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西北太平洋劍旗魚移動特徵研究

  • 日期:108-02-12
  • 計畫編號:108農科-1.2.1-水-A2
  • 年度:2019
  • 主持人:江偉全
  • 研究人員:王勝平、林憲忠、張景淳

劍旗魚(Xiphias gladius)為大型洄游性魚類,廣泛分布在熱帶及溫帶海域,本研究的主要目的為結合穩定同位素分析及電子式標識放流試驗,以解析臺灣東部海域劍旗魚之攝食生態與洄游行為特徵。由穩定同位素分析結果δ15N值介於9.3〜14.3‰之間,δ13C值介於-17.63〜-15.35‰之間,同位素δ15N值有隨著體長增加而提升,劍旗魚雖偏好攝食中水層中的餌料(例如:頭足類),但攝食餌料種類多樣。利用彈脫型衛星標識器(PSAT)結附於3尾劍旗魚魚體上,共記錄15~229天移動行為特徵。標識後之劍旗魚主要沿東南方向移動到菲律賓東南部附近海域彈脫。從標識到彈出位置之直線距離為631~1,605 km。垂直移動顯示明顯的晝夜垂直移動模式,白天期間下潛之>400 m(15~20°C),夜間則棲息於表面混合層<100m(偶爾溫度為32.9°C)。劍旗魚於白天及晚上棲息深度之時間達顯著性差異,夜間在表層並保持於該水層直到下一個黎明。劍旗魚隨著深海散色層(SSL)餌料的晝夜垂直運動,以有效地利用餌料資源,並且劍旗魚可以更長的時間來維持體溫。由於其獨特的生理和形態適應性(例如血管逆流熱交換器),使劍旗魚可以比其他魚類更有效地尋找餌料資源。

研究報告摘要(英)


Swordfish (Xiphias gladius) is a highly migratory apex predator distributed from tropical to temperate oceans. The objective of this research is to use a combination of stable isotope analysis (SIA) and electronic tagging experiments to identify swordfish trophic position and movement behavior in eastern Taiwan waters. SIA showed that δ15N values were between 9.3~14.3‰, and δ13C values between -17.63~-15.35‰. Middle waters preys were major food resources for swordfish (ex. Cephalopoda), but with high diversity in their diet. In total, 3 swordfish were tagged pop-up satellite archival tags (PSATs) and remain affixed from 14 and 229 days-at-liberty. These samples moved primarily in a southeast direction to the southeast off Philippines where the tag popped-up. The total linear displacements were 631 to 1,605 km from deployment to pop-up location and the fish demonstrated pronounced diel vertical movement patterns reaching daytime of depths >400 m (15–20°C) and occupying the surface mixed layer <100m at nighttime (occasionally temperatures of 32.9°C). Swordfish distributions of time spent at depth were significantly different between daytime and nighttime, the fish ascended into the surface layer and remained there until the following dawn. Swordfish follow the diel vertical movements of prey organisms comprising the deep sound scattering layer (SSL) to exploit them effectively as a resource and can maintain their body temperature for longer periods below the thermocline. Because of its unique physiological and morphological adaptations (such as vascular counter current heat exchangers) it can search for food resources more effectively than other fishes.