The China-Japan and Venezuela-Guyana Maritime Disputes: how the law on undelimited maritime areas addresses unilateral hydrocarbon activities

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In December 2018, two incidents brought to the fore the importance of the rules addressing activities in undelimited maritime areas.  The first incident occurred between China and Japan in the East China Sea, and the second took place between Venezuela and Guyana in the Atlantic Ocean. Whereas the establishment of maritime boundaries is the optimum choice when it comes to the creation of a stable and secure environment for the conduct of maritime activities, the UN Law of the Sea Convention 1982 (‘LOSC’ or ‘the Convention’) provides for the regulation of operations even in the absence of maritime delimitation. With a view to avoiding tension, Articles 74(3) and 83(3) LOSC impose two obligations upon states having overlapping entitlements/claims in a given undelimited maritime area. This post scrutinises the behaviour of the parties involved in the aforementioned disputes through the lens of the LOSC.

The factual background

On the 3rd of December 2018, Japan protested China’s deployment of a jack-up rig and the drilling of boreholes near the provisional median line between the two states in the East China Sea. In response, the Chinese Ministry of Foreign Affairs stated that China was carrying out hydrocarbon activities in waters falling within its jurisdiction and that it does not recognise the provisional median line with Japan.

It is worth mentioning that China has been engaged in hydrocarbon activities in the area since 2003 (a deal on the establishment of a joint development zone reached in 2008 has not been implemented). Furthermore, it is recalled that in 2014 China performed unilateral oil and gas ventures in an undelimited maritime area within 200M of the coasts of Vietnam, triggering the latter’s vehement reaction. China had attempted to justify its activities back then by invoking its claims according to the ‘9-dash line’, a claim which was put in doubt by the Award of the Arbitral Tribunal in the South China Sea (Philippines v China) case (2016).

Moving to the other side of the globe, on the 22nd of December 2018, the Venezuelan navy intercepted the ‘Ramform Tethys’, a research vessel (operated by Exxon Mobil, flying the flag of Bahamas) conducting seismic surveys at the behest of Guyana. The Guyanese government stressed that the vessel’s activities took place at a distance of 140 Km from the provisional equidistance line with Venezuela, hence in an area within Guyana’s maritime zones.

For its part, Venezuela argued that the research vessel was located in a maritime area ‘over which Venezuela undoubtedly has unquestionable sovereignty’. As previously analysed in this blog, the two nations have long been at loggerheads over the Essequibo Region and the sea waters adjacent to it.

These two latest incidents add to the ongoing conundrums between the states involved and highlight the importance of international law and, particularly, the rules on undelimited maritime areas with respect to the prevention/de-escalation of tension and the establishment of a coherent legal order for the oceans.

The legal framework

The jurisprudence of international tribunals has repeatedly emphasised the significance of maritime delimitation for the orderly conduct of maritime activities (1969 North Sea cases, para 48; 1978 Aegean Sea Continental Shelf case, para 85; 2014 Bangladesh v India, para 218; see also the 2011 UN Secretary-General’s Report on the Oceans and the Law of the Sea (Add. 2), para 351).

Nonetheless, for a variety of reasons, a large amount of sea waters remain undelimited. Should this pose impediments to economic endeavours in those areas? Indeed, one of the most challenging tasks of the Third United Nations Conference on the Law of the Sea was regulation of activities in maritime areas where two or more states have laid overlapping claims and/or have entitlements.

The drafters of the Convention found themselves in a dilemma since on the one hand they wanted to prevent unilateral exploitation of natural resources in undelimited areas, whereas, on the other, it was not their intention to freeze all activities in there (Statement by the Chairman of Negotiating Group 7, NG 7/26 (26 March 1979); see also 2007 Guyana v Suriname Arbitration, paras 460, 465, 470).

This dichotomy is reflected in identical paragraphs 3 of Articles 74 and 83 LOSC, which read as follows:

Pending agreement as provided for in paragraph 1, the States concerned, in a spirit of understanding and cooperation, shall make every effort to enter into provisional arrangements of a practical nature and, during the transitional period, not to jeopardise or hamper the reaching of the final agreement. Such arrangements shall be without prejudice to the final delimitation. (emphasis added)

These two obligations of conduct purport both not to suspend all economic ventures and at the same time to impede unilateral exploitation of natural resources, lest such actions jeopardise the reaching of a final delimitation agreement.

Be that as it may, and notwithstanding the fact that Articles 74(3) and 83(3) LOSC implicitly stipulate that states should show self-restraint and carry out any activities in good faith, they provide no guidance as to what operations may be permitted in undelimited areas. The Arbitral Tribunal in the 2007 Guyana v Suriname case, following the (pre-LOSC) 1976 Aegean Sea Continental Shelf (Interim Protection) case, resolved that seismic surveys are permissible as they do not cause irreparable physical damage. To the contrary, it pronounced that drillings undertaken unilaterally are to be deemed unlawful because they may jeopardise the reaching of the final agreement (paras 460, 466-8, 470, 480-1).

In the 2015 Ghana/Côte d’ Ivoire (Provisional Measures) case, a Special Chamber of ITLOS considered the gathering of seismic data in an undelimited maritime area by Ghana as potentially detrimental to the sovereign rights of Côte d’ Ivoire and prohibited any new Ghanaian drillings. In its final judgment (2017), the Chamber, correctly, did not find that Ghana’s unilateral activities in the undelimited area violated the Ivorian sovereign rights since they had taken place on its side of the designated maritime boundary. Nevertheless, the Chamber rejected the view that Ghana’s unilateral drillings were in breach of Article 83(3) LOSC.

At this point, it is necessary to distinguish impairment of a state’s sovereign rights from circumvention of the obligations envisaged in the said provisions. Even if an activity does not encroach upon the sovereign rights of another state, it, nonetheless, may very well violate the operating state’s duties under Articles 74(3) and 83(3) LOSC and engage its international responsibility. This is all the more so when such conduct involves drilling, which causes irreparable harm to the seabed. Unfortunately, the Chamber did not make that distinction (for a criticism of the judgment see here, here and here; see also Judge Paik’s Separate Opinion, para 19).

As regards interception incidents, the Tribunal in the 2007 Guyana v Suriname arbitration put forward that the interception of a research vessel/drillship involving threat of force constituted a violation of the UN Charter, the LOSC and general international law (para 445).


First off, bearing in mind the 2017 Ghana/Côte d’ Ivoire judgment, China’s unilateral drilling in proximity to the provisional median line with Japan could be deemed legitimate as it occurs on its side of the median line. However, this does not absolve China of its obligation ‘not to jeopardize or hamper the reaching of the final agreement.’ Drilling operations close to the provisional median line entail the risk of tapping a hydrocarbon reserve straddling the maritime areas of the two states. Such an eventuality might, among others, harm Japan’s sovereign rights over its natural resources and jeopardise the reaching of the final agreement. Hence, China should have entered into consultations with Japan prior to commencing its operations so as to act in conformity with its duties under the Convention (2007 Guyana v Suriname, paras 477, 488(3)).

In respect of the strife between Venezuela and Guyana, the two states have locked horns with regard to their overlapping maritime claims stemming to a great extent from the Essequibo dispute. Consequently, both argue that they acted lawfully within their maritime zones. In order to limit excessive claims, it is supported that only maritime entitlements should be taken into account, namely assertions made in good faith within the scope of international law paying regard to potential rights of third states (1982 Tunisia/Libya, para 34; 2009 Black Sea case, para 99; 2012 Nicaragua v Colombia, para 159; 2016 The Philippines v China Award, para 705; 2018 Costa Rica v Nicaragua, para 115). Pending the terrestrial dispute over Essequibo, it is hard to come up with a clear-cut answer. However, Guyana appears to have acted in good faith as it operated 140 Km from the provisional equidistance line. The fact that the venture took place far from the provisional line may justify no recourse to consultations, but it is submitted that Guyana should have notified Venezuela (if it had not) of its intentions. At any rate, even though there are no details as to whether the Venezuelan navy threatened the research vessel, the lawfulness of law enforcement operations in an undelimited maritime area lying at a significant distance from the provisional equidistance line is highly questionable.

In light of the soaring hydrocarbon operations in undelimited maritime areas, it is of utmost importance for states to comply with the customary rules of self-restraint and good faith, enshrined in Articles 74(3) and 83(3) LOSC. This way, the interested states will avoid tension until they hammer out a delimitation agreement or establish a joint development zone that will allow them to avail themselves of the hydrocarbon boon.

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