Effect of climate change on the fishing condition of grey mullet (Mugil cephalus) in the Northwest Pacific Ocean
| Autor: | Chuang, Che-Chen, 莊哲禎 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 In this study, we collected the long-term (1970-2010) grey mullet (Mugil cephalus) catch data, satellite data (Sea surface temperature; SST) and climatic indices. The purpose of this study was (1) Analysis different regions characteristic of mullet catch fluctuation in Taiwan, Japan, and Korea. (2) Investigate the trend of autumn and winter SST by using Empirical orthogonal function (EOFs). (3) Using wavelet analyze correlation relationships between catch and climate indices. (4) Investigated climate change influences on SST and climatic indices in the annual catch of grey mullet at multiple timescales. The total mullet catch amounted to 564,000 tonnes in the Northwest Pacific Between 1970 and 2010. There are three countries in the Northwest Pacific, respectively Japan, Korea and Taiwan. Each accounts for 46%, 45% and 9% of the total catch. Similar long-term trends were found in the catch rate data of Japan, Korea and Taiwan. Between 1970 and 2010, the catch rate experienced an (a) increasing (decreasing) trend in the period before (after) 1984. But Korea mullet catch keep increasing after 1990. The significant coherence of mullet catchs a periodicity of 13-16 years between Taiwan and Japan between 1970 and 2010, and the catch showed a periodicity of 13-16 years between Taiwan and Korea before 1990. The result show that relationship between mullet catch fluctuation and climatic indices. The identical correlated between WPO and catch rate in the Japan, Korea, and Taiwan. The catch rate in the Japan and Taiwan were significantly correlated with the PDO index, in addition, the catch rate in the Taiwan and Korea was correlated with the NPGO. The significant coherence between mullet catchs and climatic indices with a periodicity of 8-10 years in the Tawian, and the significant coherence between mullet catchs and NPI with a periodicity of 13-16 years in the Northwest Pacific, Japan, Korea and Taiwan. Through Empirical Orthogonal Function (EOFs) found that the similar pattern of SST in autumn and winter. Depending on Spatial distribution of the SST pattern is distinguish four zone, such (A) The Yellow Sea, (B)The Southwest Japan Sea, and (C) The Northeast Japan Sea, (D) in the Taiwan Strait to the East China Sea continental shelf. The results of cross-wavelet analyze showed that the A&D zone of SST with a periodicity in the Korea and Taiwan. The catch rate in the Korea were negative correlated with the A zone of SST in autumn with a periodicity of 1-3 years, but the catch rate were negative correlated with the A zone SST in winter with periodicity of 8 years. The catch rate in the Korea were correlated with the D zone of SST in autumn with a periodicity of 13-16 years between 1970 and 2010, but the catch rate were correlated with the D zone SST in winter and with periodicity of 1-2 years between 1970 and 2010. The catch rate in the Taiwan were negative correlated with the D zone SST in winter with periodicity of 8-12 years after 1995. The low-frequency coherence with PDO and NPI demonstrates the decadal modulation of meridional teleconnection via ocean-atmosphere interactions in the Northwest Pacific. The interannual coherence with WPO suggests that the shorter-term climate variability in the Japan and Korea. The grey mullet catch fluctuation may be influenced Spawning migration by multi-timescale climate variability in the Taiwan. |
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