As seen in the preceding paragraphs, the case law has suggested a pattern in which delimitation is to be affected by attributing the primary role to the geographical factors and the secondary role to certain other relevant factors. However, these general guidelines can not completely settle the practical application of the delimitation law. The principles identified so far may be sufficient to clarify what factors are primary and what factors are secondary importance. However, these principles are not sufficiently specific to indicate what effect every geographical element or other elements should have.[1]

A quick answer to the problem may be that it is the peculiar circumstances rather than the principles themselves that can determine the issue of relative effect.[2] However, in order to have a predictable and practical legal course it should at least be possible to have certain guidelines that would indicate approximately the effect to be accorded to a factor in certain circumstances. The practicality of the delimitation law should be demonstrated in solving this issue.

The previous review has already shown that geographical factors appear to be much more influential than any other relevant factors within the delimitation process. They are the factors which indicate the “initial” and “main” delimitation line in any delimitation case.[3] However, since there are many geographical factors, their relative weight in relation to one another is a matter for consideration.

The Tribunal in the UK-France Arbitration observed that as far as the determination of the initial line is concerned, coastal configuration in “its general direction” plays a significant role.[4] The ICJ Chamber in the Gulf of Maine Case similarly observed that “the delimitation line to be drawn in a given area, will depend upon the coastal configuration.”[5] When the ICJ emphasised “the coast of each of the Parties” as constituting the starting line in the Tunisia-Libya Case, it seemed to be referring to the mainland coasts, rather than the coasts of the islands.[6] The treatment of islands by the Tribunal in the Eritrea-Yemen Arbitration clearly points to the mainland geography as the primary factor.[7]

The evidence is sufficient to show that it is the coastal configuration which is the most dominant factor in the determination of the initial and main delimitation line. The elements which constitute coastal configuration has been clarified in delimitation cases as the general configurations of a coast,[8] the difference in the coastal lengths,[9] or the islands and islets in the delimitation area.[10]

However, what is important about the costal configurations is the “coastal configuration in its general direction”. Individual configurations could only play a secondary role relative to the general configurations. Moreover, individual configurations could be disregarded altogether under certain considerations.[11] As the ICJ Chamber pointed out in the Gulf of Maine Case, it is not every coastal configuration that would be reflective on the course of delimitation line.[12]

The identification of what the minor and major factors is left, to a certain extent, to the individual circumstances of every case. However, there are two general principles which play a role in identification of such factors. They are the principles of proportionality and non-encroachment.

The principle of proportionality has been introduced as a ratio between the coastal lengths and the maritime areas to be attributed to the parties. In fact, the parties’ coastal lengths could simply be one of the relevant geographical elements that may have a varied role on the initial and main delimitation line.[13]

However, the balance between the coastal lengths and the maritime areas to be attributed would indicate, the relative weight to be accorded to different geographical factors on the basis of equity.[14] Generally speaking, while the general coastal configurations determine the course of the delimitation line, it is the coastal length which is used as a yardstick in appreciating whether the effect of an individual configuration or any other factor would be excessive.[15] The role of the islands is, for instance, simply judged on the basis of the principle of proportionality.[16]

The principle of non-encroachment is the other principle that similarly determines the relative effect of the relevant geographical factors. The principle was once taken as referring to the element of natural prolongation.[17] Considering that the role of natural prolongation diminished and was replaced by the element of distance, the principle signifies that the delimitation must leave to a State the areas that are in the vicinity of its coasts.[18] Accordingly, any method that attribute an effect in a manner to cut off from the seaward projection of a given coast would not be equitable.[19] This includes geographical factors such as islands.[20]

The relative weight to be attributed to the non-geographical factors which are of a secondary role are yet to be determined in our review. As previously noted, it is certain that they do not affect the delimitation line to the same extent as the geographical factors.[21] On the other hand, their role, when compared to each other within the delimitation process, is another matter and seems to be left to the peculiar circumstances of every individual case. However, the principles of proportionality and non-encroachment again constitute a yardstick in determining their relative effect.[22]

Despite their significant roles, neither the principle of proportionality nor the principle of non-encroachment is absolute. The supervising role of the principle of proportionality does not amount to simply dividing the maritime areas with respect to the ratios between the respective coastlines and the areas to be attributed to them. If that were so, other factors would not have a role to play.[23] Clearly, equity of a delimitation process means taking all the relevant factors into account.[24]

Contrary to such an idea of proportionality, its true role is to remedy, on the basis of approximate proportions between coastal lengths and maritime areas, the “substantial disproportions” or “inequities” caused by certain configurations or factors.[25] It is not therefore to be used in the mathematical sense of an accurate test.

Similarly, the principle of non-encroachment is not as strict as it first appears. In some geographical situations, the cut-off effect is unavoidable, so that some degree of encroachment can be allowed on the basis of coastal geography such as when both coasts are concave, as in the Guinea-Guinea Bissau Arbitration.[26] The necessity of attributing some effect to the competing coastal front in the Canada-France Arbitration legitimised the cut-off effect on the projection of the Canadian coastline.[27] In fact, identifying proximity or vicinity proved to be a difficult matter in the circumstances of individual cases.[28] It certainly renders the principle of non-encroachment a quite subjective one. Eventually, the role of the principle of non-encroachment in identifying the relative effect of the relevant factors in a delimitation process is dependent to a great extent on the circumstances of the case in hand.

It should be noted here that the earliest judgment of the ICJ in the North Sea Cases that gave a dominant role to the element of natural prolongation[29] should not create confusion. As the role of sea-bed features has gradually decreased on the delimitation line,[30] there is no principle of natural prolongation that would judge the relative effect of the factors relevant to a delimitation in hand.

It is therefore clear that despite their non-absolute role, the principle of proportionality and non-encroachment constitute the most general yardsticks in evaluating the relative weight to be attributed to various relevant factors, geographical or otherwise. They will not allow excessive weight to any of the relevant factors with a view to arrive at an equitable solution.

4. Calculation of Proportionality

According to the definition made in case law, the proportionality test compares the ratios between the respective coastal lengths and the maritime areas to be attributed.[31] These ratios therefore basically involve the determination of the length of relevant coastlines and the water areas to be attributed. However, the calculations could be a matter of disagreement, as seen in case law.[32] As the ICJ observed in the Jan Mayen Case, the practical implementation of the principle may sometimes be complicated by both the difficulties in defining with sufficient precision which coasts and which areas are to be treated as relevant, and by the presence of claims of third States in the delimitation area.[33]

4.1. Relevant area

The solution of these problems in case law seems to have necessitated that the “area” relevant to the delimitation in hand should be determined first.[34] The delimitation judgments have presented certain guidelines for identifying the relevant area in a given case. First of all, relevant area did not need to be defined in very specific terms. The ICJ noted in the Libya-Malta Case that the determination needs to be only defined in broad terms.[35] Sometimes, it is not possible to define it in specific terms as the Tribunal in the Guinea-Guinea Bissau Arbitration observed that it “can have only an approximate idea of the zone to be considered, based on an approximate evaluation.”[36]

Another principle, as observed by the ICJ in the Tunisia-Libya Case,[37] is that the “relevant area” was not limited to the “area in dispute”. The Court defined the former as the “general area relevant for the delimitation” and observed that “the only areas which can be relevant for the determination of the claims of Libya and Tunisia to the continental shelf in front of their respective coasts are those which can be considered as lying either off the Tunisian or off the Libyan coast. These areas form together the area which is relevant to the decision of the dispute.” On the other hand, the area in dispute, according to the Court, is the area which forms only a “part of this whole area”, “where one claim encroaches on the other” and “lies both off the Libyan coast and off the Tunisian coast”.[38]

The criterion of the ICJ in the Tunisia-Libya Case thus depended on the element of “lying off the coast of either party”. In fact, by such an observation, the Court depended on the relevant coasts to identify the relevant area. Therefore, once the relevant coasts, which stretch to a point on the coast beyond which the coast in questions no longer has a relation with the coast of the other party, are identified,[39] delineating the relevant area is a simple matter. The areas lying off the coast of either party will simply be the relevant areas.

However, in the Gulf of Maine Case, the Chamber mostly respected the parties’ claims to identify the relevant area. Although the case mainly concerned the Gulf of Maine area, the Chamber also included the areas lying to seaward of and against the Gulf towards the outer edges of the triangle as no claim may go beyond these bounds.[40] Similarly, the parties’ claims could be said to have played the dominant role in identifying the relevant area in the Canada-France Arbitration. The Tribunal took the area as relevant which the parties agreed was the geographical concavity framed by the Canadian coast leading from the Atlantic Ocean to the Gulf of St. Lawrence.[41] In the Jan Mayen Case, the ICJ observed that the parties’ claims mostly determine the relevant area.[42]

However the above does not mean that one party could bring any area into the consideration just by expanding its claims. The areas claimed by either party must have a relation, basically in a geographical sense, with the main area covered by the arguments of both parties. Despite the first impression, the Chamber in the Gulf of Maine Case did not take the claims of the parties as fully determinant. It also pointed out that “the involvement of coasts other than those directly surrounded by the Gulf does not and may not have the effect of extending the delimitation area to maritime areas which have in fact nothing to do with it.”[43] The Chamber observed moreover that the considerations of socio-economic or human geography could also be relevant in establishing the connexion between the areas and the delimitation. But, it only had in mind “physical geography to the extent that its purpose is to describe the present-day aspect of the land and water surface of the globe.”[44]

Similarly in the Jan Mayen Case, the Court did not find the determination of the extent of Greenland’s coastline by Denmark “arbitrary”, not because its claims were determinant, but because the points selected by Denmark had geographical relations with the possible equidistant lines.[45]

The existence of a third State’s claim is another complicating factor. The ICJ in the Libya-Malta Case saw the area as involving geographical difficulties due to the claims of some other States.[46] The relevant area should not, according to the Court, comprise the areas where the claims of third States also exist. Since the Court did not have the jurisdiction to entertain their claims, the decision must be limited to a geographical area in which no claims of a third State exist.[47] Therefore, where there were claims of third States in the area, the Court refrained from defining the relevant area and the relevant coasts since it would involve an artificial prolongation of the delimitation line.

4.2. Coastal lengths

Once the relevant area is defined, there remains the issue of determining the length of relevant coasts. It should be determined for two separate reasons. As noted above,[48] the difference between the coastal lengths of States is a factor relevant to the delimitation itself, especially for the establishment of the initial delimitation line. On the other hand, the coastal lengths should be established for the purpose of conducting the proportionality test on the basis of the delimitation line which is provisionally established.

The measurement of the relevant coasts could, however, be a problem for many reasons. There could be the presence of offshore islands, coastal configurations, territorial waters, or the internal waters. The problem has eventually necessitated development of certain principles for the solution.

The first issue to come up in this context is whether all the coasts or some parts of them within the relevant area are relevant for the calculation of the coastal lengths. In general terms, the ICJ observed in the Tunisia-Libya Case that “for the purpose of shelf delimitation between the parties it is not the whole coast of each party which can be taken into account”. According to the Court, “there comes a point on the coast of the two Parties beyond which the coasts in question no longer have a relation with the coast of the other Party relevant for submarine delimitation”.[49] It does not however suggest that some coasts within the relevant area might be disregarded. As we have said in the preceding section, the Court in this case depended on the relevant coastlines to identify the relevant area[50] so that there is an overlap between the relevant area and the relevant coastlines that surround it.

Only the judgment of the Canada-France Arbitration implied otherwise. Although the parties in this case agreed on the “relevant area” as the geographical concavity framed by the Canadian coasts including the whole southern coast of Newfoundland and the whole north-eastern coast of Nova Scotia,[51] they differed on the “coasts that should be considered as fronting on the area of dispute.”[52] While Canada took all these coasts as relevant for the delimitation, France would exclude certain segments of the southern coast of Newfoundland and Nova Scotia which were already approved as constituting the parts of coasts surrounding the relevant area.[53]

The Court seemed to have accepted the French justification but observed that some of the coasts that had been excluded by France were in fact “generating projections which meet and overlap, either literally or in opposition.”[54] On the same basis, the Tribunal observed that France had justifiably excluded the Canadian line across Fortune Bay and opposite the north and east coast of the islands of St. Pierre and Miquelon, since the north and east coasts of St. Pierre and Miquelon did not face the area in dispute. The Court therefore excluded all the coasts which were not facing the area in dispute or which were not meeting and overlapping with the projection of the opposite relevant coasts.[55] By doing so, it made a distinction between the relevant area and the coasts relevant for the calculation of the coastal lengths. The relevant coasts are only those facing the area in dispute or those whose projections meet and overlap.

Therefore, it is established that only the coasts which face the disputed area or the coasts of the parties whose projections meet, would be included. Some coasts that are in the delimitation area may be included, depending on the circumstances of the case. This is to mean that there is no general principle on the identification of which coast in the delimitation area will be included into the calculation.

There is, however, a further problem to be settled and it concerns the coastlines of islands. It is almost certain that the coastal islands that are in close vicinity of the mainland are included in the determination of the general direction of the coastlines. No clear precedent exists as to whether the islands which fall out of such a general direction would be included in the calculation. It is however implied that the islands that are located off the mainland do not seem to be regarded as fully affecting the calculation of coastal lengths. To what extent the islands’ coastlines will be taken into consideration depends on the characteristics of both the delimitation area and the islands concerned.[56]

The measurement of the relevant coasts constitutes a further problem. In order to overcome the difficulties caused by various circumstances, the ICJ in the North Sea Cases observed that the respective coastlines of the parties for the purpose of proportionality are “measured according to their general direction”. While leaving the determination of the “appropriate technical method” to the parties, it proposed the “principle of coastal front” for measuring the general direction of coastline, which consists of drawing a straight baseline between the extreme points at either end of the coasts concerned or, in some cases, a series of such lines.[57] The Court’s reason for choosing the method of general direction was that it would “establish the necessary balance between States with straight and those with markedly concave or convex coasts or to reduce very irregular coastlines to their true proportions.”[58]

The fact that only the general direction of the coastlines rather than every single configuration should be taken into account was further approved in the Guinea-Guinea Bissau Arbitration. The parties were in disagreement over the calculation of coastal length. The Tribunal observed that “In fact what counts for the delimitation to be made is the length of the coastlines following its general direction”.[59] The Tribunal in the Canada-France Arbitration again measured the coastlines “by segments, according to their lines of general direction.”[60] In the Jan Mayen Case, the ICJ measured the lengths of the relevant coastlines directly and on the basis of straight lines drawn between the points that constitute the geographical limit of those relevant coastlines.[61]

4.3. Relevant water area

Another aspect of the proportionality test is the measurement of the water area which is to be compared with the ratios between the coastal lengths of the parties. In the Tunisia-Libya Case, Libya argued that the entire area of sea-bed and subsoil beyond the low-water mark of each State must be taken into account.[62] The Court in that case calculated the sea-bed areas beyond the low-water mark.[63] However, the Court observed that it is the circumstances of the area that determine whether the territorial and internal waters should be included in the calculation. The Court emphasised that if they made a significant difference in ratios, they would be excluded.[64]

It is also a problem to identify which water areas beyond the internal and territorial waters should be included in the calculation. The Tribunal in the Canada-France Arbitration emphasised a principle that it is necessary to compare like with like and observed that “in comparing like with like it is necessary to take into account not only the projection to 200 miles awarded to French islands, but also the Canadian area resulting from an identical projection extending the relevant area eastwards along Newfoundland 200 miles area to a point due south of Cape Race, and so embracing the whole economic zone generated to the south by the south coast of Newfoundland.”[65] Therefore, the Tribunal calculated the relevant maritime area on the basis of the 200-nautical mile limit generated by the Canadian and French coastlines that project into the area.

The Jan Mayen judgment presented quite a different solution. The ICJ felt it necessary to concentrate only on the area in dispute in order to to compare the water areas awarded to the parties, the 200-mile line drawn from the Greenland coastline claimed by Denmark and the equidistant line claimed by Norway.[66] However, the handling of the Court’s calculation of relevant waters should only be considered in the way in which it handled the proportionality principle in the circumstances of that case. In fact, the Court arrived at a solution that produced a division of the water area which was so different from the coastlines’ proportions, i.e. 1:9, that it appeared not to have taken the proportionality test seriously.[67]

Another difficulty in the determination of the relevant water area could be the presence of the third States’ claims in the area concerned. The ICJ in the Tunisia-Libya Case considered this matter to be significant but suggested that an imaginary line delimiting the maritime areas of the parties with other States should be fixed.[68] The difficulty is therefore settled by establishing an imaginary delimitation line that would enable the calculation of relevant water areas.[69]

5. Multi-Purpose Delimitation

Requesting a delimitation line that would govern only one maritime area is in fact just one among a number of possibilities. Another possibility in a delimitation process is a single line for the areas of continental shelf, EEZ, and territorial sea. Generally speaking, territorial sea does not seem to fit into this setting as it is significantly different from other two maritime areas in terms of nature and extent.[70] Such a line was decided in two separate cases, namely the Guinea-Guinea Bissau and the Eritrea-Yemen Arbitrations. It was possible in the former case, since the line to be indicated was an adjacent delimitation line in a certain part of the delimitation area.[71] In the latter case, a single line for three separate delimitation areas was possible since a certain part of the delimitation area was so narrow that a single line had to be established.[72] However, where such lines were delimited, they should be considered as delimiting only the territorial waters of the parties.

One other possibility is the trend in both State practice[73] and in third-party settlements whereby two States might decide to have a single line which would govern both the continental shelf and the exclusive economic or fisheries zone within 200 miles. The parties in three separate cases explicitly requested the ICJ or the competent ad hoc tribunals to delimit a single line for both the continental shelf and fisheries zone superjacent to the continental shelf.[74]

The last possibility is that the delimitation of more than one maritime area could separately be the subject of the same delimitation process. In this possibility, however, the result would not necessarily be a single line for all. The concept of the continental shelf has not altogether been swept aside by the EEZ.[75] Thus, the delimitation line could well be different for both maritime areas, as the relevant circumstances are not exactly the same for these concepts.[76]

However, the conceptual link and similarities between the two concepts in terms of their legal nature and extent[77] are so extensive that the ICJ in the Jan Mayen Case came up with a single line, although the parties did not specifically request this.[78] Since the principle of distance played a wider role in the determination of the continental shelf extent,[79] it was possible that the principles and rules underlying the concept of the EEZ be applicable, even in a case concerning only the delimitation of the continental shelf.[80] In this context, there is no reason to consider the EEZ or the fisheries zone overlying the continental shelf.[81]

In addition to these legal facts, practical considerations also confirm the same possibility.[82] If the continental margin does not extend beyond 200 miles, it is possible that the outer limit could coincide in many other sea areas. On the other hand, in an area where the distance is less than 400 miles, it is almost certain that the delimitation line will coincide. There cannot be a wider continental shelf than the EEZ as the EEZ of the other State would also cover the sea-bed and subsoil of the area.[83] But the outer limit should not coincide if the other State only possessed an exclusive fisheries zone in the superjacent waters.

The significant problem is whether these facts suggest that the delimitation principles that are applicable to the continental shelf and the EEZ should also be applicable to a single but dual-purpose line. Both the customary and the conventional law do not specifically provide a delimitation rule for such a single-line delimitation. The ICJ in the Gulf of Maine Case had a legal lacuna to fill. Due to the close link between these two concepts, the Chamber did not rule that Article 6 of the 1958 Convention which was the rule applicable to the continental shelf delimitation between the parties would also be applicable to the single-line delimitation in hand. Article 6 could not be applicable because these concepts are, in the Court’s mind, separate concepts.[84] This fact has also been confirmed in the single-line delimitations made since by the international courts.[85]

The jurisprudence established clearly that the applicable law is applied to the single-multi-purpose delimitation is the customary rule of maritime delimitation. It means that the delimitation must be affected by agreement in accordance with equitable principles in order to reach an equitable result by taking into account all the relevant circumstances.[86]

On the other hand, the way in which the delimitation law is implemented in a single-line delimitation is another significant matter. The Chamber in the Gulf of Maine Case, with a sophisticated approach, made a distinction between the circumstances peculiar to the concept of continental shelf on one hand, and those to the concept of the EEZ on the other. In such a case, it would be expected that the role of geography should, beyond any doubt, be the dominant one, given the fact that sea-bed features have nothing to do with the concept of the EEZ.[87] The judgment approved, in general, that the principles and circumstances that are relevant to both concepts should be applied in a single-line delimitation. It is a significant point that only the criteria that are common to both concepts should be applied.[88]

The criteria that are common to both concepts are those derived from the geography.[89] As the criterion of distance within 200 miles has become applicable to both concepts, it constitutes another common element to be considered.[90] Less significant factors such as fisheries and mineral resources are also to be considered.[91] What should not be relevant has also been pronounced. Factors that are related to ecology, geology or geomorphology are not to be considered as they are peculiar to either the EEZ or the continental shelf alone.[92] In the Eritrea-Yemen Arbitration for instance, the Tribunal decided to establish a single-all purpose delimitation boundary but did not consider the sea-bed features among the relevant factors.[93]

The only judgment that seemed to be at variance with what was said with regard to the role of sea-bed features is the Guinea-Guinea Bissau Award. The Tribunal in that case seemed prepared to take into account such factors even within 200 miles if the natural prolongations of the parties were physically separate from one another.[94]

It is consequently possible to conclude that single-line delimitation could be requested by States for the delimitation of both the continental shelf and the EEZ. It is also possible for coastal States to delimit the continental shelf and the EEZ separately within the same delimitation process. However, from a practical point of view, it is unlikely that they would reach a delimitation line other than a single line for both maritime areas, despite the fact that factors relevant to these concepts are different in some respects. Therefore, where a single line is to be established, the applicable delimitation law is not different from what is applicable separately. It is the customary law of delimitation that would be applied. Within this context, only those that are common to both concepts would be considered as relevant factors within the delimitation process.

6. The Role of Islands in a Delimitation Process

High-tide natural elevations which fall into the legal definition of an “island” are fully entitled to their own maritime areas including the continental shelf and the fisheries or exclusive economic zone.[95] The rocks that cannot sustain human habitation or economic life shall have no exclusive economic zone or continental shelf.[96] However, the case of the islands within a delimitation process is a different matter.[97] Both State practice and jurisprudence on delimitation provide that islands may be characterised as a “limited” or “no-effect” in a delimitation process depending on the various characteristics of both these islands and the area to be delimited.[98] The location of islands in relation to the mainlands is quite significant in this respect. Moreover, some other features of islands are considered in relation to the role of islands. All those factors will be examined on the basis of a classification according to their location.

6.1. Islands situated close to the mainland

Some of the islands which are situated in close vicinity of the mainland coast are called “coastal islands”. Here, the concept of a coastal island does not refer to every island that is situated in the vicinity of any mainland coast. It refers only to those that are situated in the vicinity of terra firma, i.e. of the mainland to which they belong.

The islands situated just off the mainland to which they belong were considered by the Arbitration Tribunal in the UK-France Arbitration.[99] The Scilly Isles of the UK and the French Island of Ushant were situated very close to their own mainlands. The Tribunal’s concern was whether giving full-effect to these islands would change the equidistant boundary between the mainlands in an unjust and inequitable sense.[100] In the Tunisia-Libya Case, the ICJ dealt with the similarly situated Tunisian islands of Kerkennah.[101] The Kerkennah Islands were a few miles off the Tunisian coast facing the maritime projection of the Libyan mainland coasts. Giving full-effect to these islands would, in the Court’s view, increase much further the Tunisian projection onto that of Libya.[102]

There was a similar situation in the Guinea-Guinea Bissau Arbitration where the islands were situated just off the mainland.[103] Moreover, Guinea and Guinea Bissau were situated as adjacent States and their position was fairly similar to that of Tunisia and Libya. The difference in the Guinea-Guinea Bissau Arbitration was the fact that rather than an island surrounded by many small islets, many islands of Guinea Bissau were situated off the mainland coast.

According to the Tribunal “when account is taken of the fact that...the two States abut on the same continental shelf with coasts not markedly different in extent and broadly similar in their relation to that shelf”, giving a full-effect to these islets would not be equitable.[104] It is a fact, however, that these islands were given some effect in shaping the delimitation line. In almost all the cases where these islands were given an effect, the way in which the effect was given was to consider them as part of the mainland coastlines. In this context, their role was limited since in some cases, they did not change the direction of coastal line as far as their location.

The Tribunal in the UK-France Arbitration thought in a similar way but observed that Ushant and Scilly “cannot be disregarded in delimiting the continental shelf boundary without “refashioning geography”, as both Ushant and Scilly were islands of “a certain size and population” constituting “natural geographical facts of the Atlantic region”.[105]

The ICJ in the Tunisia-Libya Case would not disregard the Kerkennah Islands which were surrounded by islets and low-tide elevations and were considered as “a circumstance relevant for the delimitation”, on the basis of “their size and position”.[106] The Kerkennah islands were referred to in drawing a baseline according to the coastal direction for the purpose of shelf delimitation.[107] Rather than shifting that line as far as their location, they only shifted the line in a partial manner up to a line between the island and the mainland.[108] Depending on the relevant State practice, the Court gave them “half-effect” or “half-angle” in this context.[109]

According to the Tribunal in the Guinea-Guinea Bissau Arbitration, what was important was to ensure that each party controlled the maritime territory opposite and in the vicinity of its coasts. In this context, the important factor was the coastal configuration which must include the relevant islands.[110] Rather than affecting the calculation of the length of the general coastline on the basis of their full coastal length, these islands would only affect the calculation by shifting the general direction of the coastal line as far as their location. These islands would therefore play rather a limited role in the establishment of the line representing the coastal direction.[111]

The Eritrea-Yemen Arbitration addressed a situation in which a considerable number of islands were situated off the mainland coast of both countries. Although some of the coastal islands of Eritrea, called the Dahlak Archipelago, are scattered further off the mainland, the Tribunal considered all of them as constituting the integral part of the mainland coast, which was also agreed by both parties.[112] The equidistant delimitation line was measured from the straight baseline drawn on the foremost islands of the Dahlak Archipelago.[113] The Tribunal also pointed to the fact that some of these islands were inhabited and therefore important such as the Yemeni island of Kamaran and the Eritrean island of Dahlak.[114] It is however a matter of fact that the Tribunal did not attribute any effect to the such coastal islands in the southern section of the delimitation.[115]

Only in the Gulf of Maine Case, were coastal islands given an effect in a different way. The Chamber found the island of Seal (together with its smaller neighbour, the island of Mud) to be in a similar situation, situated just off the Canadian coast and close to the closing line of the Gulf. “Though minor” said the Chamber, it might have some influence because of its “dimensions and, more particularly, of its geographical position”. However, the Court used it in establishing the ratios for the purpose of proportionality. But again, the effect given was limited. The Chamber observed that it would be excessive to treat the coastline of Nova Scotia as transferred south-west-wards by the whole of the distance between the island of Seal and that coast. Accordingly, a half-effect was appropriate.[116]

Obviously, most of the coastal islands were given an effect within the delimitation process by including them in the establishment of the coastal line from which the delimitation line was to be measured. These islands affected the coastline as far as their location in many cases. In some cases, their effect in this sense was rather limited as they did not change the direction of the coastline far as their location. In both situations, the location, size, inhabitancy and economic importance of the island played a role in assessing its effect.

It seems that the role of these elements is judged against their effect on the median line between the mainlands. This means that their eventual role seems to be appreciated on the basis of a balance between their features and the distorting effect they produce on the equidistant line between the mainlands.

The same considerations seemed to have necessitated no-effect decision on the Tunisian island of Jerba. The Court ignored the island as it was almost touched on its own coast. According to the Court “in the part of the area to be delimited in which the island of Jerba would be relevant, there are other considerations which prevail over the effect of its mere presence”.[117] The Judgment in the North Sea Cases did not consider the case of islands, but provided that in a case where the natural prolongation of two opposite States met and overlapped, the solution would be a median line which would ignore “the presence of islets, rocks and minor coastal projections” and provide equal division of the area.[118]

In the Guinea-Guinea Bissau Arbitration, the islands scattered further out to sea were not taken into account in the determination of the coastal direction and coastal lengths.[119] The enclave solution seems to be regarded as better suited, the width of which would depend on the circumstances of the islands. The Tribunal gave only 12 miles territorial sea to the islands of Alcatraz, but no continental shelf towards the north.[120]

In the Eritrea-Yemen Arbitration, the Tribunal observed the fact that the mid-sea islands of Jabal al-Tayr and the Zubayr group of Yemen, were situated “well out to sea” should mean that “they should not be taken into consideration in computing the boundary line between Yemen and Eritrea”. The Tribunal further pointed to the fact that they were “barren” and had an “inhospitable nature.”[121] It decided that they should have “no-effect” upon the delimitation line.[122]

Similar to the coastal islands, the location, size and other relevant features of the mid-sea islands and the area to be delimited play the most significant role in judging their effect. However, the location of these islands is a negative element in the determination of their role. They could even be ignored altogether due to their location. This is because islands produce dramatic change on the delimitation line which is mainly determined on the basis of the mainland coasts.

The review has so far shown that coastal islands are taken into account mostly in establishing the coastal line from which the delimitation  line is measured. Sometimes, they are also considered in establishing the coastal lengths for the purpose of proportionality. In both cases, these islands are mostly given limited effect. It seems that considerations relevant to the mainland geography override them. The limited effect given to these islands is judged on the basis of their location and other relevant characteristics identified above.

6.2. Islands situated on the “wrong side”

The other possible location for islands might be well away from their mainland and close to the coast of another State. This was the situation in the UK-France Arbitration. The Channel Islands in the British Isles of the UK were situated just a few miles off the French mainland coast. The Arbitration Court addressed their role in the delimitation between the mainlands with reference to the customary law of delimitation. Due to their location, it was almost illogical to consider them in relation to the delimitation line indicated by the mainland coasts because they were beyond the line. It seems that this fact led the Tribunal to consider an enclave solution.

The Tribunal indicated that geographical location runs contrary to the continental shelf area that they would be attributed.[123] It observed that they “are situated on the French side of a median line drawn between the mainlands” and are situated “practically within the arms of a gulf on the French coast”.[124] This clearly demonstrated that because of their geographical position, they would be considered directly against the French mainland coast but would not be attributed equal continental shelf areas as the competing French mainland coast. They constitute in the Court’s view a typical example of “special circumstances” in the meaning of Article 6, or “relevant circumstances” calling for an equitable method of delimitation in the meaning of the customary rule.[125]

The Court accordingly indicated a “secondary boundary” delimiting the continental shelf of the Channel Islands in the southern section of the mid-Channel line. The Court emphasised that their entitlement to their own continental shelf areas would be limited.[126] It gave 12 miles continental shelf to the Islands because the French continental shelf should not encroach upon the already declared 12-mile fishery zone of the islands.[127] They possessed “a considerable population and a substantial agricultural and commercial economy”. Moreover, as they enjoyed “a very large measure of political, legislative, administrative and economic autonomy”[128] and detached geographically from the UK,[129] they have their own rights separately from the UK. Moreover, they are not merely “rocks or small islands”.

It was such a limited enclave since it seemed that the overall delimitation in the Tribunal’s mind was still between the mainlands of the UK and France. The Court observed that the circumstances in the area demonstrated a geographical balance that would indicate a median line as the equitable delimitation line between the mainlands of the UK and France. Such a balance was, the Court said, disturbed by the presence of the Channel Islands in the vicinity of the French coast.[130]

Therefore, the role of such islands is again related to their location, size, and other relevant characteristics. In such cases, the location of these islands runs very much against the extent of the maritime areas they would be attributed. It seems that they would only be attributed restricted maritime areas if they were sizeable and socially and economically significant. Otherwise, it is unlikely that they would be allocated any continental shelf and EEZ areas in a delimitation between mainlands. Accordingly, the exact weight that these islands would have been given was similarly left to these individual characteristics of the case.[131]

The islands which are situated on the wrong side but not so close to the mainland of another State have not so far been addressed in judicial cases. However, like other islands, their role should depend on their location, size and relevant characteristics. It is however certain that they are better situated in terms of generating maritime areas as they are more closely associated with the delimitation line indicated. It seems however that such islands may not be allowed any maritime areas if they are not sizeable and significant from a socio-economic point of view.[132]

6.3. Islands in various situations

Many other cases introduced completely different geographical settings from those that have been considered above. In all the above judgments, the islands were considered in the delimitation between two mainland countries. However, the Canada-France Arbitration was quite different in the sense that the overseas French islands of St. Pierre and Miquelon were situated just off the Canadian mainland coast. The Arbitration Court had to treat them as competing mainland coasts since there was no French mainland nearby which could have otherwise been the main reference point.

The Tribunal emphasised the difference between the lengths of the coastlines in this case. It was, according to the Court, the particular geographical circumstances i.e. the presence or absence of competing coasts of another State, which gave way to that factor. This implied that despite their relatively short coastline, they might have wider or full maritime areas if there were no competing coasts, i.e. the Canadian coasts.[133] Accordingly, since the French islands did not conflict with any opposite or laterally aligned Canadian coast in the second sector towards the south and south-east, they were, according to the Court, fully entitled to a maritime zone of 200 nautical miles in that part. In such circumstances, these islands would be treated as a primary element rather than a secondary one having no distortion on the projection of another State.[134]

However, where they face the coasts of Canada, the disproportion between the coastline was significant. The Court explained that the difference in length of all the parties’ relevant coasts was an important factor to be taken into account for an equitable delimitation. In this case, the disproportion necessitated attributing a restricted maritime area to these islands.

Therefore, in the absence of an initial delimitation line that would have been indicated by the mainlands, the Tribunal took the criterion of proportionality as the reference point to judge the distortion that the French islands could generate in their full-effect. Similar to the statement in the UK-France Arbitration, other characteristics of these islands would have a role in determining their exact role.[135] Under all such considerations, the Court granted in the western sector 12-mile EEZ from the outer limit of its territorial sea.[136]

A small island country was in dispute with a continental country in the Libya-Malta Case. Malta, which is an island country, argued that “It is only in the case of dependent islands,... that international law gives varying effect to them depending on such factors as size, geographical position, population or economy.”[137] Libya, a continental country, urged the Court to make no distinction between an island State and an island politically linked to a mainland State.[138]

The Court approved the significance of the distinction but not in the same way as Malta put it. According to the Court, its status as an island State not only created a difference in treatment but also changed the relation of its coasts with the coasts of neighbouring countries.[139] In other words, it might well be that the sea boundaries in this region would be different if the islands of Malta were part of the territory of one of the surrounding countries rather than an independent State. It was quite similar to the Arbitration Court’s observation in the Canada-France Arbitration that “there are no grounds for contending that the extent of the maritime rights of an island depends on its political status.”[140]

Given the fact that the coasts of Libya and Malta were overlapping, the coastal lengths were the only main reference point.[141] The Court treated Malta on the basis of its relatively short coastline and its position “in the wider geographical context”, particularly in a semi-enclosed sea.[142] Rather than being an independent island State, these factors played the role and produced a relatively less continental shelf area for Malta. The Court did not, moreover, accept the relevance of economic and security factors that were put forward by Malta.

The Jan Mayen Case was another unique case since the delimitation was to be conducted between the islands of two different countries without the effect of the mainlands which were situated outside the delimitation area. Thus the mainlands would not provide any reference points. Having considered the coastal lengths and economic and coastal characteristics, Denmark considered the island of Jan Mayen as falling into the category of “special circumstances”. Thus, a median line should not be established as the initial delimitation line which would not obviously reflect the difference between the coastal lengths.[143]

The Court considered the coastal lengths and some other factors in a different way. Although Jan Mayen had a coastal length half the that of Greenland, it still “generates potential title to the maritime areas recognised by customary law, i.e., in principle, up to a limit of 200 miles from its baselines.”[144] The Court’s consideration of other factors i.e. economic and cultural factors[145] was that they did not entail attribution of half-effect to Jan Mayen.[146] Since two islands were in consideration, the Court seemed to treat them on an equal footing, but awarded less continental shelf area to Jan Mayen on the basis of shorter coastal lengths.

It seems that if the two islands were in dispute with each other in a delimitation case, the peculiar characteristics as well as the lengths of coastline would play quite a significant role. This is similar to a case where a small island State is up against a much larger continental country. In this situation, the coastal lengths seem to be the dominant factor, as supported by the principle of non-encroachment.

6.4. The natural prolongation of islands

Another significant point concerning the islands within a delimitation process is the role to be attributed to their natural prolongation. It was considered and concluded by the Court in the UK-France Arbitration that the natural prolongation of islands should be treated in the same way as the mainland territory. This is to say that its effect should be appreciated in the light of all the relevant geographical and other circumstances.[147] However, the Court emphasised the danger of giving an absolute effect to the natural prolongation of an island which could enable a small island to block the natural prolongation of the territory of the nearby mainland.[148]

The Arbitration Court in the Canada-France Arbitration addressed the issue of encroachment of an island on the natural prolongation of another State. Canada had argued that the French islands generated no continental shelf of their own since, “the islands are superimposed upon the Canadian continental shelf.”[149] It could be assumed that the Chamber accepted this observation of the Court in the UK-France Arbitration. It was evident from the Chamber’s observation that “‘natural prolongation’, in spite of its physical origins has throughout its history become more and more a complex and juridical concept.” The element of natural prolongation should be appreciated in the light of relevant geographical and other circumstances of a particular case rather than as an absolute factor.[150]

6.5. Some conclusions

The above review shows that the entitlement to maritime areas is a distinct matter from the maritime delimitation. As far as the islands are concerned, it is appropriate to say that establishing a direct link between entitlement and delimitation is not legally justified. Although islands, except rocks which cannot sustain human habitation or economic life, are fully entitled to their own continental shelf and EEZ, they may be given limited or no-effect status in a delimitation process depending on various considerations related both to the islands and to the related area.

The above review also shows that when they are considered in a delimitation between two mainlands, the geographical position of islands is critical. Because of their location, islands create a degree of distortion on the delimitation line indicated by the mainlands. Various other characteristics of the islands could also play a role in appreciating how much distortion by these islands could be tolerated.[151] The islands situated just off the mainland coasts are mostly used in establishing the line that reflects the general coastal direction. Islands situated further off the mainland or situated on the wrong side of median delimitation line between the mainlands are again attributed a limited maritime areas. It seems that unless they are quite significant in terms of size and socio-economic characteristics, they are unlikely to have any effect at all.

Islands could be in various other situations. In all these cases where the maritime projections meet and overlap, it is the coastal length and other specified characteristics of these islands which would determine the extent of maritime area they would be attributed.[152]

Apart from these general observations which could well be regarded as very significant principles applicable to future cases, they do not constitute an exact pattern to be followed, as all situations are different to some degree. Moreover, some situations could be significantly different from those considered by international courts so far. As the Court in the UK-France Arbitration observed, the treatment might be different in a situation where numerous islands stretch out one after another near the mainland of an other State.[153] This is generally the situation in the Aegean Sea.[154] It does not however mean that all the situations considered in the preceding paragraphs do not constitute a precedent for the Aegean Sea. They are in fact relevant either by providing certain general principles for the treatment of islands in a delimitation process or by addressing a similar geographical situation when the Aegean islands are considered in separate delimitation sectors.

7. Sectoral Approach to the Maritime Delimitation

The sectoral approach has legal and practical advantages in conducting an equitable delimitation process. The geographical situations in some of the judicial cases were too complex to be handled as a whole due to the existence of various coastal configurations and islands or islets. Dividing the delimitation area into separate sectors according to their differentiating characteristics was deemed to be a simplifying approach.

Principles according to which the delimitation area is divided into different sectors emerge from the jurisprudence. The geographical situation in the Tunisia-Libya Case could be regarded as a complex one as it comprised various coastal configurations and islands. The ICJ observed that it would lead to a “proper appreciation” if the certain areas were treated separately. It accordingly separated the area “close to the coasts of the Parties” from the area “further offshore”.[155] In the Gulf of Maine Case, the geographical situation was complicated with the intrinsic pattern of coastal relations and the presence of islands. The ICJ Chamber accordingly separated the delimitation area into three different areas as “innermost part”, “central segment”, and “outside” area.[156] In the Canada-France Arbitration, the situation complicated by the existence of varying coastal relations. The Arbitration Court accordingly divided the area into two different sectors. It separated the “western seaward projection” from the other area “towards the south and south-east” where the projections of the parties’ coasts did not meet.[157]

In the Eritrea-Yemen Arbitration, the Tribunal considered the delimitation area in three separate sectors. Although the coasts of the parties were opposite to each other in all delimitation areas, the distance between them was variable. Moreover, coastal and mid-sea islands were in various locations. The Tribunal accordingly considered northern, central and southern sectors separately.[158]

The geographical situation in most of the delimitation area in the UK-France Arbitration could again be considered a complex one. The Tribunal considered the delimitation area in these sectors separately. The area between the mainlands of the two parties, apart from the Channel Islands region, was considered as the English Channel region. The Tribunal considered the area in the Atlantic as a separate area since the position of the two States’ mainland coasts was adjacent rather than opposite.[159] Moreover there were some small coastal islands to be considered in the Atlantic Region.[160]

The judgements have also explained the logic behind the way in which the delimitation area is separated into different sectors. In the Tunisia-Libya Case, the ICJ observed that the difference in treatment of the area close to the coast from the areas further offshore “is ultimately dictated by the primordial requirement of achieving an overall equitable result”[161] The Arbitration Court in the UK-France Arbitration employed a very similar expression when it observed that “In order to reach an equitable result, it is necessary to examine separately two different sectors of the maritime area where the delimitation is to be affected.”[162]

It is felt that equity will be achieved more efficiently with separate sectors because the applicable principles and methods to the delimitation will be different since the circumstances are different in separate sectors. The Tribunal in the UK-France Arbitration observed that the principles and methods would be different in separate sectors.[163] Different sectors might require the application of different delimitation method or methods.[164] The Court in the Tunisia-Libya Case made it clear that “the use of any one method of delimitation which may seem appropriate, in the light of relevant circumstances close to the shores of the States concerned, may well suffer from the defect” in the areas further off.[165]

The Gulf of Maine Case presented an illustrative example. In this case, the coasts of the parties in the inner section were adjacent and thus a “lateral equidistant line” could be “convenient”. However, in the further section of the Gulf, the “geographical situation changes radically”. It “becomes a frontal opposition relationship”.[166] Moreover, the projection of the US coast in the first section was also facing this second area.[167] Evidently, a more suitable method would be appropriate in this second sector.[168] The third section posed a different geographical pattern that called for the application of some other methods.[169] The reason in the Canada-France Arbitration for a sectoral approach was the same in the sense that the different coastal relations between the parties would eventually necessitate different methods of delimitation in different sectors.[170]

Whether the sectoral approach means isolating all these sectors from each other is another issue. The ICJ observed in the Tunisia-Libya Case that when it is dealing with the first sector, i.e. the offshore area, it is really “confining its attention to the delimitation” in this section. It said that at such a stage “it is legitimate to disregard the present coastal configurations found at more than a comparatively short distance from that point, for example, the island of Jerba.”[171]

However, it does not mean that different sectors of the delimitation area would be altogether isolated. The ICJ in that case seemed to have confined its observation to the stage that it is concerned with. In fact the course of the delimitation line in one sector could be affected by the course of the line in the other segments as provided by the ICJ Chamber in the Gulf of Maine Case.[172] More importantly, the principle of proportionality that deals with the whole delimitation area[173] firmly indicates that different sectors are not completely independent from each other as all the delimitation should comply with the general test of proportionality.

It is therefore appropriate to conclude that in the judgments on maritime delimitation, the delimitation areas were divided into separate sectors according to certain guidelines. As the different sectors had different circumstances, they necessitated the application of different principles and resulting methods. However, it does not mean that they are isolated from each other. They are still linked as equity has to be achieved for the delimitation area as a whole.