2009-02-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/671981摘要：本計畫將訓練科學觀察員於延繩釣漁船上採集南方黑鮪的耳石。所採集得的耳石將用於年齡之查定，以判斷這些南方黑鮪的年齡。從年齡與體長，體重資料，將可估算得南方黑鮪的成長係數。藉由年齡與體長(體重)的轉換公式，大量的漁業記錄資料，將可用於建立我國所捕獲的南方黑鮪之年齡組成。太平洋黑鮪(Thunnus orientalis)有兩處產卵場，因為缺乏有效的判定方法，我們目前無法得知各個漁業國所捕獲的黑鮪究竟是來自哪個產卵場。藉由耳石穩定性氧同位素所記錄的海洋水文特性將可能解決此問題。因此，本計畫首先將建立孵化於日本海與黑潮區的黑鮪，其初期生活史階段耳石穩定性氧同位素特性，藉此特性判定各漁區所捕獲的黑鮪當初孵化的產卵場，以評估日本海與黑潮區產卵場對於太平洋黑鮪族群的貢獻度，以及族群混雜程度。<br> Abstract: This project aims to train the scientific observers to collect otoliths of southern bluefin tuna (SBT, Thunnus maccoyii) from Taiwan longline fishery. The age of each SBT whose otolith was collected will be estimated by examining the otolith annuli. These data together with length and weight data will be used to evaluate the growth rate parameters of SBT caught by Taiwanese longliners. Then, the mass commercial length and weight data will be transformed into age data to develop the age composition of SBT caught by Taiwan longliners via the age-length (weight) key. The extremely valuable Pacific bluefin tuna (PBT, Thunnus orientalis) has two spawning grounds. They spawn in the tropical Kuroshio areas and in the Sea of Japan. So far, there is no effective method to discriminate the origin of PBT caught by every nation. This problem may be resolved by otolith chemical composition that can record the ambient water characters. Therefore, this study aims to reveal the otolith 18O composition of the PBT hatched in the Sea of Japan and in the northwestern Pacific Ocean, respectively. Based on this knowledge, we will be able to discriminate the origin of the PBT and the contribution of the PBT hatched from each spawning ground.南方黑鮪耳石穩定性同位素SBTOtolithStable Isotope