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Part A Commentary on the Modern International Law of Maritime Boundary Delimitation, 1 Context

From: A Practitioner’s Guide to Maritime Boundary Delimitation

Stephen Fietta, Robin Cleverly

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2021. All Rights Reserved.date: 06 March 2021

Coastal states — Delimitation — Straits — Territorial sea — UNCLOS (UN Convention on the Law of the Sea) — Boundaries

(p. 3) Context

The question at issue is the OUTER SEA, the OCEAN, that expanse of water which antiquity describes as the immense, the infinite, bounded only by the heavens, parent of all things

Grotius, Mare Liberum (1609)1

I.  What is the International Law of Maritime Boundary Delimitation?

The international law of maritime delimitation is that body of rules regulating the drawing of boundaries between the overlapping maritime entitlements of neighbouring coastal States. Since the writings of Grotius, Selden, and others in the early seventeenth century, the extent of maritime sovereignty and jurisdiction at international law has been substantially clarified and developed such that, by the late twentieth century, States could legitimately claim rights over areas of maritime space extending 200 nautical miles or more from their coasts. Maritime delimitation is the process by which competing State claims are resolved definitively, according to international law, so as to identify the maritime areas within which coastal States will be left to exercise their sovereign rights.

By definition, any exercise of maritime delimitation involves overlapping claims or entitlements. As Tanja states, ‘delimitation is the determination of a maritime boundary in a situation where two (or more) states are confronted with overlapping titles’.2 Weil comments simply that ‘unless there are overlapping titles, there is nothing to delimit’.3 Nevertheless, overlapping titles are omnipresent in modern relations between coastal States. As Brownlie observes, ‘there is no coastal state in (p. 4) the world that does not have an overlapping maritime zone with at least one other state’.4 The consequences of such overlapping titles are described by Weil:

Every time the maritime projections of two States meet an overlap, each of them must inevitably forego the full enjoyment of the maritime jurisdictions it could have claimed had it not had the geographical misfortune to find its appropriation in conflict with that of its neighbour. A separation then has to be drawn which is exactly what maritime delimitation is all about.5

So what is the body of international rules that governs the delimitation of overlapping maritime titles? The sources of international law are encapsulated by Article 38(1) of the Statute of the International Court of Justice: namely international conventions (i.e. treaties), international custom, ‘general principles of law recognized by civilised nations’, and, as ‘subsidiary means for the determination of rules of law’, ‘judicial decisions and the teachings of the most highly qualified publicists’. In the context of maritime delimitation, the modern starting point is the rules set out in the United Nations Convention on the Law of the Sea of 1982 (‘UNCLOS’, or the ‘Convention’) to which, at the time of writing, there are 167 States parties.6

However, in the words of one learned tribunal, the rules of delimitation set out in UNCLOS (particularly those related to the EEZ and continental shelf) contain little more than a ‘simple and imprecise formula’.7 As such, and in the absence of any clear detailed customary rules based on State practice, it has been left to international courts and tribunals to develop the modern international law of maritime boundary delimitation.

As Adam Smith, author of The Wealth of Nations and the so-called ‘father of modern economics’, stated in his 1762 Lectures on Jurisprudence, ‘jurisprudence is that science which enquires into the general principles which ought to be the foundation of laws of all nations’. Articles 15, 74, and 83 of UNCLOS establish such ‘general principles’ of maritime delimitation, upon which the modern jurisprudence examined in Part B of this book has built for the purposes of defining the modern law. Indeed, such is the dominance of the jurisprudence that Weil concludes:

[T]he legal conquest of maritime delimitation is not the work of either treaty or custom but of the courts which, far from being a subsidiary source of international (p. 5) law, here play the role of a primary and direct source of law, even if they have chosen modesty to ascribe the credit to customary law.8

Neither UNCLOS nor customary international law identifies any prevailing method of delimitation beyond the territorial sea; rather, they specify only the objective of an ‘equitable solution’. It has been left to international courts and tribunals to identify (and frequently implement) the method (or methods) of delimitation to be adopted in pursuit of the mandated objective. As the Arbitral Tribunal in the recent Bay of Bengal arbitration between Bangladesh and India stated, ‘the ensuing—and still developing—international case law constitutes…an acquis judiciare, a source of international law under article 38(1)(d) of the Statute of the International Court of Justice, and should be read into articles 74 and 83 of the Convention’.9 It is that fundamental acquis judiciare in the law and practice of international maritime delimitation that the present work strives to identify and explain.

A cardinal principle of international law that forms the backbone of the acquis judiciare is that all States are born equal. Just as the United Nations is based on the principle of the sovereign equality of all its members,10 so the international law of maritime delimitation is based on the sovereign equality of all competing coastal States. As Weil observes:

Unless one appropriation is to be completely sacrificed to the other—and this would conflict not only with the demands of justice and good sense but also with the principle of equality of States—the sacrifices must be shared equally.11

While sovereign equality (and equal sacrifice) may not always prevail in bilaterally negotiated boundary outcomes, a review of the jurisprudence analyzed in Part B of this book demonstrates that, by and large, it is treated as sacrosanct in the practice of international courts and tribunals. Such respect for equality is perhaps the most important attribute of any third-party dispute settlement process. As explained later in this work, it has been manifested by the priority accorded to equidistance-based methods of delimitation in the modern law. More of that later.

II.  The Early History of Maritime Claims and Maritime Boundary Delimitation

The modern maritime delimitation jurisprudence, analyzed in detail in Part B of this book, begins with the North Sea Continental Shelf cases. In many senses, and (p. 6) for strictly practical purposes, the contemporary practitioner need look no further than that jurisprudence (together, of course, with the applicable provisions of UNCLOS and modern State practice) in order to understand the modern law of delimitation. However, the history of maritime claims and maritime boundary delimitation extends back several millennia. A brief review of that history, and particularly the developments of the early and mid twentieth century, provides valuable context to the contemporary position. As the South African/British jurist Lord Steyn once famously said, ‘in law context is everything’.12

The context must begin with the origins of the concept of sovereign rights over maritime space. This dates back to antiquity. In his 1635 magnum opus, Mare Clausum (‘the closed sea’), the English jurist John Selden advocated the theory of legal dominion over the seas, harking back to the days of ancient Rome, where the Emperor was ‘Lord of the whole world’, and to other historical claims of Tyrrhenian dominion over the Phoenician Sea, Egyptian dominion over the Alexandrian Sea, and the Persian King Cyrus’s claimed dominion over all the seas. Selden cited examples of forms of maritime delimitation involving the ancient Romans, Syrians, Athenians, and Persians. He urged that imaginary lines be drawn for the purposes of ‘bounding the sea’, whether with the help of a ‘seaman’s compass’ or using ‘Celestial degrees either of Longitude or Latitude together with the doctrine of Triangles arising therefrom’.13

Selden’s work was a riposte to that of the Dutch jurist Hugo Grotius, who is widely acknowledged as a forefather of modern international law. In his 1609 paper Mare Liberum (‘the free sea’), Grotius argued that the freedom of the seas formed an essential condition to the development of free trade. He did so in the context of Portuguese claims at the time to hegemony over the expanding trade routes between Europe and the East Indies. Portugal’s claims were accompanied by assertions of sovereignty over what Grotius described as ‘the whole expanse of the sea which separates two parts of the world so far distant the one from the other, that in all the preceding centuries neither one has so much as heard of the other’. He ridiculed the notion that Portugal could claim sovereignty over the Indian Ocean, whether by way of ‘occupation’, ‘prescription’, or otherwise. He argued that ‘in the legal phraseology of the Law of Nations, the sea is called indifferently the property of no one (res nullius), or a common possession (res communis), or public property (res publica)’. He accordingly rejected any prospect of Portugal and Spain (the other assertive maritime power at the time) ‘dividing up the world’ by way of ‘imaginary lines’ in the sea, observing that ‘if that were a recognised method, and such a delimitation of boundaries were sufficient to make possession (p. 7) valid, our geometers long since would have got possession of the face of the earth, our astronomers of the very skies’.14

Nevertheless, while asserting that the sea was incapable of becoming the private property of any person or nation, Grotius did recognize the legitimate assertion of sovereign rights and jurisdiction over parts of the sea for purposes of, for example, the prosecution of piracy. Such limited rights and jurisdiction were, after all, both recognized by State custom and entirely consistent with Dutch maritime and trade interests at the time. Grotius elaborated on the idea in his own 1625 magnum opus, De Jure Belli Ac Pacis (‘On the Law of War and Peace’), alluding to the existence of sovereign rights over those waters adjoining coast States over which they exercised effective control.15 Less than 100 years later, another Dutch jurist, Cornelis van Bijnkershoek, advanced the idea of coastal State sovereignty and jurisdiction, expressing the limits of such sovereignty and jurisdiction thus: ‘the power of the land properly ends where the force of arms ends’.16 Consequently, van Bijnkershoek posited that maritime dominion extended seawards from the land, but was restricted to the range of a cannon (known as the ‘cannon shot rule’). This approach ultimately gave rise to widespread State claims to a 3-mile territorial sea limit, many of which persisted until the mid or late twentieth century and the development of the 12M rule under UNCLOS (‘M’ stands for nautical mile).17 Some States still maintain 3-mile territorial sea limits today.

Thus, the state of international law by the mid seventeenth century was such that, in the Grisbådarna arbitral award of 1909 (discussed further below), the tribunal concluded that, according to ‘fundamental principles of the law of nations, both ancient and modern’, a cession of land territory to Sweden in 1658 had ‘automatically’ included ‘the radius of maritime territory forming the inseparable appurtenance of this land territory’.18

As will be seen in the following sub-section, the theories of Selden, Grotius, and van Bijnkershoek resound strongly, and have in many senses been reconciled, by the modern law of the sea as embodied in UNCLOS. Thus, for instance, UNCLOS recognizes the dominion of coastal States over areas of territorial sea, (p. 8) and sovereign rights over the resources of the EEZ and continental shelf, while at the same time preserving rights of innocent passage and freedom of navigation for all States and maintaining the status of the high seas and its resources as res communis. But what of the historical delimitation of overlapping State claims?

Prior to the First United Nations Conference on the Law of the Sea in 1958, there was no international consensus on the rules applicable to maritime boundary delimitation, in part because there was limited State practice of delimitation at that time. Methods used to delimit the territorial sea included the median-line system, the drawing of a line perpendicular to the general direction of the coast, the prolongation of the land boundary, the thalweg system, and the so-called ‘common zone system’.19

Under the ‘common zone system’, a disputed maritime area would be designated as a zone common to both States.20 An example was an 1879 treaty between France and Spain, which divided the Bay of Figuier into three distinct, equal zones, one French, one Spanish, and a third reserved for common use.21 This general approach was advocated by Bluntschli and Rivier in the late nineteenth century.22

A thalweg is most commonly understood as constituting a line joining the lowest points along the entire length of a riverbed or valley in its downward slope, defining its deepest channel.23 As such, the thalweg system is suitable for delimitation only in specific geographical circumstances, normally involving navigable boundary rivers. By the nineteenth century, the principle that boundary rivers should be delimited along the line of the deepest channel of the river was well established, although State practice regarding its use in maritime delimitation remained relatively rare.24 An example was the convention of 21 December 1923 between Denmark and Germany concerning lateral maritime boundaries in the North Sea and the Baltic Sea, where the thalweg principle was applied as an independent rule of delimitation for certain segments of the maritime boundary.25

(p. 9) In comparison with the thalweg and common zone systems, the use of the median or equidistance lines was more common in early maritime delimitation practice. Early negotiated examples included the 1809 Peace Treaty of Fredrikshamn between Russia and Sweden and the 1846 Treaty between Great Britain and the United States for the Settlement of the Oregon Boundary, along the channel separating the North American continent and Vancouver Island.26 The early twentieth century saw further examples of equidistance-based delimitations, including the 1932 Convention between Italy and Turkey for the Delimitation of the Territorial Waters between the Coasts of Anatolia and the Island of Castellorizo and the 1932 Declaration between Denmark and Sweden concerning the Boundary of their Territorial Waters in the Sound (Sund or Oresund).27

An early example of a delimitation dispute giving rise to a median line boundary following referral to a third party was the Award of 20 October 1903 in the Alaska Boundary case.28 The case concerned a dispute between Great Britain and the United States regarding the course of the maritime boundary in the Portland Channel and beyond. The United States argued that the boundary should follow the channel of maximum convenience using the thalweg principle, while Great Britain claimed that the boundary should follow a different channel based on historical evidence, and that the thalweg principle was inapplicable in matters of maritime delimitation. The Court of Arbitration rejected the thalweg approach and found in favour of Great Britain. Both parties and the court agreed that the boundary line through the preferred channel should be based on a median line.

A seminal early maritime delimitation case was the Grisbådarna arbitration of 1909 between Norway and Sweden.29 While it by no means constitutes modern jurisprudence, and is thus excluded from the analysis in Part B of this book, the award remains relevant to the contemporary law in a number of respects and is thus worthy of some attention. The dispute concerned valuable lobster fishing banks located between the Swedish mainland and certain Norwegian islands, which were fished by the nationals of both States. Sweden and Norway requested that the arbitral tribunal (1) decide whether the maritime boundary in the area in dispute had been fixed by a boundary treaty of 1661 and (2) to the extent that it (p. 10) had not, ‘determine the boundary line, having regard to the circumstances of fact and the principles of international law’. The tribunal concluded that the area had not been delimited by the 1661 treaty. It considered that, when the Norwegian province of Bohuslän was ceded to Sweden in 1658, ‘the radius of maritime territory constituting an inseparable appurtenance of this land territory must have automatically formed a part of that cession’. The tribunal therefore applied the doctrine of intertemporal law, examining what was the state of international law at the time of the cession in order to delimit the boundary. It determined that ‘the principle of drawing a median line midway between inhabited islands did not find sufficient support in the law of nations in force in the 17th century’, and reached the same conclusion in respect of the thalweg method. The tribunal decided instead that, according to ‘the ideas of the 17th century’, the boundary was to be delimited by ‘drawing a line perpendicular to the general direction of the coast’.

The Grisbådarna tribunal calculated that the perpendicular should ‘run to the west about 20 degrees to the south’. However, noting that the perpendicular would pass through the northern part of the Grisbådarna banks and recognizing ‘the great inconvenience’ this would cause, the tribunal determined to adjust the line slightly so as to run in a westerly direction 19 degrees to the south. As a result, the boundary would pass midway between the banks of Grisbådarna and those of Skottegrunde. The tribunal noted that the resulting assignment of the Grisbådarna banks to Sweden was supported by several circumstances. In particular, (1) ‘lobster fishing in the shoals of Grisbådarna has been carried out for a much longer time, to a much greater extent, and by a much greater number of fishermen on the part of the subjects of Sweden than on the part of those of Norway’30 and (2) ‘Sweden has performed in the Grisbådarna region, particularly in recent times, many acts based on the conviction that these regions were Swedish, as, for example, the placing of beacons, the survey of the sea and the installation of a lightship’.

The resulting adjusted perpendicular boundary (extending seawards from ‘point XX’) is illustrated in Figure A1.1.

The Grisbådarna award is echoed in a number of the more modern maritime delimitation precedents reviewed in Part B of this book. In particular, its use of a perpendicular and its desire to delimit consistent with the fishing practice of the parties’ nationals bears some resemblance to the Gulf of Maine case, decided by a Chamber of the ICJ in 1984,31 and the final-stage adjustment of the line presages the modern concept of ‘relevant circumstances’. Indeed, in his 2003 review of maritime (p. 11)

Figure A1.1:  The Grisbådarna award showing the general direction of the coast, the original perpendicular (W20°S), and the adjusted final award (W19°S).

delimitation jurisprudence, Kolb describes the Grisbådarna award as ‘the first precedent in which a tribunal decided for an equitable maritime delimitation’.32

Following the First World War, a number of attempts were made by non-governmental groups to codify the emerging rules of international law related to maritime jurisdiction and the delimitation of overlapping claims. In 1929, the Harvard Law School produced a Draft Convention on Territorial Waters. The Draft Convention included an article on delimitation of territorial waters in straits, providing that, in the absence of special agreement to the contrary, the territorial waters of each State bordering a strait ‘extend to the middle of the strait’.33

Shortly after the Harvard draft, the international community (through the League of Nations) convened an attempt to codify the international law related to territorial waters at The Hague Codification Conference of 1930. A clear majority of (p. 12) the forty-seven States in attendance supported the principle that the coastal State possessed territorial sovereignty over its territorial sea, the airspace above, and the seabed and subsoil below.34 Consequently, the Report adopted by the Second Committee at the Hague Conference stated that ‘it was recognized that international law attributes to each coastal State sovereignty over a belt of sea around its coasts’.35 However, the delegates at the Conference failed to adopt any convention because they were unable to reach an agreement on the breadth of the territorial sea.

By the late 1930s, starting in the Gulf of Mexico, advances in exploration and drilling technology were making the hydrocarbon resources of the seabed more accessible. Consequently, coastal States began to assert claims to sovereignty and jurisdiction over the resources of the seabed beyond the territorial sea limit. The Truman Proclamation of 1945 provided a clear and definitive assertion of authority over the resources of the continental shelf.36 The Proclamation declared that ‘the Government of the United States regards the natural resources of the subsoil and sea bed of the continental shelf beneath the high seas but contiguous to the coasts of the United States as appertaining to the United States, subject to its jurisdiction and control’. In what Brownlie correctly describes as ‘a remarkable exercise in prescience’, the Proclamation proceeded to address the question of the delimitation of competing continental shelf claims in the following terms:

In cases where the continental shelf extends to the shores of another State, or is shared with an adjacent State, the boundary shall be determined by the United States and the State concerned in accordance with equitable principles.

The reference to ‘equitable principles’ was to be taken up subsequently by other coastal States and by the ICJ in the North Sea Continental Shelf and subsequent cases, as discussed below. However, even before the Truman Proclamation, the first treaty of delimitation beyond the territorial sea was agreed in 1942 between Great Britain (on behalf of Trinidad) and Venezuela in the Gulf of Paria.37 Under the treaty, each State recognized the sovereignty of the other over the resources of the continental shelf in the Gulf beyond their (3-mile) territorial waters. The treaty defined a simple, three-legged, line of delimitation, illustrated in Figure A1.2. Each (p. 13)

Figure A1.2:  The Trinidad–Venezuela 1942 continental shelf agreement (Gulf of Paria).

State agreed not to assert any claim to sovereignty or control over those submarine areas which fell on the other State’s side of the agreed boundary line. Unusually in continental shelf delimitation, the treaty provided (at Article 4) that the parties would appoint a mixed commission to ‘take all necessary steps to demarcate the lines…by means of buoys or other visible methods on the surface of the sea’.

Soon after the advent of claims over the continental shelf, coastal States began to assert claims over vast areas of the high seas, far beyond what had been the traditional limits of the territorial sea. On 23 June 1947, Chile declared national sovereignty over the continental shelf off its coasts and islands, and over the water column above, to a distance of 200M.38 Chile was motivated by several considerations, including the protection of offshore whaling operations. Peru and Ecuador followed suit soon afterwards, on 1 August 1947 and 22 February 1951 respectively, in order to protect domestic fishing from overseas fleets.39 The year after (p. 14) Ecuador’s 200M claim, Peru and Ecuador agreed the delimitation of an all-purpose maritime boundary extending 200M from their coasts. The boundary followed a simple parallel of latitude, drawn from the point where the parties’ land boundary met the sea at the mouth of the Tumbes River. There followed a series of maritime agreements between Chile, Ecuador, and Peru in respect of the maritime areas off their Pacific coasts, from 1952 onwards.40

Several other States followed suit, generating the need for new rules regarding the delimitation of the continental shelf.

Against this background of increasingly assertive State claims to the oceans and their resources, the international community came together once more in an attempt to codify the law and, in particular, to define the limits of State sovereignty and jurisdiction and the basic rules for delimitation of overlapping claims. The International Law Commission, which was established by the UN General Assembly in 1947 to promote the progressive development of international law and its codification, commenced its examination of the law of the sea at its first session in 1949. Seven years later, at its eighth session, the ILC submitted its ‘Articles concerning the Law of the Sea’ (‘ILC Articles’) and accompanying report to the General Assembly.41 The Articles addressed, inter alia, delimitation of the territorial sea between opposite coasts (which, absent agreement or ‘special circumstances’, was to be ‘the median line’)42 and delimitation of the territorial sea between adjacent coasts (which, absent agreement or ‘special circumstances’, was to be by way of ‘the principle of equidistance’).43 It also made identical provision for the delimitation of ‘continental shelf’ claims between opposite and adjacent coasts (i.e. with reference to ‘the median line’ and ‘the principle of equidistance’, respectively, in each case absent agreement or ‘special circumstances’).44 In short, therefore, the ILC Articles stated a clear preference for an equidistance-based approach to territorial sea and continental shelf delimitation, absent agreement or special circumstances.

In its report, the ILC recommended that the General Assembly summon an international conference of plenipotentiaries to examine the law of the sea ‘taking account not only of the legal but also of the technical, biological, economic and political aspects of the problem’, and to embody the results of its work in one or more international conventions.

(p. 15) The First United Nations Conference on the Law the Sea was accordingly convened in Geneva on 24 February 1958 (the so-called ‘UNCLOS I’ conference). Eighty-six States participated in the Conference, which culminated in the adoption of four conventions. These included two multilateral treaties that codified, for the first time, rules for the delimitation of overlapping territorial sea and continental shelf claims: namely, the Convention on the Territorial Sea and the Contiguous Zone (‘1958 CTS’) and the Convention on the Continental Shelf (‘1958 CCS’).

The 1958 CTS, which made no provision for the breadth of the territorial sea, dealt with territorial sea delimitation between opposite and adjacent coasts in a single article which, like the ILC Articles, gave precedence to the rule of equidistance. Article 12 of the 1958 CTS provided that neither State is entitled ‘to extend its territorial sea beyond the median line every point of which is equidistant from the nearest points on the baselines from which the breadth of the territorial seas of each of the two States is measured’.45 This rule would only be inapplicable where it was ‘necessary by reason of historic title or other special circumstances’ to delimit the territorial sea differently.

The 1958 CCS codified the first international legal regime of the continental shelf. Article 1 of the CCS, which has now been superseded by Article 76 of UNCLOS (see section 1IIIb ‘Continental shelf’ below), defined the continental shelf as ‘the seabed and subsoil of the submarine areas adjacent to the coast but outside the area of the territorial sea, to a depth of 200 metres or, beyond that limit, to where the depth of the superjacent waters admits of the exploitation of the natural resources of the said areas’.46 It embodied recognition of the international community of the sovereign rights of coastal States over the continental shelf for the purposes of exploring and exploiting its natural resources.

On delimitation, the 1958 CCS adopted verbatim the text formulated in the ILC Articles. In the absence of agreement or ‘special circumstances’, Article 6(1) thus provided that the continental shelf boundary between opposite States was the median line, while Article 6(2) provided that the continental shelf boundary between adjacent coasts was to be determined by application of ‘the principle of equidistance’.47 As the Court of Arbitration observed in the 1977 UK/France Continental Shelf case, Articles 6(1) and 6(2) were ‘essentially the same’, albeit the Court of Arbitration also correctly noted that there was a greater risk that equidistance may produce an inequitable delimitation in the case of adjacent coasts than in the case of opposite coasts.48(p. 16)

III.  The Relevant Zones of Maritime Sovereignty and Jurisdiction under the Modern Law

As Tanaka observes, the legal framework established by the 1958 Conventions ‘very soon came to encounter serious challenges’. He identifies four factors in particular that led the international community to recognize an urgent need to review the 1958 Conventions: first, the trend towards extended claims to national jurisdiction over the water column and its resources, with some twenty coastal States having by the 1970s claimed exclusive fishery zones beyond the territorial sea; second, developments in seabed mining technology, which threatened to encourage coastal States to extend their legal continental shelf towards the deep seabed on the basis of the ‘exploitability test’ set out in Article 1 of the 1958 CCS; third, the protection of the marine environment, which had previously attracted little attention; and fourth, ‘structural changes of the international community due to the independence of former colonised regions in the 1960s’.49

On 17 December 1970, the UN General Assembly convened a conference on the law of the sea (the so-called ‘UNCLOS III’ conference50), the first session of which took place in New York in December 1973. The eleven sessions of the UNCLOS III conference took place between 1973 and 1982 and the participants included all member States of the United Nations and its specialized agencies. The mandate given to the conference by the General Assembly could hardly have been wider: ‘to adopt a convention dealing with all matters relating to the law of the sea’.51 The resulting UNCLOS text, which runs to 320 articles and nine annexes, is one of the most important and comprehensive multilateral treaties in history. Tanaka states that it ‘marked the beginning of a new era in the international law of the sea’.52 UNCLOS was adopted by 130 States signatories on 30 April 1982 and, as at the time of writing, has 167 States parties (the most recent being the State of Palestine). While a number of those States remain also parties to the 1958 Conventions, Article 311 provides that UNCLOS ‘shall prevail, as between States Parties, over the Geneva Conventions on the Law of the Sea of 29 April 1958’.

UNCLOS identifies the three principal zones of maritime sovereignty and jurisdiction that are subject to the modern law of maritime boundary delimitation: the territorial sea (regulated by Part II of UNCLOS), the exclusive economic zone (or ‘EEZ’) (regulated by Part V), and the continental shelf (regulated by Part VI). The extent of, and relationship between, these zones is illustrated in Figure A1.3. The (p. 17)

Figure A1.3:  (i) Maritime zones under UNCLOS; (ii) Definition of the continental shelf under Article 76.

relevant provisions relating to each will be summarized in turn, followed by a short discussion of the ‘régime of islands’ under Part VIII of UNCLOS.

a.  Territorial sea

The territorial sea (along with the contiguous zone) is regulated by Part II of UNCLOS. Article 2(1) provides that: ‘the sovereignty of a State extends beyond its land territory and internal waters and, in the case of an archipelagic State, its archipelagic waters, to a belt of sea adjacent to its coast, described as the (p. 18) territorial sea’. Article 2(2) provides that this sovereignty extends to the air space over the territorial sea as well as to its bed and subsoil. This text duplicates equivalent provisions contained in the 1958 CTS (with the exception of the references to archipelagic status, now governed by Part IV of UNCLOS). However, for the first time, UNCLOS sets out a limit on the territorial sea: Article 3 provides that a coastal State has the right to establish a territorial sea not exceeding 12M, measured from baselines determined in accordance with the Convention.53

All told, the UNCLOS provisions demonstrate a definitive acceptance by States of sovereignty over the territorial sea and an end to the historical debate on the juridical character and the extent of the territorial sea.54 Nevertheless, the sovereign rights of the coastal State in the territorial sea are not absolute, being subject to certain restrictions under UNCLOS.55 In particular, pursuant to Articles 17 and 24, the ships of all States enjoy the right of innocent passage through the territorial sea.

b.  Continental shelf

As Churchill and Lowe observe, during the twentieth century the law developed from an initial recognition that rights in the seabed of the high seas could be acquired by effective occupation to an acceptance that States had certain inherent sovereign rights over the seabed adjacent to the territorial sea.56 This process of development culminated in the codification of a comprehensive continental shelf regime in Part VI of UNCLOS.

A substantial theme of debate throughout UNCLOS III was the question of what should be the outer limit of the juridical continental shelf, and thus the outer limit of coastal State sovereign rights and jurisdiction over the resources of the seabed. There was widespread agreement that the establishment of a definitive international regime for the seabed would require a precise definition of what are the outer limits of the juridical continental shelf. A major division arose between those (narrow margin) States that wanted to base outer limits on a criterion of distance from the coast and those (wide margin) States wishing to introduce geomorphological criteria.57 At the fourth session of the UNCLOS III conference in 1976, Ireland proposed a compromise definition that incorporated references both to (p. 19) distance and geomorphological criteria.58 The Irish proposal provided the basis for much of what was to become Article 76 of UNCLOS.

Paragraph (1) of Article 76 sets out the modern juridical definition of the continental shelf:

The continental shelf of a coastal State comprises the seabed and subsoil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200 nautical miles from the baselines from which the breadth of the territorial sea is measured where the outer edge of the continental margin does not extend up to that distance.

A coastal State is thus entitled to a continental shelf of 200M regardless of the geological or geomorphological configuration of the seabed extending from its coast. In other words, physical natural prolongation does not form the basis of continental shelf rights within 200M under modern international law.59 However, where the geological or geomorphological configuration of the seabed allows, the coastal State may be entitled to a continental shelf beyond 200M, based on the natural prolongation of its land territory. In other words, physical natural prolongation can form the basis of continental shelf rights in areas beyond 200M from the coast.

Paragraph (3) of Article 76 defines the continental margin as comprising ‘the submerged prolongation of the land mass of the coastal State and consists of the seabed and subsoil of the [physical] shelf, slope and rise. It does not include the deep sea floor with its oceanic ridges or the subsoil thereof’. The problem then became how to define the extent of the continental rise, which is not easily identified (and not always physically present). Two solutions were proposed at UNCLOS III. The first was a suggestion from Gardiner, an Irish geologist, who proposed that the outer edge of the margin should be delineated by a line representing the outermost points where the thickness of sedimentary rocks is at least 1 per cent of the distance from the foot of the slope (known as the ‘Gardiner formula’). This was ultimately adopted as sub-paragraph (4)(a)(i) of Article 76. The second solution was proposed by Hedberg, a US petroleum geologist, who proposed that the outer edge of the margin should be defined at a fixed distance, 60M, from the foot of the continental slope (known as the ‘Hedberg formula’). This was ultimately adopted as sub-paragraph (4)(a)(ii) of Article 76.

Sub-paragraph (4)(b) provides that, in the absence of evidence to the contrary, the foot of the continental slope for the purposes of sub-paragraphs (a)(i) and (ii) shall (p. 20) be determined as the point of maximum change in the gradient at its base. Paragraph (5) sets constraints to the outer limits of the juridical continental shelf at 350M from the territorial sea baselines or 100M from the 2,500 metre isobath, except for submarine ridges, which are restricted to 350M under paragraph (6). The final outer limit is to be defined by a series of fixed points not more than 60M apart, each of which must satisfy one or other of the criteria above (Figure A1.3 (ii) above).

This combination of formulae, limits, and constraints, while providing certainty as to the outer limit of the juridical continental shelf, imposes on coastal States wishing to establish binding outer limits beyond 200M an onerous and expensive task of scientific data collection and analysis, especially the acquisition of bathymetric and seismic data. The precise technical requirements for the establishment of outer shelf entitlement are set out in the CLCS’s ‘Scientific and Technical Guidelines’.60 The difficulties of interpretation and application of Article 76 and the Guidelines have presented the CLCS with a complex and lengthy task in assessing coastal States’ outer shelf claims.

The new juridical definition of the continental shelf under Article 76 of UNCLOS did, however, lay to rest the test of ‘exploitability’ that had existed under Article 1 of the 1958 CCS, which had threatened with the advance of technology to engulf the entire ocean floor as continental shelf space subject to coastal State jurisdiction. As a result of the establishment of firm outer limits under Article 76, vast areas of deep ocean floor and their resources, beyond the limits of the juridical shelf, have been safeguarded as ‘the common heritage of mankind’.61

In its 2012 judgment in Nicaragua/Colombia, the ICJ confirmed that the definition of the continental shelf under Article 76(1) of UNCLOS represents customary international law.62 A 200M ‘distance-based’ continental shelf therefore exists automatically by operation of law and requires no action or claim on the part of the coastal State, whether or not it is an UNCLOS State party. In contrast, where a coastal State party to UNCLOS wishes to claim continental shelf rights beyond 200M, it must submit its proposed outer limits to the Commission on the Limits of the Continental Shelf (‘CLCS’), established by Annex II of UNCLOS. Any claim to an outer limit beyond 200M does not become final and binding as against other UNCLOS States parties unless and until established on the basis of recommendations from the CLCS in accordance with the procedure set out in Article 76.63

(p. 21) Article 77 outlines the rights of the coastal State over the continental shelf. Article 77(1) provides that the coastal State exercises over the continental shelf sovereign rights for the purpose of exploring it and exploiting its natural resources. The term ‘sovereign rights’ in this context therefore does not allow the exercise of complete authority over the shelf to the exclusion of other States. Rather, the rights of the coastal State extend only to activities related to exploring the shelf and exploiting its natural resources (principally, hydrocarbons and other minerals but, in addition, the ‘living organisms belonging to sedentary spaces’). Article 77(2) provides that continental shelf rights are, however, exclusive in the sense that if the coastal State does not exercise them, no other State is entitled to do so.

Importantly, Article 77(3) confirms that the rights of the coastal State over the continental shelf do not depend on any form of occupation or proclamation. This restates the position under Article 2(3) of the 1958 CCS and customary international law. As the 1969 judgment of the ICJ stated in the North Sea Continental Shelf cases, the rights of the coastal State in respect of the continental shelf are ‘inherent’ and ‘exist ipso facto and ab initio, by virtue of its sovereignty over the land’.64

Part VI sets out a number of restrictions on the rights of the coastal State over its continental shelf. For example, Article 78(2) provides that the exercise of sovereign rights over the continental shelf must not infringe or result in any unjustifiable interference with navigation and other rights and freedoms of other States. Further, other States retain certain rights over the continental shelf. For example, under Article 79(1), all States are entitled to lay submarine cables or pipelines over the continental shelf. In addition, Article 82 requires coastal States exploiting the shelf beyond 200M to make payments or contributions in kind, to be distributed via the International Seabed Authority to other States parties, particularly the least developed and land-locked States parties.65

c.  Exclusive economic zone (‘EEZ’)

The term ‘EEZ’ was introduced by Kenya in the UN Seabed Committee in 1972.66 The concept of an EEZ has origins in the Declaration of the Organization of African Unity adopted at Addis Ababa in 1973 and endorsed by the Declarations (p. 22) of the League of Arab States in 1973 and 1974.67 The broader concept of sovereign rights over the water column beyond the narrow belt of territorial sea can also be traced back to the claims made by certain Latin American States from the late 1940s, referred to above. By the early 1970s, many coastal States (including a number of island States) in Latin America and the Caribbean asserted claims to an extensive ‘patrimonial sea’, culminating in a number of regional declarations.68

The modern law related to the EEZ concept is set out in Part V of UNCLOS. Article 55 provides that the EEZ is ‘an area beyond and adjacent to the territorial sea, subject to the specific legal regime established in this Part, under which the rights and jurisdiction of the coastal State and the rights and freedoms of other States are governed by the relevant provisions of this Convention’.69 Article 56(1) states that, in the EEZ, the coastal State has ‘sovereign rights for the purpose of exploring and exploiting, conserving and managing the natural resources, whether living or non-living, of the waters superjacent to the seabed and of the seabed and its subsoil, and with regard to other activities for the economic exploitation and exploration of the Zone, such as the production of energy from water, currents and winds’. Article 56(3) provides that EEZ rights with regard to the seabed and subsoil shall be exercised in accordance with the continental shelf regime established by Part VI of UNCLOS.

Article 57 provides that the EEZ shall not extend beyond 200M from the territorial sea baseline. Consequently, in many parts of the world, the outer (200M) limit of the EEZ coincides with the outer limit of the juridical continental shelf. However, in places where the continental margin extends beyond 200M, coastal State continental shelf rights will extend further seawards than their corresponding rights over the EEZ. This can give rise to significant practical issues through the creation of so-called ‘grey zones’ of maritime sovereignty and jurisdiction, discussed further in Part C of this book.

The EEZ regime created by Part V of UNCLOS represents a balancing of competing interests between those States wishing to preserve high seas freedoms to the fullest extent possible and those States wishing to ensure that others would not plunder natural resources in waters adjacent to their coasts. As a result, the sovereign rights of the coastal State in the EEZ are variously limited. For example, (p. 23) Article 58 of UNCLOS preserves the rights of all States regarding non-resource-related activities in the EEZ, including navigation, overflight, the laying of submarine cables and pipelines, and activities associated with the operation of ships and aircraft. Articles 61 to 71 make detailed provision about exploitation of the living natural resources of the EEZ, requiring the coastal State to determine the ‘allowable catch’, promote ‘optimum utilization’, and grant access to other States to the ‘surplus of the allowable catch’. All in all, as Kwiatkowska has observed, the EEZ is a multifunctional zone in which the coastal State and other States are entitled to exercise rights with a specific function.70

In contrast to the ICJ’s remarks about the continental shelf in the North Sea Continental Shelf cases, the coastal State’s sovereign rights in the EEZ are not ‘inherent’. A State must expressly declare the existence of an EEZ to be entitled to exercise sovereign rights over the resources therein, and is required to give ‘due publicity’ to the outer limits of its EEZ.71

The declaration of an EEZ by a large number of coastal States has meant that the concept is now considered part of customary law (thus extending beyond the States parties to UNCLOS).72 This was confirmed by the ICJ in the Libya/Malta case, where the court noted that ‘the institution of the exclusive economic zone…is shown by the practice of states to have become a part of customary law.’73

d.  The ‘régime of islands’ under Part VIII of UNCLOS

Part VIII of UNCLOS (comprising just one provision—Article 121) regulates the maritime zones that can be claimed by or from an ‘island’. Pursuant to subparagraph (1) of Article 121, an island is ‘a naturally formed area of land, surrounded by water, which is above water at high tide’. It is thus different from a low-tide elevation, defined at Article 13 as ‘a naturally formed area of land which is surrounded by and above water at low tide but submerged at high tide’.

Subparagraphs (2) and (3) of Article 121 then distinguish between two types of island feature: first, ‘rocks which cannot sustain human habitation or economic life (p. 24) of their own’ and, second, all other islands. Whereas ‘rocks’ generate a territorial sea but cannot generate any EEZ or continental shelf, other islands can generate territorial sea, EEZ, and continental shelf in exactly the same way as any other land territory. Low-tide elevations, on the other hand, generate no self-standing maritime entitlements of their own.

Therefore, as observed by the ICJ in the Nicaragua/Colombia case, all rocks, however small and insignificant, can generate a territorial sea of 12M from their baselines.74 By contrast, any island feature that is capable of sustaining human habitation or economic life of its own will (subject to the overlapping claims of any neighbouring State) generate full EEZ and continental shelf rights. As observed by the Arbitral Tribunal in the St Pierre and Miquelon case, such rights are vested in island features regardless of their political status (e.g. as overseas territories of States principally located in another part of the world).75

The substantial difference between the maritime entitlements of low-tide elevations, ‘rocks’, and other island features and Article 121 of UNCLOS has given rise to a series of disputes around the world as to the legal classification of small offshore features. Well-known examples include the disputes that have arisen in connection with multiple small features located in the South China Sea and the small feature in the Caribbean Sea called ‘Aves Island’ (by Venezuela) or ‘Bird Rock’ (by Dominica). To date, while international courts and tribunals have willingly distinguished between low-tide elevations and island features in maritime delimitation disputes,76 they have provided little or no practical guidance on how to apply the Article 121 distinction to specific features.77 It is to be hoped that such guidance will, however, be forthcoming in the future.78

IV.  The Basis of the Modern Law of Delimitation: Articles 15, 74, and 83 of UNCLOS

Articles 15, 74, and 83 of UNCLOS codify the modern law on the delimitation of overlapping entitlements to territorial sea, EEZ, and continental shelf, respectively. (p. 25) As such, they will provide the starting point for any modern delimitation exercise. This is the case even in respect of non-States parties to UNCLOS because, as confirmed by the ICJ in, inter alia, the Qatar/Bahrain case (in respect of Article 15) and the Jan Mayen case (in respect of Articles 74 and 83), the delimitation provisions of UNCLOS represent rules of customary international law.

Article 15 of UNCLOS provides:

Where the coasts of two States are opposite or adjacent to each other, neither of the two States is entitled, failing agreement between them to the contrary, to extend its territorial sea beyond the median line every point of which is equidistant from the nearest points on the baselines from which the breadth of the territorial seas of each of the two States is measured. The above provision does not apply, however, where it is necessary by reason of historic title or other special circumstances to delimit the territorial seas of the two States in a way which is at variance therewith.

As the ICJ observed in the Qatar/Bahrain case, Article 15 of UNCLOS is ‘virtually identical’ to Article 12 of the 1958 CTS.

By contrast, Articles 74 and 83 of UNCLOS, which make identical provision as regards the delimitation of EEZ and continental shelf areas, were new. They provide:

  1. 1.  The delimitation of the [exclusive economic zone (Article 74)/continental shelf (Article 83)] between States with opposite or adjacent coasts shall be effected by agreement on the basis of international law, as referred to in Article 38 of the Statute of the International Court of Justice, in order to achieve an equitable solution.

  2. 2.  If no agreement can be reached within a reasonable period of time, the States concerned shall resort to the procedures provided for in Part XV.

  3. 3.  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 this transitional period, not to jeopardise or hamper the reaching of the final agreement. Such arrangements shall be without prejudice to the final delimitation.

  4. 4.  Where there is an agreement in force between the States concerned, questions relating to the delimitation of the [exclusive economic zone (Article 74)/continental shelf (Article 83)] shall be determined in accordance with the provisions of that agreement.

Articles 74 and 83 reflect a legal and diplomatic compromise reached at the UNCLOS III conference between two groups of States with very difficult legal and philosophical views of maritime delimitation: first, those that advocated EEZ and continental shelf delimitation based upon the principle of equidistance (subject to an exception for ‘special circumstances’); and, second, those that advocated delimitation based upon the more flexible (and arguably more nebulous) doctrine of ‘equitable principles’.79 While each group acknowledged that delimitation by (p. 26) agreement was always the most satisfactory way of resolving overlapping claims, they were singularly unable to agree what should be the guiding principles and methodology for delimitation in the absence of agreement. The matter became somewhat intractable during the UNCLOS negotiations. Thus, for example, at the seventh session of the UNCLOS III conference, held in 1978, a group of twenty States proposed an EEZ and continental shelf delimitation formula based on ‘the median or equidistance line’,80 only to receive a counter-proposal by twenty-seven States based on delimitation ‘in accordance with equitable principles’.81

At the tenth session, held in 1981, the newly elected President of the Conference, Tommy T. B. Koh (Singapore), undertook direct negotiations with the delegates of Ireland and Spain, as representatives of the two opposing delimitation groups. Following those negotiations, he submitted a new compromise text focused on delimitation ‘by agreement on the basis of international law’ and ‘in order to achieve an equitable solution’. The proposal thus focused on the objective of the delimitation process, rather than the contested question of the methodology to be used. It received the support of both delimitation groups and was incorporated into Articles 74 and 83 of the Convention.82

The compromise wording of Articles 74 and 83, described by the arbitral tribunal in the Barbados/Trinidad case as an ‘apparently simple and imprecise formula’,83 deliberately omitted any discussion of the methodology to be used in the delimitation of EEZ and continental shelf boundaries. It has therefore been left to subsequent State practice (in the form of delimitation treaties), learned writers, and, much more importantly, the jurisprudence of international courts and tribunals, to provide much-needed guidance about the methodologies to be applied in pursuit of the pervasive objective of an ‘equitable solution’. As the ITLOS tribunal held in its 2012 judgment in the Bangladesh/Myanmar case, ‘international courts and tribunals have developed a body of case law on maritime delimitation which has reduced the elements of subjectivity and uncertainty in the determination of maritime boundaries and in the choice of methods employed to that end’.84

(p. 27) Such has been the importance of the modern case law in defining the method or methods to be used in maritime delimitation that the arbitral tribunal in the Bangladesh/India case declared, in its 2014 award, that the case law constitutes an ‘acquis judiciare, a source of international law under article 38(1)(d) of the Statute of the International Court of Justice, and should be read into articles 74 and 83 of the Convention’.85 That case law, which ‘adds flesh to the bones’ of Articles 74 and 83, and thus forms the corpus of the modern law of international maritime boundary delimitation, is summarized in Part A.2 below, and analyzed in detail in Part B of this book.

V.  ‘The Land Dominates the Sea’

Before turning to questions of delimitation methodology, however, there is one overriding principle that must be acknowledged from the outset. That principle pervades the law of the sea generally, and the modern law and practice of maritime delimitation in particular. Indeed, every commonly used method of maritime delimitation relies upon it. The principle is that, in the words of the ICJ in the North Sea Continental Shelf cases, ‘the land dominates the sea’.

The land dominates the sea because, as the court observed in its 1969 judgment, ‘the land is the legal source of the power which a State may exercise over territorial extensions to seaward’.86 This is as true, if not more so, under UNCLOS as it was under the law as it stood in 1969. In particular, the limits of sovereign rights in the territorial sea (Article 3), EEZ (Article 57), and continental shelf (Article 76) are all defined with reference to distances from the baselines from which the breadth of the territorial sea is measured.87 As explained in Part, A Chapter 2 below, those baselines are, by definition, dictated by the geography of the coastal State, whether it be a continental mainland State, an island State, or an archipelago.

The principle that the land dominates the sea has been confirmed repeatedly by international courts and tribunals since 1969 in the context of maritime delimitation. This has often been by reference to the overriding importance of the ‘geographical configuration’ of the area to be delimited (and, in particular, the geographical configuration of the relevant coasts). Thus, for example, in the Cameroon/Nigeria case, the ICJ observed that ‘[t]he geographical configuration of the maritime areas that the Court is called upon to delimit is (p. 28) a given. It is not an element open to modification by the Court but a fact on the basis of which the Court must effect the delimitation’.88

The dominant role played by geographical configuration and coastlines in maritime delimitation has had a number of significant tangible impacts on delimitation process and methodology. Six impacts, in particular, stand out:

  1. 1.  the need to resolve land boundary, island, or other sovereignty disputes related to land territory as a necessary precursor to any maritime delimitation exercise;89

  2. 2.  the importance of identifying the coasts and areas that are ‘relevant’ to the delimitation, i.e. those coasts that generate overlapping claims in the disputed area, because, as the ICJ observed in the Romania/Ukraine case, ‘the task of delimitation consists in resolving the overlapping claims by drawing a line of separation of the maritime areas concerned’;90

  3. 3.  the need to classify any small territorial features (e.g. islands, rocks, low-tide elevations) at the outset of the delimitation process because, as described above, such classification will have a substantial impact on the potential maritime entitlement of such features;91

  4. 4.  the distinction drawn between ‘opposite’ and ‘adjacent’ coasts, which can have a substantial effect upon any given delimitation exercise;92

  5. 5.  the central role played by coastal geography in determining the delimitation methodology to be employed in any given situation (and, in particular, in determining whether there should be any deviation from the standard three-stage approach to delimitation, described in Part, A Chapter 2 below);93 and

  6. (p. 29) 6.  the overriding influence of geographical considerations throughout the standard ‘three-stage approach’ to delimitation under the modern law (i.e. in the construction of a provisional equidistance line, the consideration of relevant or special circumstances and the application of any final ‘proportionality check’).94


1  Grotius, The Freedom of the Seas (Magoffin trans, Liberty Fund, Inc.), p. 68 [trans. of Mare Liberum (first published 1609)].

2  Tanja, G. J., The Legal Determination of International Maritime Boundaries (Kluwer Law, 1990), p. 16.

3  Weil, P., The Law of Maritime Delimitation—Reflections (Cambridge Grotius Publications Ltd, 1989), p. 47.

4  Crawford, J., Brownlie’s Principles of Public International Law (Oxford University Press, 2012), p. 281 and accompanying global map at p. 282.

5  Weil, P., The Law of Maritime Delimitation—Reflections (Cambridge Grotius Publications Ltd, 1989), p. 3.

6  1833 UNTS 3; 21 ILM 1261 (1982); At the time of writing, there are a number of notable absences from the list of States parties to UNCLOS, including the United States, Turkey, Colombia, and Venezuela. Nevertheless, the rules of delimitation set out in UNCLOS are universally recognized as reflecting rules of customary international law that thereby bind non-parties to the Convention.

7  Barbados v. Trinidad and Tobago, Award (2006), para. 222.

8  Weil, P., The Law of Maritime Delimitation—Reflections (Cambridge Grotius Publications Ltd, 1989), p. 8. To similar effect, see the comments of the International Court of Justice in Libya/Malta: ICJ Reports 1985 at p. 13.

9  Bangladesh v. India, Award (2014), para. 339.

10  UN Charter, Art. 2(1).

11  Weil, P., The Law of Maritime Delimitation—Reflections (Cambridge Grotius Publications Ltd, 1989), p. 5.

12  R. v. Secretary of State for the Home Department, ex p. Daly [2001] 2 WLR 1622, HL.

13  Selden, J., Mare Clausum (1635), Book I ch. Xxii, pp. 136–45.

14  Grotius, H., The Freedom of the Seas (Magoffin trans, Liberty Fund, Inc.) [trans. of Mare Liberum (first published 1609)].

15  Grotius, H., On the Law of War and Peace (Campbell trans., Kitchener) [trans. of De Jure Belli ac Pacis (first published 1625)].

16  Bijnkershoek, C., De Dominio Maris Dissertatio (1703), reproduced in Scott, J. B. (ed.), Classics of International Law, No. 11 (Oxford University Press, 1923).

17  Adherence to the cannon shot rule and 3-mile territorial sea limit was not, however, universal. For example, from the mid eighteenth century, several Scandinavian countries claimed sovereign rights over maritime space up to 4 miles off their coasts. Other countries such as France and Italy claimed varying maritime limits for different purposes. See further Churchill, R. R. and Lowe, A. V., Law of the Sea, (Manchester University Press, 1999), p. 78 and O’Connell, D. P., The International Law of the Sea, Vol. 1 (Oxford University Press, 1983), p. 165.

18  Grisbådarna Arbitration (Norway v. Sweden), Award of 23 October 1909, 11 RIAA 147.

19  Tanaka, Y., Predictability and Flexibility in the Law of Maritime Delimitation (Hart Publishing, 2006), pp. 19–32.

20  Aasen, P. J., ‘The Law of Maritime Delimitation and the Russian-Norwegian Maritime Boundary Dispute’, Fridtjof Nansens Institute FNI Report 1/2010, p. 9.

21  Tanaka, Predictability and Flexibility, pp. 31–2.

22  Bluntschli, J. C., Le droit international codifié, translated by M. C. Lardy (Librairie Guillaumin, 1881), p. 190. Rivier, A., Principes du droit des gens, Vol. I (Librairie de droit et de jurisprudence, 1896), p. 64. Tanaka observes that, strictly speaking, the ‘common zone system’ cannot be regarded as a delimitation method, as it does not delimit overlapping maritime claims.

23  For discussion about alternative meanings of the term ‘thalweg’ in delimitation treaties, see the Kasikili/Sedudu Island case (Botswana v. Namibia): ICJ Reports 1999, pp. 1061–2, paras 24–5.

24  Jennings, R. and Watts, A., Oppenheim’s International Law, Vol. 1 (9th edn, Oxford University Press, 2008), pp. 664–5; Tanaka, Y., The International Law of the Sea (Cambridge University Press, 2012), pp. 28–31.

25  Protocol of 3 September 1921 concerning the Delimitation of the Boundary between Denmark and Germany, cf. Executive Order No. 497 of 21 December 1923. See also Convention between the Republic of Finland and the Kingdom of Norway concerning the frontier between the Province of Finmark and the Territory of Petsamo (28 April 1924).

26  (1845–46) 34 British and Foreign State Papers 14. In 1871, the German Emperor Wilhelm I arbitrated a dispute between the parties and again adopted a median line solution.

27  Convention between Italy and Turkey for the Delimitation of the Territorial Waters Between the Coasts of Anatolia and the Island of Castellorizo, 28 December 1932; Declaration between the Danish and Swedish Governments Concerning the Boundary of their Territorial Waters in the Sound (Stockholm, 30 January 1932), also cited in Tanaka, above. See also Kariotis, T. C., Greece and the Law of the Sea (Martinus Nijhoff, 1997), pp. 141–2.

28  15 Reports of International Arbitral Awards 481–540.

29  Grisbådarna Arbitration (Norway v. Sweden), Award of 23 October 1909, 11 RIAA 147.

30  Notably, the tribunal observed that this conclusion was supported by the depositions and declarations of witnesses. By contrast, the tribunal found that Norwegian fishermen had ‘almost always participated in lobster fishing in the Skottegrunde in a comparatively more effective manner than at Grisbådarna’.

31  Part B, chapter 6.

32  Kolb, R., Case Law on Equitable Maritime Delimitation: Digest and Commentaries (Martinus Nijhoff, 2003), p. 16. Moreover, as former ITLOS Judge David Anderson has noted, the award was notable from a procedural perspective, not least because the tribunal rendered its decision just five days after the close of hearings: Anderson, D., ‘Grisbadarna Revisited’ in Modern Law of the Sea: Selected Essays (Martinus Nijhoff, 2008), pp. 156–7.

33  Article 9, Draft Convention on Territorial Waters, prepared by the Research in International Law of the Harvard Law School, 23 American Journal of International Law (1929, Special Supplement), pp. 243–4.

34  This marked a significant shift since the drafting of a resolution on the territorial sea at the Institut de Droit International in 1894, where the proposition that the coastal State had sovereignty over the territorial sea was opposed by several delegates. See O’Connell, D. P., The International Law of the Sea, Vol. 1 (Oxford University Press, 1983), p. 68. The text adopted on 31 March 1894 referred instead to ‘un droit de souveraineté’ in the territorial sea: Annuaire de lInstitut de Droit International (1928–31) 517.

35  League of Nations, Report adopted by the Second Committee on April 10, 1930, reproduced in Rosenne, S. (ed.), League of Nations Conference for the Codification of International Law 1930, Vol. 4 (New York, Oceana, 1975), p. 1411.

36  Proclamation on US Policy regarding Natural Resources of the Subsoil and Sea Bed of the Continental Shelf, 10 Fed. Reg. 12305 (1945), [reproduced at Annex X below].

37  Treaty relating to Submarine Areas in the Gulf of Paria, 205 UNTS 121.

38  Presidential Declaration Concerning Continental Shelf of 23 June 1947, El Mercurio, Santiago de Chile, 29 June 1947.

39  Presidential decree No. 781 of 1 August 1947, UN Doc. ST/LEG/SER.B/1 (Peru); Maritime Hunting and Fishing Law, Decree No. 003, 22 February 1951 (Ecuador).

40  For further discussion of those agreements and their legal effect, see the ICJ’s 2014 judgment in Peru/Chile, analyzed and illustrated in Part, B Chapter 22 below.

41  Yearbook of the International Law Commission, 1956, Vol. II, pp. 265–301.

42  ILC Articles, Art. 12.

43  ILC Articles, Art. 14.

44  ILC Articles, Art. 72.

45  Convention on the Territorial Sea and Contiguous Zone of 1958, 516 UNTS 205, Art. 12.

46  Convention on the Continental Shelf, 1958, 499 UNTS 311, Art. 1.

47  Convention on the Continental Shelf, 1958, 499 UNTS 311, Art. 6.

48  See discussion of opposite and adjacent coasts at Section 2 II, and UK/France at Part, B Chapter 3.

49  Tanaka, Y., The International Law of the Sea (Cambridge University Press, 2012), pp. 24–5.

50  The so-called UNCLOS II conference was convened at Geneva in 1960 in order to discuss the outer limit of the territorial sea and fisheries zone, but failed to reach any agreement.

51  UN General Assembly Resolution 3067 [XXVIII] of 16 November 1973.

52  Tanaka, Y., The International Law of the Sea (Cambridge University Press, 2012), p. 29.

53  See Part, A Chapter 2, Ic ‘The ‘baseline’.

54  Lucchini, L. and Voelckel, M., Droit de la Mer, Vol. I (Pédone, 1990), pp. 164–7.

55  UNCLOS, Art. 2(3).

56  Churchill, R. and Lowe, A. V., The Law of the Sea (3rd edn, Manchester University Press, 1999), p. 121.

57  Moore, J. N., Nordquist, M. H., Nandan, S. N., and Rosenne, S. (eds.), United Nations Convention on the Law of the Sea 1982: A Commentary, University of Virginia (the ‘Virginia Commentaries’), Vol. II (Martinus Nijhoff, 1993), part VI, para 76.3, p. 842.

58  Notes of the 75th information meeting of the Second Committee (15 April 1976). The text proposed by Ireland was referred to as the ‘Irish formula’.

59  See, e.g., Libya/Malta, paras. 34–40, which confirmed also that physical natural prolongation is no longer a ‘relevant circumstance’ for continental shelf delimitation within 200 M.

60  Scientific and Technical Guidelines of the Commission on the Limits of the Continental Shelf, 13 May 1999 (CLCS/11), available from <http://www.un.org/depts/los/clcs_new/documents/Guidelines/CLCS_11.htm>.

61  UNCLOS created an entirely separate legal regime over the deep ocean floor beyond the outer limits of coastal State jurisdiction (defined as ‘the Area’), which is regulated by the International Seabed Authority under Pt XI of UNCLOS.

62  Nicaragua/Colombia, para. 118.

63  Report of the International Law Association Committee on Legal Issues of the Outer Continental Shelf (2006), Conclusion No. 11 and explanatory note, 16–17. Notably, non-States parties to UNCLOS are also entitled as a matter of customary international law to claim continental shelf rights beyond 200M, as the United States has done in, for example, the Gulf of Mexico. However, the CLCS has no jurisdiction in relation to the claims of such States, which are therefore not final and binding as against other coastal States absent agreement.

64  North Sea Continental Shelf cases, para. 19.

65  Developing States that are not importers of the resource concerned are exempt from making such payments as contributions under Art. 82(3).

66  Draft Articles on Exclusive Economic Zone Concept (Kenya), Report of the Committee on the Peaceful Use of the Sea-Bed and the Ocean Floor Beyond the Limits of National Jurisdiction, UN Doc. A/8721 (1972).

67  Akintoba, T., African States and Contemporary International Law. A Case Study of the 1982 Convention on the Law of the Sea and the Exclusive Economic Zone (Martinus Nijhoff, 1996); Churchill, R. and Lowe, A. V., The Law of the Sea (3rd edn, Manchester University Press, 1999), p. 160.

68  See, e.g., the Montevideo Declaration on the Law of the Sea, 8 May 1970, 9 ILM 1970, p. 1081; Declaration of Latin American States on the Law of the Sea (‘Lima Declaration’), 8 August 1970, 10 ILM 1971, p. 207; and the Santo Domingo Declaration, 1972, 11 ILM 1972, p. 892.

69  UNCLOS, Art. 55.

70  Kwiatkowska, B., The 200 Mile Exclusive Economic Zone in the New Law of the Sea (Martinus Nijhoff, 1989), p. 4.

71  UNCLOS, Art. 75.

72  Not all UNCLOS States Parties have declared an EEZ, although some that have not have enacted national legislation establishing exclusive fishing zones beyond the territorial sea. The UK did not enact legislation declaring an EEZ until 2013. The US, by contrast, has declared an EEZ, although it is not a State party to UNCLOS. The Gulf of Maine case (discussed in Part B, below) provides an example of a maritime delimitation between exclusive fishing zones rather than EEZs. At the time of the signature of the treaty in which the US and Canada agreed to submit their dispute regarding the delimitation to the ICJ, both States had claimed 200M fishing zones. Notably, however, virtually all of the non-UNCLOS maritime States have declared EEZs (Colombia, El Salvador, Israel, North Korea, Syria, Turkey, UAE, USA, and Venezuela have all done so).

73  Continental Shelf (Libyan Arab Jamahiriya/Malta), 1985 ICJ Reports 13.

74  For an extreme example of a minute rock feature generating a full territorial sea entitlement around it, see discussion of the feature labelled ‘QS 32’ (and surrounding low-tide elevations) in the Nicaragua/Colombia case, at paras. 182–3. The ICJ further confirmed that the ‘régime of islands’ under Art. 121 constitutes customary international law: see paras. 132–6.

75  St Pierre and Miquelon, para. 49.

76  See, e.g., the ICJ’s analysis of various small features in its Qatar/Bahrain judgment (2001).

77  As shown, e.g., by the ICJ’s reluctance to classify Serpents’ Island as a ‘rock’ or otherwise in Romania/Ukraine (2009).

78  In the UNCLOS Annex VII arbitration between the Philippines and China, which is pending at the time of writing, the Philippines has requested the tribunal to, inter alia, determine whether certain of the disputed features of the South China Sea are islands, low-tide elevations, or submerged banks, and whether they are capable of generating entitlement to maritime zones greater than 12M.

79  See the Virginia Commentaries, which notes that the discussion at the Sixth Session of the UNCLOS III conference was ‘equally divided’ as between the two approaches. Some of the most vociferous proponents of each approach were adverse to one another in extant delimitation disputes at the time. For example, while Turkey was a strong advocate at the UNCLOS III conference of the equitable principles approach, Greece was an equally strong advocate of the equidistance approach.

80  The twenty States proposing an equidistance-based formula comprised Bahamas, Barbados, Canada, Colombia, Cyprus, Democratic Yemen, Denmark, Gambia, Greece, Guyana, Italy, Japan, Kuwait, Malta, Norway, Spain, Sweden, United Arab Emirates, United Kingdom, and Yugoslavia.

81  The twenty-seven States proposing delimitation based on ‘equitable principles’ comprised Algeria, Argentina, Bangladesh, Benin, Congo, France, Iraq, Ireland, Ivory Coast, Kenya, Liberia, Libya, Madagascar, Mali, Mauritania, Morocco, Nicaragua, Nigeria, Pakistan, Papua New Guinea, Poland, Romania, Senegal, Syria, Somalia, Turkey, and Venezuela. Notably, the proposal stated that the equitable principles approach would be utilized ‘taking into account all relevant circumstances and employing any methods, where appropriate, to lead to an equitable solution’.

82  The Virginia Commentaries, paras. 74.10 and 83.17.

83  Barbados/Trinidad award, 11 April 2006, para. 222.

84  Bangladesh/Myanmar judgment, 14 March 2012, para. 226.

85  Bangladesh/India award, 7 July 2014, para. 339.

86  North Sea Continental Shelf cases (1969), para. 96.

87  The only exceptions relate to situations in which the physical continental margin extends beyond 200M, according to the formulae in Art. 76(4), which uses the foot of the continental slope as a point of reference. However, as the court observed in the North Sea Continental Shelf judgment, the physical continental shelf consists of ‘stretches of submerged land’ and is thereby ‘evocative of the land and not of the sea’. Accordingly, in respect of this modern outer limit of the continental shelf, it can equally be said with certainty that ‘the land dominates the sea’.

88  Cameroon/Nigeria (2002), para. 295.

89  See, e.g., the resolution of land sovereignty disputes prior to addressing maritime delimitation in the Eritrea/Yemen (1999), Qatar/Bahrain (2001), Cameroon/Nigeria (2002), and Nicaragua/Colombia (2012) cases, reviewed in Part B, Chapters 12, 13, 15, and 21 respectively, below.

90  Romania/Ukraine (2009), paras. 77 and 110. See also, to similar effect, Barbados/Trinidad (2006), para. 239: ‘To the extent that the coast is abutting on the area of overlapping claims, it is bound to have a strong influence on the delimitation…’. The ‘relevant coast’ and ‘relevant area’ are addressed at Part, A Chapter 2, ‘Methodology’, below. As discussed at Part, C Chapter 2 below, the question of how to identify them has been the subject of contrasting approaches in the delimitation jurisprudence.

91  See, e.g., the ICJ’s distinction between numerous island and low-tide elevation features in the Qatar/Bahrain and Nicaragua/Colombia cases.

92  See, e.g., the UK/France Continental Shelf case, para. 95, where the Court of Arbitration contrasted the impact of specific geographical features on an equidistance line drawn between opposite and adjacent coasts. See further discussion and illustration in Part, B Chapter 3 below. In addition, the transition between relationships of oppositeness and adjacency has frequently led courts and tribunals to separate areas of delimitation in any given dispute, and to apply different methodologies or results in those separate areas. For example, see UK/France Continental Shelf, Gulf of Maine, Barbados/Trinidad, and Nicaragua/Colombia, see Part B, Chapters 3, 6, 16, and 21 respectively.

93  See, e.g., the Nicaragua/Honduras case, where the ICJ determined that the ‘particular circumstances’ of the coastal geography rendered an equidistance-based delimitation ‘not feasible’ (para. 84), Part, B Chapter 18 below.

94  See Part, A Chapter 2, II, The ‘Three-Stage Approach’. below. As first discussed by the ICJ Chamber in the Gulf of Maine case, geographical criteria are particularly prevalent in single boundary delimitations covering the water column and seabed, since such criteria are perceived to be of a ‘more neutral character’ and ‘best suited for use in a multi-purpose delimitation’ (para. 194).