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01/08/2026 | Press release | Distributed by Public on 01/08/2026 16:30
What the Bella-1 Teaches Us About Targeting Shadow Fleets
What the Bella-1 Teaches Us About Targeting Shadow Fleets
Photo: William Farmerie/U.S. Navy/Getty Images
Critical Questions by Jose M. Macias III
Published January 8, 2026
After months-long journey marked by suspicious behavior, identity changes, and attempts to evade international scrutiny the United States seized sanctioned Russian oil tanker Marinera, formerly known as Bella-1. According to the U.S. attorney general, a U.S. federal court issued a warrant to seize the ship for transporting sanctioned oil from Venezuela and Iran. The Marinera is a very large crude carrier (VLCC) with a deadweight tonnage range between 200,000 and 320,000. Vessels in the VLCC class are estimated to have a capacity of approximately 2 million barrels of oil. Notably, Russia approved its flag registration without inspection of the vessel, occurring mid-chase and likely violating Article 92 of the United Nations Convention on the Law of the Sea, which states that flag changes cannot occur without a real transfer of ownership or change in registry. The frequent change in ownership and flags is a quintessential trick used by oil runners to keep operating and represents nothing more than new companies on paper, usually in states with minimal jurisdiction oversight. In addition, Russia submitted a rare diplomatic request to the United States that it cease its pursuit of the Marinera. In the early morning of January 7, 2026, Russia reportedly dispatched a submarine to escort the tanker.
The vessel was under sanctions because it fundamentally serves as a means for illicit revenues that fuel the autocratic policies and political repression in Venezuela and Iran. These states are part of a larger network of autocratic regimes that includes Cuba and North Korea. So what exactly triggered such extraordinary measures in this case? What was the Marinera guilty of carrying in the past-or trying to hide-that warranted this level of intervention?
Based on automatic identification system (AIS) data, the vessel loitered for months off the coast of Iran, logging over 379 suspicious rendezvous events and going dark at least 17 times within Iranian waters alone. It repeatedly disabled its transponder while transiting the Strait of Malacca, off the coast of Sri Lanka, and again in the Atlantic Ocean-indicators of illicit transfers or concealment operations. When Marinera resurfaced near the Azores, it had changed its name, Maritime Mobile Service Identity (MMSI) number, and flag state-all within weeks-capping off a transcontinental escape route stretching from the Persian Gulf to the Americas trying to reach its home, Russia.
In this Critical Questions from the CSIS Futures Lab, the research team traces the vessel's global journey using Automatic Identification System (AIS) data aggregated using Optix. The piece examines the history of U.S. maritime seizures, traces Marinera's global voyage from Iran to the Caribbean, and assesses the vessel's attempts to evade detection through AIS manipulation and illicit rendezvous. Together, the analysis reveals a pattern of sanctions evasion that implicates broader networks and illustrates how coordinated interdiction efforts can undermine authoritarian revenue streams.
Q1: What is the legal and historical precedent for the United States seizing commercial vessels or their cargo at sea?
A1: The U.S. Navy has a history of ship seizures authorized under prize law, including examples from the U.S. Civil War and the 1898 Spanish-American War. During the Civil War, the Union Army established prize courts to adjudicate the legality of captures at sea by naval ships. One series of captures is known as the "Prize Cases" and their rulings by the U.S. Supreme Court held that any seizure during a blockade of southern ports was lawful because the Union and Confederacy were in a state of war, even without a formal congressional declaration of war. In the 1898 Spanish-American War, the Supreme Court ruled that cargo seized abroad near the Philippines from a Spanish-owned vessel was legal because of a state of war between the U.S. and Spain.
More recent encounters from the 1990s focused less on keeping the cargo and enforcing trade restrictions. In one instance, the United States boarded an Iraqi ship with tea from Sri Lanka following a 1990 United Nations embargo on Iraq. The current administration has signaled that it will continue the oil blockade of Venezuela and is likely the start of continued seizures as the administration returns to focus on the western hemisphere as envisioned in the 2025 national security strategy.
Q2: What was the historical journey of Marinera, and what early indicators of illicit activity did it show?
Figure 1: The 2025 Journey of the Bella-1/Marinera
Programs & Projects
Remote Visualization
Source: Author's analysis of AIS data from Optix, EEZ from Marineregions.org, and port locations from the World Port Index.
A2: The Marinera started in Iran before heading into the Strait of Malacca, then departing for South America. The earliest detection of the tanker was off the cost of Iran, leaving its economic exclusivity zone (EEZ) by February 3, 2025, and sailing through the Omani EEZ. The traffic pattern appears normal until Marinera enters the Sri Lankan EEZ-here, abnormal activities occur. Off the Sri Lankan coast, about 8 nautical miles from Galle Harbor, there is a slowdown and southern turn, where the average speed over ground slowed to an estimated two knots before heading east under the cover of night.
Figure 2: Maneuvering South of Sri Lanka
Remote Visualization
Source: Author's analysis of AIS data from Optix, EEZ from Marineregions.org, and port locations from the World Port Index.
Traffic patterns appear normal until the vessel enters the Strait of Malacca on February 17, and leaves by approximately March 20. The vessel turned off its AIS five times in the EEZ of Indonesian and Malaysia (see Figure 3). Turning off the AIS on purpose is an indicator of illicit activity or intentional suppression of signal when a vessel is attempting to hide. These instances occur at, roughly, 63 nautical miles from Port Klang, 23 nautical miles from Port Dickson, 22 nautical miles from Sungai Udang Port, 5 nautical miles from Keppel Harbor, and twice more in the Singapore Strait.
Figure 3: Journey Through the Strait of Malacca
Remote Visualization
Source: Author's analysis of AIS data from Optix, EEZ from Marineregions.org, and port locations from the World Port Index.
Q3: What core activities suggest the vessel was supporting Iran's illicit oil trade?
A3: The vessel then leaves the Strait of Malacca and makes the journey to Iran, but stops reporting AIS after going dark off the coast of Sri Lanka on March 24, 2025, only to reappear turning on its AIS in the Iranian EEZ on July 1, 2025. Figure 4 covers AIS and activities undertaken between July 1 and November 14, 2025: The vessel loiters on the coast of Iran and registers rendezvous off the coast. The data captures 379 instances, or "pings," of rendezvous in the Iranian EEZ. The tanker turns off AIS 17 times in the Iranian EEZ and while traveling between the Emirati and Omani EEZs without visiting ports. This behavior is commonly seen in ship-to-ship transfers (STS), which happen when a vessel that wants to transfer oil and have it "cleaned" will meet up in waters with flags of convenience or minimal jurisdictional oversight. In the case of the Marinera, a sanctioned vessel for the illicit oil trade, these instances likely reflect STS transfers. While satellite imagery is necessary to definitively confirm STS activity, the AIS pattern alone presents a compelling circumstantial case that Marinera was engaged in transferring Iranian oil in violation of international sanctions.
Figure 4: Loitering and Rendezvous
Remote Visualization
Source: Author's analysis of AIS data from Optix, EEZ from Marineregions.org, and port locations from the World Port Index.
Q4: How did Marinera attempt to evade detection in the final stage of its journey?
A4: After its activities near Iran, the ship travels to the Gulf of Suez from November 23 to November 25, 2025, before crossing the Suez Canal by November 26. The Marinera continues its journey toward the Strait of Gibraltar but registers three instances on December 3, 2025, when the AIS is shut off approximately 27 nautical miles from Spain's Almeria Port. However, at approximately 240 nautical miles from the coast of Morrocco, outside of Portuguese and Moroccan EEZs, the AIS signal drops off for six hours in the early morning of December 5, 2025, before reappearing in the Portuguese EEZ of Madeira, heading west. AIS signal loss occurring outside the jurisdiction of coastal states in the high seas is typical of ships conducting illicit activities, and Marinera falls in line with this behavior. Thereafter, the journey toward Venezuela continues, until another AIS interruption occurs on December 9, 2025. In the middle of the Atlantic Ocean, the AIS is turned off in the early afternoon until the vessel reappears in the late evening, traveling one nautical mile from where it was last seen over the course of seven hours (see Figure 5). The vessel then continues to head west and enters Antiguan and Barbudan EEZs before it is targeted for seizure by the United States. The ship is picked up entering the French EEZ (Guadeloupe) before going dark one final time as Bella-1 in Antiguan and Barbudan EEZ.
Figure 5: Disappearance off the Coast of Morocco
Remote Visualization
Source: Author's analysis of AIS data from Optix, EEZ from Marineregions.org, and port locations from the World Port Index.
Figure 6: Failing to Reach Venezuela Under Pursuit
Remote Visualization
Source: Author's analysis of AIS data from Optix, EEZ from Marineregions.org, and port locations from the World Port Index.
Following the hot pursuit by the United States, the Marinera goes offline and does not reappear until December 30 outside of the Portuguese EEZ of Azores, switching from reporting as Bella-1 and under a new name, Marinera, and a new MMSI, ending its run from U.S authorities as reports start coming in that the vessel has been boarded.
Q5: How does the seizure of the Marinera demonstrate a broader strategy for countering autocratic regimes and their shadow fleets?
A5: The seizure of the Marinera offers a tangible example of how maritime interdiction can be used to disrupt the financial networks of autocratic regimes and proxy groups. The operation was not done alone-reports highlight the role the UK armed forces played in helping seize the vessel by dispatching a Royal Air Force aircraft and a Royal Navy support ship. In addition, while not as high-risk as Ukrainian drone attacks against Russian tankers, these actions are a part of a larger policy menu aimed at undermining the Russian war machine. Destabilizing the transport of oil is hurting Russia by devaluing the price of crude shipments. The United States and its partners can set a goal to drive Russia crude shipment value to below profitability through constant seizures of the shadow fleet. There is room for more countries to support this goal: Despite its attempt to seek refuge under Russia, the Marinera's trip spanned 32 EEZs across the globe. This included Greek, Italian, Spanish, and Portuguese EEZs, highlighting how more nations, including NATO members, can help interdict the shadow fleet.
Q6: What tools and methods are available to monitor and disrupt the shadow fleet and sanctions evasion?
A6: The tools for analysis span different disciplines, including data analytics using programming languages, geographic information systems (GIS) analysis, and propriety software tools, such as the Optix platform used here or ArcGIS. This analysis used a combination of tools and techniques including data wrangling in R, point in polygon (PiP) analysis with EEZs, and map styling in QGIS. Identifying abnormal activity can leverage data from these platforms to create classification frameworks that flag suspicious activity. In addition, there are machine learning techniques that perform well with noise, and can classify clusters and label abnormalities in data. New open-source tools are being developed to leverage artificial intelligence, including Meta's SAM3, in open-source tools that detect, segment, and track objects in images based on prompts and could help develop faster ways for satellite image analysis to detect STS transfers.
As maritime sanctions evasion tactics grow more sophisticated, so too must the tracking and enforcement tools. Broader adoption of these methods by partner governments and multilateral enforcement bodies could enhance the collective ability to detect and disrupt shadow fleet operations before they reach their destination.
Jose M. Macias III is an associate data fellow in the Futures Lab within the Defense and Security Department at the Center for Strategic and International Studies (CSIS) in Washington, DC.
Critical Questions is produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).
© 2026 by the Center for Strategic and International Studies. All rights reserved.
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