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|Authors: ||Yen, Kuo-Wei|
|Contributors: ||NTOU:Department of Environmental Biology and Fisheries Science|
climate change;El Niño;WCPO;skipjack tuna;catch potential;primary productivity;habitat suitability
|Issue Date: ||2018-08-08T03:24:52Z
|Abstract: ||氣候變遷正持續影響著人民的生活，現行的調適策略仍不足以控制未來的環境變化，若能及早發現氣候變遷的影響及變動趨勢，衝擊程度將可望降低。中西太平洋正鰹是世界上重要的經濟性資源，供應全球人口動物性蛋白質之需求，也助益了許多相關產銷產業並提供豐沛的就業機會。因此降低中西太平洋正鰹資源受氣候變遷的衝擊至關重要，而瞭解氣候變遷如何影響中西太平洋正鰹以及如何評估中西太平洋正鰹的漁獲潛能就成為重要的議題。過去研究已掌握短期極端氣候事件對中西太平洋海洋生態系統的運作及生產力供應造成的影響，本研究以過往經驗的漁獲資料與海洋環境數據，並透過經驗正交函數、泛線性及泛加成模型深入探討中西太平洋正鰹與總初級生產力、不同類型聖嬰現象及海洋環境棲地適合度的關係，並將經驗轉換成可作為評估工具的相關模型，再透過氣候情境模擬數據評估中西太平洋正鰹的漁獲潛能。研究結果具體說明如下： 一、 初級生產力的變動對正鰹產卵期、稚魚後期等重要生活史階段會造成影響，並導致資源加入量與初級生產力變動出現顯著的時間延遲關係。 二、 中太平洋與東太平洋聖嬰現象對正鰹的豐度及棲地適合度都存在負面的影響。若以兩者相比，中太平洋聖嬰現象對正鰹的影響比東太平洋聖嬰現象強烈，但這兩種聖嬰現象獨立的發生，對資源的影響都遠不及兩種聖嬰現象同時出現。 三、 在暖化程度最低到最高的氣候情境下，觀察中西太平洋正鰹漁獲潛能可以發現，漁獲潛能的趨勢將由持平轉向微幅上升的趨勢，但隨著暖化程度加劇，此潛能的年間振盪將更劇烈。 四、 相較於暖化程度較輕的情境，當暖化的狀況持續加劇下，正鰹漁業資源面對聖嬰現象之脆弱度將提高，漁獲潛能亦將隨之降低。 五、 未來的漁獲潛能與初級生產力的正向關係有空間上的差別，因此，在未來初級生產力可能不足以配合漁獲潛能的轉移。 為確保中西太平洋正鰹資源永續經營，氣候變遷及全球暖化的趨勢是該漁業資源管理必須持續關注的問題。|
Climate changing has been affecting human’s daily life for a certain period. Present responses to climatic impacts are yet to stop systems from global changing. It is suggested that, with appropriate preventions to climate change in early stage, the degree of climatic variations induced impacts could be relieved. The skipjack tuna stock in the Western and Central Pacific Ocean (WCPO) is a vital economic resources, which is one of main protein sources for human, and also promotes the development of associated industries, as well as plenty employments. Thus, it is significant to mitigate and minimize the impacts of climate change on skipjack. In order to achieve this, it is essential to understand how climate change affects the resources. Previous studies have revealed profound impacts of extreme events on the functioning and primary productivity of marine ecosystems in the WCPO. This study aimed to investigate the relationships among various factors, including the abundance of skipjack tuna, primary productivity, different types of El Niño events and habitat suitability. Fisheries and environmental data of certain period and Representative concentration pathways emission scenario database were adopted to assess the catch potential of skipjack in the WCPO. Key findings from the study are the following: 1. In the important stage of life history, the changes of primary productivity will affect skipjack stock and causing time delay relationships between stock recruitment and primary productivity. 2. In terms of the consequences of different types of El Niño events, Central-Pacific El Niño events can play a more influential role than do Eastern-Pacific El Niño events, and relatively higher vulnerability values were found to be associated with the simultaneous occurrence of the two types of El Niño. 3. Form lowest to highest greenhouse gas emission scenario, there could be a stable to relatively a small increase in the catch potential in WCPO. However, the annual oscillations of catch potential would be observed as more intense attributing to global warming. 4. In a moderate global warming scenario, with the intensified El Niño events, the vulnerability of the skipjack resources will increase, and the catch potential will decrease. 5. Positive correlation between catch potential and primary productivity varied in space; therefore, the primary productivity may be insufficient to meet the transfer of catch potential in the future. It is advised that the impacts of global climate variations, particularly El Niño events, on skipjack tuna should be continuously taken into consideration in the fisheries management to ensure the sustainable exploitation of skipjack resources in the WPCO.
|Appears in Collections:||[環境生物與漁業科學學系] 博碩士論文|
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