碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 101 / The present study applies the Generalized Additive Model (GMA) and the Geographic Information System (GIS) to investigate the effect of climate change on the distribution and abundance of albacore tunas in the Atlantic Ocean, using annual statistical data related to Taiwan’s Atlantic tuna fishing vessels and environmental factors such as Sea Surface Temperature (SST) and Sea Surface Height (SSH) obtained from situational simulation (A1B, A2, and B1) of climate change.
Among the four fishing areas of albacore tuna defined by the International Commission for the Conservation of Atlantic Tunas (ICCAT), the highest amount of catch is mainly from the 4th fishing area, which also has the most effort. However, the first fishing area with the least effort has the highest annual average nominal Catch per unit effort (CPUE) (21.07 fish/103hooks) among these fishing areas. The third fishing area has the lowest annual average nominal CPUE. From the spatial distribution map of overlaying albacore tuna CPUE with SST and SSH, the fishing areas with high CPUE are located at the high-latitude waters in the first and fourth area where SST is lower and SSH is higher. The results from situational simulation (A1B, A2, and B1) of the changes in SST and SSH have shown that SST of the four fishing areas in the Atlantic Ocean will continue to rise as a result of climate change. However, the change in SSH indicates a geographical change.
The best-fit model using the GAM stepwise analysis was examined and explained 72.7% of the variance. The spatial factors such as longitude and latitude had greater influences on albacore tuna CPUE. This suggests that fishing location is one of the key factors that affect CPUE. However, CPUE decreases as the environmental factor SST increases and as SSH decreases. The model has also shown a positive correlation between regional CPUE and nominal CPUE with R value as high as 0.79. Therefore, with the situational simulation of A2, the catch rate of albacore tunas continues to decrease as the surface water temperature rises, especially for the higher-latitude subtropical waters. Furthermore, the optimum simulation model predicts that CPUE in the southern Atlantic subtropical waters will decrease by 20-25% in 2080 compared to 2001.
| Identifer | oai:union.ndltd.org:TW/101NTOU5451044 |
| Date | January 2013 |
| Creators | Hsueh-Chen Chuang, 莊雪珍 |
| Contributors | Ming-An 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 | 57 |
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