共查询到20条相似文献，搜索用时 15 毫秒
1.
Maite Pons Trevor A Branch Michael C Melnychuk Olaf P Jensen Jon Brodziak Jean M Fromentin Shelton J Harley Alan C Haynie Laurie T Kell Mark N Maunder Ana M Parma Victor R Restrepo Rishi Sharma Robert Ahrens Ray Hilborn 《Fish and Fisheries》2017,18(1):1-21
Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life‐history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level. Here, we show that, particularly for tunas, stocks were more depleted if they had high commercial value, were long‐lived species, had small pre‐fishing biomass and were subject to intense fishing pressure for a long time. In addition, implementing and enforcing total allowable catches (TACs) had the strongest positive influence on rebuilding overfished tuna and billfish stocks. Other control rules such as minimum size regulations or seasonal closures were also important in reducing fishing pressure, but stocks under TAC implementations showed the fastest increase of biomass. Lessons learned from this study can be applied in managing large industrial fisheries around the world. In particular, tuna regional fisheries management organizations should consider the relative effectiveness of management measures observed in this study for rebuilding depleted large pelagic stocks. 相似文献
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Richard M Hillary Ann L Preece Campbell R Davies Hiroyuki Kurota Osamu Sakai Tomoyuki Itoh Ana M Parma Doug S Butterworth James Ianelli Trevor A Branch 《Fish and Fisheries》2016,17(2):469-482
There is considerable international concern and scientific debate about the current state and future of tuna stocks worldwide and the capacity of Regional Fisheries Management Organisations to manage the associated fisheries effectively. In some cases, this concern has extended to predictions of imminent collapse with minimal chances of recovery, even under a commercial catch moratorium. As a viable alternative to a full fishery closure, the Commission for the Conservation of Southern Bluefin Tuna (CCSBT) has adopted a scientifically tested, adaptive rebuilding strategy for the depleted southern bluefin tuna (Thunnus maccoyii) stock. The management procedure (MP) adopted involves a harvest control rule that fully specifies the total allowable catch as a function of key indicators of stock status, adjusting future harvest levels every three years so as to meet the rebuilding targets agreed by CCSBT. It was chosen from a subset of candidate MPs selected following extensive simulation testing. This involved first selecting a wide range of plausible scenarios for stock status and input data, ranging from pessimistic to optimistic, against which the alternative candidate MPs were tested to ensure that they were robust to important uncertainties. This is the first time that a comprehensively evaluated MP has been adopted for an internationally managed tuna stock. Both the process and the outcomes have broad applicability to other internationally managed stocks. 相似文献
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Total allowable catch restrictions (hereafter referred to as catch quotas) play an important role in maintaining healthy fish stocks. While studies have identified a positive relationship between catch quota implementation and improved stock status, these methods are subject to selection bias as catch quotas are typically applied to stocks that are depleted. We address this challenge using the synthetic control method, which estimates the causal effect of catch quotas on fishing mortality and biomass by predicting a synthetic counterfactual outcome. We focus on high seas stocks (tunas, billfishes, and sharks) managed by tuna Regional Fisheries Management Organizations (tRFMOs), first providing an overview of stock status and current management measures in place. We find that implementation of catch quotas by tRFMOs has more than doubled over the past decade. Second, we predict the hypothetical fishing mortality and biomass trajectory for seven high seas quota-managed stocks in absence of a catch quota. These “synthetic non-quota stocks” are predicted using a weighted selection of high seas non-quota stocks. Credibility of the synthetic non-quota stocks is evaluated through diagnostic checks, and robustness tests assess sensitivity to study design. Five credible fishing mortality synthetic controls are predicted: three add support to the hypothesis that catch quotas successfully reduce fishing mortality, while two find that catch quotas increase fishing mortality. While our analysis is limited in scope, given that all seven quota-managed stocks are managed under a single tRFMO, we highlight the potential for the synthetic control method in fisheries management evaluation. 相似文献
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本文以黄鳍金枪鱼、肥壮金枪鱼为例,从管理、资源、技术三方面分析金枪鱼渔业发展前景;并在此基础上,提出了慎重发展我国金枪鱼超低温延绳钓作业的对策和建议。 相似文献
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生物学参考点常被表示为与渔业管理相关联的捕捞死亡率和生物量,是单从生物学角度来衡量渔业资源及其开发状况的指标。通常可分为目标参考点、限制参考点和阈值参考点。目标参考点是为了持续获得某一目标渔获量所需的最小生物量和相应捕捞死亡率,包括目标生物量(Bmsy)、目标产卵亲体量(Smsy、SSB35%、SSB40%)、目标捕捞死亡率(Fmsy、Fmax、F0.1、Fmed、F40%、F40%)等参数。限制参考点用于保证捕捞死亡率不会高到危害鱼类种群的可持续利用和其生物量不会低到危害其生存,主要包括Fmsy、Fmax、F0.1、Fcrash、F20%、Bloss等参数。阈值参考点介于目标参考点和限制参考点之间,包括预防性捕捞死亡率Fpa、预防性生物量Bpa,主要对渔业资源的开发和管理进行预警,防止生物量小于BL。生物学参考点主要应用动态综合模型、产量模型和亲体量补充量关系模型来估算,估算过程中需要考虑到补充、生长、死亡等生命史过程中的不确定性。本文对生物学参考点的发展和应用进行了综述,并以金枪鱼渔业为例阐述它在渔业管理上的应用。近几十年来,我国近海渔业资源出现衰退,亟需利用生物学参考点的原理和方法对重要渔业资源种类进行... 相似文献
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Nathaniel Willse;Claire Ober;Hsiao-Yun Chang;Harlisa Harlisa;Tri Ernawati;Duranta D. Kembaren;Cody Szuwalski;Michael J. Wilberg;Yong Chen;Kristin M. Kleisner; 《Fisheries Management and Ecology》2024,31(4):e12691
Management of crustacean fisheries is often data-limited, and techniques used in finfish fisheries are often inappropriate for crustaceans due to life-history differences. Limitations in modeling capacity and data availability make it difficult to determine the status of crustacean stocks using model-based biological reference points (BRPs), but BRPs are a key component of successful fisheries management. Using crustacean fishery case studies depicting model-based and empirical management strategies, we synthesized the current state of crustacean fisheries management with respect to data availability and use of management controls. Input and output controls can be successful with supplemental BRPs, but whatever methods are used must explicitly consider species' unique life-history characteristics. In data-limited fisheries, output controls can effectively conserve a species under high levels of exploitation. Implementation of discrete BRPs can improve sustainability of both emerging and data-rich crustacean fisheries, to make these quantitative metrics a valuable tool for crustacean management globally. 相似文献
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Ruben H. Roa-Ureta;Patrícia Amorim;Susana Segurado; 《Fish and Fisheries》2024,25(5):823-836
Most fisheries are conducted without any scientific knowledge about the size and productivity of the stocks that support them. This navigation in the dark in most fisheries is a major obstacle in making them sustainable sources of nutrition for people in general and income for fishers and other economic actors along supply chains. Fisheries that have not been assessed generally are data-intermediate and data-poor, the latter usually having annual time series of landings as the single piece of data available. A major effort in the last two decades has been directed toward developing ‘catch-only’ stock assessment methods, although some of these methods have been tested and found deficient. Here we provide a novel approach to using annual landing time series as the single source of data to qualitatively judge the condition of un-assessed stocks using frequentist cumulative probability ogives, both in terms of stock biomass and fishing mortality. A meta-analysis of the FishSource database allowed us to infer statistical patterns from hundreds of assessed fisheries and thousands of annual landings, biomass, and fishing mortality observations. Four stock-management types were considered separately in the analysis: short-lived and others (mid- to long-lived) stocks, controlled or not controlled by catch limits. Obtained cumulative probability ogives provide clear evaluations of stock biomass and fishing mortality trends in all four stock-management types, leading to actionable information on probable current status and future trends. Using these probability ogives, we developed decision trees that lead to qualitative scores on the exploitation status of un-assessed stocks. 相似文献
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Julien Cucherousset Rémy Lassus Carsten Riepe Paul Millet Frédéric Santoul Robert Arlinghaus Mathieu Buoro 《Fisheries Management and Ecology》2021,28(4):295-304
Although freshwater fish stocking is widely used by managers, quantitative assessments of stocking practices are lacking in many countries. The general objective of the present study was to determine the quantity and characteristics of fish stocking in metropolitan France. Using a survey-based approach, stocking practices for 2013 by recreational angling clubs in France were quantified, which represented the bulk of fish stocking undertaken in that year. Stocking was found to be practiced by 88.6% of angling clubs in France, representing, on average, 65% of their annual budget. Overall, 22 species were stocked, including 13 native and nine non-native species, with strong variations among species in terms of life stages and body sizes used for stocking. Using Bayesian modelling, a total biomass of 2.029 t, representing approximately 90 million fishes, was estimated to be stocked in France in 2013. In terms of biomass, the most widely stocked species were rainbow trout Oncorhynchus mykiss (Walbaum), brown trout Salmo trutta L., roach Rutilus rutilus (L.), common carp Cyprinus carpio L. and northern pike Esox lucius L. A stocking volume of approximately 60 fishes or 1.5 kg of fish biomass per angler per year seems commonplace in industrialised countries for which data are available. 相似文献
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Christopher Mulanda Aura Chrisphine S. Nyamweya Monica Owili Nicholas Gichuru Rodrick Kundu James M. Njiru Micheni Japhet Ntiba 《Fisheries Management and Ecology》2020,27(4):314-324
The present study demonstrates the declining state of the major commercial fisheries of Lake Victoria, Kenya, a situation threatening sustainability of the lake's fishery. Data in the present study were derived from resource monitoring programmes that included hydro‐acoustics (2009–2018), trawl net fishing (2011–2018), frame surveys (2000–2016) and catch assessment surveys (2000–2015). The activities provided information on fish stocks and supported advice for fisheries management. The average fish stock densities for Tanzania, Uganda and Kenya of 8.92, 8.25 and 8.19 t/km2, respectively, were relatively similar. Diplomatic and sustainable efforts for harmony in fish harvesting among the fishers of the riparian countries are encouraged given the interdependence of the lake. The Kenyan and River Kagera regions had a higher proportion (≈ 4% each) of big‐sized Nile perch (≥50 cm total length) in 2018, signifying the critical breeding areas for Nile perch. To sustain the fishery, there is need to enforce a 36%–44% effort reduction for all the major fisheries, and enforcement of gear limits to avoid harvesting of immature fish and destruction of the lake ecosystem. 相似文献
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- We respond to criticism of our earlier paper where we report Australia‐wide declines in fisheries catches that parallel the declining trends in fish populations observed underwater, and we highlight concerns about the low levels of precaution applied when regulating fisheries catches using the avoidance of recruitment failure approach.
- Most fished species worldwide lack the data needed for accurate stock status assessments, and consequently exploitation of these species should be managed with high precaution.
- For the relatively few species and stocks with individually modelled assessments, the errors associated with model output are extremely large as a result of the multiplicity of confounding factors (including effects of changing climate, technological advances that increase catch efficiency, fisher behaviour, interactions with other species, and changes in habitat quality), and the compounding of error introduced by subjective assumptions in multiple parameter estimates. The magnitude of this assessment uncertainty appears to be rarely recognized and incorporated into management decisions.
- Given the difficulties in accurately predicting and managing fishing impacts, including species interactions across space and time, a well‐designed set of no‐take marine reserves is critically needed. Although not a universal panacea, an effective global network of marine reserves arguably represents the most efficient and publicly acceptable next step – in addition to greenhouse gas reduction – towards solving the unfolding global dilemma confronting fish populations and ocean ecosystems.
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John C. Field ré E. Punt Richard D. Methot & Cynthia J. Thomson 《Fish and Fisheries》2006,7(4):284-302
Marine protected areas (MPAs) have been increasingly proposed, evaluated and implemented as management tools for achieving both fisheries and conservation objectives in aquatic ecosystems. However, there is a challenge associated with the application of MPAs in marine resource management with respect to the consequences to traditional systems of monitoring and managing fisheries resources. The place‐based paradigm of MPAs can complicate the population‐based paradigm of most fisheries stock assessments. In this review, we identify the potential complications that could result from both existing and future MPAs to the science and management systems currently in place for meeting conventional fisheries management objectives. The intent is not to evaluate the effects of implementing MPAs on fisheries yields, or even to consider the extent to which MPAs may achieve conservation oriented objectives, but rather to evaluate the consequences of MPA implementation on the ability to monitor and assess fishery resources consistent with existing methods and legislative mandates. Although examples are drawn primarily from groundfish fisheries on the West Coast of the USA, the lessons are broadly applicable to management systems worldwide, particularly those in which there exists the institutional infrastructure for managing resources based on quantitative assessments of resource status and productivity. 相似文献
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Michael C. Melnychuk Charmane E. Ashbrook Richard J. Bell Lyall Bellquist Kate Kauer Jono R. Wilson Ray Hilborn Jay Odell 《Fish and Fisheries》2023,24(5):711-729
The status of federally managed fisheries in the United States is well monitored, but the condition of other marine fisheries, whether state-managed, territory-managed or unmanaged, is less understood and often unknown. We used expert surveys to characterize the management systems of non-federally managed fisheries in US coastal marine states and overseas territories. For 311 fisheries, we estimated an overall Fisheries Management Index (FMI) and a qualitative stock status score. These measures were positively correlated, and while a wide range of research, management, enforcement and socioeconomic criteria were partially met (FMI ≥ 0.5) for 66% of fisheries, stock status was considered as partially acceptable (score ≥ 0.5) for only 45% of fisheries and acceptable (score = 1) for only 16% of fisheries. Higher FMI was typically observed in fisheries with greater commercial landed weight, value, or greater recreational catches. Fisheries from continental states had higher FMI than those from overseas territories. Invertebrates and diadromous fish species had higher FMI on average compared to those of marine fishes. Extrapolating results for surveyed fisheries to nearly 2000 non-federally managed US fisheries while stratifying by state and importance designation (based on commercial, recreational, cultural or ecological importance), we estimate a mean overall FMI of 0.48, and estimate that only 19% of fisheries have a reliable estimate of stock status available; both measures are lower than similar estimates for federally managed fisheries. Funding or capacity constraints and information or data limitations were identified as common challenges faced by state agencies in managing fisheries under their jurisdiction. 相似文献
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Drifting fish aggregating devices (dFADs) are extensively used in modern tuna purse seine fisheries. The use of dFADs has greatly improved fishing efficiency and generated substantial economic returns in purse seine fisheries, but adverse impacts on tuna juveniles, associated species and marine ecosystems are still of concern. Based on an analysis of current challenges in dFAD management measures in tuna regional fishery management organisations (t-RFMOs), we explored opportunities to strengthen dFAD management in tuna fisheries. An integrated dFAD management scheme with multiple tools that account for different usage stages of a dFAD needs to be organised to regulate, track, monitor and recover in tuna purse seine fisheries. We recommend that (1) dFAD-associated definitions should be standardised to provide operational guidance for dFAD activities; (2) all deployed dFADs should be counted towards dFAD limits on active dFADs, except those reported as lost and abandoned; (3) a regional dFAD tracking and monitoring program should track dFAD paths based on daily position reported to RFMOs directly, in addition to mandatory dFAD marking requirements; and (4) a framework of compensation mechanisms should provide financial support for joint dFAD recovery and eco-compensation. 相似文献
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Matti Kotakorpi;Mikko Olin;Jukka Ruuhijärvi;Katja Kulo;Jyrki Lappalainen; 《Fisheries Management and Ecology》2024,31(2):e12670
Movements of common fish species in large lakes that are inadequately known is challenging for fisheries management. Pikeperch (Sander lucioperca) (n = 478; mean length = 42.1 cm; SD = 7.0), bream (Abramis brama) (n = 775; mean length = 31.1 cm; SD = 5.3) and roach (Rutilus rutilus) (n = 939; mean length = 21.4 cm; SD = 2.0) were marked with individual T-anchor tags to investigate movements in Lake Vesijärvi, a large lake situated in southern Finland consisting of several basins and managing by multiple entities. All species moved between basins, but only rarely moved outside tagging areas. The recapture rate of pikeperch was higher than roach and bream. Tagged fish consistently crossed municipality borders and water ownership units, thereby forming shared stocks, which underlined the importance of cooperation in lake restoration and a need to unite fragmented water ownership. Management of fisheries for cyprinid fishes could be more efficient if fishing targeted the most suitable areas without considering restrictions due to fragmented water ownership. Tagging data provided information on which parts of a large lake should be subjected to uniform pikeperch fisheries management. The importance of other species catch varied between different parts of the lake, thereby requiring different fishing regulations. Tagging data on common fish species provided valuable information on fish movements to support spatially explicit fisheries management. 相似文献
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Amaël Dupaix;Frédéric Ménard;John D. Filmalter;Yannick Baidai;Nathalie Bodin;Manuela Capello;Emmanuel Chassot;Hervé Demarcq;Jean-Louis Deneubourg;Alain Fonteneau;Fabien Forget;Francesca Forrestal;Daniel Gaertner;Martin Hall;Kim N. Holland;David Itano;David Michael Kaplan;Jon Lopez;Francis Marsac;Alexandra Maufroy;Gala Moreno;Jeff A. Muir;Hilario Murua;Liliana Roa-Pascuali;Géraldine Pérez;Victor Restrepo;Marianne Robert;Kurt M. Schaefer;Grégory Sempo;Marc Soria;Laurent Dagorn; 《Fish and Fisheries》2024,25(3):381-400
Fishers have intensively used drifting fish aggregating devices (DFADs) over the last three decades to facilitate their catch of tropical tunas. DFADs increase purse-seine efficiency, potentially increasing tuna fishing mortality. They could also have impacts on tuna natural mortality and reproductive potential, and assessing the consequences of their presence at sea on tuna populations is a challenge. The use of DFADs results in a major increase in the number of floating objects, which are spatially heterogeneous at sea. To date, no converging scientific results exist regarding the effects of DFADs on the large-scale movements and behaviour of tuna, mainly due to the difficulty of disentangling the respective roles of DFADs and environmental factors. Some biological indices show that tuna condition is lower when associated to a floating object than in a free-swimming school. However, it is not clear whether this is the cause or the consequence of the association nor if it has long-term effects on individuals' fitness. Further scientific progress requires (i) the collection of time series of indicators to monitor habitat change, individual behaviour, individual fitness, and population dynamics and (ii) experimental studies to identify the underlying behavioural and biological processes involved in associative behaviour. The extent of the modification of the surface habitat by the massive deployment of DFADs and the current uncertainty of the possible long-term consequences on the individual fitness and dynamics of tuna populations argue for the need for increased awareness of this issue by Regional Fisheries Management Organisations regulating tuna fishing. 相似文献
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Many commercial fish stocks are beginning to recover under more sustainable exploitation regimes. In this study, we document the temporal and spatial changes in one remarkable example of stock recovery: northern European hake (Merluccius merluccius). Analysing data from several scientific surveys, we document a dramatic increase in estimates of biomass between 2004 and 2011 throughout the larger area now occupied by the stock. The largest increase occurred in the North Sea, where hake have been largely absent for over 50 years. Spatio‐temporally resolved commercial landings show that high densities occur in the North Sea only between April and September, suggesting a density‐dependent seasonal habitat expansion to suitable temperature and depth conditions. These changes have implications for the management of the stock which are discussed. Notably, if discards are banned as part of management revisions, the relatively low quota for hake in the North Sea will be a limiting factor (the so‐called ‘choke’ species) which may result in a premature closure of the entire demersal mixed fishery in the North Sea, jeopardizing many commercial fisheries in the region. This example of the unforeseen consequences of improved stewardship highlight the need for a more holistic, regional and responsive approach to managing our marine ecosystems. 相似文献