碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 105 / The yellowfin tuna (Thunnus albacares; YFT) is one of the important commercial species for longline fisheries in the Indian Ocean. In this study, we collected the long-term (2003-2012) records of yellowfin tuna catch rates, length data of longline fisheries with the marine environmental data, including sea surface temperature (SST), chlorophyll-a concentration (CHL), mixed layer depth (MLD), sea surface height (SSH). Empirical orthogonal function (EOF) analysis were used to investigate the relationship between the environment variables and the catch rates for speculating the distribution of the feeding grounds and spawning grounds on each cohort of YFT. The relationships between each cohort and the environmental data with climatic indices showed that the distributions of larvae were affected by the MLD and the CHL, concentrated in the northwest Indian Ocean in the first and second season, and in southwest Indian Ocean in third and fourth season. The juvenile in the first and fourth season were affected by the DMI event, the variation of MLD would affected the distribution of Arabian sea and western and central Indian ocean. In the second season, SST and SSH would affect the distribution in Gulf of Oman and the mid-western Indian Ocean. The SST in Somalia decreased and the CHL increased, the juvenile would move to the east Indian Ocean in the third season. The distribution of spawning group in Madagascar and western and central Indian ocean would affected by CHL in the first and fourth season. The variation of SST would affect the spawning group, their distribution in mid-Western showed horizontal variability in the second season. In the third season, the SSH affected the distribution in Gulf of Oman, and the distribution in Madagascar would be affected by the MLD. The MLD and CHL influenced the distribution in Gulf of Oman, the waters off Madagascar and the Bay of Bengal. As a result, we speculating that migrations takes place between the spawning ground and feeding ground.
| Identifer | oai:union.ndltd.org:TW/105NTOU5451017 |
| Date | January 2017 |
| Creators | Chen, Ming-Wen, 陳明雯 |
| Contributors | Lan, Kuo-Wei, 藍國瑋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 73 |
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