Abstract
(1)為釐清我國中西太平洋熱帶鮪鮪釣及圍網資料可能問題，提高資料品質，以更準確掌握整體漁業的發展及回應國際組織要求,擬進行分析大目鮪作業層級資料，估計大目鮪體長/體重關係式、分析每筐鉤數年變動，及進行CPUE標準化，以解決國際組織資源評估之問題及提供我國較可靠之資源指標，提高我國在太平洋國際組織科學研究之參與度及地位。並進行時空架構之太平洋黑鮪CPUE標準化，回應國際組織之要求，提升我國在國際組織科學研究之參與度。同時積極參與國際組織之科學評估與HS之研發討論，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。在南太平洋劍旗魚、太平洋黑皮旗魚、及南太平洋長鰭鮪研究上，將執行漁獲量、漁獲努力量和體長資料等漁獲統計彙整分析暨CPUE標準化，以掌握目標魚種之主要漁獲國（包含台灣）漁獲情形及豐度時間序列變動，以瞭解資源現況、漁獲壓力及預測未來資源變化走向、參考點及制定漁獲策略所需之因素等相關資訊，可供漁業管理者進行決策。並根據我國漁業特性於WCPFC漁獲策略發展過程提供科學建議，協助我國參與國際漁業管理組織之資源評估與相關科學任務，並參與提供WCPFC科學委員會（SC）及ISC資源評估所需資料，以提出工作報告至WCPFCSC及ISC。北太平洋長鰭鮪管理策略進展研析上，將彙整分析長鰭鮪漁獲量、漁獲努力量及體長資料,並分析北太平洋長鰭鮪豐度指標變化趨勢、檢視小釣船漁獲資料時空變化、蒐集MSE相關資訊，以利探討CPUEtrend發展及掌握MSE分析階段成果。另配合國際漁業組織之管理需求，將提供長鰭鮪基礎生物學資訊及資源動力學研究成果，並參與MSE第5屆研討會及ALBGW會議，藉此蒐集有關北太平洋長鰭鮪資源管理策略評估相關的評估分析資訊。MSE目的在於釐清管理目標（managementobjectives）、確立生物參考點（referencepoints）和可接受風險（acceptablerisk）、訂定管理規則（harvestcontrolrule）等，現階段MSE的推動仍在發展中，但可能影響到未來的管理策略，因此我們應注意其發展，維護我漁船作業權益。有關太平洋鯊魚漁業資源評估研究暨無危害風險評估(NDF)研究，將配合ISC鯊魚工作小組鋸峰齒鮫資料準備會議，提交我國北太平洋鮪延繩釣釣獲鋸峰齒鮫之漁獲量、體長分布與CPUE標準化等資料。另配合WCPFC南太平洋鋸峰齒鮫資源評估會議，提交我國南太平洋鮪延繩釣釣獲鋸峰齒鮫之漁獲量、體長分布與CPUE標準化等資料。(2)印度洋長鰭鮪與旗魚類資源評估研究，將根據台灣印度洋漁業統計資料，針對台灣延繩釣漁船依長鰭鮪漁區及旗魚類漁區劃分之作業別資料進行目標魚種作業特性分析，並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、紅肉旗魚及白皮旗魚之CPUE標準化分析，另外本研究亦將進行印度洋紅肉旗魚之資源評估。擬根據我國於印度洋延繩釣之漁獲資料分析南方黑鮪漁獲量、漁獲努力量及體長資料等漁獲統計資料，並彙整相關漁業生物資訊且進行CPUE標準化及資源指標分析。同時亦彙整印度洋帶鰆類物種之漁獲量、漁獲努力量及體長資料等漁獲統計資料，初步分析印度洋帶鰆類物種之漁獲比例情形及漁獲分布狀態。於生殖生物學研究方面則是運用我國漁業科學觀察員所採集之南方黑鮪及印度洋帶鰆類物種(薔薇帶鰆及鱗網帶鰆)生殖腺樣本，分析生殖生物學特徵，以推估建立相關生殖生物學參數，供作後續相關物種於國際漁業管理組織執行資源評估分析及政策管理評估時之重要科學參考依據。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。配合印度洋鮪類委員會(IOTC)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2020年IOTC熱帶鮪類資源評估所需資料之更新。將訓練科學觀察員於延繩釣漁船上採集南方黑鮪(<em>Thunnusmaccoyii</em>)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。從年齡與體長資料，將可估算得南方黑鮪的成長係數。藉由年齡與體長的轉換公式，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(TheIndianOceanTunaCommission,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灰鯖鮫實施無危害評估(NDF)相關措施之可行性進行評估並提出建議。(3)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評估研究；(2)大西洋旗魚與溫帶鮪類資源評估研究；(3)大西洋鯊魚資源調查評估研究。
今年度ICCATSCRS將針對大目鮪、大西洋劍旗魚與鋸峰齒鮫進行資源評估，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。(4)漁業對於海洋生態系中其他物種的意外捕獲（incidentalcatch）造成了許多海洋資源的傷害，近年來亦發受到國際關注，各大區域性漁業組織陸續通過相關決議，要求各國提供物種混獲資訊。臺灣自2002年起，開始執行觀察員計畫，並自2005年起開始分析遠洋漁業混獲物種資訊。本研究旨在使用2010-2020年之遠洋鮪釣漁業的觀察員資料，分析海鳥、海龜、鯨豚之混獲率、時空變化趨勢及混獲高風險區域。本年度將去年研發之高風險區域評估模型應用於海龜混獲，並延續去年分析相關忌避措施的實施情形及成效，進一步分析忌避措施對混獲物種組成之影響，並使用RandomForest法選擇影響因子，並與109年之GLMM模型進行比較。本研究將使用2010-2020年之我國遠洋鮪釣漁業的觀察員資料進行分析。我們亦將配合國際漁業組織相關科學會議之要求，提供相關資訊。(5)近年來，RFMOs對國家觀察員計畫越來越重視，我國觀察員資料與作業報表資料的統計分析也相對越來越重要，除可提升漁獲統計資料之精確度外，瞭解觀察員資料與作業報表資料之主要魚種漁獲組成分布情形及變異，以備更趨嚴格的鮪、旗魚漁業管理及科學會議之需，亦可作為政府擬訂管理措施之依據。為提升觀察員對資料填報正確性的認知，本計畫將辦理報表品質檢核會議或舉辦培訓課程，邀請專家學者對觀測資料提出改善建議，俾簡化檢校程序。(6)分析美洲大赤魷漁獲量、漁獲努力量及漁獲率之年間(2002至2020年)及年內(月別間)變動趨勢；以每月每0.5度方格為時空單位，繪製美洲大赤魷資源豐度之年別空間分布樣式，並分析年間漁獲努力量之空間分布關係；5)以統計模式分析年間，及年內之資源豐度與環境因子(SST及放鈎深度)之關係。依SPRFMO建議分區水域，留存成熟個體之肌肉組織，以提供樣本交換使用。以及參與國際漁業管理組織：協助我國參與SPRFMO及NPFC之科學研究任務與管理需求，並視需要提交相關研究報告。為對我國之魷釣業最主要之利用資源，即阿根廷魷魚，進行歷史性資料分析，瞭解資源動態脈絡；換言之，即使用各種適當之方法分析各年單位努力漁獲量(catchperuniteffort,CPUE)高低之原因，及各年內隨時間推移之空間移動趨勢。本年計畫重要工作項目將量化及圖示化1997年-2019年年別與雙週別之漁獲量、努力量及CPUE之分布樣式，及進行年間時間序列分析和各年之空間相關分析。為保育秋刀魚漁業資源與永續利用，為協助北太平洋漁業委員會(NPFC)秋刀魚資源評估工作之進行，確保秋刀魚漁業資源之永續利用，針對我國遠洋漁業所利用秋刀魚之生物學資料和資源分布，以及CPUE標準化進行分析研究。重要工作項目包括：分析西北太平洋及台灣秋刀魚漁業現況與變化趨勢；採集秋刀魚樣本，進行NPFC資源評估所需之生物學研究；標準化台灣秋刀魚漁業CPUE資料；及協助NPFC針對秋刀魚所需生物學與相關科學研究及任務。蒐集與分析主要秋刀魚捕魚國之秋刀魚資源利用狀況與漁業動態，掌握北太平洋秋刀魚主要秋刀魚捕魚國之秋刀魚之作業漁場資訊（空間分布），漁獲量及相對豐度時間序列，以及日本研究調查船之豐度時間序列變動。配合NPFC整合各主要秋刀魚漁業國家月別空間解析度為1度的漁業統計資料，並利用地理統計模型進行聯合CPUE標準化；進行北太平洋秋刀魚資源評估、漁獲死亡係數估計、模式敏感度分析進行總容許漁獲量之資源量隨機預測模擬及風險評估等，瞭解北太平洋秋刀魚資源現況，漁獲壓力，及預測未來資源變化走向，以利漁業管理者進行決策；協助我國參與國際漁業管理組織（NPFC）之資源評估與相關科學任務，計畫成果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NPFC之公約提出相關科學數據或管理建議；協助我國北太平洋遠洋秋刀棒受網漁業相關產業之發展，並確保有效利用北太平洋秋刀魚資源並掌握資源變動趨勢。 <strong>1.Studies on the Dynamics of Tuna and Tuna-like Resources in the Pacific Ocean</strong>
Study on the Abundance Index and HS/MS of Western-Central Pacific Tropical Tunas and Pacific Bluefin Tuna The target and major studies of this project are: (1) to collate and analyze operational-level data and observer data of Taiwan large-scale longline and purse seine fisheries in the western-central Pacific Ocean to provide scientific advices to managing the fisheries. (2) to collate the operational-level bigeye fishery data, VMS and observer data, estimate the length-weight relationships, analyze annual variation of hooks per basket information, and conduct CPUE standardization on Pacific bigeye tuna resource, to meet the needs of 2021 WCPFC pan-Pacific bigeye stock assessment and respond to the concerns raised in 2020 bigeye stock assessment. (3) to collate VDR, CDS and vessels trips information and conduct spatiotemporal structured CPUE standardization, to meet the requiremen by ISC for 2021 abundance index review. (4) to collect necessary information for developing harvest strategy for WCPO tropical tunas and Pacific bluefin tuna and provide scientific advices to the government.
A study on the elements of the harvest strategy/management strategy developments of the south Pacific albacore tuna and the CPUE standardizations and stock assessments of swordfish and blue marlin in the Pacific Ocean This research project study will explore the following tasks: (1) to collect and compile fishery data including length compositions, catch, and effort distributions of south Pacific swordfish, Pacific blue marlin and south Pacific albacore caught by the Taiwanese distant-water tuna longline fleets; (2) to conduct standardization of the catch-per-unit effort (CPUE) data by using the geostatistical model (VAST) to infer and understand abundance trends; (3) to conduct the stock assessment for the Pacific blue marlin using Stock Synthesis; (4) to review and summarize management reference points of the south Pacific swordfish, Pacific blue marlin and south Pacific albacore fisheries and the factors needed to develop a harvest strategy and management strategy evaluation; and (5) to provide scientific advices on the Western and Central Pacific Fisheries Commission (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 Scientific Committee (SC) and the International Scientific Committee for Tuna and Tuna-Like Species in the North Pacific Ocean (ISC). The results of this project will be provided to the domestic fishery administrations as the comprehensive information of trends of resource changes and the future directions of Regional fisheries management organizations (RFMOs). 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.
Study on the North Pacific albacore resource and the progress of Management Strategy Evaluation This project is aiming to review the historical development of Taiwanese albacore longline fisheries operated in the North Pacific Ocean (NPO). There are three logline fisheries involving albacore catch, i.e. albacore-targeting and non-albacore-targeting large scale longline fisheries (LSL) and small scale longline fishery (SSL). The segregation of albacore-targeting and non-albacore-targeting LSL will be carried out based on their catch compositions and fishing activities, which methodology was already established by Chen and Cheng (2013). Geographical distribution and time series trend of standardized CPUE of the albacore-targeting LSL will be estimated. Effort will also be made to elucidate the catch statistics of SSL due to its increasing importance in terms of albacore catch in recent years. The spatiotemporal distribution of SSL fishing effort and its catch composition will be examined. Particularly, those with higher albacore CPUE will be elucidated regarding to their geographical and yearly distributions in relation to other major species. Furthermore, the progress of NPO albacore management strategy evaluation (MSE) will be updated. The MSE procedure has been conducted for several years and is originally scheduled to be completed by the end of 2020, however for some reasons, is postponed to the following year. The MSE is a management framework including pre-agreed management objectives, harvest strategy, harvest control rule in terms of TAC/TAE, biological reference points, performance indicator and its acceptable risk levels, etc. The implementation of MSE will bear a strong influence to the conservation and management measures, as well as to the fisheries development of NPO surrounding countries.
Stock status and NDF assessment of sharks in the Pacific Ocean To 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 utlization of shark resources, this study is to collect the fishing effort, catch, biological information and to conduct standardization of CPUE of blue shark (<em>Prionace glauca</em>) 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 data preparation meeting and the South Pacific Ocean for stock assessment meeting in 2021.
<strong>2.Study on population dynamics of tunas, billfishes and sharks in the Indian Ocean</strong>
Study on stock assessment of albacore and billfish in the Indian Ocean This study will analyze the targeting characteristics of fishing operations for Taiwanese longline vessels in the albacore sub-areas and billfish sub-areas based on the statistics data of Taiwanese fisheries in the Indian Ocean. According to the work plan of IOTC WPTmT and WPB, this study will conduct the CPUE standardizations for albacore, striped marlin and black marlin in the Indian Ocean. In addition, the stock assessments of striped marlin in the Indian Ocean will be also implemented in this study.
The studies related stock status and reproductive biology of southern bluefin tuna, oilfsh and escolar The aims of this study is reviewing the fishing data collected by Taiwanese longliner fisheries in the Indian Ocean and conducting the CPUE standardizations for SBT in the Indian Ocean. 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 using the gonad samples collected by Taiwanese scientific observer program. The other goal of this study is reviewing the fishing data of oilfish and escolar by Taiwanese longliner fisheries in the Indian Ocean. Also, it is essential to analyze the proportion and distribution of fishing capture of oilfsh and escolar separately. Furthermore, using the preliminary results related fishing capture and distribution of oilfish and escolar to establish long-term time series of CPUE. It will be helpful to understand the stock status of oilfish and escolar in the Indian Ocean. In the study related reproductive biology of oilfish and escolar, we continued to increase oilfish and escolar as others species in Taiwanese scientific observers program. The preliminary experiments will conduct for understand the reproductive characteristics for identifying the maturity stage in these two species in the Indian Ocean.
Stock assessment of tropical tunas in the Indian Ocean 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 international collaborative work helps not only the quality of the stock assessment but also promoting Taiwan to be a responsible fishing country.
The study on the age composition of southern bluefin tuna caught by Taiwanese longliner This project aims to train the scientific observers to collect otoliths of southern bluefin tuna (SBT, <em>Thunnus maccoyii</em>) from Taiwan longline fishery. We will also collect SBT otoliths from the tuna process plants in the Kaohsiung city. The age of each SBT sampled for otoliths will be estimated by examining the otolith annuli. These data together with length data will be used to evaluate the growth rate parameters of the SBT caught by Taiwanese longliners. Length 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. The otolith direct aging data will be submitted to the CCSBT in April and the results of this project will reported in the extened scientific meeting of the CCSBT.
Studies of shark by-catch, abundance index and non-detriment findings (NDFs) in the Indian Ocean 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 shortfin mako shark in the Indian Ocean will also be assessed.
<strong>3. Investigation of resources of major tuna, billfish, and shark species in the Atlantic Ocean</strong>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 Atlantic temperate tunas, (3) to study the stock status of sharks in the Atlantic Ocean. ICCAT SCRS expects to assess the stocks of Bigeye Tuna (<em>Thunnus obesus</em>), Swordfish Atl. (<em>Xiphias gladius</em>) and blue shark (<em>Prionace glauca</em>) in 2021. This study will collect the fishing effort, catch, and biological information for stock assessment meeting.
<strong>4.Investigate the impacts of bycatch mitigation measures of Taiwanese tuna longline fisheries</strong>Incidental catch of fisheries has resulted in serious damages to marine ecosystems. While the bycatch issue becomes a major concern of many regional fisheries management organizations, several management measures have been implemented by the members to monitor and reduce bycatch. Taiwan has started to record the bycatch information for the off-shore longline fisheries via the observer program since 2005. In this study, we will use the observer data from 2010-2020, to investigate the changes in bycatch of sea birds, sea turtles, and cetaceans. We aim to estimate the bycatch rate and mortality of the bycatch species and examine the changes over time. We will also identify the high-risk areas for bycatch sea birds, sea turtles, and cetaceans. We will also apply the random forest algorism to identify the important factors to examine the effectiveness of mitigation measures for the bycatch seabirds and sea turtles. We will then prepare reports for the RFMO meetings and inform the study results to the management agency.
<strong>5.Study on improving observation data of the longline fishery</strong>In recent years, there has been growing attention from RFMOs on the implementation of national observer program, which leads to the increasing importance on comparison and analyses between observer data and logbook data. Such comparison and analyses gave researchers more accurate fisheries statistical data and better understanding of species composition, distribution and variation of catches. Furthermore, observer data also can serve as the reference for the Government in the formulation of management measures. To improve the quality of data collected by observers, this project would invited experts and scholars to hold meetings for discussing observer data quality evalution, and also hold training course to simplifying the debriefing procedure.
<strong>6.Stock dynamics of squid and Pacific saury fisheries</strong>Biology and stock dynamics of Dosidicus gigas and fisheries data analysis of Ommastrephes bartramiiThe jumbo squid, <em>Dosidicus gigas</em>, is a large pelagic ommastrephid squid which distributed in the Eastern Pacific Ocean (EPO). The jumbo squid is a critical component in ecosystem of the EPO and is the main target of squid fisheries in this region. The central challenge for fisheries ecology is to understand the population structure and abundance variations of exploited resources under fishing pressure and its synergistic effects to the ecosystems. The jumbo squid fishery in Taiwan is not dominant in context of production or values, while it could act as a substitute for <em>Illex argentious</em> fishery and the jumbo squid has been managed by the SPRFMO. Therefore, it is essential to understand its population structure, connectivity and stock dynamics. In additional, the NPFC has entered into force since 2015, and neon flying squid is one of the fishing species in the convention area. Considering the potential measures, it is necessary to examine the fisheries data, which could meet the requirements of NPFC in the near future. The objectives of this project are: 1) to examine annual variations in production (in species) of Taiwanese squid jigging fleet; 2) to examine the catch and effort data of neon flying squid fishery; 3) to analyze temporal trend and spatial distribution pattern of Jumbo squid; 4) to examine the basic biological information of Jumbo squid; 5) to provide essential scientific research information and reports of Jumbo squid for the SPRFMO meetings; 6) to provide essential scientific research and information of neon flying squid for the NPFC meetings. The working items are: 1) Compile and examine catch data of Taiwanese distant-water squid-jigging fleet; 2) Examine catch and effort data of neon flying squid, and analyze the temporal variation patterns; 3) Re-arrange the dataset of jumbo squid in a monthly basis with a spatial resolution of 0.5 degrees. Explore the spatial distribution patterns of the squid; 4) Analyze the variation of CPUE using GAM which including temporal, spatial and environmental variables as explanatory variables; 5) Sampling squid from a study vessel and collect basic biological information (ML, BW and maturity stage); 6) Provide essential scientific research information and reports for the relevant SC meetings of the SPRFMO and NPFC.The expected results are: 1) Understand the development of Taiwanese distant-water squid-jigging fishery; 2) Understand the development and current situation of neon flying squid; 3) Understand temporal and spatial variability and environmental influences of jumbo squid abundances; 4) Understand basic biological information of jumbo squid; 5) Provide essential information for annual national report and catch data submitted to the Scientific Committee of SPRFMO and NPFC.
Research On Stock Assessment And Fishing Forecast: Using Argentine Shortfin Squid (<em>Illex argentinus</em>) In The Southwest Atlantic As An ExampleThe objective of this project is to analyze historical fishing data obtained from Taiwanese jigging fleet fished in the Southwest Atlantic (SWA), and further to explore annual fluctuation of Argentine shortfin squid, and to formulize spatial and temporal patterns of squid abundance. The aim of this study will construct a facility in order to predict oncoming fishing sites. Two major tasks are included: the first, we will quantify and visualize the distribution of catch, effort and catch per unit effort (CPUE) of Argentine shortfin squid in SWA with a frequency of one frame per fortnight, and the other will forecast year-class strength and intra-annual spatial-temporal distribution. The expected outcomes in this study include: (1) realizing the spatial displays of (standardized) CPUE of Argentine shortfin squid conditioned at various stock size levels, i.e., low, regular and high, (2) knowing the spatial distributions of (standardized) CPUE of Argentine shortfin squid, (3) understanding spatial features of sea surface temperature and linking the relationships between Argentine shortfin squid and environmental variables, (4) exploring the feasibility of using sea surface temperature or other environmental variables to forecast catch size of Argentine shortfin squid at fishing sites, and (5) providing scientific advice and fishery management for stock of Argentine shortfin squid.
Studies on fisheries biology and standardized CPUE of Pacific saury The Pacific saury fishery is one of the major deep-sea fisheries in Taiwan. Taiwan is the largest saury harvesting country. Taiwan is a member of the local international fisheries management organization - North Pacific Fisheries Commission (NPFC). Pacific saury is one of the main target species for sustainable utilization management in the NPFC. Therefore, it is necessary to implement the studies on the fisheries biology and resource of the Pacific saury in the North Pacific, energetically. In order to conservation and sustainable utilization of the Pacific saury, the objectives in this study are studying fish biology, spatial distribution and resource situation for the saury stock exploited by the Taiwanese fishery to facilitate the implementation of stock assessment works for saury. Specifically, the hands-on job includes: analyzing the current status and variation trends for the saury resource in the Western North Pacific and Taiwan; collecting saury samples for biological studies in order to NPFC required stock assessment; standardizing the CPUE of the Taiwanese saury fishery; and assist NPFC in the biology and scientific research of saury. The expectable benefits of this study are: understanding the current status and the annual variations of the saury resource; obtaining the saury length-frequency from the catch of the Taiwanese saury fishery to understand the changes of the saury stock structure; obtaining the information of age and gonadosomatic index to understand the changes of the age composition and maturation status of the saury stock; and providing the standardized CPUE to the NPFC for the stock assessment of saury, and the relative papers and comments on the scientific issues for the NPFC management.
Stock assessment of the Pacific Saury Cololabis saira in the North Pacific OceanThe objectives of this stock assessment project is to update and improve the Bayesian state-space surplus production model for the Pacific saury in the Western North Pacific Ocean (WNPO) with the most recent summary of available fishery-dependent data. Commercial catch of Pacific saury caught by Japan, Taiwan, Korea, China, Russia and other members in the WNPO area were collected from 1950 to 2020. Relative abundance indices for the WNPO saury consisted of standardized catch-per-unit effort (CPUE) of stick-held dip net fisheries from Japan, Taiwan, Korea, Russia and China. Production models that included various time-series of data and time-varying fishery productivity will be developed for the selection of base case. Goodness-of-fit diagnostics will be used to compare the fits of alternative model configurations. Risk analysis based on the stochastic projection of various catch levels will be conducted for the base-case model and sensitivity models. The results will provide to the Regional Fishery Management Origination (e.g., NPFC) as best available science for the input of fishery stock assessment and management. Part of the research results from this project will be presented as a working paper to the NPFC SSC PS meeting.
