| Summary: | 碩士 === 國立高雄海洋科技大學 === 漁業生產與管理研究所 === 95 === In order to understand how the marine environment changes in South China Sea affects the catch rate of yellowfin tuna and bigeye tuna for longline fishery, the data of SST (Sea Surface Temperature) and Chlorophyll a between 1990 and 2004 were collected in this study as the index of marine environment changes, along with the catch data of 5 degree square space provided by SPC (Secretariat of the Pacific Community) and carried out the correlation coefficient test. The results suggest that the CPUE of yellowfin tuna decreases with increasing of SST between 1990 and 2004, which shows significant negative correlation (r=-0.53, p<0.05). Meanwhile, the increasing CPUE of bigeye tuna increases with increasing of SST, which shows obviously positive relation (r=0.76, p<0.05).
The Chlorophyll a and SST in South China Sea between 1990 and 2004 show an significant negative correlation (r=-0.53, p<0.01), in other words, the higher sea surface temperature involving with the lower Chlorophyll a. There was an significant positive correlation（r=0.52, p<0.05）between the changes of Chlorophyll a and CPUE of yellowfin tuna during the period of abnormal high temperature in South China Sea (1997.09-1999.04, 2000.12-2001.06, 2002.11-2003.04). But Anomalies of Chlorophyll a and CPUE of yellowfin tuna during the whole period (1997.09-2004.12) did not present an significant positive correlation (r=0.18, p＞0.05), according to correlation coefficient test. Therefore the results indicate that the increase of SST would cause the reduction of Chlorophyll a and indirectly conduct the decrease of CPUE of yellowfin tuna. However no matter what period is, the whole period or abnormal higher temperature period, the bigeye tuna seemed to be not affected by the change of Chlorophyll a.
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