Faculty of Science

COMPARISON OF SOIL ORGANIC CARBON STOCK OF MANGROVE ECOSYSTEM AND PADDY AGRICULTURAL LAND IN SATHURUKONDAN , BATTICALOA DISTRICT

Mon, 01 Jan 2024 00:00:00 GMT

COMPARISON OF SOIL ORGANIC CARBON STOCK OF MANGROVE ECOSYSTEM AND PADDY AGRICULTURAL LAND IN SATHURUKONDAN , BATTICALOA DISTRICT SOBIKA, BALAKRISHNAN Present study was aimed to assess and compare the soil organic carbon stock of mangrove ecosystem and paddy agricultural land in Sathurukondan. This study was carried out from July 2023 to December 2023. Soil samples were collected from both study sites at 30cm depth form top layer and further divided into three subsamples for the analysing purpose. Sampling locations also marked while sample collection. Soil organic carbon content (%) was estimated by using Walkley and Black titration method manually and soil organic carbon stock was calculated. One way ANOVA statistical results revealed that there is a significance differences (P < 0.05) in the mean soil organic carbon stock of mangrove ecosystem and paddy agricultural land. The mean soil organic carbon stock of the mangrove ecosystem in Sathurukondan is 44.16 + 7 .56 tClhain 0 - 10 cm soil layer, 36.83 + 12.27 tClhain 10 -20 cm soil layer and 35.18 + 8.32tc/hain20 - 30 cm soil layer. The mean soil organic carbon stock of the paddy agricultural land in Sathurukondan (near to mangrove ecosystem) is 22.24 + 8.1 8.tClha in 0 - l0 cm soil layer, 19.96 + 6.15 tClha in l0 - 20 cm soil layer and21.29 + 4.57 tClha in 20 -30 cm soil layer. The soil organic maffers take major partin the organic carbon stock of soil. Finding elucidated that higher soil organic carbon stock was recorded in mangrove ecosystem, it is higher than all three layers of soil when compare to respected layers of paddy agricultural lanrl soil. Mangrove ecosystem known as Blue carbon ecosystem. They can absorb carbon from atmosphere and store it with their biomass. Due to human activities mangrove ecosystem face threats and destruction of mangroves are highly effect the soil organic carbon accumulation. In the paddy agricultural land fertilizer usage, tillage, climate also change the soil organic carbon accumulation. Appropriate methods of mitigating by raising awareness to save the mangrove environment in order to preserve carbon sequestration is important.

MAPPING OF THE ANT SCAPING AND ECO- FRIENDLY SOLUTIONS FOR Solonopsis geminata AT THE UNIVERSITY PREMISES OF THE EASTERN UNIVERSITY SRILANKA

Mon, 01 Jan 2024 00:00:00 GMT

MAPPING OF THE ANT SCAPING AND ECO- FRIENDLY SOLUTIONS FOR Solonopsis geminata AT THE UNIVERSITY PREMISES OF THE EASTERN UNIVERSITY SRILANKA GUNARATHNA, S.M. DISHANI PRAMODHYA The scarcity of ant diversity identification in the Eastern region of Sri Lanka required a systematic survey around the eastem university premises. The study airned to collect a comprehensive range of ant specimens for taxonomic identification. The survey Utilized a combination of belt transect and quadrant, bait placement, and leaf-lifting sampling methods. This ant diversity identification survey revealed potential new records for the Eastem region including Crematogaster sp7 and Crematogasler sp2, Pheidole spl (major worker), Monomorium parasonis, Trychomyrmex destructor (major worker), Nylendria yerburi, Tetramorium cf obesum, Tetramoninm spl, Camponotus sp2 and Camponotus cf reticularis, Nylendria sp, Tetramonium obesum, Longiforsatus anochitus and high morphological diversity of Sol'onopsis geminate. Solenopsis geminata, an invasive species, poses health and environmental risks due to its harmful effects on humans, animals, and the environment. This study explored the development of eco-friendly fire ant management by formulating baits using organic plant materials as sustainable rather than Conventional chemical insecticides. The preliminary survey was conducted during .Iuly of 2023 and February of 2024 through face-to-face interviews with 78 stakeholders. Findings revealed prornising results 56o% of indoor cases and 44o/o of outdoor cases, recorded with major impacts to humans. 'l'he bait formulation was developed with high mortality counts of 5%o concentration fbr Azadirachta indica (neem), Citrus attrantiifolia (citrus), Cymbopogon citratus (lemongrass), Chrysanthemltm sp, and 10o% concertation from Deruis trifoliate. The developed bait exhibits high killing effects when formulated as organic baits by using serial chemical experiments. The selected bait dose was 0.05g for the effective killing of fire ants within one day by using effective food attractants soybean oil, corn grit and honey which served as attractive feeding stimulants within the bait formulations. The median lethal dose (LDso) was 1.088 mg/kg. The Observations served as a springboard for future research on developing safer and more effective organic ant control methods. By addressing the limitations identified currently and continuing to explore ant diversity, researchers can develop environmentally conscious solutions to combat Solenopsis geminata and other pest ant species.

ASSESSMENT OF FISHING EFFORT , CATCH PER UNIT EFFORT AND FISH PRODUCTIVITY IN THE SELECTED SITES OF BATTICALOA LAGOON FOR WIDELY CONSUMED FISH SPECIES

Mon, 01 Jan 2024 00:00:00 GMT

ASSESSMENT OF FISHING EFFORT , CATCH PER UNIT EFFORT AND FISH PRODUCTIVITY IN THE SELECTED SITES OF BATTICALOA LAGOON FOR WIDELY CONSUMED FISH SPECIES USAIR, MOHAMED SIDDEEQ MOHAMED Present study was carried out in the selected site of Batticaloa Lagoon were investigated from June 2023 to September 2023. Sampling was done at three landing sites of Batticaloa Lagoon namely Paalameenmadu, Sathurukondan and Paddiruppu. When visit once at each landing site, the weight of widely consumed three species that are Arius maculatus (Spotted Catfish), Etroplus suratensis (Green Chromide) and Mugil cephalus (Mullet) which are more than 90Yo of the total catch of cast net composition was collected and recorded separately from each cast net operated canoes in the unit of kilogram through the balance that has two decimal point. In Paalameenmadu, the highest catch per unit effort (CPUE) (0.0295 kg per effort) was recorded. This site close to bar mouth too, CPUE was high and the landing were dominated by marine species. Fish productivity (9.I2 kg ha-r yr-l), total catch per month (8738.31 kg) and total annual catch (104859.71kg) also were recorded high in Paalameenmadu. The fishing effort (FE) (314545) is recorded high in Paddiruppu, The Lowest CPUE (0.0116 kg per effort), fish productivity (3.S9 kg ha-ryr-r), total catch per month (3731.54 kg) and total annual catch (44778.45 kg) were recorded in Paddiruppu. The Lowest FE (271480.5) rs recorded in Sathurukondan. The rise in CPUE resulting from large captures for mass marketing and illicit fishing is greater than the fish production rate in Paalameenmadu. If things continue as they are, there will be fewer fish at the landing place, and Paalameenmadu fisherman will become more competitive. As a result, the current rules and regulations were severely enforced, and the relevant authorities will legalize fishing operations in accordance with the necessary laws and regulations.

STUDY THE POPULATION DYNAMICS AND STOCK ASSESSMENT OF Oreochromis niloticus IN THE UNNICHCHAI IRRIGATION RESERVOIR , BATTICALOA DISTRICT

Mon, 01 Jan 2024 00:00:00 GMT

STUDY THE POPULATION DYNAMICS AND STOCK ASSESSMENT OF Oreochromis niloticus IN THE UNNICHCHAI IRRIGATION RESERVOIR , BATTICALOA DISTRICT KESHANA, JEGAANANTHAM The purpose of this study was to determine the population dynamics and stock assessment of the Nile tilapia. In Unnichchai Reservoir, it is the predominant fish that is highly preferred by consumers. The length-frequency distribution, length-weight relationship, growth and mortality parameters, and recruitment of the Unnichchai reservoir were investigated using length-frequency data and respective weight. The length-frequency distribution and length-weight relationship were computed from linear regression analysis by using MICROSOFT EXCEL Professional plus 2019 and growth mortality parameters and recruitment analyzed ELEFAN method incorporated in FISAT software. 360 fish specimens sampled two times per month, from Gill net haul over a period of 6 months starting from June 2023 to November 2023. Oreochromis niloticus exhibited negative allometric growth (b: 2.02 (l 3) and near to the strong positive correlation (t':0.8615). The von Bertalanffy growth constants for Oreochromis niloticus were TL- :38.40 cm, K: 0.69 yr-1, and with a derived growth performance index of $:3.00. The instantaneous rates of total mortality (Z), natural mortality(M),andfishingmortality(F)were l.45,l.29,and0.16peryearrespectively. The rate of exploitation (E : 0.ll) showed under-exploitation of this species. However, this reservoir be stocked annually that may be to balance the rate of exploitation of the Nile tilapia population. There might be a few possibilities for yearly stocking, which would suggest that the reservoir experiences predator attacks, heavy exploitation due to fishing, or inadequate natural recruitment. To solve that issue, implement a regular monitoring program to identify and record the O. niloticus population, improve natural recruitment, and increase public awareness of fisheries.