碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 99 / This study analyzed the landing data of set net fishery from Fishing Agency of Penghu County to estimate the trophic level (TL) indices and investigate the variation of mean trophic level (MTL) associated with the fishing-in-balance (Fib) in water around Pen-Hu Islands. We also studied the change of biodiversity in the study area from the species components. Our results are summarized below:
1. The species of set net fishery in Penghu were varied by season and dominant in the migratory species of the surface and subsurface water. The first 5 dominant species are included Euthynnus affinis, Spratelloides gracilis, Trichiurus lepturus, Siganus fuscescens, and Rastrelliger kanagurta.
2. The monthly variation of MTL showed a decreasing trend with the rate of 0.0196 (TL/year) during the study period. It is twice higher than the global trend. The FiB index also revealed a negative trend with the fishing catch variation. In addition, these two species of Euthynnus affinis and Trichiurus lepturus have more than 50% contribution on mean trophic level. It suggested that the occurrence rate of these two species was subsequently decreased by year.
3. The exceptional intrusion of cold water in 2008 winter may impact on the warm water and resident species of fishes with low trophic level, but in the meanwhile it may also bring some migratory species with high TL. It suggested that the interaction of fishing ability and marine environment with climate change may attention to further investigate their influence on set-net fishery around Penghu islands.
| Identifer | oai:union.ndltd.org:TW/099NTOU5451032 |
| Date | January 2011 |
| Creators | 王心怡 |
| Contributors | Ming-Anne Lee, 李明安 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 67 |
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