碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 99 / Catches data of 5 set-net grounds with trophic levels and 8 environmental factors in the research by applying the methods of ecological index and Grey Relational Analysis (GRA) to investigate the trends of mean trophic levels and the relations between catches and environmental factors in set-net fisheries. The results of this study are as following:
1.From the catches analysis, the fishing season of set-net fisheries mainly included winter and spring, and the species composition had significant different as geographic variations. The main species were Pelagic groups in the east, and Reef-associated groups were in the West and the Southwest.
2.The rate of TL in each set-net changed between 0.003~0.210/yr. Hsin-Hsie-Fa, San-Xian-Tai and Man-Feng fishing grounds were upward trends in TL , Chao-Jin and Rih-Fong fishing grounds were downward trends in TL . The results also revealed that the characters of set-net fisheries were to catch high trophic levels of fish species (TL>3.25), and presently were in developing stage.
3.Fishing-in-Balance index (FiB index) was downward trend in Chao-Jin fishing ground, others were upward trends. The changed rates were between 0.001~0.073/yr. After reached a high value, FiB was irregular slight changed at a certain range. It showed that different types of catches ratio in set-net fisheries were imbalance.
4.From the results of GRA in catches with environmental factors, set-net grounds among environmental factors maintained moderate above in relations (grey grade>0.5). The high relational factor was Sea Surface Temperature (SST), factors of Pressure (P) and Humidity (H) were low relations.
5.Results of GRA on high CTL species reveled that mainly affected species were the environmental factors of SST, Sunshine hours (S), Chlorophyll a (Chl), and Wind velocity (W). The same species of high CTL at different fishing grounds didn’t have the same environmental factors with high relations.
| Identifer | oai:union.ndltd.org:TW/099NTOU5451031 |
| Date | January 2011 |
| Creators | 張芸菁 |
| Contributors | Cheng-Hsin Liao, 廖正信 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 65 |
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