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035 _a.b11843640
099 9 _aAIT Thesis no.EV-01-23
100 1 _aLuhtasela, Ulla
245 1 0 _aEffect of cyanide fishing on corals
260 _aBangkok :
_bAsian Institute of Technology,
_c2001
300 _a84 leaves
490 1 _aThesis ;
_vno. EV-01-23
500 _aA thesis proposal submitted in partial fulfillment of the requirements for the degree of Master of Science. Inter-university Program on Environmental Toxicology, Technology and Management, School of Environment, Resources and Development
502 _aThesis (M. Sc.) - Asian Institute of Technology, 2001
520 _aCyanide fishing is an illegal fishing method widely used in a number of countries in Southeast Asia. It is used to stun the fish to make them easier to catch. As this deadly poison spreads around the coral reef, it has an adverse impact on marine life, including fish, corals and other invertebrates. Initial, high concentration of sodium cyanide (NaCN) is known to kill coral polyps. As the cyanide dilutes and spreads around the reef, corals are exposed to low concentrations of free cyanide for prolonged periods of time, causing chronic effects. In this experiment, corals were exposed to NaCN in two concentrations (10-5 and 10-6 mol/l) for 6 hours and given 2 weeks recovery period after the exposure. Treatment was repeated twice in this experiment. Changes in chlorophyll - a and -c2 concentrations and zooxanthellae density were measured in the laboratory. Bleaching is the discoloration phenomenon of stressed corals. It can be caused by the loss of symbiotic algae, chlorophyll concentrations or both together. No significant changes were found in zooxanthellae densities after any treatments, indicating that the selected coral species, Porites lutea does not expulse its symbiotic algae from its tissue at these concentrations and duration of cyanide exposure. Significant changes of chlorophyll - a and -c2 concentrations were found in a group a (10- 5 mol/l) immediately after both exposures. After 2 weeks of recovery, concentrations returned to normal levels as compared with the control groups. Group b (1 o6 mol/l) did not show any significant changes in either of the analysis. Cyanide fishing has a high potency to stress large coral reef areas, as the initial, used concentration can be up to 1010 times higher than the studied concentration. Environmental parameters, such as pH, temperature, solar radiation, and current velocities determine the severity of the damage caused by cyanide fishing activities.
650 0 _aCyanides
650 0 _aCorals
_xEnvironmental aspects
700 0 _aPreeda Pakpian,
_eChairperson
700 1 _aHansa Chansang,
_eExamination committee
700 1 _aJutamaad Satayavivad,
_eExamination committee
700 1 _aNguyen, Cong Thanh,
_eExamination Committee
710 2 _aEuropean Union, PTS Programme,
_eScholarship donor
810 2 _aAsian Institute of Technology.
_tThesis;
_vno. EV-01-23
856 _3Full-Text
_uhttp://203.159.5.9/ait-thesis/detail.php?q=B08380
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