碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 102 / In order to investigate the spatial and temporal distribution of the longline fishery in the eastern waters of Taiwan, this study aggregated the data of Voyage Data Recorder (VDR) and logbooks collected from 35 longline vessels in the period between January and December of 2010.
There are three major objectives of this study and the results are summarized as follows:
1.Analyzing the activities of vessel behavior: This study investigated the tracks and positions during fishing operations on the sea based on the VDR data classified by vessel tonnage and fishing season. The results indicated that the CT1 and CT2 vessels presented similar behaviors during different seasons except for the distance between the fishing area and port. Due to the variation in fishing time for CT3 vessels, it was difficult to perform the analysis for CT3 vessels.
2.Identifying the cruise speed for fishing or non-fishing activity by aggregating the VDR data and the time of throwing lines and hauling lines recorded on the logbooks: Due to the logbook records the time of throwing lines and hauling lines by hour for minimum, the variations in cruise speed were investigated based on the records of throwing lines and hauling lines within an hour. The results indicated that the longliner can be defined to be throwing lines when its speed decreased from 6.7±0.9 knot to 2.7±1.6 knot within an hour and then kept navigating with low speed, while the longliner can be defined to be hauling lines when its speed increased from 3.6±1.6 knot to 4.9±1.4 knot within an hour and then kept navigating with high speed.
3.Analyzing the spatial and temporal variation in fishing grounds based on the information of defined cruise speed for fishing operations: According to the catch compositions of the longliners based in Shinkang harbor, longliners operating in this area can be divided into two categories, which were tuna longliner and dolphinfish longliner. The results indicated that the hotspots of fishing ground located in the waters around Lanyu Island and in the offshore waters of eastern coast for tuna and dolphinfish longliners, respectively. Obvious difference in fishing grounds between these two longliners was observed. However, the fishing grounds for both longliners located in similar waters of eastern coastal in autumn of 2010 and this might be resulted from climate condition. Due only one-year data provided by Fishery Agency, insufficient evidence could be able to support the influence of climate on the fishing activity.
| Identifer | oai:union.ndltd.org:TW/102NTOU5451015 |
| Date | January 2014 |
| Creators | Chen, Kuan-Yu, 陳冠宇 |
| Contributors | Wang, Sheng-Ping, Liao, Cheng-Hsin, 王勝平, 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 | 56 |
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