04000cas|a2200433 a 4500 20260818094917.0 020201s2001 th uu|m rtt 0| a1eng d .b11843640 AIT Thesis no.EV-01-23 Luhtasela, Ulla Effect of cyanide fishing on corals Bangkok : Asian Institute of Technology, 2001 84 leaves Thesis ; no. EV-01-23 A 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 Thesis (M. Sc.) - Asian Institute of Technology, 2001 Cyanide 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. Cyanides Corals Environmental aspects Preeda Pakpian, Chairperson Hansa Chansang, Examination committee Jutamaad Satayavivad, Examination committee Nguyen, Cong Thanh, Examination Committee European Union, PTS Programme, Scholarship donor Asian Institute of Technology. Thesis; no. EV-01-23 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B08380 .b11843640 mnait u 240329 0 020201 m a u 0 mnait mnait mnarc 20 40 Barcode : 30050120711162 CREATED : 2000-04-09 RECORD # : i12268525 LPATRON : 1013495 LCHKIN : 2001-01-20 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 2 TOT RENEW : 0 Barcode : 30050120711154 CREATED : 2000-04-09 RECORD # : i12268537 LPATRON : 1013033 LCHKIN : 2008-12-07 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 2 TOT RENEW : 0 Barcode : 30050160076948 CREATED : 2016-05-24 RECORD # : i12989691 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 34254 34254 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-01-23 30050120711162 2026-08-18 09:49:17 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-01-23 30050120711154 2026-08-18 09:49:17 2 2026-08-18 20 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.EV-01-23 30050160076948 2026-08-18 09:49:17 2026-08-18 40