Abstract
一、我國身為全球鮪延繩釣漁的國家之一,而大西洋是我國遠洋漁業重要的漁場。為因應大西洋鮪類保育委員會(ICCAT)對於鮪類、類鮪類與混獲物種之各項管理措施,本研究將針對大西洋我國延繩釣漁船漁獲熱帶鮪類、溫帶鮪類、旗魚與鯊魚物種進行資源調查,以及配合ICCAT科學暨統計常設委員會(SCRS)會議進行以下研究:(1)大西洋熱帶鮪類資源研究;(2)大西洋旗魚與南大西洋溫帶鮪類資源研究;(3)大西洋鯊魚與北大西洋溫帶鮪類資源調查研究。今年度ICCAT SCRS將分別針對黃鰭鮪、大西洋白旗魚與灰鯖鮫進行資源評估,本研究將彙整分析我國鮪延繩釣漁獲資料,提出相關物種之漁獲量、漁獲努力量、體長資料與CPUE標準化分析,以提供大會資源評估會議所使用,並針對資源評估結果進行相關分析。而長鰭鮪為我國大西洋鮪延繩釣主要漁獲物種,ICCAT SCRS預計於2020年進行資源評估,本研究也將持續彙整分析我國鮪延繩釣釣獲長鰭鮪之漁獲量、體長資料與CPUE標準化,以及蒐集北大西洋長鰭鮪漁獲控制法則(Harvest Control Rule, HCR)與管理策略評估(Management Strategy Evaluation, MSE)之相關分析。二、本研究將依據印度洋鮪類委員會(IOTC)之溫帶鮪類工作小組(WPTmT)與旗魚工作小組(WPB)之工作規劃進行印度洋長鰭鮪、黑皮旗魚之CPUE標準化分析,另外本研究亦將進行印度洋黑旗魚之資源評估。配合南方黑鮪保育委員會(CCSBT)之建議,本計畫也將持續進行台灣南方黑鮪CPUE標準化之變動趨勢分析,同時本研究將根據台灣觀察員所收集之生殖腺樣本進行南方黑鮪之生殖生物學分析。檢視與分析我國印度洋熱帶鮪類作業層級資料與觀察員資料之漁獲與體長資料,以掌握漁業利用資源動態發展。同時協助檢視資料品質將有疑義之資料回報漁業署及資料庫管理單位,並提出觀察員資料之改善建議。於4月底前針對前一年度印度洋鮪類委員會(IOTC)熱帶鮪類工作小組會議評估印度洋大目鮪與黃鰭鮪資源狀況之結果提出中文摘要。配合印度洋鮪類委員會(IOTC)執行印度洋大目鮪與黃鰭鮪魚種資源評估,進行印度洋大目鮪與黃鰭鮪CPUE標準化研究分析,並提出相關研究報告,以因應2019年國際漁業組織印度洋鮪類委員會(IOTC)熱帶鮪類資源指標更新評估。將訓練科學觀察員於延繩釣漁船上採集南方黑鮪(Thunnus maccoyii )的耳石,並且從高雄冷凍廠取得南方黑鮪耳石 。所採集得的耳石將用於年齡查定,以判斷南方黑鮪的年齡。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與成長。鯊魚是台灣沿近海漁業中常見的漁獲對象,同時也是遠洋鮪延繩釣漁業中重要的混獲魚種。儘管鯊魚的捕獲量非常大,但鯊魚肉的經濟價值較低,一直以來都被視為其他漁業意外捕獲的物種,也因此其詳細的漁獲資料非常缺乏。在缺乏鯊魚種類別 年漁獲量、努力及漁獲地點資訊的情況下,也因此阻礙了印度洋海域鯊魚資源管理的實施。 為因應印度洋鮪類委員會(The Indian Ocean Tuna Commission, IOTC)之 要求,本研究蒐集印度洋漁業管理組織所需之鯊魚資料包括漁獲量、生物學資料及努力量以進行CPUE標準化,供族群評估之用。此外,並針對我國於印度洋捕獲之平滑白眼鮫實施無危害評估(NDF)相關措施之可行性進行評估並提出建議。三、鯊魚資源保育與管理之議題逐漸成為國際矚目之焦點,為因應區域漁業管理組織之需求,以養護管理該等資源,確保資源永續利用。本研究將針對我國太平洋鮪延繩釣主要鯊魚混獲之鋸峰齒鮫與灰鯖鮫,以及被規定禁止留艙之平滑白眼鮫與污斑白眼鮫,彙整分析其漁獲量、體長資料與CPUE,並配合CITES規定進行這些物種之無危害評估。最後,配合2019年ISC鯊魚工作小組將舉行鋸峰齒鮫之資源評估資料準備會議,本研究將提出會議所需之相關資料。將助益國內漁政單位預先瞭解國際漁業管理措施對我國之衝擊,維護我國之漁業權益,並配合各漁業管理組織提出相關科學數據或管理建議;協助我國相關產業之發展,並確保有效利用南太平洋長鰭鮪、太平洋旗魚資源並掌握資源變動趨勢。計畫成果將可提供為國內漁政單位及國際漁業管理組織之最佳科學依據。為因應國際漁業管理組織之需求,提供中西太平洋大目鮪、黃鰭鮪、正鰹漁業管理所需之科學依據,以養護管理該等資源,確保資源永續利用。積極參與國際組織之科學評估與MSE研發討論,以提高結果之正確性,及在訂定管理措施及配額時保障我國之漁業利益。積極參與國際組織之科學評估與MSE研發討論,以提高結果之正確性,及在訂定管理措施及配額時保障我國之漁業利益。分析北太平洋長鰭鮪之CPUE標準化及體長別、年齡別漁獲量的長期變動趨勢。並蒐集該資源目標參考點、績效指標、可接受風險及管理策略評估(MSE)等相關評估分析資訊。在研究期間配合中西太平洋漁業委員會(WCPFC)及北太平洋鮪類國際科學委員會(ISC)執行資源評估,並提出相關研究報告。太平洋黑鮪( Thunnus orientalis ) 是臺灣近海鮪延繩釣漁船重要漁獲物,主要漁季在每年的5-6月,佔全年的94.13%。台灣中小型延繩釣漁船於2001-2016年間共漁獲62,245尾太平洋黑鮪,年漁獲尾數最高為2003年的8,193尾,之後開始減少,到了2012年為最低點的713尾,2014-2016年漁獲尾數有增加之趨勢。根據漁獲個體尾叉長分析之結果2015-2016年出現大量180-220公分個體被漁穫,新的加入群有可能是漁獲尾數增加之主因。臺灣地區太平洋黑鮪主要卸漁港口在東港、南方澳與成功三地,並以東港為主,但近年來南方澳所佔比例有增加之趨勢。2005-2015年間太平洋黑鮪之CPUE為起伏不定,利用最適GLM模式(Zero-inflated with possion distribution)標準化後的CPUE與原始趨勢相似。年間漁獲太平洋黑鮪原始CPUE為每千鈎0.20尾,最低為2012年的每千鈎0.09尾,最高為2003年的每千鈎0.31尾。綜合分析結果顯示2014-2016年太平洋黑鮪漁況有轉好之趨勢,然仍未及2001-2004年之水準,未來應持續監控此資源變動情形。鮪旗魚屬於高度洄游性魚種,其洄游路徑及棲息海域經常跨越不同國家之經濟海域 ,因此其族群結構、棲息海域及生態行為特徵對於資源管理及保育為漁業科學研究 重要之課題。近年來傳統式及電子式標識器廣泛被使用於解析族群動態、季節性聚 集分散型態及不同漁業之衝擊。本研究主要研究目的在於利用電子式標識器探討臺灣東部高經濟價值之大洋性鮪旗魚類族群動態,區域性漁業管理組織提供彈脫型衛 星標識記錄器,由水試所執行鮪旗魚標識放流試驗研究及進行資料分析與發表學術論文,這些研究結果也將是進行北太平洋旗魚資源評估之重要參數與 管理策略擬定之重要科學依據。 一、Taiwan is one of the major longline fishing countries. The Atlantic Ocean is one of the major fishing grounds for the Taiwanese distant water tuna longline fleets. In response to the management measures on major tuna, billfishes, and shark species in the International Commission for the Conservation of Atlantic Tunas (ICCAT), this study aims to focus on the studies of target species and bycatch species in the Atlantic Ocean including (1) to understand the stock status of tropical tuna in the Atlantic Ocean , (2) to study the stock status of the Atlantic billfishes and South Atlantic temperate tunas, (3) to study the stock status of sharks in the Atlantic Ocean and temperate tuna in the North Atlantic Ocean. ICCAT SCRS expects to assess the stocks of yellowfin tuna (Thunnus albacares), Atlantic white marlin (Kajikia albidus) and shortfin mako shark (Isurus oxyrinchus) in 2019. This study will collect the fishing effort, catch, and biological information of the yellowfin tuna, Albacore Tuna (Thunnus alalunga), Atlantic white marlin and shortfin mako shark in the Atlantic to conduct the standardization of CPUE and the results will be provided to stock assessment meeting of these species. This study will also collect the HCR and MES related information of Albacore in the North Atlantic Ocean. Based on the work plan of IOTC WPTmT and WPB, this study will conduct the CPUE standardizations for albacore, blue marlin in the Indian Ocean. The stock assessments of blue marlin in the Indian Ocean will be also implemented in this study. Based on the recommendation by CCSBT, this study will continue to standardize the CPUE of the southern bluefin tuna caught by Taiwanese longline fishery and also carry out the analysis of reproductive biology for southern bluefin tuna based on the gonad samples collected from Taiwanese observer program. The goals of the project include the analysis of Taiwanese tuna longline logbook data and observer data in the Indian Ocean and the standardization of CPUE series. The latest four years, the international collaborative work among Taiwanese, Japanese, Korean, Seychelles and IOTC scientists researched on the integrated standardized CPUE series and related issues. The collaboration is very productive. It provided a deeper understanding of the status of Indian tropical tuna. However, there are still many issues to be addressed. IOTC keep encouraging the international collaborative work to facilitate the tropical tuna stock assessment. Involved in the international collaborative work helps not only the quality of the stock assessment but also promoting Taiwan to be a responsible fishing country. This project aims to train the scientific observers to collect otoliths of southern bluefin tuna (SBT, Thunnus maccoyii) from Taiwan longline fishery. We will also collect SBT otoliths from the tuna process plants in Kaohsiung. The age of each SBT sampled for otoliths 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 the SBT caught by Taiwanese longliners. Length and weight data of all SBT caught will be transformed into age data to understand the age composition via the age-length key, which will be used to estimate the age composition of the total SBT catches. Sharks are important components of Taiwanese offshore fisheries and are the major by-catch of high seas tuna longline fisheries. Despite the large catches of sharks, the low economic value of shark meat continues to makes it a by-catch species of other fisheries. A lack of detailed data on catch, effort, and fishing grounds for individual shark species in the Indian Ocean hinders the implementation of management of shark resources. The objectives of this study are to fulfill the requirement of the Indian Ocean Tuna Commission (IOTC), the fishing effort, catch, and biological information of sharks will to collected to conduct the standardization of CPUE. In addition, the non-detriment finding of the silky shark in the Indian Ocean will also be assessed.二、Stock status and NDF assessment of sharks in the Pacific Ocean fulfill the requirement and planning of the regional fisheries management organizations (RFMOs) and understand the scientific basis for the fisheries management of their major bycatch species under RFMOs jurisdiction in order to conserve and manage such resources and ensure the sustainable using of resources.This study is to collect the fishing effort, catch, biological information and to conduct the non-detriment finding assessment of blue shark (Prionace glauca), shortfin mako (Isurus oxyrinchus), silky shark (Carcharhinus falciformis) and oceanic whitetip shark (C. longimanus) by the Taiwanese longline fisheries in the Pacific Ocean. In addition, this study will collect the fisheries information of the blue shark in the North Pacific Ocean for the data preparatory meeting of stock assessment in 2019.A study on the harvest strategy, management strategy evaluation of South Pacific albacore tuna, Pacific billfishes CPUE standardizations and stock assessments. This research project study will explore the following tasks: (1) to collect and compile fishery data including length compositions and catch distributions of south Pacific albacore and the striped marlin in the Western and Central North Pacific Ocean (WCNPO) by the Taiwanese distant-water tuna longline fleets; (2) to conduct standardization of the catch-per-unit effort (CPUE) data by species for the Taiwanese tuna longline fleet to infer and understand the abundance trend and provide basic input data for the model of stock assessments of south Pacific albacore and the WCNPO striped marlin; (3) to review and summarize management reference points of the South Pacific albacore and the WCNPO striped marlin and the factors needed to develop a harvest strategy and management strategy evaluation, and to provide scientific advice on the WCFPC development of the above topics according to the characteristics and benefits of Taiwanese distant-water longline fishery. Part of the research results from this project will be presented as a working paper to the WCPFC SC and ISC. The results of this project will provide to the domestic fishery administrations as the comprehensive information of trends of resource changes and the future directions of RFMO. The results of this study will also provide as the best available science information to the domestic fishery administrations and RFMOs for the management of international fisheries resources. This project is to meet the requirements of RFMO by providing scientific data for the management of WCPO bigeye, yellowfin and skipjack tunas. 三、Study on abundance index of Pacific bluefin tuna and development of HS/MS elements. This project is to meet the requirements of RFMO by providing scientific data for the management of Pacific bluefin tuna. Major works this year are: (1) to analyze fishery data of the Pacific bluefin tuna and conduct CPUE standardization; (2) to collect information on biological reference points, performance indicators, acceptable risk level, etc., for providing scientific advices to the development of harvest strategy;(3) to conduct aging studies on Pacific bluefin tuna otoliths and estimate age composition of the catch; (4) to provide a Chinese version report on the stock status of Pacific bluefin tuna; (5) to produce necessary reports for the WCPFC stock assessment of Pacific bluefin tuna. The outcomes of this project could (1) provide standardized CPUE series that can most represent Taiwanese fishery, which is a obligation of a fishing nation and can also increase the impact of Taiwan in the RFMO; (2) provide detail understanding of the age composition of Taiwanese Pacific bluefin tuna fishery and monitor the dynamics of the age structure of the catch which is necessary for a proper management of the fishery; (3) promote active participation in the stock assessment of the resource and the MSE development of the RFMO; (4) produce one domestic conference paper and one international meeting paper, as well as provide training to three young scientists. This project is to elucidate the stock status of North Pacific albacore exploited by Taiwanese longline fishery, and also to provide a scientific basis for the RFMO to conduct stock assessments aiming to ensure the conservation and sustainable exploitation of the albacore stock. Standardization of CPUE will be carried out based on the catch composition and fishing activity of Taiwanese longline fleets. Efforts will also be made to elucidate the CPUE time series trends, catch-at-size and catch-at-age for the albacore. These information will be provided for the ISC-ALBWG to conduct stock assessments. In addition, attentions will be paid to the development of Management Strategy Evaluation (MSE) for this species, particularly, the selections of management objectives, reference points, performance indicators, acceptable risks and harvest control rule, etc. Based on the results of current study, and also by actively participating the relative meetings and workshops held by ISC, it will hopefully stand a better chance to maintain the interests of Taiwanese longline fishery under a rational and sustainable exploitation of the N. Pacific albacore. Pacific Bluefin Tuna (PBF) are caught by the tuna longline fishing vessels in the offshore waters of Taiwan. The fishing seasons of PBF are in May and June. The annual catches in number of PBF ranged from 713 (in 2012) to 8,193 (in 2003). There is an increasing trend in total catch recently, because large number of smaller individual (180-220 cm in fork length) caught by Taiwanese small-scale longline vessel during 2014-2016. The best-fitted general linear model selected by AIC and Chi-squared is Model 4: Zero-inflated with possion distribution. The standardized CPUE shows similar trends with nominal CPUE in 2005-2016. The annual nominal CPUE range from 0.09 (1/1000 Hooks) in 2012, to 0.31(1/1000 Hooks) in 2003. Our analysis suggest the current (2014-2016) stock status of PBF are recovering but still overfished. The current PBF abundance are also less than 2001-2004, and should be monitored continually in the future. Tunas and istiophorid billfishes are highly migratory species,with their habitat and migratory pathways often crossing the Exclusive Economic Zone (EEZ) of different countries. The extent of population structure, habitat and behavior of these fishes are emerging management and conservation issues requiring the attention of fisheries managers scientists. Conventional and electronictagging programs are widely recognized as important tools for understanding the population dynamics, dispersal patterns and fisheries interactions of populations. The objectives of this project are to conduct electronic tagging studies of the main commercial species of istiophorid billfishes and tunas captured in Taiwan. Regional Fisheries Management Organizations (RFMOs) provided the pop-up satellite archival tags (PSATs) to conduct tagging operations and itis anticipated that collaborators will share results and cooperate on writing reports and manuscripts for the peer-reviewed literature. The PSAT tagging results are necessary to obtain important information about life history parameters and habitat requirements to advance regional and international stock assessments and to provide important information for management strategies to conserve these valuable resources.