Prognosis for long‐term sustainable fisheries in the African Great Lakes

Declines in fish yields and shifts in species composition are serious concerns in the African Great lakes of Tanganyika, Malawi (Nyasa/Niassa) and Victoria. Despite management and regulatory structures, all the lakes remain open‐access fisheries, severely depressing yields, economic returns and threatening biodiversity. While the lakes require an ecosystem‐based approach to management, this has not been realised because of a lack of institutional capacities, insufficient political will or simply being overwhelmed by the scale of the endeavour. Sustainable fisheries management can only be achieved through a refocus towards a stronger socio‐ecological approach and re‐evaluating how to realistically improve fish yield and environmental protection. This requires a combination of the following: (1) acceptance of suboptimal fish yields; (2) community‐enforced regulations that restrict access to fisheries and destruction of inshore habitats; (3) enhanced national and local institutional capacities and collaboration among the riparian states; and (4) major awareness and educational efforts that demonstrate the national and international importance of these lakes for food supply and biodiversity in pursuance of the Sustainable Development Goals. Without such actions, the prognosis for long‐term sustainable fisheries is bleak, and international projects and conferences will merely bear witness to further degradation of resources and the livelihoods they support.     

Changes in life history and ecological characteristics of coral reef fish catch composition with increasing fishery management

Abstract Length, life history and ecological characteristics of landed fish communities were studied over a 10‐year period to test theories of fishing disturbance during a time of increased gear and closure management in heavily utilised fisheries. It was predicted that with greater management restrictions: (1) the earliest and fastest responses in the fishery will be seen in those species with faster turnovers, or relatively lower vulnerabilities to fishing; (2) the fishery would transition to a landed catch with higher mean trophic levels, and greater mean body lengths. In addition, the removal of a non‐selective, small‐mesh seine nets should benefit the catch of gears that previously had the greatest species selectivity overlap with the seine net. Many predictions were supported, although maximum lengths and lengths at maturity responded more rapidly than anticipated. The response to eliminating the non‐selective seine net was a more rapid increase in sizes caught by gears with a larger overlap in size (hook and lines) than species selectivity (gill nets). The simultaneous comparison of management systems over time indicates that open‐access fishing grounds can benefit from restrictions imposed in adjacent fishing grounds. The study indicated that multi‐species coral reef fisheries management objectives of maximising yields, as well as maintaining the fish community’s life‐history diversity, require management trade‐offs that balance local socio‐economic and biodiversity needs.     

Community participation in conserving and managing inland waters

• 1. Many international and national bodies have stressed the need for community participation in the conservation and management of inland waters. Community participation is needed for three basic reasons: to implement management measures difficult to enforce without community support; to act as a mechanism in protecting inland waters through support of conservation bodies; and, through voluntary actions, to monitor, restore and rehabilitate inland water‐bodies.
• 2. It is important to conserve and manage inland waters because of their many values and uses. To participate fully in conservation and management measures, the community needs to (a) recognize the importance of inland waters as a part of the global hydrological cycle, (b) have some knowledge of the nature and effects of major human impacts on inland waters, and (c) be aware of certain legal issues.
• 3. The ‘community’ is heterogeneous in nature but community groups of similar interest can be recognized. They vary from small, local action groups, through national groups to international bodies. They provide advice to and support government actions; others oppose and seek to change government actions. Community involvement can be at various levels, from the relatively inactive to the vigorously proactive.
• 4. Environmental education of the community should begin in childhood, continue at school and other educational institutions, and last throughout life. Information on the conservation and management of inland waters is available from many sources, but a powerful, modern source is the World Wide Web.
• 5. Four case studies are discussed with particular reference to community participation: Lake Washington and Mono Lake in the US (successful outcomes), the Aral Sea in central Asia and Lake Pedder in Australia (unsuccessful outcomes).

Copyright © 2002 John Wiley & Sons, Ltd.     

Implementing ecosystem‐based management: evolution or revolution?

As a dominant paradigm, ecosystem‐based fisheries have to come to terms with uncertainty and complexity, an interdisciplinary visioning of management objectives, and putting humans back into the ecosystem. The goal of this article is to suggest that implementing ecosystem‐based management (EBM) has to be ‘revolutionary’ in the sense of going beyond conventional practices. It would require the use of multiple disciplines and multiple objectives, dealing with technically unresolvable management problems of complex adaptive systems and expanding scope from management to governance. Developing the governance toolbox would require expanding into new kinds of interaction unforeseen by the mid‐twentieth‐century fathers of fishery science – governance that may involve cooperative, multilevel management, partnerships, social learning and knowledge co‐production. In addition to incorporating relatively well‐known resilience, adaptive management and co‐management approaches, taking EBM to the next stage may include some of the following: conceptualizing EBM as a ‘wicked problem’; conceptualizing fisheries as social‐ecological systems; picking and choosing from an assortment of new governance approaches; and finding creative ways to handle complexity.     

Something old,something new: Historical perspectives provide lessons for blue growth agendas

The concept of “blue growth,” which aims to promote the growth of ocean economies while holistically managing marine socioecological systems, is emerging within national and international marine policy. The concept is often promoted as being novel; however, we show that historical analogies exist that can provide insights for contemporary planning and implementation of blue growth. Using a case‐study approach based on expert knowledge, we identified 20 historical fisheries or aquaculture examples from 13 countries, spanning the last 40–800 years, that we contend embody blue growth concepts. This is the first time, to our knowledge, that blue growth has been investigated across such broad spatial and temporal scales. The past societies managed to balance exploitation with equitable access, ecological integrity and/or economic growth for varying periods of time. Four main trajectories existed that led to the success or failure of blue growth. Success was linked to equitable rather than open access, innovation and management that was responsive, holistic and based on scientific knowledge and monitoring. The inability to achieve or maintain blue growth resulted from failures to address limits to industry growth and/or anticipate the impacts of adverse extrinsic events and drivers (e.g. changes in international markets, war), the prioritization of short‐term gains over long‐term sustainability, and loss of supporting systems. Fourteen cross‐cutting lessons and 10 recommendations were derived that can improve understanding and implementation of blue growth. Despite the contemporary literature broadly supporting our findings, these recommendations are not adequately addressed by agendas seeking to realize blue growth.     

Environmental determinants of fish community structure in gravel pit lakes

Gravel pit lakes are increasingly common, and there is an urgent need to better understand the functioning of these artificial and disconnected ecosystems. However, our knowledge of the environmental determinants of fish community structure within these types of lakes remains poor. In this study, we quantified the taxonomic diversity, fish species and life‐stage composition in 17 gravel pit lakes sampled in 2012 and 2013 located in south‐west France to determine the potential role of environmental variables (i.e. lake morphology, productivity, water quality and human‐use intensity) as drivers of fish community structure and composition. Our results demonstrated that fish community structure significantly differed between gravel pit lakes, and we notably found that lakes managed for angling hosted higher levels of taxonomic diversity. We also found that young and large lakes supported higher native species biomass and were dominated by native European perch (Perca fluviatilis). Older, smaller and more productive lakes, located closer to the main urban area, supported a higher biomass of non‐native species such as largemouth bass (Micropterus salmoides). Native and non‐native sport fishing species such as northern pike (Esox lucius), pikeperch (Sander lucioperca), common carp (Cyprinus carpio) and cyprinid prey species were positively associated with fishery management effort, suggesting that management practices play also a critical role in shaping fish species composition. Overall, our study demonstrated that fish community composition followed a predictable shift along environmental gradients associated with the maturation of gravel pit lakes and the associated human practices.     

Integrated management to address the incidental mortality of seabirds in longline fisheries

1. Of the myriad of anthropogenic and natural threats to seabirds, one of the most critical global problems is incidental mortality in longline fisheries. Hesitance or failure by fishery managers and longline industries to adequately address this acute problem could result in the extinction of several albatross and petrel species within our lifetimes. 2. An integrated management approach is needed to comprehensively manage longline fisheries to address seabird bycatch. A review of relevant multilateral accords, declarations and actions by regional and international organizations reveals the need to augment international collaboration, especially to address pirate longline fishing. Management authorities and stakeholders need to collaborate to: promote adoption and compliance with effective legally binding accords that cover the ranges of all affected seabirds; ensure that all Range States and relevant distant water fishing nations become contracting parties to these accords; coordinate national implementation of the Food and Agriculture Organization's International Plan of Action on seabirds; set management goals; establish and implement policies to employ seabird deterrent measures; disseminate information on new deterrent measures; locally tailor seabird deterrent measures; standardize data reporting and establish a centralized data repository; coordinate research and monitoring; develop regional surveillance and enforcement systems; and augment less developed countries' capacity and resources to mitigate seabird and longline fishery interactions. 3. Establishing protected areas containing seabird colonies and adjacent waters within a nation's Exclusive Economic Zone (EEZ) is potentially an expedient method to reduce interactions between seabirds and longline fisheries. However, establishing high seas marine protected areas to restrict longline fishing in seabird foraging areas, which would require extensive and dynamic boundaries and large buffer zones, may not be a viable short‐term solution due to the long time it is anticipated it could take to resolve legal complications with international treaties, to achieve international consensus and political will, and to acquire requisite extensive resources for surveillance and enforcement. High seas marine protected areas may eventually become a feasible mechanism to address seabird bycatch if nations develop the will to close ocean areas to commercial fisheries to attempt to rehabilitate depleted pelagic fish stocks. 4. Direct involvement of longline industries, through partnerships with national governments and regional organizations, to develop seabird mitigation measures and policies prescribing the use of these measures, is critical. Direct involvement of stakeholders to find solutions to resource management problems leads to stakeholder groups taking ownership of and supporting rules. Bottom‐up approaches are successful in changing interest groups' attitudes and behaviour, to maximize voluntary compliance and minimize conflict and resources required for enforcement. 5. Data gaps must be filled and scientific uncertainty addressed through multilateral collaboration. Research to develop and improve practicable mitigation measures is most urgently needed. Information on the status and trends of albatross populations, where albatrosses forage, the causes of population declines, seabird mortality rates and levels in each longline fishery, and the type of impacts from longlining on seabird populations is also needed. It is well documented that several seabird species are at risk of extinction, incidental bycatch in longline fisheries significantly contributes to many species' decline, and proven mitigation measures are available. Thus, while additional research is critically needed, we should not delay taking precautionary action to wait for additional information, but should immediately act to protect seabirds from the known acute threat of mortality in longline fisheries. Copyright © 2001 John Wiley & Sons, Ltd.     

以生态系统为基础的国际河流流域的管理制度

生态系统管理是指在对生态系统组成、结构和功能过程的最佳理解的基础上,在一定的时空尺度范围内将人类价值和社会经济条件整合到生态系统经营中,以恢复或维持生态系统的整体性和可持续性.在可持续理论的指导下,采用生态系统管理的方法对国际河流流域进行综合性的开发与管理是发展的必然趋势.因此,国际河流流域管理的理念与制度应向流域生态系统整体保护方向变革.在分析现代国际水法中有关综合性流域管理的法律制度缺失、关于国际水道生态系统保护与保全的规定又过于原则和不全面,严重制约和妨碍了国际河流流域的可持续发展的基础上,提出国际河流流域综合性管理,应以满足人类基本需要和保护生态系统为核心,不能将流域内的环境资源割裂开,应关注流域生态系统整体的保护,更要关注外界因素对流域生态环境的影响,把流域内有关的经济、社会问题也纳入流域管理范围.笔者认为,基于生态系统管理的国际河流流域管理制度的基本原则主要应包括:公平合理利用和不损害国外环境原则;可持续发展原则;整体性原则;预防原则;流域信息共享原则;对阈值进行识别与规定的原则;区域联合管理与国家管理相结合的原则.同时提出构建如下法律架构:行政综合决策制度;流域环境影响评价制度;流域水资源保护与分配制度;流域生态工业及循环经济产业制度;流域生态补偿制度;流域生态恢复与重建制度.     

Typology of landowners in Norwegian salmon angling: attitudes towards river owner organisations and management actions

Abstract Atlantic salmon, Salmo salar L., recreational fisheries in Norway are facing shorter seasons and harvest restrictions because of low adult migration runs. Private fishing‐right holders (landowners) are important stakeholders, being co‐managers of the stocks, owners of salmon habitat and suppliers of angling. Landowners saw measures addressing salmon farming and Gyrodactylus salaris (Malmberg) as the most important management actions to strengthen stocks and downplayed actions restricting their own activity or gain. The results showed a need to build knowledge and improve communication between landowners and river owner organisations about the effects of stocking, catch and release, and other management actions. Four distinct landowner types were identified, based on their objectives for the fishing right. The diversity in the landowner group suggests managing angling tourism will be challenging, and cooperation is required to manage salmon stocks. Policy instruments to facilitate cooperation are discussed for each landowner type.     

Science,capacity building and conservation knowledge: The empowerment of the local community for marine conservation in Rapa Nui

1. Marine protected areas have been scaling up from small areas located in coastal waters to large‐scale marine protected areas in remote areas, partly in response to the international agenda to conserve 10% of marine and coastal areas.
2. Chile has made considerable progress in the designation of large‐scale marine protected areas in its oceanic islands with varying degrees of top‐down and bottom‐up processes, scientific knowledge and interplay among institutions.
3. The process of designating the multiple‐uses marine protected area in Rapa Nui (Easter Island) involved interplay among scientific research, capacity building, local knowledge and collaboration between sectors, which contributed to the community transformation toward marine conservation in Rapa Nui.
4. A recent increase in scientific research on the marine ecosystems was transmitted to stakeholders and the local community via capacity‐building actions. The knowledge‐based empowerment of the Rapanui population (inhabitants of Rapa Nui) involved the definition not only of the objectives, the extension and the conservation goals of the Rapa Nui multiple‐uses marine protected area, but also of the implications beyond the designation, such as issues of governance, management and financing.
5. The implementation of the Rapa Nui multiple‐uses marine protected area will test local and Rapanui government relationships. The continuous science‐knowledge‐based dialogue in a strengthened relationship between the government and the local community in a ‘process of relating’ might be the pathway to future effective conservation efforts and successes.

     

Regional fisheries management organizations and the new biodiversity agreement: Challenge or opportunity?

In 2018, the international community began formal intergovernmental negotiations over a new legally binding instrument for the protection of marine biodiversity of areas beyond national jurisdiction. Protecting marine biodiversity is imperative for a sustainable future, and all the different organizations and agreements will have to work together to achieve this common goal. One of the first key principles to be agreed was to “not undermine” the existing legal instruments or mandates of regional and sectoral marine governance organizations. While fisheries are not being discussed during the negotiations, a marine biodiversity agreement is likely to still impact regional fisheries management organizations (RFMOs), due to overlapping areas of interest. This article aims to firstly, assess the potential constraints posed by the commitment to “not undermine”; secondly, consider how aspects of the biodiversity agreement, such as area‐based management and environmental impact assessments, might enhance RFMOs; and thirdly, suggest meaningful ways to ensure cooperation between RFMOs and the marine biodiversity agreement.     

Policy analysis for tropical marine reserves: challenges and directions

Marine reserves are considered to be a central tool for marine ecosystem‐based management in tropical inshore fisheries. The arguments supporting marine reserves are often based on both the nonmarket values of ecological amenities marine reserves provide and the pragmatic cost‐saving advantages relating to reserve monitoring and enforcement. Marine reserves are, however, only one of a suite of possible policy options that might be used to achieve conservation and fisheries management objectives, and have rarely been the focus of rigorous policy analyses that consider a full range of economic costs and benefits, including the transaction costs of management. If credible analyses are not undertaken, there is a danger that current enthusiasm for marine reserves may wane as economic performance fails to meet presumed potential. Fully accounting for the value of ecological services flowing from marine reserves requires consideration of increased size and abundance of focal species within reserve boundaries, emigration of target species from reserves to adjacent fishing grounds, changes in ecological resilience, and behavioural responses of fishers to spatially explicit closures. Expanding policy assessments beyond standard cost–benefit analysis (CBA) also requires considering the impact of social capital on the costs of managing fisheries. In the short term, the amount of social capital that communities possess and the capacity of the state to support the rights of individuals and communities will affect the relative efficiency of marine reserves. Reserves may be the most efficient policy option when both community and state capacity is high, but may not be when one and/or the other is weak. In the longer term, the level of social capital that a society possesses and the level of uncertainty in ecological and social systems will also impact the appropriate level of devolution or decentralization of fisheries governance. Determining the proper balance of the state and the community in tropical fisheries governance will require broad comparative studies of marine reserves and alternative policy tools.     

Real‐time spatial management approaches to reduce bycatch and discards: experiences from Europe and the United States

Spatial management measures are currently being used to manage bycatch and discards, given the spatial heterogeneity of fish distributions. However, permanent fishing closures are often poorly implemented, unresponsive to stock dynamics and do not achieve their management objectives. Recently, real‐time spatial management tools for managing bycatch and discards implemented under either a comanagement or self‐governance approach have been introduced in Europe and the US. Real‐time catch and discard information is shared among fishers to incentivise and encourage vessels to leave areas of high bycatch. Here, the similarities and differences, in governance, implementation and management of ten real‐time spatial management systems from across Europe and the US are reviewed. A framework is developed to characterize the attributes associated with voluntary, private and regulatory real‐time spatial management tools. Challenges and management practices in the different case studies are reviewed providing insights for designing these spatial management tools. The results illustrate that real‐time spatial management approaches can create incentives for fishers to develop, use and share information and technology to avoid undesired catch. Compared with Europe, the US has developed spatial management tools with more truly real‐time mechanisms and with greater involvement of the fishing industry in designing and operating the tools.     

The evolution of farm management,production efficiencies,and current challenges to catfish production in the United States

Abstract

The catfish industry is the most successful aquaculture business in the US. The development and growth of the catfish industry has resulted in complex fish farm businesses that require intensive management. Technological innovations have resulted in increased yields (land use efficiency). However, in more recent years, productivity gains have not kept pace with the rate of increase in input costs. Increasing intensification of catfish production over time has been accompanied by increased use of debt capital that results in higher levels of financial risk. While still a profitable activity, real profit margins have declined as financial risk has increased. New technologies will likely continue to increase productivity over time. Market‐oriented agribusiness approaches to catfish marketing are likely to become the norm. The challenge for the catfish industry is to coordinate adoption of new higher‐cost technologies with demand increasing market development to sustain farm price levels.     

Does MPA mean ‘Major Problem for Assessments'? Considering the consequences of place‐based management systems

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.     

Challenges to traditional management of connected ecosystems within a fractured regulatory landscape: A case study from southern New Zealand

1. Indigenous people often manage natural environments and resources based on landscape features. Rights and management responsibilities that follow pathways of water from their source in alpine areas down and ultimately into and out to sea are common. Contemporary frameworks that seek to support management of the environment, ecosystems and resources from marine areas to alpine zones are not so connected.
2. The East Otago Taiāpure and Waikouaiti Mātaitai are Customary Protection Areas (CPAs) that connect from fresh water into the marine environment. These CPAs fall within the cultural landscape of Kāti Huirapa ki Puketeraki, the hapū (sub‐tribe) of Ngāi Tahu, the iwi (tribe) who holds mana whenua (authority) over East Otago. CPAs may provide a way for iwi and hapū to manage a catchment as a whole, and to allow for traditional approaches to management within a contemporary legislative framework.
3. Despite local successes in restoring habitat, changing legislation, gaining knowledge and building community support for change, fundamental issues remain. Members of the East Otago Taiāpure Committee reflect on the last 15 years of management and identify constraints and enablers of community‐led management across inherently connected ecosystems using a kaupapa Māori approach. A compartmentalized view of connected ecosystems, complex legislation and government‐focused processes emerge as issues that make even seemingly simple issues complicated for community managers.
4. If locally led management models are to work, continuity of the relationships between government agencies and the community, an understanding of the long‐term and connected view of community groups, resourcing and support beyond the issue of the day, and clear pathways to affect change are key.
5. For true community‐led ecosystem management to be effective, we must focus on the needs and the perspectives of the community and move away from structures designed to ease the role of government in managing natural resources and the environment.

     

Integrating collaborative research in marine science: Recommendations from an evaluation of evolving science‐industry partnerships in Dutch demersal fisheries

The increasingly complex nature of marine resource management calls for stronger stakeholder participation in advancing knowledge and developing management approaches. Studies on stakeholder involvement in marine resource management have primarily focussed on participation in resource use negotiation and not on participation in science. Using fishers' knowledge research frameworks, we evaluate over 15 years of science‐industry research collaboration (SIRC) in Dutch demersal fisheries. Four key lessons emerge: (a) Capacity building in SIRC works multiple ways and triggers shifts in the fishers' knowledge research spectrum; (b) Successful SIRC depends on acceptance of industry collected data for scientific advice, which necessitates close involvement of end‐users from the outset to provide feedback and obtain support; (c) (Fisher) participation raises often‐overlooked equity questions and may result in selection bias; and (d) The governance context strongly influences structure of SIRC and integration of SIRC knowledge. To ensure a sustainable, continuous process of stakeholder participation and use of their knowledge in marine resources research, collaborative research should be embedded in the institutional frameworks for science and management. It demands continuous maintenance of the relationship between scientists and stakeholders in the context of management developments, calls for reflection about selection and equity considerations, and requires continuous attention for communication with all parties involved at different levels. The lessons learnt in science‐industry research collaboration in fisheries are also relevant for the wider field of marine science, where stakeholder participation is necessary but not yet common.     

Realizing the potential of trait‐based approaches to advance fisheries science

Analysing how fish populations and their ecological communities respond to perturbations such as fishing and environmental variation is crucial to fisheries science. Researchers often predict fish population dynamics using species‐level life‐history parameters that are treated as fixed over time, while ignoring the impact of intraspecific variation on ecosystem dynamics. However, there is increasing recognition of the need to include processes operating at ecosystem levels (changes in drivers of productivity) while also accounting for variation over space, time and among individuals. To address similar challenges, community ecologists studying plants, insects and other taxa increasingly measure phenotypic characteristics of individual animals that affect fitness or ecological function (termed “functional traits”). Here, we review the history of trait‐based methods in fish and other taxa, and argue that fisheries science could see benefits by integrating trait‐based approaches within existing fisheries analyses. We argue that measuring and modelling functional traits can improve estimates of population and community dynamics, and rapidly detect responses to fishing and environmental drivers. We support this claim using three concrete examples: how trait‐based approaches could account for time‐varying parameters in population models; improve fisheries management and harvest control rules; and inform size‐based models of marine communities. We then present a step‐by‐step primer for how trait‐based methods could be adapted to complement existing models and analyses in fisheries science. Finally, we call for the creation and expansion of publicly available trait databases to facilitate adapting trait‐based methods in fisheries science, to complement existing public databases of life‐history parameters for marine organisms.     

梁子湖与后官湖浮游细菌的群落结构特征

探究浮游细菌群落结构以及微生物与环境因子的相关性,可为湖泊环境评价和生态治理提供理论依据。选取湖北境内的梁子湖和后官湖,于2018年4月分别设置10个和5个采样点,进行浮游细菌与水体理化指标采样调查;通过16S rRNA基因高通量测序,分析比较浮游细菌群落结构及其多样性的差异,并通过冗余分析(RDA)探讨环境因子与浮游细菌群落结构的关系。结果表明,梁子湖和后官湖均有较高的浮游细菌群落多样性,其Shannon指数分别为3.974~4.743和3.924~4.500;梁子湖与后官湖的浮游细菌群落结构有所差异,梁子湖菌群隶属于放线菌门(Actinomycetes)、变形菌门(Proteobacteria)、拟杆菌门(Bacteroides)、蓝细菌门(Cyanobacteria)、疣微菌门(Verrucomicrobia)、绿菌门(Chlorobi)、绿弯菌门(Chloroflexi)、装甲菌门(Armatimonadetes)、厚壁菌门(Firmicutes)和硝化螺旋菌门(Nitrospirae);后官湖菌群隶属于放线菌门、蓝细菌门、变形菌门、拟杆菌门、疣微菌门、芽单胞菌门(Gemmatimonadetes)、绿弯菌门、绿菌门、浮霉菌门(Planctomycetes)、装甲菌门和螺旋体菌门(Saccharibacteria);其中,梁子湖的优势菌群为放线菌门(20.09%~43.23%)和变形菌门(21.35%~35.28%),而后官湖的优势菌群为放线菌门(20.70%~42.69%)和蓝细菌门(14.40%~45.77%)。RDA分析表明,总氮(TN)、pH、总磷(TP)是影响微生物群落结构的主要环境因子。     

The utility of simple fish community metrics for evaluating the relative influence of fishing vs. other environmental drivers on Caribbean reef fish communities

Fish community metrics have been extensively investigated as indicators of fishing effects for ecosystem‐based fisheries management (EBFM) in temperate systems. Little similar work has been performed in the coral reefs of the Caribbean, where simple indicators are urgently needed. Here, we use 415 coral reef surveys throughout the Caribbean to assess the potential of four simple and intuitive fish community metrics, namely, fish biomass, fish density, average fish weight and species richness, to separate fishing effects from those of other environmental factors at both local (tens of kilometres) and broad (hundreds to thousands of kilometres) spatial scales. We found that these fish metrics differed considerably in environmental correlates and the spatial scales underlying fish metric–environment associations. Average fish weight and fish biomass were most sensitive to fishing indices at both spatial scales, although average fish weight responded more sensitively and specifically to fishing than fish biomass. Fish density and species richness were most sensitive to temperature over broad scales and to macroalgae and relief height over local ones. All fish metrics were negatively correlated with macroalgae over broad scales, supporting the utility of macroalgae to inform about the integrity of entire reef ecosystems. Most of the fish metric variance associated with fishing pressure operated over broad scales, highlighting the need for a Caribbean‐wide view of fish community status to establish local management objectives and avoid shifting baselines. Our study clarifies the utility of simple fish community metrics as indicators of fishing effects for EBFM in the Caribbean.