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研究報告

更新日期: 2015-02-09
點閱數: 1,500

三大洋熱帶鮪類生物暨資源研究

年度 2013
計劃名稱 三大洋熱帶鮪類生物暨資源研究
中文摘要 「三大洋熱帶鮪類生物暨資源研究」之中文摘要: 一、「大西洋熱帶鮪類與太平洋黑鮪資源指標標準化及資源評估研究」        一、太平洋黑鮪資源生物學與漁業概況 太平洋黑鮪生物學,包括外部形態、分類,分布與生活史,成長,生殖,洄游,仔稚魚及幼魚洄游路徑,生理生態等之描述。兩處產卵場(西北太平洋和日本海海域)存在引發系群評估反映下列議題:幼魚出生地的認定;評估在南西群島產卵場向北迴游的幼魚分開比例;澄清幼魚洄游路徑和環境因子的關係;了解卵、仔稚魚到加入時的洄游路徑;應用數值方法模擬洄游路徑和採用幼魚喜好的游泳方向評估太平洋/日本海的分離比。太平洋黑鮪幼魚沿黑潮流域被捕獲,較小的體型(1-3cm標準長)和中度體型(2-8cm標準長)的幼魚分別在沖繩主島西部和奄美群島海域被捕獲;太平洋黑鮪幼魚沿著黑潮洋流北上洄游,逐漸成長;除外,幼魚如何分離洄游到日本海的機制,尚未清楚。同時,做太平洋黑鮪漁業的描述及最近資源評估之系群狀態展望。   二、大西洋黃鰭鮪資源量指標標準化試驗檢測採用泛線性模式進行台灣鮪延繩釣漁業在大西洋捕撈黃鰭鮪的資源量指標標準化試驗檢測。計算以年、季、次漁區、漁船噸級類別和其雙向交敢為分析因子。在估計資源量指標之前,歷年之漁獲量、漁獲努力量和名目單位努力漁獲量被選定和對其時空分布再檢測。本報告以1990-2011年之資料進行試驗檢測分析。並選定在大西洋熱帶海域(15oN – 20oS)之漁獲量和漁獲努力量,以及參考名目單位努力漁獲量均勻分布,將該選定海域劃分成5各次漁區層級。和線性模式和三角泛線性模式用來標準化黃鰭鮪的單位努力漁獲量。結果顯示,台灣鮪延繩釣漁業捕撈黃鰭鮪的標準化資源量指標,不因模式之不同和不因因子之不同,除有年度位移之外,而有趨勢之差異。和日本延繩釣漁業的標準化黃鰭鮪資源量指標相比較,歷年之趨勢截然不同。 二、「印度洋熱帶鮪類(大目鮪及黃鰭鮪)資源研究(CPUE標準化)」        此計畫之研究成果可提供2012年IOTC國際漁業組織進行印度洋大目鮪與黃鰭鮪進行資源評估分析工作之參考依據,對於我漁業國責任制漁業形象有正面助益。台灣鮪延繩釣漁業利用印度洋大目鮪與黃鰭鮪漁業概況說明,完成漁獲統計資料與觀察員資料檢視與處理解析,彙整歷年印度洋熱帶鮪類台灣鮪延繩釣漁業大目鮪與黃鰭鮪CPUE標準化研究方法與結果。 利用泛線性模式估計台灣鮪延繩釣漁業利用印度洋大目鮪與黃鰭鮪單位努力漁獲量標準化變動趨勢。大目鮪CPUE標準化結果,由變方分析表研判,確認長鰭鮪與黃鰭鮪漁獲比例是解釋大目鮪單位努力漁獲量變動的最主要的因子。 然而整體而言,自1980年至2011年,除了2002年至2005年相對呈現較高的CPUE值與2008年至2010年相對呈現較低的CPUE值外,不論是名目單位努力漁獲量或是標準化單位努力漁獲量的變動趨勢皆相對平穩,沒有明顯趨勢。 然而2012年CPUE大幅增加,主要原因是2012年作業位置有明顯差異,索馬利亞海盜活動區域有活耀的漁業活動,且名目單位努力漁獲量相當高。 黃鰭鮪CPUE標準化結果,由變方分析表研判,確認長鰭鮪與大目鮪漁獲比例是解釋大目鮪單位努力漁獲量變動的最主要的因子。 然而整體而言,自1980年至2012年,除了2004年至2009年呈現持續下滑的趨勢外,不論是名目單位努力漁獲量或是標準化單位努力漁獲量的變動趨勢皆相對平穩,沒有明顯趨勢。 根據近十年來我國觀察員所記錄的資訊,觀察船的漁具規格每筐鉤數似乎無法有效作為標的魚種的替代因子,因為台灣鮪延繩釣漁業漁撈作業使用之每筐鉤數與理論作業深度的關係並非屬於簡單的比例關係,現階段仍無法確認利用每筐鉤數的作業資訊作為標的魚種的替代因子的可行性。 三、「中西太平洋台灣鮪釣漁業黃鰭鮪CPUE標準化模式比較研究」            我國在太平洋的三個鮪魚國際組織(WCPFC, IATTC, ISC)皆為(或將為)會員國份,因此加強資源研究更是我國之責任與義務。本計畫檢視並篩選中西太平洋黃鰭鮪類歷史鮪釣漁業漁獲統計資料,並針對努力量、漁獲組成、漁獲量等資料進行比對檢討,以釐清資料特性及漁業行為在資料上之反應,之後應用該資料進行不同模式的CPUE標準化研究,包括統計模式GLM、GLMM、GAM及ZINB。
英文摘要 Abstract of "Biology and stock assessment studies of tropical tunas for far seas fisheries": 1. "Stock Assessment of tropical tunas in the Atlantic and Pacific bluefin tuna" :       一、Biology and fishery of Pacific Bluefin tuna Biology of Pacific bluefin tuna (Thunnus orientalis) was described including its external morphology, taxonomy, distribution, life history, growth, reproduction, migratory route of larvae and juveniles, and physiological ecology. Two spawning areas (Western North Pacific and the Sea of Japan) were investigated to reflect the problematic evaluation of stock status and issues of identification of birth place, the proportion of migration northward of juveniles from Nasei Shoto waters, the migratory routes of juveniles and the relationship to their environmental factors, the understanding of migration routes from eggs, larvae and juveniles of Pacific Bluefin tuna as occurrence of recruitment, introduction of numerical method to simulate the migratory routes, and evaluation of the separated proportion of juveniles migrated into either side of Pacific Ocean or the Sea of Japan by using the preference of their swimming direction. Pacific Bluefin tuna is harvested along the regime of Kuroshio Current, juveniles of small sized (about 1-3 cm SL) and medium sized (2-8 cm SL) is caught in the waters of western area of Okinawa main island and Amami Islands, respectively. Juveniles of Pacific bluefin tuna grow when they migrate northward along regime of Kuroshio Current. Besides, the mechanism of separation of juveniles into either the Sea of Japan or Pacific side was not known. The report was also dealing with the description of Pacific bluefin tuna fishery and evaluation outlook of stock status assessed recently.   二、Trial estimation of standardized catch per unit effort of yellowfin tuna by Taiwanese longline fishery in the tropical waters of Atlantic OceanThe trial standardized catch per unit effort (CPUE) of Atlantic yellowfin tuna caught by Taiwanese longline fishery was estimated by delta general linear models. For the manipulation, several factors were used including year, quarter, subarea, vessel category and the two-way interactions. Before estimating CPUE, historical catch and effort data were selected and re-examined by spatial and temporal distribution; then the 1990-2011 catch and effort data within the tropical area (15oN – 20oS) were selected and stratified into 5 subareas to make the nominal CPUE homogeneous as possible among subareas. The GLM and Delta-GLM were used to standardize yellowfin tuna CPUE for Taiwanese longline fishery in the Atlantic tropical waters from 1990 to 2011. The results obtained are very similar trend but the displacement of peaks in the series; and different trends were occurred between Japanese longline CPUE series and anyone of the Taiwanese 3 series. 2. "The impact of different target proxies on CPUE standardization of Indian Bigeye and Yellowfin tuna based on Taiwanese longline fishery data" :       The nominal bigeye CPUE was ranged between 4 no./ 1000 hooks and 9 no./ 1000 hooks in the tropical and whole Indian Ocean. As for the standardized CPUE series, they showed very similar trend with the nominal CPUE except after 2005 in the whole Indian Ocean. In 2012, the CPUE increased to the peak since lots of fishing activities occurred in the Somalia area.  Before 2007, the nominal yellowfin CPUE was ranged between 2 no./ 1000 hooks and 5 no./ 1000 hooks in the tropical and whole Indian Ocean. After that, the nominal yellowfin CPUE continually dropped to the historical lowest CPUE of 1 no. / 1000 hooks. And then came back to the level of 2 no. / 1000 hooks in 2012. As for the standardized yellowifin CPUE series, they showed very similar trend with the nominal CPUE except before 1986. The treatment of target species proxy is considered as a crucial part in CPUE standardization. The information of number of hooks per basket seems not to be a proper target species proxy since there is a clear proportional relationship between the number of hooks per basket and the theoretical depth based on the observer data which collect from 2002. 3. "Comparisons of effects from different CPUE standardization models on WCPO yellowfin tuna for Taiwanese longline fishery" :           Taiwan is a member of the three organizations in the Pacific Ocean (WCPFC, IATTC, ISC) which impose the responsibility of enhancement of researches on Taiwanese tuna fisheries. This project is to review and screen the historical Taiwanese yellowfin catch data to reveal the data feature.; then to apply different CPUE standardization models to the data and discuss the appropriateness of each model. The models to be examined include GLM, GLMM, GAM and ZINB.
計畫編號 102農科-11.1.1-漁-F2(Z)
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