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L'aquaculture joue un rôle important dans la sécurité alimentaire et fournit des moyens de subsistance et des emplois à des millions de personnes dans les communautés côtières du monde entier. Cependant, le secteur aquacole en pleine croissance a également suscité des débats sur sa durabilité écologique à long terme, sa viabilité économique, les inégalités sociales potentielles et les problèmes de gouvernance. Nous avons étudié les défis et les opportunités perçus pour parvenir à une aquaculture durable du crabe de boue dans les régions côtières tropicales en utilisant l'étude de cas des fermes côtières de crabe de boue dans l'Andhra Pradesh, en Inde. Sur la base des perceptions et des données financières indicatives d'un échantillon de parties prenantes, nous avons étudié les résultats économiques potentiels dans différents scénarios représentant des niveaux de rendement, des facteurs de risque et des périodes de projet variables. Les principaux risques identifiés par les parties prenantes étaient associés à l'approvisionnement limité en graines de crabe de boue et au manque d'accès aux programmes de soutien gouvernementaux et non gouvernementaux. Il n'y a pas de tampons financiers, donc des épidémies majeures ou des conditions météorologiques extrêmes causées par le changement climatique entraîneraient une perte de moyens de subsistance. Cet article met également en évidence le facteur le plus critique déterminant le niveau de succès de l'élevage du crabe de boue étant le taux de survie du crabe qui est influencé par une variété de facteurs, y compris l'augmentation de la température de la surface de la mer. Les résultats de cette étude montrent que l'élevage de crabes de boue à petite échelle comporte moins de risques et une plus grande flexibilité que l'élevage de crabes de boue à grande échelle. Il pourrait s'agir d'une entreprise économiquement durable et servir d'outil de réduction de la pauvreté dans les pays en développement si un soutien et une formation en matière de microfinance sont disponibles. La acuicultura desempeña un papel importante en la seguridad alimentaria y proporciona medios de subsistencia y empleo a millones de personas en las comunidades costeras de todo el mundo. Sin embargo, el creciente sector de la acuicultura también ha creado debates en torno a su sostenibilidad ecológica a largo plazo, viabilidad económica, posibles desigualdades sociales y problemas de gobernanza. Investigamos los desafíos y oportunidades percibidos para lograr una acuicultura sostenible de cangrejo de fango en las regiones costeras tropicales utilizando el estudio de caso de las granjas costeras de cangrejo de fango en Andhra Pradesh, India. Con base en las percepciones y los datos financieros indicativos de una muestra de partes interesadas, investigamos los posibles resultados económicos en diferentes escenarios que representan diferentes niveles de rendimiento, factores de riesgo y períodos de tiempo del proyecto. Los principales riesgos identificados por las partes interesadas se asociaron con el suministro limitado de semillas de cangrejo de fango y la falta de acceso a esquemas de apoyo gubernamentales y no gubernamentales. No hay amortiguadores financieros, por lo tanto, los grandes brotes de enfermedades o las condiciones climáticas extremas causadas por el cambio climático conducirían a la pérdida de los medios de vida. Este documento también destaca que el factor más crítico que determina el nivel de éxito del cultivo de cangrejo de fango es la tasa de supervivencia del cangrejo, que está influenciada por una variedad de factores, incluido el aumento de la temperatura de la superficie del mar. Los resultados de este estudio muestran que el cultivo de cangrejo de fango a pequeña escala tiene menos riesgos y una mayor flexibilidad que el cultivo de cangrejo de fango a gran escala. Podría ser una empresa económicamente sostenible y servir como una herramienta para el alivio de la pobreza en los países en desarrollo si se dispone de apoyo y capacitación en microfinanzas. Aquaculture plays a significant role in food security and provides livelihoods and employment for millions of people among coastal communities worldwide. However, the growing aquaculture sector has also created debates around its long-term ecological sustainability, economic viability, potential social inequalities and governance issues. We investigated the perceived challenges and opportunities to achieving sustainable mud crab aquaculture in tropical coastal regions by using the case study of coastal mud crab farms in Andhra Pradesh, India. Informed by perceptions and indicative financial data from a sample of stakeholders we investigated the potential economic outcomes under different scenarios representing varying yield levels, risk factors and project time periods. The main risks identified by the stakeholders were associated with the limited supply of mud crab seeds and the lack of access to governmental and non-governmental support schemes. There are no financial buffers, therefore major disease outbreaks or extreme weather conditions caused by climate change would lead to a loss of livelihoods. This paper also highlights the most critical factor determining the level of success of mud crab farming being the crab survival rate which is influenced by a variety of factors including increasing sea surface temperature. The results of this study show that small-scale mud crab farming has fewer risks and higher flexibility involved than large-scale mud crab farming. It could be an economically sustainable enterprise and serve as a tool for poverty alleviation in developing countries if microfinance support and training are available. تلعب تربية الأحياء المائية دورًا مهمًا في الأمن الغذائي وتوفر سبل العيش وفرص العمل لملايين الأشخاص بين المجتمعات الساحلية في جميع أنحاء العالم. ومع ذلك، فإن قطاع تربية الأحياء المائية المتنامي قد خلق أيضًا مناقشات حول استدامته البيئية طويلة الأجل، وقابليته الاقتصادية، وعدم المساواة الاجتماعية المحتملة، وقضايا الحوكمة. لقد حققنا في التحديات والفرص المتصورة لتحقيق تربية مستدامة لسرطان البحر الطيني في المناطق الساحلية الاستوائية باستخدام دراسة حالة لمزارع سرطان البحر الطيني الساحلية في ولاية أندرا براديش، الهند. استنادًا إلى التصورات والبيانات المالية الإرشادية من عينة من أصحاب المصلحة، قمنا بالتحقيق في النتائج الاقتصادية المحتملة في ظل سيناريوهات مختلفة تمثل مستويات عائد متفاوتة وعوامل خطر وفترات زمنية للمشروع. ارتبطت المخاطر الرئيسية التي حددها أصحاب المصلحة بمحدودية المعروض من بذور سرطان البحر الطيني وعدم الوصول إلى خطط الدعم الحكومية وغير الحكومية. لا توجد حواجز مالية، وبالتالي فإن تفشي الأمراض الرئيسية أو الظروف الجوية القاسية الناجمة عن تغير المناخ ستؤدي إلى فقدان سبل العيش. تسلط هذه الورقة الضوء أيضًا على العامل الأكثر أهمية الذي يحدد مستوى نجاح زراعة سرطان البحر الطيني وهو معدل بقاء سرطان البحر الذي يتأثر بمجموعة متنوعة من العوامل بما في ذلك زيادة درجة حرارة سطح البحر. تظهر نتائج هذه الدراسة أن زراعة سرطان البحر الطيني على نطاق صغير تنطوي على مخاطر أقل ومرونة أعلى من زراعة سرطان البحر الطيني على نطاق واسع. يمكن أن يكون مشروعًا مستدامًا اقتصاديًا وأن يكون بمثابة أداة للتخفيف من حدة الفقر في البلدان النامية إذا توفر الدعم والتدريب في مجال التمويل الأصغر.

Integrated Multi-Trophic Aquaculture takes advantage of the mutualism between some detritivorous fish and phytoplankton. The fish recycle nutrients by consuming live (and dead) algae and provide the inorganic carbon to fuel the growth of live algae. In the meanwhile, algae purify the water and generate the oxygen required by fishes. Such mechanism stabilizes the functioning of an artificially recycling ecosystem, as exemplified by combining the euryhaline tilapia Sarotherodon melanotheron heudelotii and the unicellular alga Chlorella sp. Feed addition in this ecosystem results in faster fish growth but also in an increase in phytoplankton biomass, which must be limited. In the prototype described here, the algal population control is exerted by herbivorous zooplankton growing in a separate pond connected in parallel to the fish-algae ecosystem. The zooplankton production is then consumed by tilapia, particularly by the fry and juveniles, when water is returned to the main circuit. Chlorella sp. and Brachionus plicatilis are two planktonic species that have spontaneously colonized the brackish water of the prototype, which was set-up in Senegal along the Atlantic Ocean shoreline. In our system, water was entirely recycled and only evaporation was compensated (1.5% volume/day). Sediment, which accumulated in the zooplankton pond, was the only trophic cul-de-sac. The system was temporarily destabilized following an accidental rotifer invasion in the main circuit. This caused Chlorella disappearance and replacement by opportunist algae, not consumed by Brachionus. Following the entire consumption of the Brachionus population by tilapias, Chlorella predominated again. Our artificial ecosystem combining S. m. heudelotii, Chlorella and B. plicatilis thus appeared to be resilient. This farming system was operated over one year with a fish productivity of 1.85 kg/m2 per year during the cold season (January to April).

Poster presented during the H2020 "MUSES" project stakeholder workshop ’Embracing opportunities – Ocean Multi-Use Action Plan development workshop’ (Venice - June 27th, 2018). The poster analyses the potential for development of Multi-Use in the Northern-Adriatic coastal waters by combining existing and innovative touristic services with other traditional economic sectors and assets on the area. Drivers, added values, barriers, and impacts of Multi-Use have been identified integrating desk analysis and stakeholders perception. The results show the existence of a good potential for Multi-Use development and Blue-Growth in the area, still limited by barriers, particularly in the field of legislation, administrative processes and stakeholders capacity. Needed actions at local and regional (sub-national) level are highlighted in order to exploit this potential.

The aims of this work are to provide an overview of the current stresses of estuaries in Argentina and to propose adaptation strategies from an ecohydrological approach. Several Argentinian estuaries are impacted by pollutants, derived mainly from sewage discharge and agricultural or industrial activities. Anthropogenic impacts are expected to rise with increasing human population. Climate-driven warmer temperature and hydrological changes will alter stratification, residence time, oxygen content, salinity, pollutant distribution, organism physiology and ecology, and nutrient dynamics. Good water quality is essential in enhancing estuarine ecological resilience to disturbances brought on by global change. The preservation, restoration, and creation of wetlands will help to protect the coast from erosion, increase sediment accretion rates, and improve water quality by removing excess nutrients and pollutants. The capacity of hydrologic basin ecosystems to absorb human and natural impacts can be improved through holistic management, which should consider social vulnerability in complex human-natural systems.

AbstractThis paper assesses how parameter uncertainties in the model for rise velocity of CO2 droplets in the ocean cause uncertainties in their rise and dissolution in marine waters. The parameter uncertainties in the rise velocity for both hydrate coated and hydrate free droplets are estimated from experiment data. Thereafter the rise velocity is coupled with a mass transfer model to simulate the fate of dissolution of a single droplet.The assessment shows that parameter uncertainties are highest for large droplets. However, it is also shown that in some circumstances varying the temperature gives significant change in rise distance of droplets.

The effects of climate change (CC) on contaminants and their potential consequences to marine ecosystem services and human wellbeing are of paramount importance, as they pose overlapping risks. Here, we discuss how the interaction between CC and contaminants leads to poorly constrained impacts that affects the sensitivity of organisms to contamination leading to impaired ecosystem function, services and risk assessment evaluations. Climate drivers, such as ocean warming, ocean deoxygenation, changes in circulation, ocean acidification, and extreme events interact with trace metals, organic pollutants, excess nutrients, and radionuclides in a complex manner. Overall, the holistic consideration of the pollutants-climate change nexus has significant knowledge gaps, but will be important in understanding the fate, transport, speciation, bioavailability, toxicity, and inventories of contaminants. Greater focus on these uncertainties would facilitate improved predictions of future changes in the global biogeochemical cycling of contaminants and both human health and marine ecosystems.

BACKGROUND There is ample evidence for human alteration of Europe’s regional seas, particularly the enclosed or partly enclosed Baltic, Black, Mediterranean, and North Seas. Accounts of habitat and biodiversity loss, pollution, and the decline of fish stocks in these economically, socially, and ecologically important seas demonstrate unsustainable use of the marine environment. At the same time, there is an insufficient quantity and quality of information to enable purely evidence-based management of Europe’s seas despite this being a declared goal of many decisionmakers; for example, less than 10% of the deep sea has been systematically explored (UNEP 2006). Evidence-based management alone is rarely possible in situations with complex value-laden policy options (Greenhalgh and Russell 2009), and unfortunately, many of the most pervasive problems in the marine environment are “wicked” second-order problems (Jentoft and Chuenpagdee 2009): they are complex in nature and their management will often involve both winners and losers. Solutions to these problems involve less politically attractive, valuebased choices and may require long time lags before tangible results are observed. Fisheries management, habitat and species protection, competition for marine space, and invasive species are all examples of “wicked” problems. These are some of the biggest issues facing Europe’s seas and are the major focus of this article and Special Feature. For the first time in European history, most countries have adopted a common maritime policy (the 2007 Integrated Maritime Policy) and a legally binding environmental directive (the 2008 Marine Strategy Framework Directive [MSFD]). These comprehensive policy vehicles encompass, or closely interface with, more specific measures, such as the recently reformed Common Fisheries Policy, the Water Framework Directive, the Habitats and Birds Directive, and a number of targeted policy instruments that deal with aspects of pollution control and coastal zone management. The overall array of measures has the potential to ensure the sustainable use of Europe’s seas and the restoration of marine environments, but the pathway between the current situation and the implementation of an ecosystem approach to management (the aspiration of the European Commission; see Our Approach to Research) is fraught with “wicked” problems. Science can help society resolve these problems, but in many cases this requires the broad and integrative vision of Odum’s (1971) “macroscope” rather than trying to piece together an ill-fitting jigsaw puzzle of discipline-focused information. This paper and the others in this Special Feature employ a systems approach. We describe the approach, how it can be applied practically, and some of the challenges in making it work. Though the work is based on research on Europe’s seas, it has much wider implications for regional seas throughout the world. OUR APPROACH TO RESEARCH ON MARINE SOCIALECOLOGICAL SYSTEMS The research described in this paper (and Special Feature) was conducted in the framework of the EU-FP7 funded project Knowledge-based Sustainable Management of Europe’s Seas (KnowSeas). The interdisciplinary research spanned 4 years and involved 33 institutions from 16 European countries (KnowSeas 2013). Its primary objective was to develop “a comprehensive scientific knowledge base and practical guidance for the application of the ecosystem approach to the sustainable development of Europe’s regional seas.” Given the knowledge gaps and uncertainties in the way Europe’s marine social-ecological systems function (e.g., unresolved causal links, poorly mapped habitats, nonlinear dynamics), an iterative approach to inquiry was adopted, based partly on the reasoning behind soft systems analysis (e.g., Checkland 2000).