Understanding the issue about Chinese survey vessels in Benham Rise

Benham Rise is an underwater plateau that stretches from the coasts of Cagayan and Bicol up to approximately 300-350 nautical miles (nm) in the Pacific Ocean. A large part of this plateau is within the 200 nm Exclusive Economic Zone and continental shelf of the Philippines.

An additional area of seabed extending around 150 nm was successfully claimed by the Philippines as its “extended continental shelf” (ECS) in accordance with Article 76 of the UN Convention on the Law of the Sea. The region may not be “territory” in the same sense as land territory, but it is definitely “territory” for the purposes of Philippine laws and regulations over natural resources. The 1987 Constitution considers as legally part of the National Territory all areas over which the Philippines has sovereignty or jurisdiction; Benham Rise falls squarely within this definition.

Within 200 nm, the Philippines has exclusive sovereign rights to explore for, and exploit, living and non-living natural resources of both the water column (the EEZ) and the seabed beneath (the continental shelf). “Sovereign rights” may not be the same as full “sovereignty”, and people usually confuse these two terms. It is like confusing a person’s rights over property he holds under lease and rights to property he holds as a full owner. But the fact that the former is of a different status than the other does not make them any less enforceable under law.

These waters are subject to high seas freedoms available to all nations (including freedom of navigation and overflight), but such freedoms must be exercised in a way that respects, and gives due regard to, the sovereign rights of the Philippines. In addition, the Philippines has the right to regulate and participate in any marine scientific research (MSR) conducted in this area.

Beyond 200 nm, but within the area of the ECS, the water column is considered to be part of the high seas subject to the common rights and freedoms of all States. But the seabed underneath is still subject to the exclusive sovereign rights of the Philippines for purposes of exploration and exploitation of seabed resources. No other State may carry out activities for these purposes in the seabed in this area, even though they may exercise rights and freedoms on the waters above it. This is the area that was recognized by the Commission on the Limits of the Continental Shelf (CLCS) to be the Philippines’ ECS.

Passing through?

The reported activities of China therefore have to be viewed with an eye for careful legal nuances. SND Lorenzana described Chinese survey vessels to have been passing through, or to have been stationary for extended periods of time, or moving in a criss-cross/back-and-forth pattern. Naturally he cannot describe in detail what these vessels were doing, he can only see how the vessels are moving. But that is enough to make some reasonable assumptions. Even without direct visual sighting, the movement of a ship (such as that recorded on a radar plot, or by satellite) tells a lot about its activities.

The first point is this: a vessel is merely passing through if it is moving at a steady pace in one direction, obviously travelling from a distinct place of origin to a specific destination. UNCLOS Part II guarantees the right of foreign vessels to pass through the waters of coastal States subject to certain rules. If it is moving through territorial waters (i.e., within 12 nm from shore) its right to do so is guaranteed by the “right of innocent passage.” Beyond territorial waters, i.e., in the EEZ and high seas, it does so in exercise of “freedom of navigation,” likewise guaranteed by UNCLOS, but such freedom of navigation, by its very name, refers only to the act of navigating on water. It does not connote freedom to undertake any other activity. Such other activities will be governed by the rules applicable to either the EEZ or the high seas, wherever the ship may be located at the time.

Mesophotic zone from the Latin words, “meso”, i.e., mid-and “photos”, i.e., light, are found in depths from 30down to 150meters .Even with low light penetrating this zone, corals and photosynthetic algae can still grow. Photo by OCEANA/UPLB.

This takes us to the second point: within the EEZ of a coastal State, a ship exercising freedom of navigation must respect the exclusive sovereign rights of the coastal State to its EEZ and continental shelf. These rights of a coastal State include regulatory jurisdiction over activities which have the purpose of exploring and exploiting the living and non-living resources of the water column and the seabed within 200 nm from shore. These are guaranteed by UNCLOS Part V and VI. They also include regulatory jurisdiction over activities that fall within the purview of “marine scientific research.” This is governed by UNCLOS Part XIII. While the extent of coastal State jurisdiction varies, they all require the basic element of coastal State consent.

A ship may be assumed to be doing more than exercising freedom of navigation if it is moving in a way that is not in accord with the general objective of navigation: to get from one place to another. If, for example, a ship becomes stationary for a long period of time in one place, either keeping in one specific spot or drifting somewhat, before again moving purposely, or doing so repeatedly, it is reasonable to assume that it is not merely navigating. It is likely doing something else, such as taking soundings, dropping probes, deploying divers or remotely-operated vehicles, or some other activity that requires the ship to stop navigating.

If a ship moves in a direction that is not a straight line, it does so not merely to navigate, but in connection with another activity entirely. If it is moving in circular, zigzagging, or other irregular patterns, it is reasonable to assume that it is chasing fish (or some other object), or actually fishing (or something similar), or doing something else entirely (like military exercises). If it is moving in a regular criss-crossing or back-and-forth pattern at regular intervals, it is likely mapping the ocean floor with sonar or other device. All of these activities indicate that the ship is not merely passing through (i.e., exercising either the right of innocent passage or the freedom of navigation) but is actually doing something else: either marine scientific research, or military activities such as exercises or hydrographic/oceanographic surveys. It becomes even more probable if the ship either returns to its port of origin, or goes to another place that it could have gotten to very easily and in far less time had it not carried out its various movements.

Bringing the situation back to Benham Rise

For China to correctly claim that its ships were merely exercising navigational rights and freedoms, its vessels must have moved from one place to another in a regular and efficient pace. It would be best if the ship also followed the usual navigational routes through the Benham Rise Region like any other foreign vessel. In those cases, it may be said that the ship was merely exercising navigational rights and freedoms, and China had the right to do so even within Philippine waters because it is in accord with international law.

But if it is shown that the Chinese vessel did not simply move from one place to another along the usual navigational tracks, but instead either took an unreasonably long time or followed an irregular route with patterns such as those described above, then the Philippines may have reason to complain.

A team of technical divers in one of their safety stops as they ascend from the bank. Safety stops are very important in dives deeper than 30 meters (100ft) to prevent divers from getting decompression sickness. Photo by OCEANA/UPLB.

China is under obligation to respect the Philippines’ jurisdictions in the relevant area. If within 200 nm from the coast of Luzon, that ship may be presumed to be undertaking marine scientific research at best, or conducting marine resource assessment and/or exploitation at worst (assuming it is a civilian vessel). Whatever its form or purpose, in this area, marine scientific research can only be undertaken with the Philippines’ knowledge or consent. Resource exploration and exploitation activities can only be undertaken with the Philippines’ express permission. It appears from these reported cases that no such knowledge was made known, nor was consent requested, nor was permission granted.

For such activities within 200 nm from shore, therefore, the Philippines has every right to question China. At minimum, China owes the Philippines an explanation to describe exactly what its vessels where doing since they were clearly not merely navigating for the purpose of getting from place to place.

Marine research?

If it is found that China was undertaking marine scientific research, it is under an obligation to share all of its findings, information, and access to samples, data, and research results with the Philippines and internationally. Refusal to do so entitles the Philippines to demand that China cease and desist from again conducting any such activities in the future, unless and until it is with the Philippines’ prior knowledge, consent, and participation.

If it is found that China was undertaking resource exploration and/or exploitation activities, it is under an obligation to respect and comply with the laws and regulations of the Philippines pertaining to such resources. The Philippines is entitled to demand that China cease and desist from such activities in the future, as such activities can only be undertaken by Philippine citizens and corporations duly authorized by the Philippine government.

Beyond 200 nm from shore, but within the area of the ECS, China may undertake marine scientific research within the water column, as long as it does not pertain to the exploration and exploitation of the seabed resources in the ECS. The waters being part of the high seas, Chinese vessels are entitled to conduct marine scientific research and resource exploration and exploitation activities, so long as generally they do not cause damage to the marine environment. The only other restriction that would probably be applicable is that resource exploitation activities should not contravene the conservation and management measures of the Western and Central Pacific Fisheries Commission, which has jurisdiction over some of the fishery resources and fishing activities in the Pacific Ocean. But this is another matter entirely.

So far, all these presume that the activities fall within the category of MSR; a different set of rules apply if the activities are in fact military activities such as military hydrographic and oceanographic surveys. These kinds of activities are very similar to MSR because they use many of the same techniques and technologies; this similarity is the basis for China to assert that they are one and same, and for which the same rules apply. However, since military activities are generally not included within the purview of UNCLOS except in certain very limited instances, maritime powers such as the US, UK and Russia have asserted that military hydrographic and oceanographic surveys are not subject to coastal State regulation and jurisdiction beyond 12 nm from shore.

Military hydrographic and oceanographic surveys are needed by maritime powers in order to obtain accurate information about the ocean environment so that military vessels, especially submarines, can best take advantage of that environment in battle. The undersea terrain, underwater currents, thermal layering, saline differences, water temperatures, etc. are all environmental factors that can play pivotal roles in the movement and detection of undersea and surface vessels. Knowledge of sea conditions provide a skilled ship/submarine commander with enormous tactical and strategic advantages.

China is known to be expanding the reach of its naval power, both on the surface and under the sea. It can therefore be expected to be undertake military hydrographic and oceanographic survey activities in all ocean areas that it expects to operate in. The Benham Rise region, being a possible area of approach for naval forces coming from the Pacific, is obviously one of those potential areas of operation.

Arc -eye hawkfish (Paracirrhites arcatus) is a cryptic reef fish that usually hides in holes and crevices. Photo by OCEANA/UPLB

From a military standpoint, it is not surprising that China would undertake military surveys in the Benham Rise region. It is not for the purpose of claiming territory; rather, it is for the purpose of gaining practical military advantage. This would be consistent with China’s well-known need, under the so-called Two Island Chain Strategy, to gain the ability to control the seas in the area of the so-called Second Island Chain that spans the Pacific Ocean from southern Japan to northern Indonesia/PNG.

But then, this places China in a policy dilemma. On one hand, given the advantages of military surveys and the perceived vulnerability of its navy and coastal area, China prohibits by law all such surveys without its knowledge and consent within 200 nm from its coastline. It considers such activities to be contrary to its national security interest to protect itself from external aggression by naval powers. On the other hand, by necessity it must also carry out such activities in all waters it expects to operate in, which includes the Pacific Ocean, which in turn includes the area of Benham Rise. In carrying out such surveys without the Philippines’ knowledge and consent, it is therefore placed in the opposite position of being the external naval power acting against the national security interest of the Philippines.

It also puts the Philippines’ national security between the devil and the deep blue sea, so to speak. On one hand, it seeks friendly relations with China and is trying to establish an equidistant position between the potential rivals to maritime dominance in the region. But on the other hand, the Philippines’ friendship with China will not impede China’s national defense imperative to develop its capabilities to operate in the deep waters of the Pacific, some of the most strategic of which happen to be Philippine waters.

How then should the Philippines react toward China’s activities in the Benham Rise region?

First, within the 12 nm territorial sea of the Philippines, the relevant parts of which are those connecting the northern part of Luzon with the Babuyan and Batanes Islands, and the strait between Bicol and Samar, China may exercise the right of innocent passage. That is not questionable as long as that is all that they are doing. However, these waters are technically not part of the Benham Rise region, so these incidents are beside the point. The Philippines’ rights over this area, and what it is entitled to undertake in case passage is not innocent, are clearly established in international law.

Second, beyond the territorial sea but within the EEZ and continental shelf of the Philippines within 200 nm from the eastern coast of Luzon, China’s survey vessels cannot do more than navigate steadily to another destination beyond the Philippine EEZ and continental shelf. If they have done anything more than that, they owe the Philippines an explanation based on basic facts, such as the tracks of such vessels.

If the activity falls under either MSR or resource exploration/exploitation, the Philippines is entitled to demand that (a) such activities stop, (b) the output of all such research already finished be disclosed and shared with the Philippines, and even the world, and (c) require any future such activities to be carried out with Philippine knowledge, consent, and participation.

If the activity falls within military activities, the Philippines is entitled to ask China to clarify its policy on military activities in the EEZ. It is also entitled take measures to protect itself from, or neutralize the possible advantages gained by such activities, including establishing monitoring facilities along its eastern seaboard, carrying out its own maritime patrols and surveys, and joining with allies in conducting other military activities in the same area. It is fully entitled to patrol these areas and find out for itself exactly what any vessels, Chinese or otherwise, are doing.

Third, beyond 200 nm from shore but within the area of the ECS of the Philippines, China’s survey vessels may exercise freedom of marine scientific research and military activities, for as long as such activities do not contravene its exclusive sovereign rights to the seabed resources there. There is not much it can do against such activities unless they clearly are related to seabed exploration and exploitation, or if they appear to cause harm to the marine environment.

The counter-measures against activities other than navigation that have been mentioned so far by Philippine officials must be similarly assessed. China’s rights and freedoms in any location must be weighed against the Philippines’ own rights and entitlements in that area. There is no one single response to each situation.

The Philippine Navy is entitled to “shoo away” Chinese survey activities if they are taking place within the territorial sea. Beyond the territorial sea, PN ships may shadow/escort Chinese ships and challenge them if they carry out activities other than simple navigation, and demand that they cease and desist from any activities which appear to be MSR or resource exploration/exploitation if they take place within 200 nm from shore. If they continue nonetheless, although the Philippine Navy cannot directly interfere, it may fully document such activities until they depart, and later on file the requisite protest, require compliance with Philippine laws and regulations, or perhaps even consider dispute resolution mechanisms under UNCLOS Part XV, which incidentally could include filing an arbitration case in accordance with Annex VIII (Special Arbitration for Marine Scientific Research, or Fisheries) if sufficient evidence warrants it. Activities undertaken beyond 200 nm may be shadowed and not interfered with, but should be carefully documented for possible future reference and use.

At this point, given the information available, the DND is absolutely correct in questioning China’s activities in the Benham Rise region. DFA is likewise correct in sending a diplomatic note asking China for an explanation. But these are just initial steps. What happens next can be decided by two things: (a) a graphic plot illustrating the track of each one of the Chinese vessels monitored, showing recorded path, time and location, and (b) the commitment of the two countries in improving their relations on the basis of sincerity, equality and mutual trust. By all means, they should engage in talks; but they cannot simply dismiss each other’s concerns. This may not be about full and absolute sovereignty over Benham Rise, but it is definitely about the Philippines’ exclusive sovereign rights under international law. The fact that it is not an issue of sovereignty over territory like land does not make it any less important: it is still about the Filipinos’ maritime heritage, and the resources of their future generations.

(Jay Batongbacal is Assistant Professor and Director, Institute for Maritime Affairs and Law of the Sea, University of the Philippines (UP-IMLOS).Above article first came out in his Facebook page.)


​Justice Carpio’s Benham Rise 101

The notes of Supreme Court Senior Associate Justice Antonio T. Carpio on Benham Rise is very useful…

Who is protecting PH national interest in South China Sea?

A tense situation transpired 50 nautical miles northwest of Subic Bay in Zambales last Thursday when…

Primer on the PH-China Arbitration

The purpose of this primer is to inform the reader of the nuances of the case that is to be decided…

About Vera Files

Founded in March 2008, VERA Files is published by veteran Filipino journalists taking a deeper look into current Philippine issues. Vera is Latin for “true.”

Contact Us

Email us at