The past,present and future use of drifting fish aggregating devices (FADs) in the Indian Ocean

The use of drifting fish aggregating devices (FADs) has become the dominant practice in tropical tuna purse seine fishing. However, just as FADs can increase fishing efficiency, their use has been associated with several negative ecosystem impacts, and moves are being made to manage the use of FADs. In the evaluation of potential management options it is important to consider how fishers will respond to the introduction of control measures, which first requires an understanding of fishery and fleet dynamics. This paper addresses this need by characterising the past and present use of FADs in the Indian Ocean tropical tuna purse seine fishery. The paper describes historical trends in fishing practices, summarises spatiotemporal patterns in the use of FADs and establishes and attributes variation in FAD fishing strategies within the fleet. It also provides an overview of current FAD management policies in the Indian Ocean and examines the observed effects of existing measures on the behaviour of the purse seine fleet. Using this comprehensive understanding, the potential impact on the purse seine fleet of a number of plausible FAD management options are discussed and inferences are drawn for the future sustainability of tropical tuna purse seine fishing in the Indian Ocean.     

Factors that influence the entry–exit decision and intensity of participation of fishing fleet for the Galapagos lobster fishery

The Galapagos Islands are a prime example of a place where fishery management policies have been established without first understanding the behavior of fishermen. Since the creation of the Galapagos Marine Reserve in 1998, there has not been a single study in the archipelago that investigates fishing behavior and the factors affecting this behavior. This paper addresses this gap in the literature by describing and analyzing the decisions of the fishing fleet for the red spiny lobster fishery. It focuses on factors that affect the short-term decisions regarding both participation and intensity of participation in the lobster fishery. This paper finds that the fishing fleet in the Galapagos Islands behaves as profit maximizing firms, because they consider all the benefits and costs that affect both their participation decision as well as their decision about how frequently to be active after they have decided to participate. The results also show that there is a large latent effort in the lobster fisheries that could threaten the sustainability of any initiatives aimed at increasing catchability, prices, or markets. It is expected that this analysis will be valuable to policy makers when designing or improving the management plans for Galapagos fisheries.     

Slow steps towards management of the world's largest tuna fishery

Today, the tuna fishery of the western and central Pacific is one of the world's largest fisheries. Annual catches exceed 2 million mt—approximately 50% of the global tuna catch—with an estimated landed value of USD 3 billion (in 2005). The fishery expanded rapidly from the mid 1980s, following the development of the purse-seine fishery. From the mid 1990s, it was recognised that a Regional Fisheries Management Organisation was required to facilitate cooperation in the management of the resource. Following almost a decade of negotiations and planning, the Western and Central Pacific Fishery Commission (WCPFC) was established in 2004. During the interim period, stock assessments for the key tuna species were developed and revealed that for two species (yellowfin and bigeye tuna) there was concern regarding the increased levels of fishing mortality. However, declarations and resolutions calling for restraint in the expansion of fishing effort were largely unheeded over the last decade and, to date, the WCPFC has been unable to introduce any measures to effectively reduce (or limit) the level of fishing mortality on yellowfin and bigeye tuna. This paper proposes a number of mechanisms for improving the performance of the WCPFC with respect to meeting the conservation and management objectives of the commission and argues that Pacific Island nations need to collectively take the lead to ensure the effective management of the resource.     

Considering community allocations: Power and the politics of enclosure in the Gulf of Alaska

In 2012, the North Pacific Fishery Management Council initiated the process of designing a new management structure for the Gulf of Alaska trawl groundfish fleet. The new program is currently structured as a catch share program and driven by the need to end the ‘race for fish’ and provide the trawl fleet with the tools to reduce bycatch. To date much of the discussion among policy makers and stakeholders has centered on community protection measures and how best to avoid the negative social and economic impacts of catch share programs including impacts to crew, consolidation and the flight of quota and resource wealth from Gulf of Alaska fishery dependent communities. This paper examines how community protection measures related to the distribution of benefits and access to fishery resources are considered and challenged in the North Pacific today. Special attention is given to the ongoing debate surrounding the potential inclusion of an initial allocation to place-based Gulf of Alaska communities via a Community Fishing Association. As part of this effort, this paper examines the political space and underlying power dynamics in which consideration of alternatives to the commodification of fishing rights occurs.     

Bluefin tuna fishery policy in Malta: The plight of artisanal fishermen caught in the capitalist net

The bluefin tuna fishery has undergone a major shift in Malta, moving from an open access artisanal nature to a privatized and industrialized activity dominated by the purse seining fleet and the BFT ranching industry. The shift has been exacerbated by the national implementation of an individual transferable quota system, which has enabled the concertation of quotas into fewer hands. The main objective of this article is to understand how privatization has evolved within the sector and the way the Maltese artisanal fishermen are experiencing the shift. This study takes an exploratory mixed-method approach to quantitatively and qualitatively understand how policy underpinnings interplay with the sustainability dimension of the small-scale fishing sector. Results show that the transition of the bluefin tuna fishery from artisanal to industrial has generated a legitimacy crisis over fishing rights, decreased profitability amongst most of the artisanal fleet, and led to a series of socio-ecological impacts on the artisanal fisheries system at large. It is concluded that the neo-liberal trajectories of industrialization have directly undermined the continued sustainability of artisanal fishing communities.     

Application of a vessel monitoring system to advance sustainable fisheries management—Benefits received in Taiwan

Vessel monitoring systems (VMS) are considered important instruments for fisheries monitoring, control and surveillance (MCS) to reverse the current depressed state of the world’s fisheries, and have been mandated worldwide by fishery management agencies. The essential function of the system is to provide near-real time vessel position; the potential applications could, however, be more than that. This study explores the additional benefits, with practical examples, that Taiwan has received from implementing the system: in improving the quantity and quality of logbooks recovered, obtaining access to fishery-independent fishing effort estimates and prompt catch/effort reporting, enabling the possibility of regional management and understanding of both fleet dynamics and vessel behavior, and increasing efficiency of vessel safety protection. For other distant-water fishing nations, Taiwan’s experiences serve to demonstrate how the application of VMS technology can advance sustainable fisheries management.     

The influence of economic factors in the change of fishing strategies of anchored FAD fishers in the face of declining catch,General Santos City,Philippines

Decline in tuna fish stocks due to weak enforcement of regulations on fishing effort poses a challenge to the sustainability of tuna fishery. Intervention programs to address this problem require an understanding of the operational behaviour of the fishers and how various socioeconomic factors may impact fishers’ decisions to continue or discontinue their fishing efforts. A semi-structured interview questionnaire was developed to find whether fishers are willing to keep, change their fishing strategies or exit the fishery if their regular catch will decline by half. Boat captains, assistant boat captains and crew from General Santos City, Lupon, Mati City and Governor Generoso in the Philippines (n=293) were purposively selected for interviews. Results show that fishers from General Santos City with ancillary industries and Lupon with fewer economic development are more willing to adapt or change their fishing strategies. The catch value or price was found to have a strong influence on the likelihood that anchored FAD tuna fishers will adapt or change their fishing strategy when their catches decline. Fishers whose catch fetched a price of PhP 151.00 (US$ 3.48) and above Php 200 (US$ 4.61) have 80% probability to change their fishing strategy. The proportion of catch sold also had a high influence on the decisions to adapt in the fishery with fishers selling 36% and 73% of their catches have 100% and 70% probability to adapt. The results suggest a reluctance to exit the fisheries even when tuna fishing is no longer economically viable, fishers opt to adapt.     

The artisanal fishery of Cynoscion guatucupa in Argentina: Exploring the possible causes of the collapse in Bahía Blanca estuary

Cynoscion guatucupa Cuvier 1829 is a migratory pelagic fish species, which has a wide geographical distribution. It is the most important fishing resource for local communities in Bahía Blanca estuary and has been captured by artisanal fishermen since the 1900s. The industrial fleet has been fishing this species in the coastal area of Buenos Aires province since the 1950s, and, since 1970, landings have increased sharply. Between 2000 and 2004, the artisanal fishery in the estuarine waters of Bahía Blanca collapsed. Variations in total landings of the artisanal fleet might have arisen from the environmental variables within the estuary, fishing activity in the surrounding sea region, local pressure within the estuary and/or several other variables. Our results suggest that neither oceanographic parameters nor local pressure seem to have influenced the artisanal fishery of C. guatucupa in the estuarine region. Instead, this fishery seems to have been partially influenced by the increasing fishing pressure exerted by the industrial fishing fleet operating in open waters around the estuary. This study emphasizes the need to take into account fisheries data from both the estuarine environment and the surrounding sea region, particularly when designing management plans for the sustainable use of migrating fish resources.     

台湾海峡及其邻近海域渔业资源的管理

应用Ｓｃｈａｅｆｅｒ和Ｆｏｘ剩余产量模式及其由此衍生的生物经济模式和Ｇｕｌｌａｎｄ最适产量Ｙ０．１模式,分别估算了台湾海峡及其邻近海域渔业资源的最大持续产量、最大持续捕捞力量,并对各模式计算的诸项经济指标进行比较,讨论了渔业管理方案,确定了近期适合国情,并对各模式计算的诸项经济指标进行比较,讨论了渔管理方案,确定了近期适合国情、省情的管理目标。     

Fishermen responses on marine protected areas in the Baltic cod fishery

Much of the research that concerns the impacts of management measures in the eastern Baltic cod fishery has focused on fish stock rather than understanding fishermen's attitudes towards regulations. Hence, there is little information available on fishermen's responses although they are the ones whom the regulations affect most profoundly. This study analyses the views of fishermen towards management measures with an emphasis on fishing closures (marine protected areas, MPAs). Swedish log-book data from 1996 to 2005 were used to describe MPA induced fishing effort displacements. Fishermen argued that MPAs have been inefficient in conservation of cod stock. The enlargement of Bornholm MPA in 2005 caused substantial effort displacement towards areas dominated by smaller sized fish. This contributed to the increased discarding of juvenile cod. Enlarged MPAs also intensified competition between different fleet segments and reallocated fishing areas. To reduce fishing mortality, fishermen suggested days-at-sea (effort) regulation and an effective landings control system for all fleets that exploit cod stocks in the Baltic Sea Main Basin. These measures would better motivate fishermen for mutual rule compliance, which is a prerequisite for a sustainable cod fishery.     

大西洋大眼金枪鱼渔业概况

大西洋大眼金枪鱼（Ｔｈｕｎｎｕｓ ｏｂｅｓｕｓ）是高经济价值鱼种,其分布几乎覆盖整个大西洋水域。研究大西洋大眼金枪鱼的渔业对于我国远洋渔业意义重大。所以在此对其渔业及资源状况进行研究。根据三种主要渔业（延绳钓、围网和竿钓）的渔获量,可看出大眼金枪鱼渔业的发展概况。为了分析资源状况,文中使用了Ｗａｌｔｉｒｓ ａｎｄ Ｈｉｌｂｏｒｎ（１９７６）产量模型。其结果是９９．６千公吨的最大持续产量和１１４．７     

印度洋鲣鱼围网资源渔场时空变化及其与ENSO的关系

鲣鱼是印度洋重要的金枪鱼种类之一,其资源丰度与海洋环境关系密切。本研究根据1980-2010年印度洋鲣鱼围网生产统计数据以及海洋环境与厄尔尼诺-南方涛动（ENSO）指数等,对印度洋鲣鱼围网资源渔场时空分布,以及厄尔尼诺年和拉尼娜年等不同尺度气候条件下鲣鱼资源渔场时空变动及其与海洋环境因子的关系进行分析。研究结果表明,1980-2010年印度洋鲣鱼围网渔获量基本保持不断增加的趋势,但CUPE值变化幅度较大,最低仅为0.68 t/d（1997年）,最高达到1.58 t/d（2002年）。同时鲣鱼资源丰度（CPUE）与Ni?o3.4区指数存在显著的负相关关系,即厄尔尼诺年,鲣鱼CPUE 随之下降,拉尼娜年,CPUE 随之上升。ENSO现象对鲣鱼渔场时空分布也有显著影响,厄尔尼诺发生时,鲣鱼围网作业渔场重心会向东、向北移动,而拉尼娜年则向西、向南移动。     

Comparative advantage and distant water fishing fleets: The Australian east coast tuna longline fishery

A coastal state benefits from importing the services of a distant water fishing nation (DWFN) fleet if the DWFN has a comparative advantage in exploiting the fishery, based on factors such as market access, costs or technology. The paper compares the activities of the Australian and Japanese vessels in the east coast tuna longline fishery and finds the Australian vessels receive higher prices, have higher costs and use a different technology from the Japanese fleet. These differences suggest a pattern of comparative advantage which can lead to Australia benefitting from importing the services of the Japanese fleet.     

大眼金枪鱼的资源现状

大眼金枪鱼的分布很广 ,在南、北纬 4 0°以内的太平洋、印度洋和大西洋均有分布 ,是金枪鱼渔业的重要捕捞种类之一。本文分别论述了大眼金枪鱼在大西洋、印度洋和太平洋的渔业概况、生物学特性、资源状况和管理对策。     

Improving fleet efficiency to maximise economic yield in a Western Australian prawn fishery

The Shark Bay trawl fishery is Western Australia's most valuable prawn fishery (worth AUD$25 million in 2014). The 18-vessel fleet targets western king prawns (Penaeus latisulcatus), brown tiger prawns (P. esculentus) and also retains saucer scallops (Ylistrum balloti) and blue swimmer crabs (Portunus armatus). Increased fuel prices, falling prawn prices and lower catches of other species, following extreme environmental events, have impacted fishery profits. A biomass dynamics model with an economic component indicated that total revenue levels start to decline when annual effort increases beyond ~ 200 fishing days per boat. Annual effort required to achieve MEY, when based solely on prawn fishing, is 115–150 days per boat after accounting for fixed and variable fishing costs and annual fishing efficiency increases of 1–2%. From 2007–2014, the adjusted effort was 188–192 days per boat. Fishing occurred between March and November during 7–8 fishing periods, separated by 5–8 day (low catchability) moon closure periods. An empirical daily profit assessment (2007–2015), accounting for recruitment variation, daily prawn size compositions, monthly market prices for different prawn species and sizes, and daily fishing costs, showed vessels made profits on ~ 115–160 days and losses on ~ 15–55 days per year, when fishing occurred near the full moon. The fishery benefitted in 2013–2015 by starting later in the year and better targeting within-season effort. This management strategy within the effort-control framework, which improved profitability, maintained higher spawning stocks and reduced ecosystem fishing impacts, has wider application in prawn fishery management.     

Biology, fishery, conservation and management of Indian Ocean tuna fisheries

The focus of the study is to explore the recent trend of the world tuna fishery with special reference to the Indian Ocean tuna fisheries and its conservation and sustainable management. In the Indian Ocean, tuna catches have increased rapidly from about 179959 t in 1980 to about 832246 t in 1995. They have continued to increase up to 2005; the catch that year was 1201465 t, forming about 26% of the world catch. Since 2006 onwards there has been a decline in the volume of catches and in 2008 the catch was only 913625 t. The Principal species caught in the Indian Ocean are skipjack and yellowfin. Western Indian Ocean contributed 78.2% and eastern Indian Ocean 21.8% of the total tuna production from the Indian Ocean. The Indian Ocean stock is currently overfished and IOTC has made some recommendations for management regulations aimed at sustaining the tuna stock. Fishing operations can cause ecological impacts of different types: by catches, damage of the habitat, mortalities caused by lost or discarded gear, pollution, generation of marine debris, etc. Periodic reassessment of the tuna potential is also required with adequate inputs from exploratory surveys as well as commercial landings and this may prevent any unsustainable trends in the development of the tuna fishing industry in the Indian Ocean.     

Emerging fisheries,emerging fishery interactions with sea turtles: A case study of the large-mesh gillnet fishery for flounder in Pamlico Sound,North Carolina,USA

Emerging fisheries and changes in fishery practices are not always readily apparent, nor are their impacts on non-target species such as seabirds, sea turtles, and marine mammals. Data from several different sources led managers to discover high rates of sea turtle bycatch in an inshore large-mesh gillnet fishery in North Carolina, USA, particularly the emerging deep-water gillnet fishery. This paper reviews the history of how increased numbers of observed stranded sea turtles in 1999 led to the discovery that turtles were becoming entangled in the large-mesh gillnet fishery in Pamlico Sound, North Carolina. It also demonstrates how a variety of data sets from fisheries observers, aerial surveys, and fisheries statistics programs contributed to shaping management of the large-mesh gillnet fishery in Pamlico Sound to decrease turtle bycatch and now point towards the need of additional assessment of gillnet bycatch in other parts of North Carolina. Finally, potential approaches are discussed for a more timely detection of future fishery conflicts and development of a plan to reduce otherwise inevitable bycatch and disruptions to fishing effort.     

History,effort distribution and landings in an artisanal bottom longline fishery: An empirical study from the North Atlantic Ocean

Commercial fishing data were used to reconstruct historical spatio-temporal patterns of fishing effort and landings in the bottom longline fishery of the Azores. Key events during an important 15-year period were charted, through fisher interviews together with GIS analysis. While effort distribution varied over time, the prevailing pattern was a shift in focus from eastern to western areas and from shelf/slope to offshore banks and seamounts in response to policy measures (e.g. banning bottom longline inside 3 NM, public aids for modernization of the fleet) and reduced fishing yields. Areas 12–50 NM from shore represented the most vital fishing grounds in terms of fishing effort and production. Declining landings of the major demersal species, in recent years, indicate that present catch levels are not sustainable and further measures need to be taken in order to sustain fisheries resources. Knowledge of fleet behavior and the distribution of fishing effort, particularly in patchy environments, provide valuable insights into the impacts of past management decisions and help predict the outcome of new policies both in this region and elsewhere.     

Stock assessment for Atlantic yellowfin tuna based on extended surplus production model considering life history

The modern fishery stock assessment could be conducted by various models, such as Stock Synthesis model with high data requirement and complicated model structure, and the basic surplus production model, which fails to incorporate individual growth, maturity, and fishery selectivity, etc. In this study, the Just Another Bayesian Biomass Assessment (JABBA) Select which is relatively balanced between complex and simple models, was used to conduct stock assessment for yellowfin tuna (Thunnus albacares) in the Atlantic Ocean. Its population dynamics was evaluated, considering the influence of selectivity patterns and different catch per unit effort (CPUE) indices on the stock assessment results. The model with three joint longline standardized CPUE indices and logistic selectivity pattern performed well, without significant retrospective pattern. The results indicated that the stock is not overfished and not subject to overfishing in 2018. Sensitivity analyses indicated that stock assessment results are robust to natural mortality but sensitive to steepness of the stock-recruitment relationship and fishing selectivity. High steepness was revealed to be more appropriate for this stock, while the fishing selectivity has greater influence to the assessment results than life history parameters. Overall, JABBA-Select is suitable for the stock assessment of Atlantic yellowfin tuna with different selectivity patterns, and the assumptions of natural mortality and selectivity pattern should be improved to reduce uncertainties.     

Transferable quotas,efficiency and crew ownership in Whalsay,Shetland

The resource economic theory tells us that individual transferable quotas (ITQs) improve efficiency in the fishing industry by removing the least efficient actors from a fishery and allowing ownership to concentrate in the hands of the most efficient operators. Assertions about the nature of this allocative efficiency are, however, often based on purely theoretical assumptions. This paper presents a case study of the efficient operators remaining in the UK pelagic fishing fleet. After over 30 years of rights-based management (RBM) and 12 years of ITQs, the UK pelagic fleet numbers only 31 large-scale boats. Seven of these operate from the island of Whalsay in Shetland, which, with a population of approximately 1000 people (0.000016% of the population of the UK), is entitled to land around 22% of the UK pelagic catch. A key characteristic of the economically efficient Whalsay fleet is a crew ownership structure. This is now under threat from the long-term dynamics of the UK's ITQ system, as the high price of quota prevents the renewal of the fishery through new entrants. In the majority of global fisheries, where vessel ownership structures do not follow an assumed economic norm, fully marketised transferable rights may not be the most efficient method of management.