The views expressed by contributors are their own and not the view of The Hill

China’s maritime strategy: To own the oceans by adverse possession

Even as states and conservation organizations are still celebrating the new United Nations treaty that hopefully will protect 30 percent of the high seas, China is working, in plain sight, to take sovereign control of the world’s oceans.

The global presence of China’s “distant water fishing fleet” has garnered substantial attention, particularly since its heightened visibility around the Galapagos Islands in 2020. Most of that attention has centered on concerns about sustainability and allegations of illegal, unreported and unregulated fishing. In many cases, however, China’s activities have been on the high seas, making such fishing arguments limited at best, since no state can claim sovereignty over the living marine resources outside of its Exclusive Economic Zone.

Ironically, however, it seems that is exactly what China wants: sovereignty over the high seas. What perhaps has been the most overlooked aspect of the distant water fishing fleet is China’s express strategy — since at least 2010 — to occupy the oceans in an effort to gain “rights and interests.” In other words, China likely believes that, in time, the presence of its distant water fishing fleet on the high seas will convert into some degree of sovereign control over those waters and the resources in them. Put differently, China is working to gain ownership of the oceans through adverse possession.   

The doctrine of adverse possession does not actually exist in maritime law. An Anglo-American property law concept, it is sometimes known as “squatter’s rights” and allows for an individual to obtain the legitimate, legal title to real estate simply by occupying that property for an extended period of time without the permission of the real owner. Each jurisdiction has slight variations, particularly with regard to the length of time required to obtain these real property rights and interests. Most, however, contain similar elements. In Maryland, for example, the requirement is that the individual engage in “actual, open, notorious and visible, exclusive, hostile and continuous possession.” Not only are those elements similar throughout the United States and the United Kingdom, they are similar throughout most common law jurisdictions.

Through its fisheries policies, it appears that the People’s Republic of China is effectively translating this property law doctrine into a global maritime strategy. By its actual, open, notorious (observable) and visible, exclusive, hostile and continuous effort to occupy the high seas of the world, China is quietly working to gain “rights and interests” over both the water and the marine resources of the open ocean. In some cases, this adverse possession may even include the Exclusive Economic Zones of different states. The basis for understanding this strategy can be found in China’s express maritime territorial claims.  


China has asserted its “Nine Dash Line” claim to maritime areas and territory in the South China Sea and East China Sea (beyond what would be permitted under international law) using an argument about “traditional fishing grounds.” Essentially, because Chinese fishers have fished in those areas, China claims it should be able to exert sovereign control over them. Under the United Nations Convention on the Law of the Sea (UNCLOS), to which China is a party, sovereign rights over maritime spaces are limited by zones determined by their distance from a coastal landmass.  China’s claims constitute an attempt to go beyond those limitations to allow for sovereign rights based on traditional fishing, even beyond the distances provided under UNCLOS.

That claim to be able to “own” water that is outside the limits of the legally defined maritime zones, and within either the high seas or the Exclusive Economic Zones of other states, is the argument that China is likely to begin making about the areas where its distant water fishing fleet has been operating in recent years. And just as the implications of the Nine Dash Line claim have included the development of military bases, expanded naval presence, and advances on both Taiwan and sovereign states in the region, China is preserving similar options in other parts of the world, including off Africa, South America, the Middle East, South Asia and even the Caribbean.

The potential resource grab alone is significant given the implications for food and energy security. Fish make up 20 percent of global dietary protein, and China is by far the world’s largest consumer of fish. At the same time, subsea rights to oil and gas and minerals also may be in China’s intentions, particularly as China extends its lead as the largest consumer of energy.  That said, reducing this occupation strategy to a ploy for gaining fish and fuel betrays a misunderstanding of China’s ambitions. The military, intelligence and communication infrastructure that China could then install in “its own” waters would ensure that the sun never set on China’s capacity to monitor and control much of the world.

While this attempt to turn a real property concept into a strategy to claim the global maritime commons may seem spurious, its potential success should not be overlooked. China has become an expert in “unlawfare,” using baseless legal arguments to bully states into positions that traditionally would have required a military action. In this case, the very presence of the distant water fishing fleet may be forming the strategic foundation for China to claim sovereignty over the world’s oceans. And the People’s Liberation Army Navy, along with the Maritime Militia and other forces, may be prepared to back up such claims, particularly in parts of the world where China has used other forms of influence to sway critical decision-makers. This strategy must therefore be countered, clearly and unequivocally. 

Regional Fisheries Management Organizations are moving toward allocating degrees of sovereign rights over certain areas of the high seas. At the moment, China is likely to be first in line for accessing those rights in much of the world. Understanding China’s strategy, therefore, is critical for these organizations, which may wish to reconsider their approach. At the same time, states around the world must recognize this effort at adverse possession and devise national approaches to limiting China’s options for making a “traditional fishing grounds” claim over the high seas.

With 70 percent of the earth covered in water, any one state’s effort to establish rights and interests over the global commons should be a concern. The new High Seas Treaty may seem like a step in this direction, but if China already sees the Exclusive Economic Zones of coastal states as fair game — as it continually demonstrates in even major states such as Indonesia and the Philippines — it is unlikely that it will be dissuaded from its strategy. The way to counter adverse possession in property law is for the true owner to recognize the squatter and either give permission for them to be there or expel them. All states, therefore, should help shine a light on China’s strategy and reduce its points of argument for any “rights and interests” it believes it may be accruing in the high seas. 

Ian Ralby, Ph.D., an expert in maritime law and security, has worked in more than 90 countries on issues ranging from illegal fishing and counter-trafficking to piracy, hybrid aggression and naval warfare. He is CEO of I.R. Consilium, a global consultancy that concentrates on maritime and resource security, and a fellow at the Center for Maritime Strategy. Follow him on Twitter @ImRalby.