Research Symposium-2016

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Browsing Research Symposium-2016 by Subject "Aquaculture"

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    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 management
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    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.