A Call for Cooperation in the Southwest Atlantic Ocean

The Southwest Atlantic Ocean is one of the most productive and ecologically important marine regions on the planet. Stretching from northern Brazil to the southern tip of South America, the region hosts a remarkable combination of ocean currents, ecosystems, and species that support both global biodiversity and major fisheries. Yet despite its immense importance, the region remains one of the few large ocean areas without a coordinated system for managing its shared marine resources. A new international study, led by researchers at UBC’s Institute for the Oceans and Fisheries (IOF), calls for stronger cooperation among countries in the region to ensure the long-term sustainability of its ecosystems and fisheries particularly under climate change.

Covering more than 17 million square kilometres and including diverse habitats ranging from tropical waters in northern Brazil to colder subantarctic environments of the Argentinean Patagonia, the Southwest Atlantic Ocean supports complex marine ecosystems that provide spawning grounds, feeding habitats, and migratory routes for a wide range of species including fish, sharks, squid, and marine mammals, such as whales. The region’s productivity is driven by powerful ocean currents like the Brazil Current and the Malvinas Current, which mixes warm and cold waters and create nutrient-rich conditions that sustain marine life. As a result, the area has become one of the world’s most important fishing grounds. However, changes in wind patterns are leading to significant changes in ocean circulation, temperature distribution, and vertical stratification, all of which have a profound impact on species distributions.

The economic importance of these fisheries is enormous. Fisheries in the Southwest Atlantic employ nearly 900,000 people and produce around two million tonnes of catch each year, valued at approximately five billion dollars. These fisheries support coastal economies across Brazil, Uruguay, Argentina, and other neighbouring regions, providing jobs, food security, and export revenue. However, the ocean does not recognize national borders, and many of the species that sustain these fisheries migrate across multiple jurisdictions throughout their life cycles. Fish, shrimp, and squid stocks often move seasonally between different parts of the region and the local high seas, linking ecosystems and economies.

Because of this connectivity, effective management of marine resources requires cooperation between countries. However, despite bilateral agreements and various scientific collaborations, there is still no dedicated regional body responsible for coordinating fisheries and ocean governance across the entire Southwest Atlantic. “The Southwest Atlantic Ocean is a region of incredible ecological and economic importance, yet it lacks a comprehensive governance framework that brings countries together to manage shared resources,” said Dr. Juliano Palacios-Abrantes, postdoctoral fellow at IOF and lead author.

This lack of coordination is increasingly problematic as environmental pressures intensify. Over the past four decades, sea surface temperatures have risen significantly in much of the Southwest Atlantic, altering ocean circulation patterns and affecting the distribution of marine species. Some species are shifting their ranges southward or moving into deeper waters in search of suitable ocean temperature conditions. This has altered fisheries catches, created competition between fleets, and complicated management strategies that were designed for more stable ecosystems. “The main challenge is no longer simply to understand ecological connectivity in the Southwest Atlantic, but to translate that knowledge into workable cooperation. From Argentina’s perspective, stronger regional dialogue will be increasingly important for managing shared fisheries under climate change,” said Dr. Facundo Llompart, co-author of the study and a researcher at CONICET’s Austral Center for Scientific Research in Argentina.

“Climate change is fundamentally altering the ocean,” said Brazil-based researcher Dr. Palacios-Abrantes. “Species are moving, ecosystems are shifting, and fisheries are changing as a result. These changes are happening across borders, which means countries must work together to respond effectively.”

Another growing concern in the region is the presence of distant-water fishing fleets operating near the edges of national jurisdictions. These fleets often target valuable species, such as squid and tuna, and compete directly with local fishing industries. In some cases, vessels exploit regulatory gaps or operate in areas where enforcement is limited. Illegal, unreported, and unregulated fishing further complicates management efforts, allowing vessels to move between jurisdictions and evade oversight. These challenges highlight the need for stronger regional cooperation to ensure that fisheries remain sustainable and equitable.

Effective ocean management also depends on reliable data, yet large gaps remain in scientific knowledge about the region’s ecosystems and fisheries. Small-scale fisheries, which play a crucial role in coastal livelihoods across Latin America, are often poorly documented. In Brazil, for example, national fisheries monitoring programs have experienced disruptions over the past decade, leaving researchers and policymakers with limited information about catch levels and stock conditions. These data gaps make it harder to track changes in marine ecosystems and design effective conservation measures.

To address these challenges, the researchers emphasize the importance of what they call ocean science diplomacy. This approach encourages collaboration between scientists, governments, and institutions across national borders in order to generate shared knowledge and support cooperative decision-making. By developing joint monitoring programs, harmonizing data collection methods, and sharing scientific findings, countries can build trust and improve their ability to manage shared resources. “The Southwest Atlantic region already has a strong technical and scientific capacity, as well as a long-standing tradition of collaboration among researchers. However, the absence of binding regional cooperation mechanisms limits the ability to translate this knowledge into effective management of shared stocks. Advancing in this direction is less a question of capacity and more one of governance”, said one of the authors, Luís Gustavo Cardoso, Professor at the Universidade Federal do Rio Grande and Vice-Chair of the ICCAT Standing Committee on Research and Statistics.

The timing may also be favourable for advancing new governance initiatives. Brazil is set to host several major international environmental meetings in the coming years, including global climate and ocean conferences that will bring international attention to marine sustainability. These events create opportunities for countries in the region to strengthen cooperation and develop new strategies for managing fisheries and protecting biodiversity.

“The ocean connects our countries, ecosystems, and communities,” Palacios-Abrantes said. “If we want to safeguard the future of the Southwest Atlantic, cooperation will be essential. The challenges we face are shared, and the solutions must be shared as well.”

Integrated ocean governance is needed in the Southwest Atlantic Ocean to foster fisheries, conservation and resilience to climate change, was published in Discover Ocean, and authored by Juliano Palacios-Abrantes and an international team of researchers from institutions across Argentina, Brazil, and Uruguay.

Tags: Argentina, Atlantic, Brazil, climate change, CORU, ecosystems, fish, fish catch, fisheries economics, fisheries management, fishing fleets, industrial fishing, IOF postdoctoral fellows, Juliano Palacios-Abrantes, marine ecosystems, regional governance, shrimp, small-scale fisheries, South America, Southwest Atlantic Ocean, squid, temperatures, Uruguay, whales