the inhibitory zones were obtained and statistically analyzed by using One way-ANOVA incorporated in Minitab version 16. Results and Discussion All six mangrove species showed antibacterial activity against Listeria monocytogenes, Pseudomonas fluorescens, and Pseudomonas aeruginosa significantly (p<0.05) but insignificant for Shigella flexneri (p>0.05). Highest inhibition zones were observed in Rhizophora mucronata leaf extract against all bacteria examined for the study (Table 1). Rhizophora mucronata extracts (root, bark, fruit and flower) also exhibited positive inhibition zones for all the tested bacterial species cultured in vitro. Root and bark extracts possessed higher antibacterial potential when compared to the fruit and flower extracts. Rhizophora leaf extracts showed highest inhibition for Listeria monocytogenes and Pseudomonas fluorescens while root and bark extracts were effective against Shigella flexneri and Pseudomonas aeruginosa respectively (Figure 1). The overall mean comparative evaluation on antibacterial efficacy of Rhizophora mucronata extracts displayed the highest in leaves followed by the root, bark and fruit extracts. The minimum antibacterial activity was observed in the flower extracts.
Antimicrobial Activity of Seagrss (Cymodocea serrulata) from South West Coast of Sri Lanka
(Uva Wellassa University of Sri Lanka, 2013) Arulananthan, A.; De Silva, D. P. N.; Jayamanne, S. C.; Dalpatadu, S.L.; Senaratne, S. G.
Sri Lanka has rich oceanic vegetation along its coastal water bodies. However, utilization of them is limited when compared to terrestrial plants which are used as natural alternatives especially in Ayurveda remedy. It is expected that marine vegetation also ensure the potential bioactivity. Marine plants derived natural products are known as secondary metabolites which are bioactive compounds responsible for antimicrobial activities. Documented results from most of the Atlantic, Pacific, and Indian Ocean resultant macro algae exhibits broad range of biological activities. Some of these are antibacterial, antifungal, antiviral etc. On the other hand, few literature are available on the therapeutic values of seagrasses in Sri Lanka. Therefore, the objective of this study was to test the antimicrobial activity of some selected seagrass species collected from the Beruwela beach rocky platforms and Hikkaduwa coast of Sri Lanka. Methodology Collection and preparation of samples - The fresh seagrass species (Cymodocea serrulata) was collected by hand picking during the low tidal conditions from the submerged rocky platforms of Barberrian reef and in Hikkaduwa coast. The collected vegetation was cleaned well with tap water and distilled water. Then the samples were drained and spread on the filter paper to remove excess water. Samples were chopped into nearly 1cm length pieces prior to grinding using liquid nitrogen. Solvent extraction - Coarsely powdered samples were subjected to solvent extraction by using chloroform, methanol and water solvents. The powdered form of samples and solvents were taken (1:10 w/v) and kept for 24 hours at room temperature (27 °C) in the orbital shaker at 150 rpm. Later, the extracts were filtered through a Buchner funnel with muslin cloth followed by Whatman number 1 filter paper. The resulting filtrates were concentrated by using rotary evaporator. Test microorganism - Human pathogenic Gram positive bacteria Staphylococcus aureus, Gram negative bacteria- Escherichia coli, and a fungal species Candida albicans were used to defeat the antimicrobial activity of C. serrulata. Antimicrobial susceptibility test - Antimicrobial activity of extracts was performed by using the disc diffusion method and agar well diffusion method. The stock solution was prepared with extract of 100 mg/ ml concentration of respective solvents. Sterile discs of 6 mm diameter were prepared in three different quantities (1 mg, 2 mg, and 5 mg). Each plate contained discs with three different quantities and negative control. Agar well diffusion method was carried with all extracts in same concentration as 100 mg/ ml in three different quantities (5 mg, 10 mg and 20 mg). In positive control Kanamycin 10 µl (3µg/ µl) was used for bacterial species and Flucanozole (1.25 µg/ µl) was used as antifungal agent. The plates were incubated overnight.
Application of GIS to Identify Potential Areas for Aquaculture in Badulla District in Uva Province
(Uva Wellassa University of Sri Lanka, 2013) Sandamali, M.A.N.; Rathnayake, R.M.C.W.M.; Liyanage, N.P.P.; Jayamanne, S.C.
Aquaculture is farming aquatic organisms including fish, mollusks, crustaceans and aquatic plants (FAO, 1990). The main intent of the present study is to highlight the role Geographic Information System (GIS) in identifying potential areas for aquaculture in Badulla district. The study was carried out in Badulla district in Sri Lanka by the geographical coordinates of longitude 80 .45 to 81 .15. Latitude 6 .34 to 7 .18. Data have been collected from secondary sources and used to generate maps to identify fresh water bodies in Badulla district. Map of seasonal tanks, reservoirs and tanks, stream network and rivers of Badulla district were developed. Water availability (proximity to rivers), soil texture, soil pH, rainfall, temperature and topography (slope, elevation) and land use factors were considered to identify potential areas for aquaculture (pond culture). Protected areas are considered as constraints. Water availability, soil texture, soil pH, slope, elevation, rainfall, temperature, land use/ land cover thematic layers were created using ArcGIS 10.1 software. All these thematic layers have been assigned the weights according to their relative influence on pond construction using Analytic Hierarchy Process (AHP) and GIS approach. Finally, all thematic layers have been integrated in a ArcGIS 10.1 environment to generate an aquaculture potential map. Thus, four aquaculture potential areas have been Identified, viz. “Most suitable”, “Suitable”, “Fairly suitable”, “Unsuitable”. The north part of the Badulla district is identified as most suitable and the southern part of the Badulla district is identified fairly and unsuitable for aquaculture in Badulla district. Methodology Data collection: Secondary data were collected from secondary sources. GIS analysis: reservoirs and tanks, Rivers, Stream network of Badulla district were digitized using Arc View 3.1 software. GPS coordinates of seasonal tanks were stored & developed a map using ArcGIS 10.1 software to identify fresh water resources in Badulla district and all data were stored in ArcGIS 10.1 environment and factor thematic layers were generated to identify potential areas for aquaculture. Analytic Hierarchy Process (AHP) - AHP is a multi-objective, multi criteria decision making approach that employs a pair wise comparison procedure to arrive at a scale of preference among a set of alternatives (Dai et al., 2001). Thematic layers were evaluated using scores and each weighted according to their relative importance on the aquaculture using Analytic Hierarchy Process (AHP) and GIS approach. Map Generation -Each thematic layer was evaluated using the scores that were obtained according to the weighted linear combination in ArcGIS 10.1 environment. Vector format was converted to raster format. To reject the constraints the final result was multiplied by absolute constraints. The protected areas were allocated a zero score. Finally, the potential areas for aquaculture map was created and categorized into four levels: Most suitable, Suitable, Fairly suitable, Unsuitable based on the total scores obtained from the weighted linear combination.
A Comparative Study on the Diversity of Seagrass Species in a Selected Area of Puttalam Lagoon
(Uva Wellassa University of Sri Lanka, 2013) Ranahewa, T.H.; Jayamanne, S.C.; Gunasekara, A.J.M.
Seagrasses are aquatic angiosperms which are widely spread in shallow marine environment (Kuo and Hartog, 2000). Providing habitat grounds for large numbers of fish and shellfish species, act as a largest carbon sink, support a large number of epiphytic organisms, bind the sediment together and stabilizing sea bottom (Johnson and Johnstone, 1995) are the importance of seagrasses. Puttalam lagoon which is located in Puttalam district of Northwestern Province of Sri Lanka that covers 32700 ha (Johnson and Johnstone, 1995). There are fifteen species of seagrasses have been recorded in Sri Lanka including two families, 12 genera (Amarasinghe and De Silva, 2007). Main objective of the research is to compare changes of seagrass distribution from 1991 to 2013 where as to evaluate relationship between distribution of seagrasses with the states of water quality of selected locations of Puttalam lagoon and to compare the distribution of seagrass species according to salinity levels of each location are specific objectives. Methodology The present study was carried out in selected areas of Puttalam lagoon during the period of May to September in 2013. Kalpitiya, Kuringipitiya, Palliwasalthurai, Kandakuda, Palavi and Puttalam were the selected sites for the data collection (Figure 1). Geographic Position System (GPS) data of the site were recorded and point transect method was used for the sampling. Three line transects of each location were used. Typically transects were perpendicular to the shore and parallel to each other. Cover of seagrasses within a quadrant with 0.5 m * 0.5 m was measured at every 3 m mark of the 30 m by walking and snorkeling until transect was completed. Transects were selected and procedure was carried out in such a way that as same as Jayasuriya, 1991 conducted. Water quality parameters including water temperature (°C), pH, salinity (ppt), conductivity (mS/cm) and dissolved oxygen (mg/L) were measured at the middle of transect two at 10 cm below to the sea surface using Multiparameter meter (Orion Water quality testing was repeated at the same time in the same place once a month and average values were calculated. Same procedure was repeated in other selected locations. Average abundance of seagrass distribution of three transects were calculated. Diversity of seagrass species of each sites were calculated using Shannon - Weiner diversity index. Comparision was conducted using analysis of variance (ANOVA). Percentage abundance of each species were calculated by dividing six sites into two regions as Northwestern and Southeastern according to Jayasuriya, 1991 and compared with the values recorded by Jayasuriya, 1991. Linear regression was conducted to find out relationship between seagrass distribution and water quality parameters.
Determination of Efficiency of Crab Shell Powder for the Treatment of Fish Waste Water
(Uva Wellassa University of Sri Lanka, 2013) Wijesundara, A.P.; Rajapaksha, R.M.G.N.; Jayamanne, S.C.; Fonseka, W.R.K.
Water is the most important and basic requirement for life on earth. However, only about 1% of the world’s water can be used for the human consumption. Seafood processing is one of the major industry, which threatens the quality of natural water bodies due to its composition (Zvezdov and Zvezdova, 2010). It elevates the Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Fats, Oil and Grease (FOG) in natural waters and causes eutrophication (Tahir et al., 2013). Some toxic residues may be produced as by-products due to chemical reagents used in conventional wastewater treatment methods, which are toxic for human health and the environment (Gaherwar and Kulkarni, 2012). Hence the utilization of shellfish waste has been proposed as a low cost and eco-friendly wastewater treatment method to solve environmental problems and as a waste management alternative to the masses of shellfish wastes (Muhaemin, 2005). Shells of Portunus pelagicus were used in this study to examine its effectiveness as an adsorbent in treatment of fish processing wastewater. Methodology Crab shells collected from Alpex Marine (pvt)were cleaned and dried at 100 °C for 8 hours using MICHCHEL tray dryer and crushed then sieved to raw powder with 0.1-0.5mm particle size range.50 g of raw powder was heated at 950 °C for three hours in a muffle furnace ( Xy- 1100x-L) to prepare heat treated crab shell powder. Chitin and Chitosan were collected from Industrial Technology Institute laboratory. Wastewater samples were collected from Ceylon Fresh Seafood(pvt) and initial COD (Golterman and Clymo, 1970), pH, temperature (MARTINI pH 55 pH meter), Total Dissolved Solid (TDS) (EUTECH CON 510 TDS meter) and turbidity (TN-100 turbidity meter)values of the wastewater were recorded. The first experiment was done to find out best powder dosage and 5.0 gl dosages were taken from each powder type then placed into 250 ml glass beakers. Then 100 ml of fish wastewater was added to each beaker and stirred for 2 minutes Three replicates were used for each treatment. A beaker containing wastewater only was used as the control. After 24 hours final pH, temperature, TDS, turbidity and COD of treated wastewater were measured using AOAC (1985). During the second experiment initial pH value of the wastewater samples were adjusted to pH 5, 7 and 9 by adding 0.1 M HCl or 0.1 M NaOH. Then selected the best powder dosage from the experiment 1 was used for the second experiment and same procedure was followed to find best pH value which allows highest COD reduction. In the third experiment pH of the wastewater was maintained at the best pH value which was selected from the second experiment. Combinations of Chitosan and heat treated crab shell powder was used in1:1, 1:2, 1:3, 3:1 and 2:1 ratios. Total powder weight in each combination was equal to the best powder dosage which was selected from the first experiment. After 24 hours same procedure was followed as in the early experiments. Finally best powder combined ratio was selected based on highest COD reduction. Significant effect of each treatment was analysed by analysis of variance (ANOVA) using General Linear Model (GLM) procedure of Minitab 16 statistical package.
Development of Calcium Supplement from the Bones of Yellow Fin Tuna (Thunnus albacares)
(Uva Wellassa University of Sri Lanka, 2013) Gunawardane, K.A.D.D.S.; Thushari, G.G.N.; Jayamanne, S.C.; Malavige, M.
The mineral calcium is mainly important in building of bones and teeth and regulating certain metabolic processes in human body. According to the sources of Health ministry, daily dietary requirement of calcium for adults in Sri Lanka is 750-800 mg. Insufficient intakes of dietary calcium produce hypocalcaemia and osteoporosis (Piratheeban, 2013). Therefore, it is important to use food supplement to enhance the calcium content in various kinds of foods. Fish bones are well known to contain a high amount of calcium and fishbone ash normally contains 34 -36% calcium, particularly calcium phosphate (Hamada et.al., 1995). Yellow fin Tuna (Thunnus albacares) is one of the commercially valued fish species in fish processing industries in Sri Lanka and its’ bones are discarded as waste by processing industries causing environmental pollution. The present study therefore, focuses on developing a method for producing a calcium supplement suitable for human consumption using the bones of Yellow fin Tuna (Thunnus albacares) and reduces accumulation of fish bone as waste causing environmental pollution. Development of a calcium supplement using fish bone will be a new implication in value addition sector of aquatic products in Sri Lanka. Methodology Bones of Yellow Fin Tuna were collected from Global Sea Foods (Pvt) Ltd., Badalgama. Collected samples were manually rinsed to remove adhered muscle residue after transporting to Animal Science laboratory of Uva Wellassa University. The processing steps include pretreatment using NaOH, neutralization, drying, grinding and sifting. Two experimental trials with different treatments were conducted including three replications for each treatment. Trial I was carried out to find out the best NaOH concentration and boiling time combination based on the softness of fish bones (T1- 9%, 80 minutes, T2- 9%, 90 minutes, T3-9%, 100 minutes, T4- 10%, 80 minutes,T5-10%, 90 minutes,T6-10%, 100minutes,T7-11%, 80 minutes,T8-11%, 90 minutes,T9- 11%, 100 minutes).The best treatment was selected by assessing the easiness of grinding 10 g of pretreated fish bones by mortar and pestle for 1 -2 minutes. After neutralization (rinsing by water 7 times), selected best pretreated sample was subjected to Trial II. Trial II was conducted to find out the best time and temperature combination (S1- 80 ºC, 70 minutes; S2-80 ºC, 80 minutes; S3-80 ºC, 90 minutes; S4-90 ºC, 70 minutes; S5- 90 ºC, 80 minutes;, S6- 90 ºC, 90 minutes; S7-100 ºC,70 minutes; S8-100 ºC, 80 minutes and S9- 100 ºC, 90 minutes) for powder form final products. All final products were packed using polyethylene cover and stored at room temperature. Then all final products were analyzed for different parameters. Moisture contents and Drying ) (MR- Moisture ratio, Mt- Moisture content at a specific time, Mo- Initial moisture content, Me- Equilibrium moisture content, k- Drying kinetic rate constants, t-Time) (Techochatchawal et al., 2009) were evaluated for all final samples of Trial II. Calcium content (AOAC Standard Method 927.02) was determined for final treatments of Trial II and most suitable treatment was selected using above parameters. Proximate composition of selected final product was determined for Pb content (AAS, Method 7082), crude fat, ash and crude protein level (AOAC, 1995). Microbiological analysis was conducted using Total Plate Count (TPC) for selected treatment at 37 C. Finally, best treatment was compared with Standards for Supplementary food (Notification of the Ministry of Public Health o.293 B.E. 2548, 2005). Results were analyzed using Kruskal-Wallis test and Analysis of Variance (ANOVA) incorporated in MINITAB 14 soft ware.
Distribution and Abundance of Seaweeds at Polhena Reef-Matara
(Uva Wellassa University of Sri Lanka, 2013) Ediriweera, A.N.; Jayamanne, S.C.
Polhena reef is among the most valuable marine ecosystems existing along the southern coastal belt of Sri Lanka. The reef is a fringing coral reef and is highly diverse both in flora and fauna. It is well known as an ecosystem that has significant ecological and economical value. Senaratne et al. (2013) has indicated that the reef is exposed to anthropogenic activities and is disturbed to some extent. Coral reef is covered with seaweeds that belong to categories of green, brown and red. Seaweeds also play a major role as live feed, breeding grounds and as habitats for marine fauna existing in coral reef. It is also economically important as human food, animal feed, pharmaceutical, fodder, stationary and cosmetic production. Growth, distribution and abundance of seaweeds vary spatially, seasonally and with other external factors of the environment. This study was focused on the identification of seaweed species, distribution and their abundance within a selected area of Polhena coral reef with an aim of finding their value as an ecological resource. Methodology The study was carried out during the period May, 2013 to July, 2013. An area with a length of 3 km parallel to the shore was selected for the study and five parallel transect lines (T1-T5) were laid across the coral reef perpendicular to shore up to the sea end of the reef using colour coded nylon ropes. An equal distance was maintained between every adjacent two transect lines by using a GPS (Garmin GPS 72). Each rope was marked at each 4 m. Triplicate samples of seaweeds were collected between each and every two marks using a 50 cm x50 cm quadrat and photographs were taken at each quadrat using an underwater camera (Panasonic-Lumix FT-20). Data on species composition and percent cover of the seaweeds that were collected from each quadrat. Species were identified at the laboratory using hand lenses and a binocular microscope (SN090933909 labomed binonular) (Coppejans et al., 2009). Species of seaweeds recorded in five transects during the study period was entered to a table created in Minitab-15 data sheet and Microsoft Excel data sheet. Statistical analysis was done using a Two-way ANOVA, One-way ANOVA and Turkey’s Test in Minitab 15 statistical software.
Evaluation of Post-Harvest Quality Losses of Tuna Catch of Multiday Boats in Beruwala- Kalutara
(Uva Wellassa University of Sri Lanka, 2013) Amrin, A.H.M.; Wickramarathne, I.U.; Gunawardane, N.D.P.
Fishery industry provides an important source of protein, livelihood for people and foreign earnings. Fish is a highly perishable food, requiring proper handling, processing and distribution, to be utilized in a cost effective and efficient manner. Physical losses, Biochemical losses and Economical losses are three major types of fish post-harvest quality losses that cause food insecurity, low income to fishers, processors and traders. So it is necessary to develop systematic, practical tools for assessing post-harvest losses. The study was focused on Tuna catch of Multiday (IMUL) fishing vessels at Beruwala fishery harbour in Kalutara district. Fishermen who operated multiday fishing vessels were interviewed using a standardized questionnaire to obtain the attitudes and opinion of fishermen regarding the quality control aspects of fishery activities in study area within the period of 8 weeks during 5.30 am to 8.30 am. The minimum sample size among these IMUL vessels was selected using “Likert scale (1932)” and “Moving Average” method, where the minimum sample size determined as the sample size achieved the stable mean in Likert scale. Organoleptic surveys were used to identify level of post-harvest losses. The post-harvest economic loss of the tuna fish was determined according to the market value. The weights of undamaged and damaged fish which are used to produce dry fish when landing were measured using the electronic platform balance. The weight of the salted harvest of tuna and tuna like fish species were, 54 kg of Thunnus albacares, 12,244 kg of Katsuwonus pelamis, and 69 kg of Auxis thazard. When consider the fish harvest: weight of the harvest per boat for yellow fin tuna is 199.65 kg, skipjack tuna 1515.19 kg, big eye tuna 0.01 kg, frigate tuna 6.10 kg and salted weights of the harvest per boat are 1.05 kg, 240.07 kg, and 1.35 kg and post harvest loss percentages are 0.53%, 15.84%, and 22.15% respectively for each fish species. When consider fish harvest for gear category, long line (LL), gill net (GN) , LL+GN and Others (other gears): total weight of harvest 3116 kg, 60000 kg, 23819 kg and 4443.5 kg per each gear category respectively. Total salted weight of harvest is 43 kg, 8882 kg, 3210 kg and 232 kg while estimated total income is Rs. 1,638,080/=: 15,226,325/=: 7,241,100/= and 1,068,530/= per each gear category respectively. Income loss percentage is recorded as 0.34%, 5.23%, 6.58% and 1.43% for each gear category respectively. The effect of above gear categories on total harvest, the total weight of trashed or damaged fish (used for salted) and the total actual revenue for the fish harvest of IMUL vessels sample was analyzed using Analysis of variance (ANOVA), (p < 0.05).It revealed, the gear categories significantly effect on total harvest, the total weight of trashed or damaged fish (used for salted) and the total actual revenue for the fish harvest of IMUL vessels. The level of fish post-harvest in Beruwala fishery harbor was determined by using sensory characteristics available in quality control division of DFAR. quality based on quality level. ANOVA analysis and results confirmed that the gear categories significantly contribute to the post-harvest economic loss by reducing the post-harvest quality of the tuna fish in Beruwala fishery harbour. Results of the study confirmed that there is no any quantitative loss in fish post-harvest.
Evaluation of the Response to the International Resolution on Responsible Fishing: A Case Study on the Fishermen of Beruwala- Kalutara on Evidence of IUU Fishing
(Uva Wellassa University of Sri Lanka, 2013) Madhushani, H. A.; Wickramarathne, I.U.; Jayamanne, S.C.; Gunawardane, N.D.P.
Increasing international demand for fish and fishery product has resulted more fisheries activity in many parts of the world in recent years and IUU fishing methods are also used for fishing. So long term sustainability and responsibility of fish stocks are affected and responsible fishing as well. This has been internationally agreed and countries should make sure to avoid IUU fishing in their respecting fishing zones. Regional resolutions related to IUU fishing is developed by the Indian Ocean Tuna Commission (IOTC) an organization who is responsible for the international tuna fisheries activities in the Indian Ocean region. It is functioned for conserving, managing tuna fishery resources and reducing illegal, unregulated, unreported tuna fishing. Though these resolutions it is targeted to take the regional fishery industry to unique control level. Sri Lanka has to comply these resolutions as a member country of the IOTC. Fisheries sector is one of the most significant industries in Sri Lanka which contribute about 2.5% to the GDP. Fisheries production is significantly increased over the years and total export earnings for year 2012 are about 22 Billion Rupees. However, when consider Sri Lanka fishery sector several difficulties occurred regarding IUU fishing activities over the years. When considering the hierarchy of fishery community, fishermen especially the Multiday Fishermen who are operating in international waters have the ultimate responsibility to comply these resolutions. Therefore, awareness of fishermen on the international resolutions is important. In 2010, the compliance rate of IOTC resolutions in Sri Lanka was 18% and it was increased up to 47% in 2013. Most of the fisheries administrative and management measures were extreme lined in order to achieve that. However, it is learnt that evaluating attitude and awareness level of the fishermen on these resolutions is essential for the further improving of this level. Methodology Beruwala Fishery Harbor which is one of the main harbor of Sri Lankan multiday boat operations situated in the Kalutara District was selected for the study sienc the harbor facilitates number of fishery activities and most of the fishery stakeholders are benefited from the services. Sample was selected from multiday boat owners, skippers, crew members and other related fisheries service providers in the multiday fishing sector by the stratified random sampling technique. Minimum sample size was determined by “moving average method”. Data were collected from both primary and secondary sources. Primary data were collected through the interviews and questionnaire. Secondary data were collected from Department of Fisheries and Aquatic Resources. Data were analyzed by “Likert method” to identify the level of agreement of the fishermen on several statements related to the responsible fishing and one way Analysis of Variance (ANOVA) on 95% confidence interval was used to compare the results within strata.
Perfecting Explants Sterilization Procedure and Multiple Shoot Induction Medium for In-Vitro Propagation of Lagenandra Species
(Uva Wellassa University of Sri Lanka, 2013) Premathilake, P.G.A.D.; Bambaranda, M.; Jayamanne, S.C.; Krishnarajah, S.A.
Lagenandra species are important aquatic plants in the aquaculture industry of Sri Lanka (Yapabandara and Ranasinghe, 2006). In the absence of a regular supply due to lack of effective propagation methods, Lagenandra species are indiscriminately harvested from the wild to supply to the export market. In order to overcome the problem of species loss and inadequate supply to the local and foreign markets, an in vitro micro- propagation method was developed for Lagenandra lancifolia and Lagenandra ovata. The maintenance of aseptic or sterile conditions is essential for successful tissue culture procedures. Various sterilization agents are used for surface sterilization the tissues. These disinfectants are also toxic to the plant tissues, hence proper concentration of disinfectants, duration of exposing the explants to the various disinfectants, the sequences of using these disinfectants has to be standardized to minimize explants injury and achieve better survival (CPRI, 1992). Mercuric chloride and sodium hypochlorite were used for the present study to standardize the best sterilization protocol for in vitro culture of Lagenandra ovata and Lagenandra lancifolia. Culture initiation and multiplication, to a great extent, are dependent on the type and genotype of explants as well as the type of hormone and their concentration. Many commercial ornamental plants are being propagated by in-vitro culture on the culture medium containing auxins and cytokinins (Peril, 2003).BAP (6- Benzylaminopurine) and IAA (Indole acetic acid) hormone with different concentration were used in the present study to perfect the best combination of IAA and BAP in shoot multiplication procedure. Methodology The research was conducted at the tissue culture laboratory, Floriculture research and development unit, Royal botanic gardens, Peradeniya. The rhizomes (1 cm - 2 cm pieces) were used as explants. In the first experiment, explants were soaked in different concentrations of sodium hypochlorite (15%, 20%, and 25%) and mercuric chloride (0.1%, 0.2%, and 0.4%) to perfecting explants sterilization procedure. Each explant was soaked for twenty minutes in Sodium hypochlorite solution and two minutes in Mercuric chloride solutions. Number of contaminated cultures was observed after two weeks from explants establishment in hormone free Murashige and Skoog medium. In second experiment, effect of different hormone combinations (hormone free MS medium, , BAP 7 mgl +IAA 0.1 mgl ) in 0.5 MS semi solid medium, full MS semi solid medium and full MS liquid medium for shoot initiation and multiplication were evaluated. Number of shoot initiation, shoot length, number of shoots per culture and number of leaves per culture were recorded after six weeks from explants establishment in MS medium.All the data were analyzed using ANOVA in SAS and Minitab statistical package.
Preliminary Study of Salinity Change on Vibrio Count and Gut – Muscle Ratio of Penaeus monodon Post Larvae
(Uva Wellassa University of Sri Lanka, 2013) Kumara, B.W.V.P.S.; Thushari, G.G.N.; Jayamanne, S.C.; Pradeeban, S.
Marine shrimp farming is one of the most important aquaculture practices in the world. It showed a booming expansion since start and soon became a multimillion dollar industry (Islam et.al., 2004). However, there are many issues and challenges of the sector especially related to the culture techniques, environmental quality, biodiversity and natural brood-stocks. Natural brood stock is not enough to fulfill requirements of shrimp seed for culture practices. As a solution, farmers and other relevant stakeholders have established hatcheries which can provide shrimp seeds for stocking of shrimp farms throughout the year. Gut – Muscle Ratio (GMR) is a standard main parameter that can be used as an index to measure the quality of the post larvae in shrimp industry. GMR is defined as the microscopic examination of the relative thickness of abdominal segment of the tail of post larvae stages (Madhukiran et al., 2009). Microbiological count (availability of Vibrio bacteria) is a critical factor affecting growth and survival rate of shrimp post larvae from hatching to grow- out stage. As chemical water quality parameter, salinity has a potential on changing microbial count and Gut - Muscle Ratio. Therefore, present study was conducted to find out the effect of salinity on those two factors for the quality of selected post larval stages of the Peneaus monodon. Methodology Study was carried out in King Aqua Hatchery (Pvt) Ltd, Udappuwa, Chilaw. Nine hundred and sixty post larvae (PL) were selected for the study. Four hundred and eighty post larvae were used as experimental sample and remaining 480 PL were maintained as replacement stock. PL was obtained from same brood stock. Bulk stored tank was monitored from hatching stage to the nursery stage with same condition. Randomly selected PL were transferred into 06 glass tanks (S1, S2, S3, S4, S5, S6) from nursery tank representing 20 PL in each treatment . Four replicates were used for each treatment. Temperature (30 ˚C), pH (8.2) and Dissolved Oxygen (7 mg/l) were maintained at constant levels. Salinity levels were changed in each glass tank by adding fresh water and concentrated brine solution based on final salinity level (S1 – 27 ppt, S2 – 28 ppt, S3 – 29 ppt, S4 – 30 ppt, S5 – 31 ppt, S6 – 32 ppt). S3 (29 ppt) was used as control. Gut-Muscle Ratio of the post larvae was determined under microscope (x10). Ten post larvae ventral muscle was recorded. Water samples were collected twice per day (8.00 a.m. and 8.00 p.m.) for bacterial detection. Water samples were diluted with sterilized distilled water up to 10x1 and cultured using TCBS agar medium. After 24 hours of incubation, plates were observed by using colony counter. Recorded data was analyzed by using MINITAB 15 statistical software (Two-Way ANOVA, α – 0.05). Results and Discussion Results of mean Gut-Muscle Ratio and Vibrio count with salinity are given in Table 1. At the salinity level of 27 ppt, mean Gut Muscle Ratio shows the minimum value for all stages, while highest GMR for PL 9 and PL 10 was recorded at 30 ppt (Table 01). With increasing salinity, mean Gut Muscle Ratio for PL9 and PL 10 stages are gradually increasing up to a specific salinity level (30 ppt). At highest level of salinities (>30 ppt) there was a slight decline of Gut Muscle Ratio for these stages, but it is closer to the maximum mean value of GMR recorded for 30 ppt level of salinity. GMR for PL 11, PL 12 and PL 13 stages had not changed at grea ter level of salinities (30, 31 and 32 ppt). Commonly highest mean value of GMR was recorded at 30 ppt. There was no significant difference for Gut Muscle ratio and PL11, PL12 and PL13 stages of Peneaus monodon post larvae with salinity levels of 30, 31 and 32 ppt (p > 0.05). Muscle gut ratio is one of the major criteria for selecting the good post larvae (Bauman et al., 1990). Usually high muscle to gut ratios is preferable (FAO, 2013). According to manual of Asean Good Shrimp Farm Management Practice (n.d.), Muscle Gut Ratio of 4:1 (or >4:1) is recommended as accepted ratio for high quality PL stages. However, in practice, it was found that this measurement can always be difficult due to the unacceptable management practices. Therefore, salinity level that always records gut muscle ratio closer to recommend value (4:1) is concerned as the best salinity for shrimp hatchery practices.
A Preliminary Study on the Effect of Feeding Frequency on Survival and Growth Rate of Catla Catla Post Larvae
(Uva Wellassa University of Sri Lanka, 2013) Dasanayake, P.D.M.V.D.K.; Liyange, N.P.P.; Jayawardana, S.
Feed management is a very important part in larval rearing in terms of optimization of feeding rate and frequency is become imperative in the culture of marine and freshwater fishes and it has become one of the crucial areas of research in the field of aquaculture. By controlling the optimum feeding frequency, farmers can successfully reduce the feed cost and maximize growth and also able to manage other factors such as individual size variation and water qualities which are deemed important in rearing of fish in culture conditions. Different species of fish have been shown to have different optimum feeding frequencies. There are numerous reports available on the nutritional requirements and use of practical diets for Indian Carp species but limited information is available on feeding schedules for Catla (Catla catla).There is a need to know what feeding frequency is optimal, in terms of production. The objective of this study was to evaluate the effects of different feeding frequencies on growth performance and survival of Catla (Catlacatla) post larvae which will lead to better larval rearing management during the critical period of larval phase. Methodology Experimental trials were conducted at the National Aquaculture Development Authority, Carp breeding centre, Udawalawa. A total of 1500 (approximately) 5 day old Catla (Catla catla) post larvae (PL) obtained from hatchery jar of the breeding centre. Selected PL were divided equally into fifteen 50 l glass tanks and 100 fish were housed in each glass aquaria. Average wet weight was recorded as 0.0007±0.000031 g and average total length recorded as 0.7±0.042 cm. The stocking density was two PL per one liter of water. Post larvae in treatment F4were fed four times a day while those of group F3, F2 and F1 were fed thrice, twice and once a day respectively. F0 was the controller and those larvae were not fed. The larvae were fed with soya bean milk up to 10 days and then up to 21 days they were fed with Prima commercial powder feed. Feed was offered at an allowance of 10% bodyweight (FAO, 2011) splitted equally among the allocated number of meals. Feed allowance was calculated once a week by using wet weight measurements. Satiation of feed was assumed. The duration of this study was 8 weeks and during the experiment water temperature was measured daily and pH and Nitrate concentration were measured once a week. Total length and wet weight body measurements were taken once a week and Number of survivals were calculated finally. Based on the average length, average weight increments and number of fish; the Specific growth rate, Weight gain, length gain, survival rates variables were calculated. All data were subjected to one-way analysis of variance (ANOVA) and differences between means compared by the Tukey test at a 95% confidence interval (p<0.05). Results and Discussion Mean water temperature and pH level ranged from 27-30 C and from 6-8, respectively. The mean weekly values of the lengths and weights of post larvae at each feeding frequency are shown in Figure 1 and 2, respectively. Total length increased from an initial value of 0.7± cm to final value 1.23 ± 0.1 cm in no feed group (F0) and 2.53 ± 0.11 cm in feeding frequency F4 group. Other feeding frequencies (F1-F3) had length values intermediate between the 2 extremes. There was a significant difference (P<0.05) in length values between these feeding frequencies. For weight values feeding frequency F0 had the lowest final mean weight (0.0077 ± 0.0003 g) while feeding frequency F4 had the highest mean weight value (0.101 ± 0.001).Mean weight values for other feeding frequencies (F1-F3) ranged progressively between two extremes. There was also significant difference (P<0.05) in final weight values at the different feeding frequencies.
Preliminary Study on the Mud Crab Fishery in Mannar District
(Uva Wellassa University of Sri Lanka, 2013) Puveenthiraraja, G.; Jayamanne, S.C.; Niroobaraj, B.
Mannar district situated along the west coast of Sri Lanka lies between north latitude 8.8667 and east longitude 80.0667 . The district is the unique assemblage of marine, brackish and freshwater and adjacent ecosystem with numbers of economically significant wild harvest. Scylla serrata (Forskal), popularly known as mud crab and widely distributed throughout the Indo-West pacific region is also found here. It belongs to the family portunidae and to the group of swimming crabs. Scylla serrata is locally known as Kali nandu (in Tamil) and Kalapu kakuluwa (in Sinhala). They are predominantly estuarine but move towards the offshore and mangrove habitats for spawning and early larval life. In recent years, mud crab appears to be the most important export commodity in Sri Lanka and it triggered the continuous and irresponsible exploitation of the species. Hence, the present study was undertaken to study the status of mud crab fishery in Mannar. Methodology The present study was carried out during May 2013 to August 2013. Four landing sites, Southbar, Pallemunai, Achankulam and Illuppakadavai were selected after the careful analysis of available literature considering the mangrove density and the mud crab availability. Live mud crab specimens, which were collected from the morning till evening was observed daily in roster basis at each landing center in the evening during the study period. After the cautious observation of the crabs the suitable individuals were selected for the study. The width of carapace (CW) between the ninth teeth of left and right antero-lateral boarder was measured with a caliper and the body weight was recorded in grams using a digital weighing scale. Identification of mud crab species in the field was performed following Keenan (1994). Additional information regarding the capture method, capture time and number of fishers engaged in this activity were recorded by interviewing the fishermen. The meteorological data were obtained from the meteorological department of Mannar while the monthly harvest data were obtained from the daily records of fishers. The carapace length frequency pattern of Scylla serrata was drawn separately for both male and female of each sampling site to observe the length frequency distribution of the harvest. Results and Discussion Two species of mud crabs; Scylla serrata and Scylla olivacea were recorded from Mannar Lagoon. Scylla serrata was found in almost all the sites throughout the district but Scylla olivacea existed in sites where mangrove forests occur (Table 1). Baited traps, gill nets and hand picking from crab holes using a stick are practiced for catching crabs, but the baited traps was the most dominating gear type used by fishers in all the sites. The size of the trap and the mesh size of the nets vary from lagoon to lagoon.
Production of Imitation Caviar Using Yellow Fin Tuna Fish Species: Thunnus albacares – A Novel product using Fish Roe in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2013) Abeyrathna, I.G.S.N.K.; Liyanage, N.P.P.; Thushari, G.G.N.; Jayamanne, C.
Caviar is defined as salted fish roe that basically prepared with eggs or roe of sturgeon fish. Imitation caviar is defined as roe that comes from a fish other than the sturgeon, and it can be classified as a caviar substitute. This product is not so popular among Sri Lankans, because of lack of knowledge regarding processing of caviar and its cost. In Sri Lanka, fish roe is discarded from processing plants and sold in the local market. Therefore it is important to add value to fish roe and make them a high demanded product. Since discarded fish roe is used for this product, there will be no threat of over exploitation by production of imitation caviar. Local people can acquire nutritional benefits from the imitation caviar due to high nutritional quality. Yellow fin tuna: (Thunnus albacares) was selected as the resource fish species for the present study. T. albacares is a species in family Scombridae found in pelagic water of tropical and subtropical oceans waters. In Sri Lanka, it is considered as a commercially important food fish that represent considerable portion of tuna fishery. Therefore, main objective of present study is to develop proper methodology and select suitable maturity stage of fish roe for production of imitation caviar. Methodology Roe samples of T. albacares were collected from Ceylon Fresh sea food (Pvt) Ltd. and Jay sea food (Pvt) Ltd. in Ja-Ela, Sri Lanka. Then collected samples were transported to the Animal Science laboratory of Uva Wellassa University using cooler boxes with ice. First, ovary sacks with fish roe were separated according to maturity stage as immature roe, half mature roe and mature roe using external features of ovary sac. Then fish roe were separated from the ovary sac using manual screening method. Blood and other connective tissue on the roe were removed by rinsing with 5 % brine solution and fish roe were sieved using the sieve set. Prepared roe samples were subjected to “dry salting method” separately. Surface moisture of the roe samples were removed using clean cloth and arranged in plastic boxes with one layer of powder form Iodized salt and one layer of roe alternatively. Three different salt (g): fish roe (g) ratios as 0.05:1, 0.25:1 and 0.45:1 were used to determine the best ratio/s of each maturity stage after preliminary experimental trials (S:immature roe : S1 -0.05:1, S2-0.25:1 S3-0.45:1/ X:half mature roe: X1-0.05:1, X2- 0.25:1, X3-0.45:1, Y: mature roe: Y1- 0.05:1, Y2- 0.25:1, Y3- 0.45:1). Three replicates were used for each treatment. Salted roe samples were kept for two and half hours. During this period they were pressed gently by fingers for five minutes for effective absorption of salt. Afterwards they were dipped in tap water bath to remove excess salt and then covered with a wet cloth for 4-4.5 hours. Then the caviar were placed in a dry cool place (approximately 20 C) to be dried (Celic et al., 2012). Final products were filled into glass jars manually and pasteurized using hot water bath at 68 C for 45 minutes. Final products were analyzed for different parameters. Protein and fat contents were determined using Kjeldahl method (6.25×N) and Soxhlet method respectively (AOAC, 1990). Moisture content was determined by drying the sample at 105 C to a constant weight (AOAC, 1990). The pH values of the samples were determined with a pH meter and microbial Count (TPC) of the final products was determined. pH and TPC values were recorded once in 07 days for 02 months of storage period (0, 07, 14, 21, 28 days). All final products were evaluated using 30 untrained panelists in terms of color, texture, aroma, salty taste, mouth feel and overall acceptability on a 5 point hedonic scale to identify the organoleptic properties. Differences between mean values of proximate composition, pH values and microbiological factors were analyzed using ANOVA. Friedman non parametric test was used to analyze the results of sensory evaluation. MINITAB statistical package (16 Version) was used for analysis of results at 0.05 probability level. Results and Discussion Based on the results obtained from protein level, lipid content, sensory evaluation and microbial count studies, three samples (Salt: Fish roe by weight) 0.05:1 g, 0.25:1 g and 0.45:1 g of each maturity stage were separately compared to select best sample. Treatment that shows highest protein level, lowest lipid content, greatest consumer preference and lowest microbiological content was selected as the best sample for each maturity stage. S1 (0.05:1; salt: fish roe) was selected for immature stage, whilst X1 (0.05:1; salt: fish roe) and Y2 (0.25:1; salt: fish roe) were selected for half mature stage and mature stage respectively. The ratio of 0.45: 1 (salt: fish roe) was recorded having lowest nutritional quality, unsatisfactory consumer preference and greater microbial count for each maturity stages compared to other two treatments.
Study on the Effect of Different Levels of Heat on the Quality of Dark muscle of Yellow Fin Tuna Thunnus albacares
(Uva Wellassa University of Sri Lanka, 2013) Jayasinghe, L.L.S.L.; Wijesundara, W.M.N.M.; Liyanage, N.P.P.; Madage, S.S.K.
Coastal and off shore marine production in Sri Lanka has an increasing trend. According to Department of Fisheries and Aquatic Resources, a catch of 417,220 metric tons was recorded in 2012. Yellow fin Tuna (Thunnus albacares) is included in large pelagic fish catch of Sri Lanka and it composed 10% of total marine catch in 2012. Yellow fin tuna (YFT) is mainly exported as Loins, Steaks, Centre cuts, Cubes, Medallions and Saku in processed form. Currently there are 27 European Union approved fish processing factories in Sri Lanka. Considerable parts of fish are removed as by-products during processing; this includes dark muscle, fins, skin, head and viscera parts. The amount of by-products produced during fish processing is vary between 40-75% of the total weight of fish according to the way of processing (Shahidi (1994), cited in Zapata et al., 2011). Though some value addition is done to these by-products there are plenty of opportunities to add value to by-products like YFT dark muscle. Thermal preservation is one of the current techniques used in value addition. Therefore, it is very important to know the quality changes of YFT dark muscle when they undergo thermal preservation techniques. Although many studies have been conducted to determine the initial quality of this muscle, still the quality changes with the different heat treatments are not studied. Therefore, objectives of this study were to evaluate the effect of different levels of heat treatments on the physical, chemical and organoleptic properties of YFT Dark muscle (DM). Methodology DM of YFT fish processed at Ceylon Fresh Seafood Private Limited in Ja-Ela were collected and transported with gel ice at 4°C to Industrial Technology Institute (ITI) and stored in -18 °C until used for the experiment. Experiment was conducted as three stages as fresh fish quality determination, pre-trial and heat treatment study using 0.5 kg, 1.5 kg and 2 kg amounts respectively. For fresh fish quality determination, physical properties including colour (Minolta Chroma meter CR-200, Japan), texture (as firmness using GUSS fruit texture analyser, United States of America) and water holding capacity and chemical properties including moisture, ash, crude protein, crude fat, water soluble protein content, pH of 10% muscle solution and water activity (AquaLab® apparatus-Series 3 TE, USA) of fresh muscle were determined by following respective AOAC methods. Colour and texture of approximately 3×2.5×1 cm sized undisturbed muscle chunks were recorded. Sensory evaluations (acceptance test with five point hedonic scale) were conducted with seven trained panellists of sensory panel of ITI using fish chunks as pre-trials. Those chunks were marinated overnight with 2% salt, to determine the best deep frying and boiling durations. As time durations 05, 10 and 15 minute durations were selected and frying was done in coconut oil at 185 ºC while boiling was performed at 100 ºC. For the heat treatment study, fish chunks were prepared as in pre-trial and those were boiled and deep fried for five minutes. Fish chunks were canned in A-1 sized cans with2% salt solution at 121.1 ºC for ten minutes. Finally the chemical and physical properties of heat treated DM were determined. Final organoleptic quality of the heat treated DM was evaluated by nine trained panellists of ITI using acceptance test with nine point hedonic scale. Physical and chemical quality data were analysed using one way analysis of variance procedure in Minitab 16 statistical package. Sensory evaluation data were analysed using Friedman non parametric test in SPSS 22.0 statistical package. All mentioned significant differences are given at P<0.05.
Uptake of Nitrate and Phosphate by Hydrilla verticillata and Vallisneria spiralis
(Uva Wellassa University of Sri Lanka, 2013) Karunarathna, K.K.C.K.; Jayamanne, S.C.; Bambaranda, M.; Bandaranayake, R.
The phosphate and nitrate are major inorganic components which are directly and indirectly accumulate in water bodies (Boundless, 1997). High concentrations of phosphates and nitrates present in the wastewater causes eutrophication that severely affects natural water bodies (Kenneth, 2006). To avoid accumulation of nitrate and phosphate in waterbodies, water purification systems should be established with P and N removal facilities. The cost of the advanced instruments that can purify water is not affordable by the developing countries such as Sri Lanka and water purification by aquatic plants is considered as a suitable method. The present study was carried out to evaluate the ability of two fresh water aquatic plants, Hydrilla verticillata and Vallisneria spiralis in removing nitrate and phosphate from the waste water. The main objective of the study was to identify the best plant which can absorb a large amount of nitrate and phosphate from the wastewater. Methodology The research was conducted in two stages to investigate the fluctuation of nitrate and phosphate in the wastewater with aquatic plants. The first experiment was conducted to investigate the changes of nitrate and phosphate by using Hydrilla verticillata and Vallisneria spiralis in equal biomass. The Hydrilla verticillata, Vallisneria spiralis, a combination of Hydrilla verticillata and Vallisneria spiralis and control treatment were used as different treatments and the same biomass was provided for each treatment units (16 g) except for the control. Then water samples were collected daily in the morning (8.00 a.m.) and used to estimate the nitrate and phosphate concentration. The experimental design was completely randomized design. The data was analyzed using one-way ANOVA and general liner model in Minitab 14. The second experiment was conducted to compare the ability of two aquatic plants Hydrilla verticillata and Vallisneria spiralis in removing nitrate and phosphate from wastewater and the appropriate density that can be used for controlling eutrophication. Different biomasses of 8 g, 16 g, 24 g and 32 g of Hydrilla verticillata and Vallisneria spiralis were used as treatments and the nitrate and phosphate concentration were measured daily following AOAC standard methods (1985). Two factor factorial design was employed as the experimental design and two- way ANOVA in Minitab 16 was used to analyze the data. Result and Discussion According to the Figure 1, T1 (Hydrilla) and T2 (Valisneria) could reduce phosphate concentration in the wastewater than T3 (combined plants) and T4 (Control). T1 and T2 had shown approximately same phosphate removal ability. Phosphate concentration in the water is significantly different between the treatments except T1 and T2 (p<0.05). Figure 2 shows that nitrate concentration of the T1 was lower than T2, T3, and T4. Nitrate concentration is significantly different between the treatments (p<0.05). The concentrations of the Nitrate and phosphate in the water has reduced in T1, T2 and T3. In T4, reduction of nitrate and phosphate in the water was lower than in treatment tanks with aquatic plants. According to Figure 3 the highest nitrate absorption was recorded in T1 with 8 g of biomass by absorbing 76 %. The nitrate absorption is significantly different between treatments and the level of biomass. The interaction among the plant type and biomass is also significantly affected on the nitrate absorption (p<0.05). Figure 4, shows the highest phosphate absorption in T1 with 32 g biomass and it absorbed only 40% in 5 days. Phosphate absorption is significantly different between treatment and the amount of biomass (p<0.05). The interaction among the plant species and biomass were also significantly affected on the phosphate absorption
Use of Side Scan Sonar in identification of submerged objects in the shallow sea area
(Uva Wellassa University of Sri Lanka, 2013) Illangasinghe, M.J.B.; Liyanage, N.P.P.; Thushari, G.G.N.; Jinadasa, S.U.P.
North east coast is playing a significant role in economy of the country via fishery. Beach seine fishery has been initiated in this area after 30 years of civil war. Under water war remnants buried in the bottom of the north east shallow sea acts as a major impediment in improving of beach seine fishery in the area. Generally, unidentified buried objects are discovered with the help of divers and underwater cameras. However, this technique is ineffective, due to absurd searching in the sea bottom, time consuming and high cost. So survey becomes unsuccessful, most of the time. In this study, Side Scan Sonar (SSS) survey technique which has been developed using medical ultrasound technology was used to detect the specific objects that affect the beach seine fishery, their exact location and distribution on the seafloor. North east coast of Mullaithivu area in Northern Province was selected as the study area for four waypoints / 80°49'15.06"E, Z-9°17'30.00"N/80°48'30.00"E) using the Integrated Global Positioning System (inbuilt GPS or DGPS Garmin Colorado 300 handheld GPS). Survey was carried out by towing vessel along predetermined survey lines just above the bottom of the seafloor depending upon the water depth. Data was collected using Imaginex Model 872 “YellowFin” side scan sonar combination with data acquisition using “YellowFin version 2.0.1.4” software. Image processing techniques of “sonarWiz” 5 and “ArcGIS” software was used to detect and classify buried objects in side-scan sonar images. According to the results, three objects were identified in three different locations. Object 01was at 09˚ 17.97244’ N/080˚ 48.66892’E with 85 m length and 21 m width, while object 02 was at 09˚ 18.71599’ N/080˚ 48.02634’E with 55 m length and 15 m width at the widest point. Location of object 03 was at 09˚ 18.87650’ N/080˚ 47.48114’E with 120 m length and 25 m width at its widest point. Highest coverage (with greatest length and width), was recorded for object three (3000 m ) which was distributed over a larger area of sea bed. Distance from coastal area to object one, two and three are reported as 400 m, 575 m and 200 m respectively. Third object is in close proximity to beach environment compared to other two. Average depth of the studied area was recorded as 10 -12 m. Sharp edges and curvy features of first and second objects indicated that these two objects are ship wrecks. Images show vast amounts of ship debris around these identified ship wrecks. Since these two artificial objects were identified within boundary of coastal area, there is a high potential to damage coastal fishing gears, especially beach seines by entangling and will waste time and money in repairing the damaged nets. Third object exhibits blunt edges with smooth curvatures and can be a natural structure such as a bed rock or a sand bar. The identified objects can be marked as the objects that directly influence on commercial beach seine industry. Side Scan Sonar can be recommended as a modern technique useful in detection of underwater objects with their precise location.

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