農業部-水產試驗所全球資訊網農業部-水產試驗所全球資訊網

太平洋黑鮪屬於高度洄游性魚類，具高經濟價值。根據漁獲統計資料指出近年來太 平洋黑鮪資源量劇減並呈現過漁現象。本研究採集臺灣東部海域太平洋黑鮪與相關 餌料生物肌肉樣本進行穩定同位素分析，並結合電子式標識放流試驗，解析臺灣東 部海域太平洋黑鮪的營養階層與其移動、產卵行為特徵。本研究所採集黑鮪樣本標 準體長範圍多集中在200~220公分，平均年齡15歲，同位素分析結果顯示臺灣東部海 域太平洋黑鮪的營養位階為5.1，屬於頂級掠食者，且其δ 13 C值與δ 15 N值有月 別間的差異，此差異可能受到海洋基礎生產力、海溫等環境因子影響。此外，本研 究與美國史丹佛大學霍普金斯海洋研究所合作，利用彈脫型衛星標識紀錄器追蹤太 平洋黑鮪移動行為，在美國加州外海標放3尾太平洋黑鮪配置彈脫型衛星標識紀錄器 、5尾配置超音波標與8尾配置植入型紀錄器。本研究結果初步指出台灣東部海域太 平洋黑鮪的營養階層，並將進一步探討西北太平洋黑鮪的族群結構與洄游習性，以 提供資源評估之重要參數及漁業管理策略擬定之重要科學依據。

Pacific bluefin tuna is highly migration species with important commercial value. Their populations are overfishing due to the increasing numbers of removal from fishery in recent years. To analysis the trophic level, migrating and spawning behavior, we investigated the population structure of Pacific bluefin tuna by using the stable isotope analysis and electronic tagging in eastern Taiwan. Fishery data was collected from 2011 to 2017 and the range of standard length were from 200 to 220 cm, age was 15 in average. The stable isotope analysis results indicated that the trophic level of Pacific bluefin tuna was 5.1, belonging to top predator. Their δ 13 C value and δ 15 N value were different among months, and the differences could be related to the environmental factors such as primary production and water temperature of ocean. Additionally, we cooperated with the Hopkins Marine Station of Stanford University, to track the movements of Pacific bluefin tuna. We released 3 individuals with pop-up satellite archival tags, 5 with acoustic tags and 8 with archival tags. The study explored the trophic level and population structure of Pacific bluefin tuna in eastern Taiwan, and gained further understanding of the population structure and migrating behavior in western Pacific Ocean.