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Nous nous trouvons à un carrefour critique pour la gouvernance future de la haute mer, mais l'éloignement perçu de l'océan mondial crée un obstacle psychologique pour que les gens s'y engagent. Compte tenu des défis de la surexploitation, de l'accès inéquitable et d'autres préoccupations en matière de durabilité et d'équité, les mécanismes actuels de gouvernance des océans ne sont pas adaptés à leur objectif. Cette décennie offre des opportunités d'impact direct sur la gouvernance des océans, cependant, déclencher une transformation mondiale sur la façon dont nous utilisons et protégeons la moitié de notre planète nécessite un effort concerté guidé par des valeurs et des principes partagés entre les régions et les secteurs. L'objectif de la série d'ateliers décrits dans ce document était d'entreprendre un processus de réflexion sur l'avenir qui pourrait utiliser le cadre Nature Futures comme un mécanisme pour apporter plus d'énergie transformatrice dans la façon dont les humains conceptualisent la haute mer et donc comment nous visons à gouverner l'océan. Nous avons constaté que l'engagement avec l'avenir à travers des récits de science-fiction permettait une appréciation plus radicale de ce qui pourrait être et que l'infusion d'éléments artistiques dans la science peut inspirer un public au-delà du milieu universitaire. Ainsi, les efforts créatifs de coproduction qui favorisent et encouragent l'imagination pour relever les défis actuels devraient être considérés comme des outils importants dans l'interface science-politique, également comme un moyen de susciter des réponses empathiques. Cette série d'ateliers était une première étape, et, espérons-le, prometteuse, vers la génération d'une pratique plus créative dans la façon dont nous imaginons et agissons pour un avenir meilleur pour la haute mer. Nos encontramos en una encrucijada crítica para la futura gobernanza de la alta mar, pero la lejanía percibida del océano global crea una barrera psicológica para que las personas se involucren con él. Dados los desafíos de la sobreexplotación, el acceso inequitativo y otras preocupaciones de sostenibilidad y equidad, los mecanismos actuales de gobernanza de los océanos no son adecuados para su propósito. Esta década ofrece oportunidades para un impacto directo en la gobernanza de los océanos, sin embargo, desencadenar una transformación global sobre cómo usamos y protegemos la mitad de nuestro planeta requiere un esfuerzo concertado que se guíe por valores y principios compartidos en todas las regiones y sectores. El objetivo de la serie de talleres descritos en este documento era emprender un proceso de pensamiento sobre el futuro que pudiera utilizar el Marco de Futuros de la Naturaleza como un mecanismo para aportar más energía transformadora a la forma en que los humanos conceptualizan la alta mar y, por lo tanto, cómo pretendemos gobernar el océano. Descubrimos que comprometerse con el futuro a través de narrativas de ciencia ficción permitía una apreciación más radical de lo que podría ser e infundir a la ciencia elementos artísticos puede inspirar a audiencias más allá de la academia. Por lo tanto, los esfuerzos creativos de coproducción que promueven y fomentan la imaginación para abordar los desafíos actuales deben considerarse como herramientas importantes en la interfaz ciencia-política, también como una forma de obtener respuestas empáticas. Esta serie de talleres fue un primer paso, y esperemos que prometedor, hacia la generación de una praxis más creativa en la forma en que imaginamos y luego actuamos para un futuro mejor para la alta mar. We find ourselves at a critical crossroads for the future governance of the high seas, but the perceived remoteness of the global ocean creates a psychological barrier for people to engage with it. Given challenges of overexploitation, inequitable access and other sustainability and equity concerns, current ocean governance mechanisms are not fit-for-purpose. This decade offers opportunities for direct impact on ocean governance, however, triggering a global transformation on how we use and protect the half of our planet requires a concerted effort that is guided by shared values and principles across regions and sectors. The aim of the series of workshops outlined in this paper, was to undertake a futures thinking process that could use the Nature Futures Framework as a mechanism to bring more transformative energy into how humans conceptualise the high seas and therefore how we aim to govern the ocean. We found that engaging with the future through science fiction narratives allowed a more radical appreciation of what could be and infusing science with artistic elements can inspire audiences beyond academia. Thus, creative endeavours of co-production that promote and encourage imagination to address current challenges should be considered as important tools in the science-policy interface, also as a way to elicit empathetic responses. This workshop series was a first, and hopefully promising, step towards generating a more creative praxis in how we imagine and then act for a better future for the high seas. نجد أنفسنا في مفترق طرق حاسم للإدارة المستقبلية لأعالي البحار، لكن البعد المتصور للمحيط العالمي يخلق حاجزًا نفسيًا أمام الناس للتعامل معه. بالنظر إلى تحديات الاستغلال المفرط والوصول غير العادل وغيرها من شواغل الاستدامة والإنصاف، فإن آليات إدارة المحيطات الحالية ليست مناسبة للغرض. يوفر هذا العقد فرصًا للتأثير المباشر على إدارة المحيطات، ومع ذلك، فإن إحداث تحول عالمي حول كيفية استخدامنا لنصف كوكبنا وحمايته يتطلب جهدًا متضافرًا يسترشد بالقيم والمبادئ المشتركة عبر المناطق والقطاعات. كان الهدف من سلسلة ورش العمل الموضحة في هذه الورقة هو إجراء عملية تفكير مستقبلي يمكن أن تستخدم إطار عمل مستقبل الطبيعة كآلية لجلب المزيد من الطاقة التحويلية إلى كيفية تصور البشر لأعالي البحار وبالتالي كيف نهدف إلى حكم المحيط. وجدنا أن الانخراط في المستقبل من خلال روايات الخيال العلمي سمح بتقدير أكثر جذرية لما يمكن أن يكون وغرس العلم بالعناصر الفنية يمكن أن يلهم الجماهير خارج الأوساط الأكاديمية. وبالتالي، يجب اعتبار المساعي الإبداعية للإنتاج المشترك التي تعزز وتشجع الخيال لمواجهة التحديات الحالية أدوات مهمة في واجهة العلوم والسياسات، وأيضًا كوسيلة لاستنباط استجابات متعاطفة. كانت سلسلة ورش العمل هذه خطوة أولى، ونأمل أن تكون واعدة، نحو توليد ممارسة أكثر إبداعًا في كيفية تخيلنا ثم العمل من أجل مستقبل أفضل لأعالي البحار.

One-third of maximum fish biomass must be available for seabirds to sustain high breeding success.

The world's eastern boundary upwelling systems (EBUSs) contribute disproportionately to global ocean productivity and provide critical ecosystem services to human society. The impact of climate change on EBUSs and the ecosystems they support is thus a subject of considerable interest. Here, we review hypotheses of climate-driven change in the physics, biogeochemistry, and ecology of EBUSs; describe observed changes over recent decades; and present projected changes over the twenty-first century. Similarities in historical and projected change among EBUSs include a trend toward upwelling intensification in poleward regions, mitigatedwarming in near-coastal regions where upwelling intensifies, and enhanced water-column stratification and a shoaling mixed layer. However, there remains significant uncertainty in how EBUSs will evolve with climate change, particularly in how the sometimes competing changes in upwelling intensity, source-water chemistry, and stratification will affect productivity and ecosystem structure. We summarize the commonalities and differences in historical and projected change in EBUSs and conclude with an assessment of key remaining uncertainties and questions. Future studies will need to address these questions to better understand, project, and adapt to climate-driven changes in EBUSs.

The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N2P2Z2D2-OSMOSE). Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects of fishing and environmental variability.

Several commercially and ecologically important species in the southern Benguela have undergone southward and eastward shifts in their distributions over previous decades, most notably the small pelagic fish sardine Sardinops sagax and anchovy Engraulis encrasicolus. Understanding these changes and their implications is essential in implementing an ecosystem approach to fisheries in the southern Benguela and attempting to appreciate the potential impacts of future environmental change. To investigate possible impacts of these shifts at an ecosystem level, distribution maps for before (1985-1991), during (1997-2000) and after (2003-2008) the shift in small pelagic fish were constructed for 14 key species from catch and survey data, and used to calculate spatial indicators including proportion east and west of Cape Agulhas, relative overlap in biomass and area, index of diversity, connectivity. Potential interactions on the south and west coasts were also compared. For several species (redeye; chub mackerel; kingklip; chokka squid; yellowtail), previously unidentified increases in the proportion of biomass east of Cape Agulhas were shown to have occurred over the same period as that of small pelagic fish, although none to the same degree. On average, overlap with small pelagic fish increased over time and overall system connectivity was lowest in the intermediate period, possibly indicating a system under transition. Connectivity declined over time on the west coast while increasing on the east coast. Distributions of other species have changed over time, with the region east of Cape Agulhas becoming increasingly important in terms of potential trophic interaction. Variations in distribution of biomass and structural complexity affect the trophic structure and hence functioning of the system, and implications should be considered when attempting to identify the possible ecosystem impacts of current and future system-level change.

High harvest levels of low–trophic level fishes may have cascading marine ecosystem effects.