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From the North Sea to the Bay of Bengal: Maritime Delimitation at the International Tribunal for the Law of the Sea

From the North Sea to the Bay of Bengal: Maritime Delimitation at the International Tribunal for the Law of the Sea

Last week, the International Tribunal for the Law of the Sea delivered its judgment in the Dispute concerning delimitation of the maritime boundary between Bangladesh and Myanmar in the Bay of Bengal (Bangladesh/Myanmar). Although Bangladesh and Myanmar started negotiations for the delimitation of their maritime boundaries since 1974, when Bangladesh became independent from Pakistan, the boundary had still to be settled by 2009, when Bangladesh initiated the proceedings. The dispute was fuelled in 2008 when, following the discovery by Indian and Myanmar of gas deposits, Myanmar authorised exploration in the contested area. Bangladesh replied by sending its warships in the disputed area. Luckily, conflict was avoided following intense negotiations between the parties and the dispute has now been solved peacefully by having recourse to the dispute settlement provisions (Part XV) of the United Nations Convention on the Law of the Sea (UNCLOS).

 The decision established the boundary of the territorial sea, exclusive economic zone and continental shelf [including the area of continental shelf beyond 200 nautical miles (nm) from the baselines], between the two States in the Bay of Bengal. It also addresses navigation in the territorial waters of Bangladesh by vessels of Myanmar and discusses the rights and duties of the parties in the area where the continental shelf of Bangladesh beyond 200 nm overlaps with the water column within 200 nm from the coast of Myanmar.

This case is the first to be decided between the two initiated by Bangladesh for the delimitation of its maritime boundaries with its neighbouring States, Myanmar and India. As Dapo has already reported, delimitation of the Bangladeshi-Indian boundary has been submitted to arbitration. It is to be expected that, following the decision on the boundary, Bangladesh and Myanmar will now start exploitation activities in the bay of Bengal.

For those familiar with maritime delimitation, a quick glance at the map of the region will bring immediately in mind the geography of the North Sea continental shelf cases, decided by the ICJ in 1969. There are indeed at least three similarities between the two cases. The first is the concavity of the coast of one State. In the North Sea case it was Germany, in this case it is Bangladesh. The second is the role of geology and the relevance of the concept of natural prolongation. The third is the necessity for the judge seized with the dispute to exercise “law-making” functions, absent any judicial precedent. In the North Sea case, the ICJ had to determine the rules for the delimitation of the continental shelf according to custom (since the 1958 Geneva Convention on the Continental Shelf was not applicable), in the 2012 case ITLOS had to determine the method for delimiting the continental shelf beyond 200 nm. Of course, the distance between the North Sea and the Bay of Bengal is not only geographical, since the lapse of more than 40 years has added much to the law of maritime delimitation. In 1969 there was no international decision on delimitation save the Grisbadarna award, and the rules and methods finally determined by the ICJ were developed against scant state practice. Nowadays, numerous decided cases provide a robust case law. More importantly, the merits of rules and methods used by courts have been tested several times in state practice. This practice, for example, has confirmed the significance of the equidistance/special circumstances rule and has generally rejected methods such as the corridor method employed in the St Pierre and Miquelon case (one of the very few cases not mentioned at all by the ITLOS).

There are many interesting bits in this decision, not only for the law of the sea scholar, but also for the international lawyer. One issue that is addressed, albeit rapidly, by the Tribunal concerns the elements necessary for the existence of a treaty (this is done in discussing the Agreed Minutes, paras. 88-99). Tacit agreement (paras. 100-118), and estoppel (119-125) are also briefly discussed. The commitment by Bangladesh to allow for the innocent passage of ships of Myanmar in its territorial waters around St Martin’s Island is an example of unilateral act of state producing legal consequences (paras. 175-176) although one could wonder for the need of it, in light if the legal regime provided by Part II UNCLOS. Unfortunately ITLOS did not expand on many issues of interest to the specialist in law of the sea or to international lawyers more generally (this has been commented upon by Judge Wolfrum in his separate opinion). The concise manner of dealing with of many points is probably due to the wish to take on board as many judges as possible. Notably, almost all judges voted in favour of the dispositive, including the two ad hoc judges. The latter not only voted in favour of each point in the dispositive, but also attached a joint declaration to the judgment. While this is unusual in international adjudication, it is in line with the purpose of delimitation, which does not consist in establishing whether a State has complied or not with international law, but aims at drawing a boundary that did not exist before.


ITLOS and the Case Law of Other Tribunals

As Dapo has already reported, this was the first time in which the Tribunal was called upon to draw a maritime boundary between two States. Maritime delimitation cases had so far been decided either by the ICJ or by arbitral tribunals and it was indeed feared by some judges and scholar that bringing a new court into this field would lead to fragmentation of the law. This first decision of ITLOS in this area suggests that these fears are unfounded.

The Tribunal was very keen to emphasise that it will respect previous case law (e.g. para. 184, para. 226 and para. 240) and most of the judges in their declarations or opinions also stressed this fact, sometimes openly acknowledging that this decision far from justifies threats of fragmentation proposed by some . For example, Judge Treves, in his declaration, stated that:


“all courts and tribunals called to decide on the interpretation and application of the Convention, including its provisions on delimitation, should … consider themselves as parts of a collective interpretative endeavour, in which, while keeping in mind the need to ensure consistency and coherence.”


Many elements in the decision reinforce this conclusion. These elements include the constant reference to previous case law (ITLOS cites almost all previous decisions in the field), the language used, the distinction between delimitation of the territorial sea and delimitation of the single boundary between exclusive economic zones and continental shelves (as in the ICJ Qatar/Bahrain decision and subsequent case law), the method of delimitation chosen (the three steps approach adopted by the ICJ in the more recent Romania/Ukraine case), the paramount role of geography in establishing the boundary line and the discharge of geology as a basis for the delimitation or even as a special circumstance. Among many other elements that may have strengthened this approach, there is certainly the experience in maritime boundary delimitation of some among the judges of the Tribunal. Just to make a few examples, Judges Treves, Wolfrum and Judge ad hoc Mensah are also members of the tribunal addressing the delimitation between Bangladesh and India; Judge Nelson was president of the tribunal in the Guyana/Suriname case; Judge Cot was or is ad hoc judge in the ICJ in the Romania/Ukraine case and the Nicaragua/Colombia case; Judge ad hoc Oxman has been an ad hoc Judge in the Romania/Ukraine case.


In addition to the great advantages of judicial consistency, transparency and predictability of the law, adherence to judicial precedents produces two drawbacks. The first is that the Tribunal also follows very much the general trend in endorsing some misunderstandings or equivocal solutions of its predecessors. Thus, for example, in delimiting the single boundary between the exclusive economic zones and the continental shelves, ITLOS professes that it will start by a provisional equidistance line (para. 240). However, it then immediately proceeds to choose the base-point for this line, thus producing what in reality is a modified equidistance line. The second drawback is the absence of elaboration on some points, in the likely wish to avoid discussing critically previous decisions. One cannot help feeling that the absence of any discussion is probably due to the wish to accommodate as many views as possible and to achieve general endorsement of the final delimitation line, even if single judges may disagree on the method used for arriving at it. The effort of the Tribunal to achieve this aim is noteworthy (and praiseworthy) even though more elaboration would have been welcomed in clarifying the law and ensuring legal certainty and predictability.

The decision therefore does not significantly depart from the established law as developed by the ICJ and arbitral tribunals in their “law-making” capacity. The fact that there are no striking innovations does not however mean that the Tribunal does not participate on an equal standing to this process. Far from that, the Tribunal has taken care to add its little bit to the existing case law and to move it one step forward. The two most evident examples are the delimitation of the continental shelf beyond 200 nm and the regime applicable in the so-called “grey areas”. The Tribunal has also, more subtly, indicated what the law is with respect to another issue in maritime delimitation – that of the prevalence of one maritime zone on the other. The Tribunal clarifies that the territorial sea will prevail upon the exclusive economic zone (para. 169) and that a State may exercise rights in an area of overlap that do not impede the exercise of rights by the other State (as in the case of the exclusive economic zone water column overlapping the continental shelf). It has also shed light on the meaning of “agreement” in Art. 15 UNCLOS, on the basis for the entitlement to a continental shelf beyond 200 nm and on the relationship between the role of the Commission on the Limits of the Continental Shelf and that of the binding dispute settlement mechanism in Part XV UNCLOS.


While it is quite probable that the ICJ will remain as busy as ever with delimitation cases, it is also true that the first attempt of the ITLOS at delimiting a maritime boundary has been successful (not only Bangladesh, but also other States such as France and Japan have commented positively on the decision). States, scholars and other judges may rest assured: the ITLOS will follow the tradition and will not innovate any more than is necessary. It is therefore a valid alternative for the delimitation of maritime boundaries.


The Delimitation

The delimitation of the single maritime boundary between Bangladesh and Myanmar follows very much the trend in recent (i.e. since the 1993 Jan Mayen decision) delimitation cases. The ITLOS first divides the boundary line to be drawn into three segments: the first will delimit the territorial seas of the parties, the second their exclusive economic zones and their continental shelves up to 200 nm, and the third the continental shelves beyond 200 nm. The reasons for this differ. In the case of the territorial sea, the applicable rules is formally different from that applying for the delimitation of the exclusive economic zone and the continental shelf. In the case of the continental shelf beyond 200 nm, the Tribunal has to first to address the contention by Myanmar that it does not have jurisdiction and that, even if it had, it should not exercise it. ITLOS then proceeds to delimit each segment on the basis of the applicable rules and principles. Finally, it evaluates the proportionality of the boundary thus reached in the light of the ratio between the relevant coasts of the two States and the ratio between the areas attributed to each.

The first task of the ITLOS was to delimit the territorial sea between the parties, since it decided that the Agreed Minutes adopted jointly by the heads of delegations during one of the negotiations rounds did not constitute a binding agreement, and that there was no tacit agreement or estoppels, in the light of the lack of consistent evidence. Delimitation was effected according to Art. 15 UNCLOS, which requires that an equidistance line be adopted, unless there are special circumstances or historic title justifying another line. The provisional equidistance line became the final boundary for this area, since according to ITLOS there are no special circumstances to justify departure from it. St Martin’s Island, part of Bangladesh, was afforded full effect and was used for plotting the equidistance line. This outcome is very much in line with previous decisions and with the established State practice, that has privileged equidistance in the delimitation of the territorial sea and has given full effect to islands.

The Tribunal rules out the possibility to have the exclusive economic zone of Myanmar prevail over the territorial sea generated by St Martin’s Island:


“the Tribunal recognizes that Bangladesh has the right to a 12 nm territorial sea around St. Martin’s Island in the area where such territorial sea no longer overlaps with Myanmar’s territorial sea. A conclusion to the contrary would result in giving more weight to the sovereign rights and jurisdiction of Myanmar in its exclusive economic zone and continental shelf than to the sovereignty of Bangladesh over its territorial sea” (para. 169).


The second task concerned the delimitation of the single boundary for the exclusive economic zone and continental shelf within 200 nm. The applicable law, according to the Tribunal, is to be found in the UNCLOS (para. 182), customary international law (para. 183) and judicial decisions (para. 184). ITLOS adopts the three-step method used by the ICJ, according to which it first draws an equidistance line, it then checks its equitableness in the light of relevant circumstances and finally assesses the outcome on the basis of the proportionality criterion (para. 240). The provisional delimitation line is, in reality, already a modified equidistance, since ITLOS operates a selection of the basepoints to be used towards this task (para. 241). The Tribunal decided not to use St Martin’s Island as a basepoint, because of the alleged cut-off effect on the projection of Myanmar’s coast (265). Turning to relevant circumstances, the Tribunal accepts Bangladesh’s contention that its concave coast is relevant. According to the Tribunal, it is not concavity itself that is relevant, but it is rather the cut-off effect that a concave coast produces (para. 292). Accordingly, it decides to modify the provisional line, by drawing a geodetic line starting at an azimuth of 215° (para. 334) from a point on the provisional line close to the coast (para. 331). While in principle considered as a relevant circumstance for the purpose of the law on maritime delimitation (para. 318), ITLOS eventually does not attribute any effect to St Martin’s Island for practical reasons, because of the alleged cut-off effect it would produce (para. 318-319). Geology of the seabed, on the other hand, is considered irrelevant in law and in practice, because the delimitation of a single maritime boundary is to “be determined on the basis of geography” and not geology or geomorphology (para. 322). The final line, visible in Sketch-map no. 9 (p. 146 of the decision) is however better appreciated in the Illustration map 4 attached to the separate opinion of Judge Gao.

While the line thus drawn does appear to be somewhere in between the claims of the two parties and does not seem particularly inequitable for either, the very concise treatment of the issue of relevant circumstances by the ITLOS is rather surprising. Relevance of concavity is discussed in the light of previous case law, although the conclusion of the Tribunal on the point is very terse. Islands and geology are very hurriedly dismissed without any reference to precedents or any discussions of the reasons why this is done.

The third and final task of the Tribunal concerns the delimitation of the continental shelf beyond 200 nm. This is the most innovative part of the decision. Despite the fact that some recent treaties have established boundaries beyond 200 nm, it was the first time that an international court or tribunal had to address the law and practice of delimiting such area. ITLOS has thus set the principles and rules not only for this case, but also for future use.

Firstly, it has made clear that a court or tribunal having jurisdiction on the basis of Part XV of the UNCLOS can delimit the continental shelf beyond 200 nm even in the absence of recommendations by the Commission on the Limits of the Continental Shelf (para. 363) and that there are no reasons to abstain from exercising its jurisdiction (para. 394). Secondly, the ITLOS defines that “natural prolongation” for the purposes of Art. 76 UNCLOS is very much the same as the continental margin, as defined in the same article (para. 434). Thus, only geomorphology (describing the seabed) and not geology (which describes the composition of the subsoil, i.e. under the seabed) is relevant in determining whether there is an overlapping of entitlements and thus the need to draw a boundary. This is essentially a rebuttal of natural prolongation as a geological concept. The Tribunal even arrives at the conclusion that a “significant geological discontinuity” is not relevant for determining entitlement (para. 438) and that the geographic origin of the sedimentary rocks is similarly irrelevant (para. 447). An interesting dictum confirms that entitlement to the continental shelf does not depend on any procedural requirements (para. 408) implicitly lending support to the opinion that submission to the Commission on the Limits of the Continental Shelf is not a necessary prerequisite for claiming a continental shelf beyond 200 nm (arguably, it is required to fix the outer limit). Thirdly, the method to be applied for the delimitation of this area is the same as for the single boundary: equidistance/special circumstances (para. 455). An interesting point with respect to relevant circumstances is that the Tribunal does not consider geology as a relevant circumstance and does not accept Bangladesh’s argument of “the most natural prolongation” (para. 460). The only relevant circumstance for ITLOS is the concavity of the coast (para. 461). This part of the delimitation is aptly completed by a reference to the so-called “grey area” issue. In this regard, the ITLOS authoritatively affirms that when, by reason of the employment of a delimitation method other than the equidistance line, the extended continental shelf of a State, as delimited by a boundary line, is beneath the exclusive economic zone of the other, the latter still exercises all its rights over the water column (474). In such situation, each state, in exercising its rights and obligations, is under an obligation to have due regard to the rights and obligations of the other (para. 475-476). This part of the judgement thus provides valuable guidance for future cases, with respect to entitlement, delimitation and management of overlapping rights. Discussion of the legal consequences of a “grey area”, an issue so far avoided by international judges, is particularly welcome and should have a strong influence in future litigation. The issue could come to the attention of the ICJ in the Peru/Chile delimitation (which will be heard by that Court in December), and it will be interesting to see what role will be attributed by the ICJ to the ITLOS decision.

In the concluding proportionality test, aptly defined in the decision “disproportionality test”, the Tribunal, after noting that mathematical precision is not required in carrying out this task (para. 477), wraps up the delimitation exercise stating that a ratio of 1:1.42 (length of coasts) to 1:1.54 (area attributed to each) is not significantly disproportionate.


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