The oceanographic machinery behind the region’s productivity is extraordinary. Powerful western boundary currents, including the North Brazil Current, the Brazil Current and the Malvinas Current, drive intense mixing between subtropical and subantarctic water masses. Frontal zones, eddies, upwelling cells and massive river discharges combine to fertilize shelf ecosystems that rank among the most productive marine regions worldwide. This physical complexity carves the coast into distinct biogeographic provinces and ecoregions with high endemism, sustaining biodiversity hotspots, migratory corridors and critical habitats for fish, sharks, cephalopods and marine mammals such as southern and humpback whales and orcas. Spawning grounds, nurseries and feeding areas are distributed across and beyond national jurisdictions, meaning that no single country can manage the system in isolation.

The economic stakes are enormous. Designated by the Food and Agriculture Organization of the United Nations as Major Fishing Area 41, the Southwest Atlantic hosts more than 32,000 artisanal and industrial vessels employing 896,000 people. In 2021, catches in these multispecies fisheries were estimated at 2 million tonnes with a landed value of roughly 5 billion dollars. Along northern Brazil, continental shelf waters support small-scale multispecies fisheries, often with limited statistical reporting, while further south industrial fleets from Brazil, Uruguay and Argentina target shared stocks of high commercial value. Seasonal connectivity is striking: in winter, fish, shrimp and squid stocks move northward from the Patagonian and Uruguayan shelves onto the southern Brazilian shelf, where they form a substantial component of the national fishing industry. The result is a catch composition dominated by transboundary and straddling stocks that ignore maritime boundaries drawn by treaty.

On paper, the region’s nations are committed collaborators. Brazil, Uruguay and Argentina are signatories of the United Nations Convention on the Law of the Sea, the Convention on Biological Diversity and the new BBNJ Agreement on marine biological diversity in areas beyond national jurisdiction, which Brazil and Uruguay have ratified. All three cooperate within the International Commission for the Conservation of Atlantic Tunas and belong to the Zone of Peace and Cooperation of the South Atlantic. Yet the record of integrated regional management is thin. The most ambitious experiment, the FAO-established Regional Advisory Fisheries Commission known as CARPAS, coordinated fishery statistics, biological research and stock assessments from 1962 until its abolition in 1997. Its successor in spirit, the bilateral Comisión Técnica Mixta del Frente Marítimo, manages the shared Argentine-Uruguayan fishing zone and is recognized by FAO as the only regional fisheries body in the Southwest Atlantic, leaving Brazil largely outside formal regional arrangements since CARPAS dissolved.

The governance vacuum is most visible in the fight against illegal, unreported and unregulated fishing. The Port State Measures Agreement, a key instrument designed to keep vessels engaged in illegal fishing from landing their catches, has so far been ratified only by Uruguay in the region. Because the three countries share borders, vessels can simply divert to ports in non-member states or opportunistically reflag to domestic registries, a practice known as flag domestication. Between 2016 and 2021, port visits by vessels that reflagged to a domestic flag increased by roughly 27 percent in Brazil and 57 percent in Uruguay. Meanwhile, distant-water fleets from Asia and Europe, armed with state-of-the-art technology and subsidized by their home states, compete unequally with domestic industrial and small-scale fleets for squid, tuna and other valuable resources, exploiting institutional gaps on the high seas at the margins of national jurisdictions.

Geopolitics compounds the problem. The sovereignty dispute between Argentina and the United Kingdom over the Islas Malvinas/Falkland Islands, South Georgia and the South Sandwich Islands and their surrounding maritime areas remains a central obstacle, intensified by the potential exploitation of shared marine resources. More than 42 coastal small-scale fisheries operate along the Patagonian coast of Argentina, most managed independently with little joint research or coordinated, inclusive management. South of 45°S, valuable transboundary stocks such as the southern king crab and stone crab fishery in the Beagle Channel are shared between Argentina and Chile but managed unilaterally, and the South Atlantic Fisheries Commission, which once delivered joint measures, has been suspended since 2020. The authors note that diplomacy from Brazil, Uruguay and Argentina has resisted creating a Regional Fisheries Management Organization, partly out of concern that multilateral regulation could hand a legal foothold to extra-regional actors and dilute national sovereignty over strategic fish stocks.

Data deficits make every one of these challenges harder. Sharks of conservation concern have limited observational coverage, reef fish assemblage structure is understood only in specific sub-regions, deep-sea ecosystems remain virtually unexplored by visual surveys, and fisheries statistics are chronically incomplete, particularly for small-scale fleets across Latin America and the Caribbean. Brazil’s experience is emblematic: from 1990 to 2007 the national environmental institute IBAMA coordinated broad fisheries statistics, but successive institutional reforms disrupted data compilation, producing a near-complete national halt. No sustained national program has been restored, leaving the North and Northeast, where small-scale catches surpass industrial ones and underpin local food security, severely under-monitored. Without systematic monitoring, the status of shared stocks such as seabob shrimp and acoupa weakfish on the Brazil-Guianas shelf remains poorly resolved, impeding any coordinated, climate-ready management.

Climate change is now amplifying every existing pressure. Most of the region has undergone substantial surface warming over the past four decades, and compound events combining marine heatwaves, high acidity and low chlorophyll have increased rapidly in the equatorial and South Atlantic. An intensifying Brazil Current is shifting fish and shellfish assemblages along the Brazilian and northern Argentine-Uruguayan shelves, and catch records reveal a tropicalization of fisheries, with warm-water species becoming more prevalent as cold-water species decline and distributions shift poleward. Under high-emission projections, a weakened Atlantic Meridional Overturning Circulation would warm the South Atlantic further, while changing wind patterns could alter nutrient fluxes, biological connectivity and species distributions. Ecosystem models project that commercially important transboundary species will shift southward, new shared stocks will emerge across exclusive economic zones, and straddling stocks will move proportionally onto the high seas, where unilateral management loses effectiveness and exposure to distant-water fleets and governance conflict rises.

The authors argue that the moment for action is unusually favorable. Brazil is at the center of the global environmental agenda, hosting the UNFCCC COP30 in Belém in November 2025, the third BBNJ Agreement symposium in March 2026 and the UN Ocean Decade Conference in Rio de Janeiro in 2027. At the third UN Ocean Conference in Nice, Brazil helped launch the Blue Nationally Determined Contributions Challenge, a global call to embed the ocean in national climate plans, with climate-resilient fisheries grounded in ecosystem-based management as a key strategy. Existing instruments such as the Port State Measures Agreement and the BBNJ Agreement offer ready-made platforms that can be adapted to regional realities, and the revitalized ZOPACAS, along with scientific networks like ALICMAR, whose members met in 2024 to discuss exactly these themes, could provide neutral arenas where science diplomacy builds trust, shared monitoring systems and joint assessments even amid geopolitical tension.

Ultimately, the researchers contend that a flexible, polycentric regional framework anchored in science-based adaptive management, strengthened data sharing and inclusive participation of fishers, industry, academia and civil society is both feasible and necessary. Far from threatening sovereignty, they argue, a regional organization for cooperative governance could strengthen it, giving Argentina, Brazil and Uruguay a united front to defend shared resources against governance gaps and the advance of distant-water fleets, while negotiated engagement with extra-regional actors proceeds through instruments like the BBNJ Agreement. Bioregionalization of coastal and shelf areas offers a macroscale template for aligning institutions with ecological reality, and a network of transboundary marine protected areas, connected to the high seas and to designated Ecologically and Biologically Significant Areas such as the Atlantic Equatorial Fracture Zone and the heavily fished Blue Hole off Argentina, could boost biodiversity protection, stock recovery and climate resilience. The transformation will take time and political will, the authors acknowledge, but the alternative, remaining reactive while the ocean warms and stocks move, is a future in which one of the world’s great marine regions is managed by no one at all.

Subject of Research: Integrated ocean governance, fisheries management and climate resilience in the Southwest Atlantic Ocean

Article Title: Integrated ocean governance is needed in the Southwest Atlantic Ocean to foster fisheries, conservation and resilience to climate change

Article References: Palacios-Abrantes, J., Llompart, F., Cardoso, L. G., Defeo, O., Gianelli, I., Jaureguizar, A. J., Lopes, P. F. M., Perez, J. A. A., Piccolo, N. I. P., Piola, A. R., Polejack, A., Prado, L. F., & Saraceno, M. (2026). Integrated ocean governance is needed in the Southwest Atlantic Ocean to foster fisheries, conservation and resilience to climate change. Discover Oceans, 3(1), Article 19. https://doi.org/10.1007/s44289-026-00134-4

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00134-4

Keywords: ocean governance, Southwest Atlantic Ocean, fisheries management, climate change, BBNJ Agreement, IUU fishing, marine conservation, transboundary fish stocks, ocean science diplomacy, marine protected areas, ecosystem-based management, small-scale fisheries

Distant water fishing, by definition, describes fleets that harvest marine resources outside their own exclusive economic zones, often under access agreements, joint ventures, or flag arrangements with coastal states in Africa, the Pacific, and Latin America. For Southeast Asian nations, whose own waters are among the most productive and most heavily exploited on the planet, distant water operations have become both an economic outlet and an ecological escape valve. When domestic stocks are depleted or domestic licensing becomes restrictive, vessels and their investors look outward. The new research examines this outward push not as a static fact but as a dynamic system, one that shifts with fuel prices, bilateral agreements, enforcement regimes, and the health of the fish stocks themselves.

The study’s central contribution lies in treating fleet behavior as something that can be characterized quantitatively over time rather than described anecdotally. Rather than simply counting vessels, the analysis focuses on the patterns of activity that emerge when large numbers of fishing vessels operate in concert: where they concentrate, how long they remain in particular grounds, how their presence changes in response to regulatory signals, and how the composition of the fleet evolves as older vessels retire and newer, often larger and more technologically capable ships enter service. This kind of systems-level view is essential because distant water fishing is not merely a collection of independent boats. It is an industry organized around supply chains, processing capacity, ports of convenience, and market demand that spans continents.

Southeast Asia provides a particularly revealing setting for this kind of analysis. The region contains some of the world’s largest fishing nations, with enormous domestic fleets that have historically been supported by fuel subsidies, loan programs, and development policies aimed at expanding seafood production. Those same policy instruments, designed to strengthen food security at home, have inadvertently fueled the capacity that now seeks opportunity abroad. The research highlights this feedback loop: capacity built for domestic waters spills into international ones, and the resulting pressure on foreign stocks can replicate abroad the very overfishing problems the fleets were escaping. Understanding this dynamic is critical for any honest assessment of global fishing effort, because vessels that leave home waters do not simply disappear from the global ledger of exploitation.

The technical challenge of studying distant water fleets has always been data. Fishing vessels operating in remote waters, sometimes under flags of convenience and sometimes with limited transponder coverage, are notoriously difficult to track. The study engages with this problem by synthesizing available information on fleet composition, operational ranges, and the institutional arrangements that govern access to foreign waters. Such synthesis work matters because policy debates about distant water fishing frequently proceed from fragmented or outdated information. Without a coherent picture of how fleets are actually distributed and changing, attempts at regulation, whether by flag states, coastal states, or regional fisheries management organizations, risk targeting the wrong vessels in the wrong places at the wrong times.

One of the most striking themes the research surfaces is the role of governance asymmetry. Coastal states in the waters where Southeast Asian distant water fleets operate often possess limited monitoring, control, and surveillance capacity, while the vessels themselves may be registered in jurisdictions with minimal oversight obligations. This mismatch creates conditions in which illegal, unreported, and unregulated fishing can flourish, and it places honest operators at a competitive disadvantage relative to those willing to cut corners. The study situates fleet dynamics within this institutional landscape, showing that the movement and behavior of vessels cannot be understood purely in terms of fish abundance or economics. Where the rules are weak, the fleets concentrate; where enforcement tightens, activity shifts to new grounds. The geography of fishing, in other words, mirrors the geography of regulation.

The implications of these dynamics extend well beyond the fishing industry itself. Distant water fishing touches on food security for coastal communities that depend on fish as a primary source of protein, on the livelihoods of small-scale fishers who compete with industrial vessels for shared stocks, and on the marine ecosystems that absorb the cumulative pressure of decades of industrial extraction. When highly migratory species such as tuna are harvested across vast ocean basins by fleets from many nations, the sustainability of the resource becomes a collective action problem. The research’s systematic account of how Southeast Asian distant water fleets fit into this equation helps clarify which actors bear which shares of the pressure, a necessary precondition for fair and effective international management.

The findings also speak to an ongoing transformation in how the global fishing industry is monitored. Satellite-based vessel tracking, automatic identification systems, and machine-learning analyses of vessel behavior have begun to peel back the opacity that once shielded distant water operations from scrutiny. Studies like this one demonstrate the value of bringing such analytical tools to bear on specific regions and fleet segments. As more nations adopt requirements for electronic monitoring and as regional fisheries management organizations expand their data collection, the possibility of genuine, evidence-based management of high-seas and foreign-access fisheries moves from aspiration toward practice. The Southeast Asian case examined here suggests both the promise of that trajectory and the distance still to be traveled.

For policymakers in the region, the research carries a pointed message: distant water fleets are not an externality of domestic fisheries policy but a direct product of it. Decisions about subsidies, licensing, fleet modernization, and labor standards at home reverberate through fishing grounds on the other side of the world. Conversely, international agreements on fisheries access, port state measures, and transshipment regulation shape the economic calculus of fleet owners in Southeast Asian ports. The study’s systemic framing underscores that meaningful reform requires coordination across this entire chain, from the shipyards and banks that finance vessels to the markets in Europe, North America, and East Asia that consume their catch. Sustainability, in this view, is not a property of individual fishing trips but of the whole interconnected system.

As global demand for seafood continues to rise and wild-capture fisheries approach or exceed their biological limits, the behavior of distant water fleets will only grow in importance. The analysis of Southeast Asian fleet dynamics published in npj Ocean Sustainability provides a rigorous foundation for understanding one of the major forces acting on the world’s ocean resources. It replaces a vague sense of concern about far-water fishing with a structured account of how these fleets operate, where they concentrate, and how they respond to the shifting landscape of regulation and opportunity. In doing so, it gives scientists, managers, and the public something increasingly rare in ocean governance: a clear view of an industry that has spent decades just beyond the horizon.

Subject of Research: The operational dynamics of distant water fishing fleets based in Southeast Asian countries

Article Title: Dynamics of distant water fishing fleets in Southeast Asian countries

Article References: Alam, L., Teh, L., Teh, L., Palomares, M. L., Skerritt, D. J., Issifu, I., Lam, V. W. Y., Villasante, S., Lazzari, N., Kinds, A., Carvalho, A. R., Majluf, P., Aheto, D., Mokhtar, M., & Sumaila, U. R. (2026). Dynamics of distant water fishing fleets in Southeast Asian countries. npj Ocean Sustainability. https://doi.org/10.1038/s44183-026-00242-w

Image Credits: AI Generated

DOI: 10.1038/s44183-026-00242-w

Keywords: distant water fishing, Southeast Asia, fisheries, ocean sustainability, overfishing, IUU fishing, fleet dynamics, fisheries management, maritime governance, satellite vessel tracking, tuna fisheries, flag states