Introduction: An expanding but under-examined risk
A growing maritime risk emerging in global waters is the increasingly common threat of ‘ghost’ or ‘shadow’ fleets navigating the same, densely populated shipping routes, alongside registered, corporately owned ships.
Recent geopolitical developments, such as global conflicts and the closure of regular routes like the Strait of Hormuz, have highlighted the potential dangers these ships pose and the environmental and cost implications in the event of an incident, as increased traffic density could escalate the likelihood of a collision or grounding. In a risk and compliance analysis by Kpler, they estimate that the ‘shadow fleet’ accounts for roughly 22% of global tankers.
The use of real-time satellite visualisation tools, such as the programme designed by Kpler, paints a concerning picture of the routes that experience high traffic, and show heavy clusters of ‘shadow fleets' in areas like the English Channel. These vessels operate in the same waters as the larger corporate fleets, but with limited transparency regarding ownership, insurance, and compliance.
What is a Ghost Fleet?
A ghost fleet (sometimes called a shadow or dark fleet) refers to a loosely connected group of vessels, predominantly product tankers, that operate on the fringes of the global maritime system, often to move energy cargoes under heightened regulatory pressure. These ships are frequently older vessels, including hull types that were previously phased out of mainstream service but later returned to operation, and they commonly operate outside traditional insurance, classification, and P&I club structures, increasing operational and environmental risk.
Taken together, these characteristics mean that incidents involving ghost fleets are more likely to expose gaps in governance, liability, and response coordination than those involving conventionally operated vessels.
Identification and monitoring are deliberately made difficult through AIS manipulation or spoofing, such as switching transponders off, broadcasting false positions, or changing identifiers, while vessel identities may be masked by mimicking legitimate ships through name changes, flag hopping, or cloned IMO details. Importantly, the existence and operation of ghost fleets represent a broader industry-wide and geopolitical issue, driven by global market dynamics and sanctions environments, and are not attributable to individual companies or responsible operators.
Why identification and accountability matter
In the event of an incident, identifying the vessel and holding the operating company accountable are important but can prove difficult when the vessel is recognised as a ‘ghost’ ship. In these circumstances, the vessel's ownership may be unclear, and the ship may be uninsured.
In the absence of a valid insurance policy, the compensation mechanisms may not apply, leaving national authorities, such as local maritime agencies, to bear the cost. This effectively transfers financial, operational, and reputational risk from private operators to public institutions, often with limited notice or preparedness.
Case Studies: What past incidents tell us
Delayed reporting and coordination gaps
OSRL was recently activated to respond to an incident involving a ‘ghost’ barge in Tobago. The response was initially led by the Tobago Emergency Management Agency (TEMA), and the moderate level of severity required both national and international assistance for the clean-up operations.
The Tobago ghost barge incident illustrates how the absence of clear vessel ownership can significantly delay the initiation of an effective response, with tangible environmental and operational consequences.
When the abandoned barge grounded and released an estimated 35,000 barrels of oil, uncertainty over ownership and liability immediately complicated reporting, decision-making, and mobilisation, as no responsible party could trigger the established response and funding mechanisms.
This lack of accountability contributed to delayed reporting to the appropriate authorities, compounded by local capacity constraints and disrupted communications, which in turn slowed coordination between agencies and limited the ability to respond quickly. The resulting coordination gaps meant that response efforts had to be built reactively rather than proactively, increasing environmental exposure along Tobago’s coastline and placing additional strain on national resources before international technical support could be received.
After around nine weeks of response operations supported by OSRL, the teams successfully contained and recovered a substantial quantity of released oil.
Even “Insured” incidents can be challenging
The MV Rena grounding off the coast of New Zealand and the Sea Empress incident on the Pembrokeshire coast both demonstrate that even fully insured, conventionally operated vessels can still present major challenges for the response efforts.
In the Rena incident, despite clear ownership and established insurance arrangements, response operations were hindered by severe weather, rapid structural failure of the vessel, and the complexity of safely accessing fuel and cargo on a damaged reef. Similarly, the Sea Empress incident also demonstrated how environmental conditions and the scale and speed of the release can quickly overwhelm initial response actions.
Together, these incidents underscore that oil spill response is inherently complex, and that the presence of insurance and established systems does not eliminate delays or operational difficulties.
In unregulated or opaque shipping scenarios, these inherent challenges are compounded by uncertainty over responsibility, funding, and authority to act.
The reality of spill response capability
Unfortunately, the environmental impact of a spill is often unavoidable after a major incident. Although technology and resources continue to advance, they still have limits that will ultimately affect capability.
The public perception of an effective clean-up process in oil spill response does not always align with the operational reality. The reputational damage local authorities or operators face in the event of an incident is often significant, even if the spill is not their responsibility. Public expectations of a rapid or complete clean-up can diverge sharply from operational reality, making clear, honest communication essential.
Being upfront about these limitations and investing in preparedness rather than reassurance is critical to maintaining trust and enabling effective decision-making during a response.
Geographic disparities in preparedness
Oil spill preparedness is not level across the globe, creating significant disparities in response capability. In many regions, there are established equipment stockpiles, dedicated response organisations, and clearly defined coordination frameworks that enable rapid, structured responses.
In contrast, other transit regions frequently used by shadow or non‑traditional fleets may lack essential equipment, trained personnel, and reliable funding mechanisms, limiting their ability to respond effectively when an incident occurs.
The result is uneven global resilience, where the outcome of a spill can depend as much on geography as on the scale of the incident itself. This reality reinforces the importance of preparedness planning that recognises and addresses these gaps, rather than assuming consistent capability worldwide.
These inconsistencies expose a central strategic challenge for coastal states and responders: when prevention reaches its limits, response capability becomes the deciding factor.
The strategic question: If prevention is limited, what is left?
OSRL’s experience, from the Sea Empress response to more recent incidents, such as the abandoned “ghost” barge off Tobago, highlights a persistent strategic reality: while prevention remains essential, it is not always within the control of coastal states or responders.
Legislative enforcement across jurisdictions is inherently complex, and the effectiveness of traditional oversight is increasingly constrained by AIS spoofing, ambiguous ownership structures, and vessels operating outside conventional regulatory and insurance frameworks. In such conditions, incidents may occur despite best efforts to deter them.
When prevention is limited, response capability becomes the decisive factor, demonstrating the stark difference between a managed incident and an incident that may cause long‑term environmental and socioeconomic harm.
The enduring question for governments and coastal states, therefore, is not simply “Will it happen?” but rather “Are we prepared, operationally, financially, and organisationally, when it does?”
Conclusion: A risk that sits between governance and response
Ghost fleets represent a structural risk within the modern maritime system, not an isolated irregularity. Gaps in accountability, driven by sanctions, elusive ownership, weak enforcement, and limited oversight, increase environmental exposure.
This type of incident could expose the limited capability and efficiency of outcomes shaped by preparedness and coordination. In this context, realistic expectations matter; managing the public’s expectations for the outcomes of a response is as important as the assets themselves.
For organisations involved in maritime operations, this trend reinforces the importance of clear response frameworks, defined roles, and tested contingency plans, not as a guarantee against incidents, but as the primary means by which their environmental, economic, and reputational consequences will be limited.
