碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 99 / Abstract
The swordtip squid, Uroteuthis (Photololigo) edulis, is an important torch-light fishery resource in the northeastern waters of Taiwan. In order to explore the fluctuation characteristics of the resources, the study collecting the fishing activities of the torch-light fishery sample boats in the northeastern waters of Taiwan between 1998 to 2009. The generalized linear model (GLM) and generalized additive model (GAM) were applied to investigate the correlation of these factors on catch per unit effort of the swordtip squid catches (CPUE) by the temporal variables, spatial variables, vessel fishing characters, environmental variables and the biotic variable by torch-light fisheries (1998-2009). Furthermore, the standardized CPUE for swordtip squid was processed by the GAMs to explain the annually and seasonally spatial patterns.
The results indicated that the temporal and spatial variables were the most relevant explanatory variables (48.58% of variance explained) on CPUE. The explanatory variables of Bycatch was 14.94%. The vessel fishing characters and the environmental variables were only 1.18% and 0.06% respectively. The distribution of the fishing ground between 1998 to 2009 indicated that the spatial pattern of the standardized CPUE showed a reduction in the range of fishing grounds and a decrease in CPUE of the swordtip squid since 2003. The monthly distributions of CPUE showed an obviously seasonal pattern that the main fishing seasons were between spring and autumn. However, a large number of bonitos occurred near the squid fishing area might cause the lower CPUE during summer period. Some of the horse power was for the electricity of the freezing equipment in the large tonnage sample boats. There were better gathering effects with low light intensity. The better CPUE of the swordtip squid were in 23℃ and 28℃. The main distribution of these waters were located in higher than 26°N areas where the Kuroshio Current, China Coastal Current front ,and the upwelling occurred.
Keywords: swordtip squid, torch-light, CPUE, GAM, northeastern waters of Taiwan
| Identifer | oai:union.ndltd.org:TW/099NTOU5451035 |
| Date | January 2011 |
| Creators | Chien-Hao Tseng, 曾建豪 |
| 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 | 70 |
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