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|Authors: ||Chang, Chi-Hsuan|
|Contributors: ||NTOU:Department of Environmental Biology and Fisheries Science|
Blue marlin;Feeding ecology;IRI;Stable isotope analysis
|Issue Date: ||2020-07-02T07:40:25Z
|Abstract: ||中文摘要 黑皮旗魚(Makaira nigricans)為台灣東部海域生態及經濟上重要資源，同時也是洄游性頂級掠食者，控制由上而下的食物網變化，台灣東部因為黑潮帶來豐富攝食資源，為了探究該區的攝食生態，本研究透過胃內容物分析及同位素分析預判黑皮旗魚營養階層與黑潮生態系之間的相互關係。黑皮旗魚在春季圓花鰹、飛魚為主(IRI = 1144.44、805.52)；夏季以白帶魚、頭足類為主(IRI = 1913.27、1077.53)；秋季以圓鰺、鯖科為主(IRI = 2086.68、1538.12)；冬季以頭足類、正鰹為主(IRI = 1464.51、828.3)在季節間有顯著差異。在體長組別間Class 1 (100-150 cm)主要以頭足類、圓鰺為主(IRI = 928.43、707.14)；Class 2 (151-200 cm)頭足類、圓花鰹為主(IRI = 886.58、622.66)；Class 3 (200 cm以上)以頭足類、白帶魚為主(IRI = 1734.65、821.46)，在比例體長組別結果之間有變化。同位素結果δ15N介於8.7~14.4‰，δ13C為 -15.7~-20.7‰，δ15N與體長之間關係顯著；δ13C與體長之間關係不顯著。Trophic level結果顯示Class 1 = 3.5；Class 2 = 4；Class 3 = 4.6，同位素δ15N值及Trophic level有隨著體長增加而提升。同位素結果可以發現黑皮旗魚的食物階層會隨著體長增加而有所提升，Trophic Level證明體長越大攝食位階越高，大型黑皮旗魚運動能力強可攝食較高位階的生物，小型黑皮旗魚游泳能力較差攝食位階較低的生物，胃內容物結果顯示較常見大洋性表層獵物，黑皮旗魚為專一性的機會攝食主義者，攝食位階證實了在台灣東部頂級掠食者的重要性。|
英文摘要 Blue marlin (Makaira nigricans) play an important ecological and economic role in pelagic ecosystems, exerting top down control on their prey in waters off eastern Taiwan. Rich food resources were found in the Kuroshio Current, but little is know about the feeding ecology of the area. This study aims to understand the trophic level of the blue marlin and the relationship to ecology of Kuroshio Current. Results from the index of relative importance (IRI) showed variation among season. The most common prey species in spring were Auxis rochei rochei and Exocoetidae (IRI = 1465 and 828). The most important prey species in summer were Trichiuridae and Cephalopoda (IRI = 1913 and 1078). Carangidae and Scombridae were major prey species in autumn (IRI = 2087 and 1538), while Cephalopoda and Katsuwonus pelamis were found commonly in winter (IRI = 1465 and 828). However, the most important prey species were Cephalopoda and Carangidae for class 1 (100-150 cm), but for Cephalopoda and Auxis rochei rochei in length class 2 (IRI = 887 and 623). In length class 3 (larger than 200 cm), the most important prey species were Cephalopoda and Trichiuridae (IRI = 1735 and 821). The proportion of prey intake by blue marlin changed significantly with sizes. Stable isotope analysis showed that δ15N values were between 8.7~14.4‰, and δ13C values between -15.7~-20.7‰. Results indicated a relationship between trophic level and length class. Pelagic preys were major food resources for blue marlin, but with high diversity in their diet. Blue marlin were demonstrated to be an opportunistic pelagic predators, with diet varying among seasons and sizes. Results from this study suggested that as a high level trophic level species, blue marlin play an important role in marine food webs.
|Appears in Collections:||[環境生物與漁業科學學系] 博碩士論文|
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