碩士 / 國立臺灣海洋大學 / 海洋事務與資源管理研究所 / 100 / Longline fishery is one of the most important fisheries of Taiwan,
which were accounted for over 10% of total catch. For understanding the fishing pattern of Taiwanese coastal longline fisheries, 554 trips data collected from 24 vessels Taiwanese coastal longline fishing CT0~CT4 vessels (CT0 is less than 5 tons, CT1 is for more than 5 tons less than 10 tons, CT2 is for more than 10 tons but less than 20 tons, CT3 is for more than 20 tons but less than 50 tons, CT4 is for more than 50 tons but less than 100 tons) were used to analysis of fishing pattern of these vessels. The results showed the fishing speed were 2.37 knot, 3.76 knot, 3.45 knot, 3.27 knot for CT0 to CT3 pelagic longline fishing vessels, respectively. For bottom longline fishing vessels, the fishing speed were less than 2.82 knot, 3.80 knot, 3.31 knot, 5.62 knot, and 5.91 knot for CT0 to CT4, respectively. Use this speed add a standard deviation as indicator can distinguish fishing and steaming, the accuracy was more than 80%. Regarding the appropriate time intervals, it is suggested that vessels larger than CT2 vessels interval should use 60 minutes interval. For those smaller than CT2, 3 minutes interval would be appropriate. For position, both of pelagic and bottom longliners showed the average fishing position difference of CT0, CT1, CT4 fishing vessels were less than 3.5 nautical miles between VDR and logbook data. However, the average fishing position difference were more than 5 nautical miles for CT2 and CT3 fishing vessels. Regarding the linear regression function of catch, fishing effort(number of hooks), season, tonnages, fishing time, speed, catch position(latitude and longitudes) were used as independent variables. Tuna longline catches were correlation to season, fishing effort, average hauling speed and fishing time for tuna longline fisheries. The fishing position and the fishing time are correlated to catch of bottom longline catch. It showed tuna longline has high catch in summer, and bottom longline has higher catch in western than eastern, higher catch in north than south waters of Taiwan. This study suggests that average setting’s speed add a standard deviation could be defined as the fishing speed of longline fisheries. This study showed VDR data could be used to understand the fishing area, fishing time, and fishing speed, and further be applied to compare with the logbook and get useful information for management purpose.
| Identifer | oai:union.ndltd.org:TW/100NTOU5277007 |
| Date | January 2012 |
| Creators | Yan-Chun Chen, 陳彥君 |
| Contributors | Hsiang-Wen Huang, 黃向文 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 66 |
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