Six months of dramatic enforcement actions and military escalation have transformed the shadow fleet crisis, but the environmental threat remains the core concern.

In August 2025, SEVENSEAS Media published my article “The Shadow Fleet Crisis: When Ocean Conservation Meets Global Security,” which examined the emerging environmental threat posed by the global shadow fleet: more than 700 aging, poorly maintained tankers operating outside international law, carrying millions of barrels of oil through the world’s most sensitive marine ecosystems. I called for proactive intervention to prevent an uncontrollable environmental catastrophe. This article provides a six-month update on that crisis, and documents how dramatically the situation has evolved.

As I explained in that earlier piece, a single oil tanker grounding in a region such as the Caribbean could result in the destruction of acres of coral reef, the oiling of miles of island and coastal shoreline, the death of vital populations of fish and other species, and permanent harm to the economies of many coastal communities. The potential for widespread harm is amplified by the lack of response capacity and adequate funding mechanisms in the Caribbean and along trade routes through vulnerable areas.

At that time, there were fairly straightforward options for addressing the threat that vulnerable island states and the conservation community could pursue. What I could not have predicted was how rapidly the situation would escalate; not toward resolution, but toward a confrontation that has now drawn in navies, fighter jets, and the highest levels of government from multiple nations.

The shadow fleet crisis has transformed from a maritime environmental concern into a more complicated geopolitical scenario. But amid all the dramatic headlines about seizures and naval escorts, we must not lose sight of what matters most from an ocean conservation perspective: the environmental threat has grown more urgent, not less.

U.S. forces have seized seven sanctioned tankers in rapid succession. Russia has deployed military assets to protect shadow fleet vessels. France intercepted a tanker in the Mediterranean. NATO has established a new task force. These geopolitical developments complicate, but do not diminish, the environmental risks posed by aging, poorly maintained vessels carrying millions of barrels of oil.

A Note on Terminology: Shadow Fleet vs. Sanctioned Vessels

The terms “shadow fleet” and “sanctioned vessels” are often used interchangeably, but from an environmental perspective, they describe fundamentally different categories of risk.

A “sanctioned vessel” is any ship designated as violating trade sanctions, typically for carrying oil from Russia, Iran, Venezuela, or North Korea. Some sanctioned vessels continue to maintain insurance, undergo regular inspections, employ professional crews, and comply with maritime safety standards. These vessels represent a trade dispute: politically contentious, but far less threatening to marine ecosystems.

The “shadow fleet,” by contrast, refers specifically to vessels that combine sanctions evasion with wholesale abandonment of maritime safety infrastructure. These ships operate with falsified documentation, lack legitimate insurance, use aging and poorly maintained equipment, exploit their crews, and engage in dangerous practices such as turning off AIS transponders, refusing pilot services, and conducting risky ship-to-ship cargo transfers at sea.

The distinction matters for policy. When a shadow fleet vessel reflags to Russia (as more than 40 have done since June 2025), it gains state protection but does not necessarily improve its safety profile. The environmental threat persists regardless of which flag is painted on the stern.

Geopolitical Context: A Complicating Factor

The past six months have seen extraordinary geopolitical developments that have complicated, though not fundamentally changed, the environmental calculus. Understanding these events is important, but we should view them as context rather than as the core story.

On December 10, 2025, U.S. forces seized the Venezuelan oil tanker Skipper in international waters between Grenada and Trinidad; notably, on the high seas rather than within any nation’s Exclusive Economic Zone (EEZ). In a dramatic made-for-TV move, armed law enforcement agents rappelled from helicopters onto a vessel carrying nearly 2 million barrels of crude oil. The crew, mostly Russian nationals, offered no resistance. After U.S. forces seized the oil tanker Skipper near Venezuela, they took control of the crew and cargo. They redirected the vessel to the Texas coast off Galveston for forfeiture proceedings and likely offloading.

But the Marinera chase was something else entirely. For eighteen days, U.S. Coast Guard vessels pursued the tanker (previously Guyana-flagged and known as Bella 1) across the Atlantic Ocean. During the pursuit, the crew hastily painted a Russian flag on the hull. Russia formally added the vessel to its Maritime Register and demanded the U.S. halt pursuit. Moscow dispatched a naval escort. The U.S. intercepted the vessel between Iceland and Scotland before Russian ships arrived. After U.S. and allied forces seized the Marinera in the North Atlantic, they placed the crew in U.S. custody. They moved the tanker to the United States to enter judicial forfeiture proceedings as a stateless, sanctions-violating “shadow fleet” vessel, with those involved in its escape attempt facing potential prosecution under U.S. law.

By January 21, the United States had seized seven sanctioned tankers in rapid succession. France, with UK intelligence support, intercepted the tanker Grinch in the western Mediterranean. President Macron personally ordered the operation.

Russia responded by abandoning any pretense of plausible deniability. More than 40 shadow fleet tankers have switched to the Russian flag since June 2025, with 21 reflagging immediately following the Skipper seizure. In May 2025, Russia deployed a Su-35 fighter jet in response to Estonia’s attempt to stop the tanker Jaguar, the first overt military intervention to protect a shadow fleet vessel.

All seven U.S. seizures occurred on the high seas, in international waters beyond any nation’s territorial sea or EEZ. Under traditional maritime law, flag states exercise primary jurisdiction over their vessels on the high seas. The high-seas location makes these actions legally complex, and helps explain why Russia felt emboldened to dispatch naval escorts and why France ultimately had to release the Grinch.

These geopolitical confrontations have significant implications, but from an environmental perspective, the key question remains unchanged: Are these vessels safe? The answer remains no, regardless of whose flag they fly. Vessels that operated as poorly maintained shadow-fleet tankers last month do not suddenly become environmentally sound simply because they fly a Russian flag this month. The aging hulls, inadequate maintenance, undertrained crews, and missing insurance that made them environmental hazards persist.

The Core Environmental Risks: Compounding Threats

Our ongoing research into the shadow fleet has revealed multiple compounding risks that threaten marine ecosystems worldwide. These hazards exist independently of the geopolitical drama, and in many ways are exacerbated by it.

Aging vessels and inadequate maintenance have led to Russia’s shadow fleet expanding from fewer than 100 vessels in February 2022 to over 343 vessels today. Before Russia invaded Ukraine in 2022, just three percent of the global tanker fleet was more than 20 years old. That share has more than tripled to 11%. The newly sanctioned vessels are an average of 16.8 years old. Some shadow fleet vessels have been documented using single-hull designs for oil transport, configurations banned under international regulations precisely because of their vulnerability to catastrophic failure.

Inadequate insurance: Over 70% of shadow fleet vessels lack adequate coverage through International Group P&I clubs. When tankers are uninsured or underinsured, coastal states bear the cost of environmental cleanup and damage. There is no readily available funding mechanism for rapid response mobilization.

Crew competence and exploitation: Reports indicate that forced labor and human trafficking in the maritime sector remain severe problems. Crews are often ill-equipped to handle the unique navigational challenges of regions such as the Baltic Sea, where harsh winter weather, ice cover, and narrow shipping lanes require specialized training. The data we have reviewed shows that there have been significant increases in the number of tankers refusing to use experienced Danish pilots when navigating the Baltic’s dangerous shipping straits. This troubling trend has accelerated, rising from 1 in 20 in July 2023 to 1 in 5 tankers in July 2024.

Navigation interference: GNSS jamming and spoofing (the deliberate interference with satellite navigation systems) has become endemic in certain maritime regions. The Baltic Sea has experienced persistent navigation interference that degrades situational awareness and increases the risk of collisions and groundings.

A Growing Crisis: Abandoned Vessels

A troubling new dimension of the shadow fleet crisis has emerged: the dramatic increase in abandoned vessels. According to the International Transport Workers’ Federation (ITF), ship abandonments have skyrocketed from 20 vessels worldwide in 2016 to 410 in 2025, with 6,223 merchant seafarers left stranded. Both figures were up by almost a third from the previous year.

The ITF reports that shadow fleet vessels are contributing significantly to this spike. These aging vessels of obscure ownership, often unseaworthy and uninsured, are being abandoned when operations become unprofitable or when enforcement pressure increases. Flags of convenience (FOC) vessels accounted for 82% of all abandonments in 2025.

From an environmental perspective, abandoned vessels represent a compounding risk. A tanker abandoned with cargo aboard (as has occurred with several vessels carrying hundreds of thousands of barrels of Russian crude) is an environmental time bomb. Without an active crew to maintain systems, monitor conditions, or respond to emergencies, the risk of cargo spill, leak, or loss increases dramatically. When owners disappear into shell company structures and flag states disclaim responsibility, there is no one to hold accountable for cleanup costs.

The human dimension compounds the environmental risk. Abandoned crews face shortages of food, fresh water, and essential supplies. Unpaid, hungry, and demoralized seafarers cannot be expected to maintain vessel safety systems or respond effectively to emergencies. Last year, abandoned merchant navy crews worldwide were owed a total of $25.8 million in unpaid wages.

Infrastructure Incidents: Evidence of Operational Hazards

A series of incidents in the Baltic Sea demonstrated, in dramatic fashion, the operational hazards posed by shadow fleet vessels. While media attention focused on the infrastructure damage and potential that these acts are sabotage, the incidents also reveal how poorly these vessels are operated, and what that means for environmental risk.

On Christmas Day 2024, the Russian oil tanker Eagle S, operating under a Cook Islands flag, cut the Estlink 2 power cable and four data cables by dragging its anchor for 62 miles through Finnish waters. Whether intentional sabotage or negligent operation, this incident demonstrates the reality: a vessel dragging its anchor for 62 miles is a vessel that could be dragging through even more sensitive marine habitat or run aground on a reef.

Finnish authorities seized the Eagle S and found 32 safety deficiencies, including problems with fire protection, navigation equipment, and ventilation systems. The vessel’s S-band radar did not work. Its insurance had expired months earlier. This is the condition of the vessels carrying millions of barrels of oil through our oceans. The Eagle S was released after three months of detention but was subsequently scrapped in Turkey in late 2025.

These same vessels, uninspected, poorly maintained, operated by crews who manipulate navigation systems to avoid detection, are navigating congested waterways where a single miscalculation could result in catastrophic collisions and spills. The infrastructure sabotage concern and the environmental concern are two sides of the same coin: vessels operating outside established safety systems pose threats everywhere they operate.

Beyond Sanctions Evasion: The Hybrid Warfare Dimension

Our research has also revealed concerning evidence that some shadow fleet vessels serve purposes beyond oil transport. In July 2025, Danish pilots reported crew members photographing bridge infrastructure during transit. A Danwatch investigation found that many shadow fleet crew members had backgrounds in Russian defense or intelligence services. Swedish naval authorities documented unusual antenna configurations suggesting intelligence-gathering capabilities.

In August 2025, drawing on the accumulating evidence from DanPilot reports, the Danwatch investigation, and Swedish Navy observations, the U.S. Naval Institute’s Proceedings published an analysis concluding that shadow fleet vessels should be viewed as “multirole tools” for sanctions evasion, intelligence collection, and potential sabotage.

NATO responded by announcing its “Baltic Sentry” operation. Germany established Commander Task Force (CTF) Baltic, a shore-based tactical maritime headquarters at Rostock that coordinates frigates, patrol aircraft, submarines, and naval drones to protect undersea infrastructure.

This hybrid warfare dimension is concerning in its own right, but for ocean conservation purposes, it reinforces a key point: these are not normal commercial vessels subject to normal oversight. They operate in a gray zone where the usual assumptions about vessel behavior, crew competence, and emergency response cannot be trusted. This uncertainty compounds environmental risk.

When Disaster Strikes: The Response Capacity Gap

The January 2026 seizures in the Caribbean highlighted a vulnerability that extends far beyond enforcement. What happens when a shadow fleet vessel spills its cargo in waters that lack the infrastructure to respond?

In European waters, the European Maritime Safety Agency operates 20 pollution response vessels and maintains satellite monitoring through its CleanSeaNet service. But even this capacity has gaps; remarkably, there are currently no EMSA pollution response vessels stationed in the Baltic Sea, despite the concentration of shadow fleet activity in those waters.

The Caribbean and Latin America would face even greater challenges in the event of a catastrophic spill. When U.S. forces seized the Skipper between Grenada and Trinidad, they intercepted a vessel carrying enough oil to devastate marine ecosystems and the economies that depend on them. These coastal states lack response infrastructure, equipment pre-positioning, and coordinated contingency planning. Local and migratory fisheries, fragile reef and mangrove areas, and coastal tourism remain at serious risk.

The insurance gap compounds this vulnerability. With no guarantee of repayment, communities may have to choose between mounting expensive cleanup efforts with uncertain cost recovery and continuing to provide ordinary but necessary services to their residents.

The Enforcement Paradox

The Grinch case exposed a critical gap in the legal framework. When France intercepted the vessel, President Macron declared it a triumph of sanctions enforcement. Three weeks later, he informed Ukrainian President Zelensky that France would be forced to release the tanker because current French and international maritime law do not permit prolonged detention of civilian vessels, even when under sanctions.

This is not an argument against enforcement. It is an observation that enforcement alone cannot solve the environmental crisis. The shadow fleet continues to grow. Russia’s seaborne oil exports now account for almost 70% of shipments via shadow-fleet vessels. Iran maintains exports of approximately 1.6 million barrels per day. The total reaches approximately 3.7 billion barrels annually: 6 to 7 percent of global oil flows moving in vessels that operate outside safety systems designed to protect marine environments.

The Path Forward: Focusing on Environmental Protection

The conservation community faces the same choice I outlined six months ago, but with greater urgency. The shadow fleet crisis has attracted the attention of governments, militaries, and international institutions. It has become a subject of great power competition. But amid all this geopolitical attention, the environmental dimension remains neglected.

What the crisis demands is not a political position on sanctions. It is a relentless focus on the environmental consequences of vessels operating outside established safety systems, regardless of whose flag they fly or whose cargo they carry.

What can nations do? Coastal states can strengthen Port State Control regimes: refusing entry to suspicious vessels, demanding proof of adequate insurance, and requiring comprehensive documentation of cargo origin. The EU’s approach of denying port access to vessels that turn off their AIS transponders provides a model. Nations can enforce MARPOL requirements, including the 48-hour notification for ship-to-ship transfers in their territorial seas or EEZ. Financial pressure matters too: targeting insurance providers, financiers, and service providers that enable shadow fleet operations can significantly increase operational costs and risks.

What should the ocean conservation community do? First, we must acknowledge this issue as part of our mandate. The shadow fleet threat is not separate from ocean conservation; it is a direct and growing threat to marine ecosystems. Second, we need to invest in monitoring and documentation. Organizations like SkyTruth have demonstrated how satellite imagery and remote sensing can expose environmental violations. Third, we must develop and advocate for risk-based policy frameworks that distinguish between environmental compliance and political affiliation, frameworks that create incentives for safety even within sanctioned trade. Fourth, we should build regional response capacity, particularly in vulnerable areas such as the Caribbean. Finally, we need to bring our collective voice to international forums (the IMO, UNCLOS processes, and bilateral negotiations) to ensure that environmental protection remains central to any framework addressing the shadow fleet crisis.

The window for proactive intervention remains open, but it will not remain open indefinitely. The current period of heightened attention offers an opportunity to establish frameworks before a catastrophic incident forces reactive responses. The question is whether the conservation community will rise to meet this challenge, or whether we will wait for the next spill, the next grounding, the next preventable disaster to force our hand.

The Ocean Foundation will continue to monitor developments and share what we learn. The ocean deserves better. The choice, as always, belongs to all of us.

By: Mark J. Spalding, J.D.

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About the Author

Mark J. Spalding, President of The Ocean Foundation, was part of the group that founded the Shipping Safety Partnership and has responded to shipwrecks, such as the MV Selendang Ayu, and worked on addressing forced labor on ships and chronic noise pollution from shipping. He co-led Project Tangaroa and has authored several publications on sustainability in the maritime domain. His previous article, “The Shadow Fleet Crisis: When Ocean Conservation Meets Global Security,” was published by SEVENSEAS Media in August 2025.