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1.
    
Gear-based management for coral reef fisheries is often overlooked in the scientific literature. Empirical studies have demonstrated the conservation benefits of gear-restricted areas (i.e. prohibiting fishing gears), which can support greater biomass than unrestricted areas and protect species that play key functional roles. However, population dynamics of functional feeding groups of reef fishes under specific gear-restriction regimes remains uncertain. Here, we constructed a multi-species, length-based fisheries model to observe relative biomass and catch of reef fishes under various gear-restriction management scenarios. We used fishery-dependent and fishery-independent data to determine the catchability of functional groups and selectivity of size classes for hook-and-line, net and spear fishing, which are widely used gear types on coral reefs globally. Our model revealed trade-offs involved with gear-restriction management such that no single management strategy was able to maximize biomass or catch of all functional groups simultaneously. Also, we found that spear fishing (i.e. prohibiting hook-and-line and net fishing) maintained the highest total biomass summed across functional groups, whilst hook-and-line fishing (i.e. prohibiting net and spear fishing) and a ban on spears maintained the lowest biomass. However, hook-and-line fishing generated the highest catch-per-unit-effort. Our model results were primarily driven by differential growth rates, maximum per capita production of recruits, and catchability of functional groups targeted by each fishing gear. We demonstrate that gear restrictions can be a critical management tool for maintaining biomass and catch of certain functional groups but will likely require additional management to protect all key functional feeding groups of coral reef fishes.  相似文献   

2.
Towards ecosystem-based fisheries management   总被引：12，自引：0，他引：12  
Performance measures and reference points for the management of target species are now widely used in the fisheries of the developed world. To move us closer to an ecosystem‐based fisheries management framework, we look at the prospects for expanding current single‐species approaches for target species, by considering nontarget species. We also examine the development of performance measures and reference points for emergent ecosystem‐level properties. We conclude that the expansion of single‐species reference points to take account of the nontarget species of a fishery is tractable and desirable. In contrast, the use of performance measures for a single or a small selection of ecosystem metrics is not possible at present, owing to the absence of a clear understanding of their dynamics and a lack of underlying theory to explain their behaviour. However, recent methods that aggregate a wide range of metrics to provide an overall picture of the ecosystem status show promise and have a particular attraction because they have the potential to provide a framework for establishing a dialogue on management issues between all interested parties.  相似文献   

3.
Ecosystem‐based management is an emerging paradigm influencing the management of commercial fisheries. Increasingly, developed nations are adopting explicit legislation and policy governing the assessment and management of their fisheries against criteria of ecological sustainability. Yet the ability to evaluate ecosystem impacts of fisheries is compromised by a general lack of understanding of marine ecosystem function (beyond the population level) and a lack of robust and practical indicators for ecosystem health and management. Recent technological advances can assist in developing criteria, including structural analyses of seafloor communities potentially impacted by fishing gears (e.g. demersal trawling). Similarly, advances in fishing gear technology, including improved selectivity and the development of gears which have a more benign environmental impact, can mitigate some of the ecological impacts of fishing. Such technological advances are summarized in the context of contemporary fisheries management.  相似文献   

4.
    
We investigate the impact of oceanographic variability on Pacific bluefin tuna (Thunnus orientalis: PBF) distributions in the California Current system using remotely sensed environmental data, and fishery‐dependent data from multiple fisheries in a habitat‐modeling framework. We examined the effects of local oceanic conditions (sea surface temperature, surface chlorophyll, sea surface height, eddy kinetic energy), as well as large‐scale oceanographic phenomena, such as El Niño, on PBF availability to commercial and recreational fishing fleets. Results from generalized additive models showed that warmer temperatures of around 17–21°C with low surface chlorophyll concentrations (<0.5 mg/m3) increased probability of occurrence of PBF in the Commercial Passenger Fishing Vessel and purse seine fisheries. These associations were particularly evident during a recent marine heatwave (the “Blob”). In contrast, PBF were most likely to be encountered on drift gillnet gear in somewhat cooler waters (13–18°C), with moderate chlorophyll concentrations (0.5–1.0 mg/m3). This discrepancy was likely a result of differing spatiotemporal distribution of fishing effort among fleets, as well as the different vertical depths fished by each gear, demonstrating the importance of understanding selectivity when building correlative habitat models. In the future, monitoring and understanding environmentally driven changes in the availability of PBF to commercial and recreational fisheries can contribute to the implementation of ecosystem approaches to fishery management.  相似文献   

5.
    
Despite continued calls for the application of ecosystem-based fisheries management, tactical fisheries management continues to be heavily reliant on single-species stock assessments. These stock assessments rarely quantitatively integrate the effects of ecosystem processes on fish stock productivity. This lack of integration is ultimately driven by the complexity of interactions between populations, ecosystems and fisheries, which produces uncertainty when defining which processes to include and how to include them. Models developed using a structured hypothesis testing framework would allow formalizing uncertainties while underscoring the importance of incorporating different population and ecosystem processes to explain non-stationary stock productivity. Here, we develop a conceptual framework for extending and comparing population dynamics models of increasing complexity. We illustrate the utility of the framework by investigating the population and ecosystem processes that most likely affected the differential recovery of two flatfish populations (American plaice and yellowtail flounder) on the Newfoundland Grand Banks over the past three decades. We found that yellowtail flounder population dynamics were primarily driven by recruitment variability, which was negatively affected by warmer climatological conditions, as indicated by an integrated regional climate index. Meanwhile, American plaice population dynamics were affected by a combination of temporal variability in recruitment and natural mortality, where natural mortality increased during colder than average conditions. By exploring hypotheses about the effects of population and ecosystem processes on population dynamics, this modelling framework will improve understanding about the drivers of shifts in population productivity while serving as a transparent and robust approach to support ecosystem-based fisheries management.  相似文献   

6.
    
Three years after the 2015 collapse of the northern stock of Pacific Sardine that is predominantly located off the west coast of the United States, acoustic-trawl (A-T) surveys documented an increase in the presence and persistence of the southern stock off coastal Southern California. Then in 2020, the biomass of Sardine that was landed in Mexico and attributed to the northern stock exceeded the estimated biomass for the entire northern stock. To investigate if the landings were incorrectly classified, we revisit a model of northern-stock potential habitat and the associated range of sea-surface temperature (SST) used to apportion the A-T survey data and monthly fishery landings to the two stocks, respectively. We update the probabilistic model of potential habitat with data on sardine-egg presence and absence and concomitant satellite-sensed SST and chlorophyll-a concentration through 2019 and apply the new model to more accurately attribute the A-T observations and fishery landings data to the northern or southern stock. The addition of recent data, with increased coverage in SSTs between 15°C and 17°C, improves the model accuracy and spatial precision of the stock attribution. The attribution accuracy is critically dependent on the temporal and spatial coincidence of the environmental and survey or landings data and should be corroborated with other characteristics indicative of biological isolation such as spatial separation, distinct spawning areas and seasons, and uncorrelated demographics.  相似文献   

7.
东太平洋赤道海域茎柔鱼主要生物学特性比较研究   总被引：1，自引：0，他引：1       下载免费PDF全文
根据中国远洋鱿钓船于2018年2—4月在东太平洋赤道(110°W～114°W、2°40'S～2°N)作业期间现场取样的1200尾茎柔鱼(Dosidicusgigas)样本进行研究,利用频率分布法分析了2—4月胴长、体重、性腺成熟度和摄食等级的分布,并通过拟合求出了胴长-体重的关系和初次性成熟胴长。根据采样海域的遥感温度,讨论了茎柔鱼不同月份雌雄个体生长的差异。结果显示, 2—4月雄性茎柔鱼优势胴长依次为26～28 cm (19.33%)、30～32 cm (26.46%)、28～30 cm (31.82%),雌性分别为24～26 cm (16.8%)、28～30 cm (24.95%)、26～28 cm (21.79%); 2—4月雌雄茎柔鱼优势体重均依次为400～600 g (28%、20.67%)、600～800 g (29.14%、28.25%)、600～800 g (25.64%、31.82%)。协方差表明3月雌性茎柔鱼与同月雄性茎柔鱼以及2月、4月的雌性茎柔鱼生长模式均存在显著性差异(P_30.01, P_(2-3)0.01,P_(3-4)0.05)。2—4月雌、雄性茎柔鱼摄食等级均以1～2级为主,高摄食等级占比逐月降低。雄性茎柔鱼性腺发育均以Ⅱ期为主,性成熟比例逐月升高,初次性成熟胴长为32.72cm;雌性性腺发育缓慢,各月发育均以Ⅰ期为主,未成熟比例占97%以上,茎柔鱼胴长和体重随性腺等级的提高呈逐级增长状态。综合判断雄性茎柔鱼性成熟比雌性早,性成熟雄性个体或因交配正在离开赤道海域开始向美洲沿岸洄游。  相似文献   

8.
    
Understanding what diversity of small-scale fisheries translates to in practice, and what this means for management regimes seeking sustainability, continues to be a challenging undertaking. This is particularly so in the tropical Pacific Islands region, where small-scale coastal fisheries play a significant role in domestic food and livelihood systems. A renewed regional policy focus on supporting coastal fisheries, combined with momentum built from a decades-long ‘Pacific renaissance’ in community-based fisheries management approaches, has increased resourcing and support for coastal fishery data collection and knowledge production. In this context, there is growing demand to explicitly characterise diversity and complexity of community-based coastal fisheries to inform how national co-management programs can adequately support the many communities within national constituencies. This study presents findings from a community-based coastal fisheries monitoring programme implemented in ten communities across Kiribati and Vanuatu between 2019 and 2021. Findings illustrate the intra- and inter-country diversity of contextual drivers, fishing practices, and fisher participation. We discuss the implications of this enhanced understanding of community-based fisheries for applied co-management practice in these two countries. In doing so, we add to a growing knowledge base about fishing practices in Pacific Island coastal communities and elucidate avenues through which to incorporate this knowledge into adaptive co-management practice.  相似文献   

9.
    
Pacific halibut (Hippoglossus stenolepis) are an ecologically, commercially, and culturally important Alaskan groundfish species. Commercial harvest of halibut dates back to the late 19th century and has been managed by the International Pacific Halibut Commission (IPHC) since 1921. IPHC surveys have revealed declining trends in survey biomass in multiple regions and region‐specific declines in mean size‐at‐age (size‐at‐age) over the past two decades (>50% in some areas). Changes in size‐at‐age can arise from a variety of physical, ecological, sampling, and fishery effects, including size‐dependent fishery or predation mortality, alteration in growth from variability in prey quality or quantity, and changes in temperature‐dependent metabolic demands. Here, we develop and apply a bioenergetics model for halibut using survey‐based diet and temperature data for Alaska to evaluate potential environmental drivers of size‐at‐age. In general, juvenile (<40 cm fork length) foraging rates were highest in the Gulf of Alaska concomitant with higher potential growth and elevated basal metabolic demands during warm summer conditions. In contrast, adult (40–120 cm FL) potential growth was highest in the Eastern Bering Sea, potentially reflecting lower metabolic costs and higher rates of prey consumption in that region. We additionally find evidence for interannual variation in potential growth, with a higher frequency of reduced growth potential in the last decade, particularly in the Eastern Bering Sea in 2015 and 2016 for both juvenile and adult halibut. These results suggest the potential for patterns in size‐at‐age to arise from trophic and environmental constraints that collectively limit growth in some regions and years.  相似文献   

10.
    
Strong latitudinal gradients in species composition were revealed by two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) of 41 species of epipelagic fishes and squids in 513 gillnet collections by research vessels of Hokkaido University over a huge area of the northern North Pacific during the summers of 1978–1993. Salmonids inhabited northern subarctic water and skipjack tuna (Euthynnus pelamis) and flying squid (Ommastrephes bartrami) inhabited the region of the Subarctic Boundary, but distinct boundaries between species groups and sample groups were lacking, largely because abundant species, such as Pacific saury (Cololabis saira) and Pacific pomfret (Brama japonica), migrated across most of this region during the summer. Longitudinal differences were not pronounced, but some species, including Japanese sardine (Sardinops melanostictus) and Japanese anchovy (Engraulis japonicus), were only found in the western Pacific. Pacific saury was more common in the western Pacific, whereas sockeye salmon (Oncorhynchus nerka) was concentrated in the eastern Pacific. Interannual fluctuations in the latitude of species groups were most closely correlated with changes in sea surface temperatures. In the western Pacific, 1982, 1983, 1985, 1987-88, and 1992-93 were cool years when subarctic and transitional assemblages were found farther to the south than other years. Temperature and salinity at various depths were highly correlated with each other and with first-axis DCA ordinations scores. Long-term trends in community structure were not apparent during the 1.6 decades.  相似文献   

11.
为了探究不同印度洋偶极子模态(Indian Ocean Dipole,IOD)下西南印度洋深海散射层(Deep scattering layer,DSL)热点栖息地分布,研究选取2012年10月到2020年7月间的西南印度洋海域声学调查数据,利用热点分析方法和最大熵模型,分析不同IOD模态下DSL热点栖息地的变动规律。结果显示,不同IOD模态的最大熵模型精度均大于0.9,模型预测效果较好,其中溶解氧是对栖息地分布贡献率最高的因子,平均贡献率为50.88%。DSL热点适宜栖息地的重心主要在西北-东南方向移动,第一个IOD冷相位时期热点适宜栖息地重心变动最为明显。DSL热点的适宜栖息地分布在30°S-45°S和11℃和22℃等温线之间,具有一定的纬度相关性。研究表明,不同IOD模态下DSL热点受溶解氧和海表面温度等变化的影响,其适宜栖息地变动明显,最大熵模型可以较好的预测DSL热点栖息地的分布。本研究可为阐明DSL空间分布和资源变动规律提供新的参考。  相似文献   

12.
    
Fisheries science uses quantitative methods to inform management decisions that reflect cultural preferences which, in turn, indirectly influence the states of ecosystems. To date, it has largely supported Eurocentric preferences for the commodification of marine organisms under the tenets of maximum sustainable yield, whereby abundances are intentionally maintained far below their historical baselines despite broader socio-ecological trade-offs. In contrast, Indigenous Knowledge Systems (IKS) adhere to the principle of “take only what you need and leave lots for the ecosystem,” implementing lower fishery removals to support socio-ecological resilience. Despite the power imbalance favouring Eurocentric preferences in decision-making, fisheries scientists increasingly recognize that the pairing of IKS and Western science, or Two-Eyed Seeing, would lead to more holistic management goals. For recognition to transcend tokenism, meaningful collaborations and co-governance structures underlying knowledge co-production must carry through to legislated policy changes. Using recent co-governance developments for fisheries management and spatial protections involving federal, provincial and Indigenous governments in Pacific Canada, we illustrate how the precautionary approach, including reference points and harvest control rules broadly applied in international fisheries, could be revised to make collaborative fisheries management compatible with IKS and improve biodiversity and fisheries protections. Our recommendations may create socio-economic trade-offs at different timescales for commercial fishers. Pre-empting that challenge, we discuss IKS-compatible economic approaches for addressing shorter term costs arising from reduced exploitation rates. Although our case study derives from Pacific Canada, the insights provided here are broadly applicable elsewhere in the world.  相似文献   

13.
    
This study was undertaken to address the increasing need for a strategic approach to industry–science data collections in the face of reducing resources and growing need for evidence in fisheries management. The aim was to evaluate progress in the development of plans and procedures that can be employed to collect, record and use fishing industry knowledge and data in the evidence base for managing fisheries. This was achieved by reviewing industry‐led data initiatives already undertaken or ongoing within the United Kingdom to document how these projects have/are incorporating fishing industry data into the process of management decision‐making; canvassing stakeholder opinion on data gaps and whether these could be filled by data gathered by commercial fishing vessels; establishing what issues might prevent or stimulate commercial fishing vessels in collecting data when they have the opportunity; and describing guidance on a step‐by‐step process for gathering scientific information such that fishers are empowered to collect the right data, at the right times and in the right format for their fishery. Given recent advances in the collection, interpretation and application of fisheries‐dependent data, we compare progress made in the UK to other areas of the world. We conclude that there is considerable evidence of a paradigm shift from the conventional practice of scientists asking fishers to provide data for scientific analyses towards full engagement of key stakeholders in data collection.  相似文献   

14.
By-catch and (or) discards in fisheries have been considered a serious problem and have been unanimously criticized by politicians, environmental groups, the public and scientists. However, it is possible to determine biologically acceptable amounts of discards that fulfil the objectives of ecosystem-based fishery management (EBFM). For instance, while discards have been shown to impact some systems negatively, they can be a potential benefit in other systems. Using a prawn trawl fishery as an example, this paper discusses some of the potentially positive effects of discards. As in many facets of EBFM, the key for the management of discards is sustainability and precaution. In particular, it is important to give full consideration to the implications of reducing discards to the lowest extent possible.  相似文献   

15.
    
We have extracted information on the habitats of bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis) and yellowfin (Thunnus albacares) in the Eastern Tropical Pacific Ocean by matching the spatial‐temporal distribution of catch and effort of purse seine and longline fleets collected by the Inter‐American Tropical Tuna Commission with oceanographic conditions and subjecting the matched data to Quotient Analysis and General Additive Models (GAMs). These analyses yielded the following results. The habitats defined by the GAM analysis of young fish differ significantly between two periods, one before and one after the introduction of fish aggregation devices (FADs). This was not true for the older fish caught by longline. We speculate that these changes were caused by the extensive use of FADs. Younger bigeye and yellowfin caught by the purse seine fleet have a different preference of environmental variables compared to older fish caught by longline. This is to be expected since tuna of different age groups have different sizes, metabolic capabilities and swimming skills. Moreover, as revealed by GAMs, the habitats of young fish differ between species to a much larger degree than those of older fish. Our results indicate the fundamental differences between fishing methods, targeted species, and operating region of the two fisheries. Specifically, young bigeye occupy equatorial waters farther from the coast and where the hypoxic layer is deeper, young skipjack occupy more productive waters associated with equatorial and coastal upwelling, and young yellowfin occupy broad areas where waters are underlain by a shallow hypoxic layer.  相似文献   

16.
    
  1. In Panama, shark fisheries were initially developed in the 1980s and progressively increased in production in the 1990s mainly due to the high demand for shark fins and meat from the international Asian market. Since then, and despite the exploitation rate (average 3,514 t year–1) and endangered status of some species, shark fisheries have seldom been studied, and official statistics are general or incomplete and not suitable for the development of appropriate conservation and management strategies.
  2. To understand the dynamics of shark fisheries in Panama, field surveys were conducted between 2007 and 2009 at several landing ports of small‐scale and industrial fisheries, at fish processing plants and on‐board fishing vessels in Pacific Panama, where most of the fishing vessels of the country operate.
  3. In general, it was found that the artisanal and industrial fisheries of the Pacific coast of Panama regularly exploit at least 18 species of sharks, which are also being exploited by neighbouring countries in the eastern Pacific, suggesting the importance of coordinated conservation initiatives across the multiple jurisdictions. A large number of the individuals caught were immature, implying a certain level of impact on recruitment rates. This pattern was particularly evident in species such as Sphyrna lewini, for which immature individuals represented at least 99% and 63% of the total catch by small‐scale and industrial fisheries, respectively. Catch per unit of effort analyses showed that Carcharhinus and Sphyrna species were the most exploited (representing ~80% of the catches) by industrial fisheries in Panama between 2006 and 2009, suggesting that fishery management should provide special attention to these groups.
  4. It is expected that the information presented here provides a baseline to develop new regulations, including the implementation of annual quotas and fishing seasons and the protection of nursery areas, for the long‐term sustainability and conservation of sharks in Panama.
  相似文献   

17.
Views about aquatic resource management are changing, particulaly now that resource yields from world fisheries have been shown to be not only unsustainable, but steadily declining under conventional management practice. There is ample reason for re-examination, and more pragmatic definitions of what is meant by sustainability There have nearly always been clear, reasonable means for making appropriate decisions that would have safeguarded most of the ocean's living resources, hut in general greed and lack of societal will, as articulated it national governmental levels, have promoted the present resource deterioration. I also posit that the underlying science in support of sustainable fisheries decision-making has been responsible for a great proportion of this deterioration. Revitalization of fisheries science, indeed rehabilitating the affected fisheries, will he required to regain the losses in credibility of the agencies and of the underlying science. This will depend upon resumption of integrated environmental monitoring, more enlightened application of what is already known, and reconnection of the science to the several industries involved, i.e. fishing, processing and marketing. Management implemented at the market place may be one of the few remaining options to secure the sustainability of natural resources  相似文献   

18.
Abstract  It is possible to use an ecosystem-based management approach to incorporate knowledge of climate regime impacts on ecosystem productivity to manage fishery resources. To do so, it requires the development of a coherent framework that can be built using existing stock assessment and management activities: ecosystem assessment, risk analyses, adaptive management and reference points. This paper builds such a framework and uses two population simulations to illustrate the benefits and tradeoffs of variable regime-specific harvest rates. The framework does not require prediction of regime shifts, but assumes that detection can occur soon after one has happened. As such, decisions do not need to be coincident to regime shifts, but can be delayed by an appropriate period of time that is linked to a species' life history, i.e. age of maturity or recruitment. Fisheries scientists should provide harvest recommendations that reflect a range of levels of risk to the stock under different assumptions of productivity. Coupling ecosystem assessment with ecosystem-based management would allow managers to select appropriate regime-specific harvest rates.  相似文献   

19.
林志锋  张敏 《海洋渔业》2006,28(1):79-82
本文关注《南极海洋生物资源养护公约》的背景,着重介绍了《南极海洋生物资源养护公约》涉及的水域、管理的鱼种和公约成员国概况,阐述了《南极海洋生物资源养护公约》对我国南大洋渔业的影响,涉及对我国远洋渔业生产的影响,对我国在南大洋作业水域渔船的法规性限制,对我国在南大洋区域与相关各国渔业合作的推动。文章对我国南大洋的渔业进行了分析,提出了相应的分析与建议,即:开展南大洋水域海洋渔业资源调查和评估,积极参与南大洋水域的渔业管理事务,加强对南大洋作业渔船的监控和管理,促进国际渔业信息交流。  相似文献   

20.
    
Coral reefs support numerous ornamental fisheries, but there are concerns about stock sustainability due to the volume of animals caught. Such impacts are difficult to quantify and manage because fishery data are often lacking. Here, we suggest a framework that integrates several data‐poor assessment and management methods in order to provide management guidance for fisheries that differ widely in the kinds and amounts of data available. First, a resource manager could assess the status of the ecosystem (using quantitative metrics where data are available and semi‐quantitative risk assessment where they are not) and determine whether overall fishing mortality should be reduced. Next, productivity susceptibility analysis can be used to estimate vulnerability to fishing using basic information on life history and the nature of the fishery. Information on the relative degree of exploitation (e.g. export data or ratios of fish density inside and outside no‐take marine reserves) is then combined with the vulnerability ranks to prioritize species for precautionary management and further analysis. For example, species that are both highly exploited and vulnerable are good candidates for precautionary reductions in allowable capture. Species that appear to be less vulnerable could be managed on a stock‐specific basis to prevent over‐exploitation of some species resulting from the use of aggregate catch limits. The framework could be applied to coral reef ornamental fisheries which typically lack landings, catch‐per‐unit‐effort and age‐size data to generate management guidance to reduce overfishing risk. We illustrate the application of this framework to an ornamental fishery in Indonesia.  相似文献   

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