Individual opinion, partly concurring and partly dissenting, of Judge Robinson

INDIVIDUAL OPINION, PARTLY CONCURRING AND
PARTLY DISSENTING, OF JUDGE ROBINSON
1. In this opinion, I explain the reasons for my disagreement with paragraph 214 (5) of the
Judgment and make observations on other parts.
2. Paragraph 214 (5) of the Judgment reads as follows:
“[The Court] . . . [d]ecides that from Point B, the maritime boundary delimiting
the continental shelf continues along the same geodetic line until it reaches the outer
limits of the continental shelf or the area where the rights of third States may be
affected[.]”
3. Since Point B is the outer limit of the exclusive economic zone and continental shelf within
200 nautical miles, the formulation of this paragraph makes clear that the Court has delimited the
continental shelf beyond 200 nautical miles. However, for the following reasons, the Court was not
in a position to carry out such a delimitation.
4. First, the régime for a coastal State’s entitlement to a continental shelf within 200 nautical
miles is different from the régime for its entitlement to a continental shelf beyond 200 nautical miles,
and it is this difference that makes the Court’s finding in paragraph 214 (5) questionable.
Article 76 (1) of the United Nations Convention on the Law of the Sea (hereinafter “UNCLOS” or
the “Convention”) provides as follows:
“The continental shelf of a coastal State comprises the sea-bed 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.”
5. Although the Convention defines the continental shelf in geological and geomorphological
terms as the sea-bed and subsoil of the submarine areas throughout the natural prolongation of its
land territory to the outer edge of the continental margin, it also provides that, in cases where the
outer edge of the continental margin does not extend to 200 nautical miles from the baselines from
which the breadth of the territorial sea is measured, the continental shelf will extend to that distance.
In effect, therefore, the distance criterion supersedes the geological and geomorphological criteria in
defining a coastal State’s entitlement to a continental shelf up to 200 nautical miles. However, where,
as here, the question relates to a State’s entitlement to a continental shelf beyond 200 nautical miles,
different considerations apply.
6. In order to determine a State’s entitlement to a continental shelf beyond 200 nautical miles
there must be in existence a continental margin that extends beyond 200 nautical miles because, by
virtue of Article 76 (1) of the Convention, the continental shelf extends to the outer edge of the
continental margin. Paragraph 3 of Article 76 of the Convention defines the margin as “compris[ing]
the submerged prolongation of the land mass of the coastal State, and consist[ing] of the sea-bed and
subsoil of the shelf, the slope and the rise”. Therefore, in order to delimit, the Court must have before
it reliable evidence that there is in existence, in the area beyond 200 nautical miles, a “submerged
prolongation of the land mass of the coastal State”. According to paragraph 6 of Article 76 of the
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Convention, the outer limit of the continental shelf “shall not exceed 350 nautical miles from the
baselines from which the breadth of the territorial sea is measured”.
7. Thus, in relation to the delimitation of the continental shelf beyond 200 nautical miles,
geological and geomorphological criteria supersede the distance criterion, because there can be no
entitlement to a continental shelf in the area beyond 200 nautical miles and up to a distance of
350 nautical miles, unless there is certainty that there is in existence a continental margin in that area.
Since under the Convention a coastal State’s entitlement to a continental shelf beyond 200 nautical
miles is determined by geological and geomorphological factors, the Court must ensure that those
factors exist before delimiting the continental shelf beyond 200 nautical miles.
8. The distinction between delineation of the outer limit of the continental shelf by the
Commission on the Limits of the Continental Shelf (hereinafter the “CLCS” or “Commission”) and
maritime delimitation by the Court is clear. It is equally clear that recommendations by the CLCS on
the outer limit of the continental shelf do not constitute a necessary precondition for maritime
delimitation by the Court. But in order to carry out such a delimitation, the Court must have reliable
evidence confirming the existence of a continental shelf in the area beyond 200 nautical miles.
9. The Judgment reflects an awareness of the requirement that the Court must have at hand
reliable information confirming the existence of a continental margin in the area beyond 200 nautical
miles if it is to be in a position to carry out a delimitation in that area. However, as will be seen, the
Court ignores this requirement.
10. After citing Article 76 (4) of the Convention, the Judgment concludes that “[t]he
entitlement of a State to the continental shelf beyond 200 nautical miles thus depends on geological
and geomorphological criteria. An essential step in any delimitation is to determine whether there
are entitlements, and whether they overlap” (paragraph 193). The Court noted that the Tribunal in
Bangladesh/Myanmar was only able to carry out delimitation of the shelf beyond 200 nautical miles
because of what the Tribunal described as the “unique situation in the Bay of the Bengal”, a feature
which the Judgment states explicitly “is not the same as [present case]”. The Special Chamber of the
International Tribunal for the Law of the Sea (“ITLOS”) in Ghana/Côte d’Ivoire held that it “can
delimit the continental shelf beyond 200 [nautical miles] only if such a continental shelf exists”1, and
that it had the benefit of the Commission’s affirmative recommendations in relation to Ghana; it also
observed that the “geological situation [of Côte d’Ivoire was] identical to that of Ghana”2. The
Special Chamber emphasized that there is “no doubt that a continental shelf beyond 200 [nautical
miles] exists in respect of the two Parties”3. The need for a court or tribunal to be certain about the
existence of a continental shelf beyond 200 nautical miles if it is to carry out a delimitation in that
area was also emphasized by the Tribunal in Bangladesh/Myanmar. The Tribunal stated that it would
have been hesitant to proceed to delimit the area beyond 200 nautical miles if there was uncertainty
about the existence of a shelf in that area4.
1 Delimitation of the Maritime Boundary in the Atlantic Ocean (Ghana/Côte d’Ivoire), Judgment, ITLOS
Reports 2017, p. 136, para. 491.
2 Ibid., p. 136, para. 491.
3 Ibid., p. 137, para. 496.
4 Delimitation of the Maritime Boundary in the Bay of Bengal (Bangladesh/Myanmar), Judgment, ITLOS
Reports 2012, p.115, para. 443.
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11. As if to contradict the cautionary note it had sounded in relation to any reliance on the
decisions in Bangladesh/Myanmar and Ghana/Côte d’Ivoire, the Court in paragraph 194 rather
unexpectedly announced its decision to delimit the continental shelf boundaries up to the outer limit
of the continental shelf.
12. It is ironical that, having taken the pains to isolate and identify the critically relevant
information that ITLOS and its Special Chamber had in the Bangladesh/Myanmar and
Ghana/Côte d’Ivoire cases, the Court proceeded to delimit the Parties’ continental shelf in the area
beyond 200 nautical miles without any convincing evidence as to the existence of a shelf beyond
200 nautical miles. This contrasts with the decision of the Court in Nicaragua v. Colombia not to
delimit the continental shelf beyond 200 nautical miles, because Nicaragua relied on information it
had submitted to the CLCS that did not substantiate its claim to a continental shelf beyond
200 nautical miles5.
13. The Judgment is bereft of even a scintilla of reliable evidence that the geological and
geomorphological criteria, which the Judgment itself refers to in paragraph 193 as being essential in
the determination of State entitlements, have been met.
14. The Court comes closest to identifying evidence of the existence of a continental shelf
beyond 200 nautical miles when it noted “that in their submissions to the Commission both Somalia
and Kenya claim on the basis of scientific evidence a continental shelf beyond 200 nautical miles
and that their claims overlap” (paragraph 194 of the Judgment). However, this observation does not
provide a sufficient basis for the delimitation because nowhere in the Judgment is there any reference
to the content of this scientific evidence and, more importantly, nowhere in the Judgment is there
any analysis of that content to show that the Court is satisfied that the necessary geological and
geomorphological criteria have been met for the existence of a continental shelf beyond 200 nautical
miles. It must be made clear that in this case the Court was not asked to examine any scientific data
that would establish the existence of a continental shelf beyond 200 nautical miles. It is, of course,
perfectly proper to refer to the Parties’ submissions to the Commission. However, if it relies on these
submissions, the Court must explain why it finds them persuasive. Such an explanation is the more
necessary where, as in this case, the Commission has not yet made any recommendations on the
submissions of the Parties. Thus, it appears that the principal factors that explain the Court’s decision
to delimit the continental shelf beyond 200 nautical miles are the criterion of the 350-nautical-mile
distance as the outer limit of the continental shelf and the volition of the Parties to have the Court
effect a delimitation. But, in delimiting the continental shelf beyond 200 nautical miles, geological
and geomorphological factors supersede distance as the criteria for determining a State’s entitlement
to that shelf, thereby rendering less consequential the request of the Parties to have the Court effect
a delimitation in that area.
15. The lack of any evidence of geological and geomorphological data to substantiate the
existence of a continental shelf, and thus, of the entitlement of the Parties to a continental shelf
beyond 200 nautical miles, undermines the validity of the finding in paragraph 214 (5), which is the
principal conclusion of the Court in the part of its Judgment devoted to the delimitation of the
continental shelf beyond 200 nautical miles. Nonetheless, the present opinion will comment on other
aspects of the Judgment relating to this finding.
5 Territorial and Maritime Dispute (Nicaragua v. Colombia), Judgment, I.C.J. Reports 2012 (II), p. 669, para. 129.
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16. Second, in the delimitation of the continental shelf in the area beyond 200 nautical miles
the Court has overvalued the volition of the Parties and the fact that “neither Party questions the
existence of the other Party’s entitlement to a continental shelf beyond 200 nautical miles or the
extent of that claim” (paragraph 194 of the Judgment). In the delimitation of the continental shelf up
to 200 nautical miles, it is appropriate for the Court to act entirely on requests of the Parties for it to
carry out such a delimitation, because in that area the distance criterion of 200 nautical miles prevails.
However, where, as here, the Court is delimiting the continental shelf in the area beyond 200 nautical
miles, the requests of the Parties, and the congruence of their views as to their respective entitlement
to a shelf beyond 200 nautical miles and the extent of that entitlement, do not constitute a sufficient
basis for delimitation in that area. By effecting a delimitation of a party’s continental shelf beyond
200 nautical miles without any reliable evidence of the existence of a shelf in that area, the Court has
effectively eliminated the important difference drawn by the Convention between a coastal State’s
entitlement to a shelf within and beyond 200 nautical miles. In the result, by delimiting on the
presumption that the Parties are entitled to a shelf up to 350 nautical miles, the Court has replaced
the geological and geomorphological criteria required by the Convention for such an entitlement with
a simple distance criterion of a maximum of 350 nautical miles. There is nothing in the Judgment
that comes close to the categoric findings in Bangladesh/Myanmar and Bangladesh v. India cases as
to the existence of a continental shelf beyond 200 nautical miles.
17. Third, the Court has carried out a delimitation of the continental shelf beyond 200 nautical
miles in an environment riddled with uncertainty. Although the use of a directional arrow, such as
the one contained in sketch-map No. 13, is not uncommon in delimitation of the continental shelf
beyond 200 nautical miles, there must be some doubt as to whether this approach provides the level
of certainty that one would expect in an exercise as consequential as the delimitation of a boundary
between two States, which will have sovereign rights in the area attributed to them.
18. This uncertainty is even more evident in paragraph 197 of the Judgment, which reads:
“Depending on the extent of Kenya’s entitlement to a continental shelf beyond
200 nautical miles as it may be established in the future on the basis of the
Commission’s recommendations, the delimitation line might give rise to an area of
limited size located beyond 200 nautical miles from the coast of Kenya and within
200 nautical miles from the coast of Somalia, yet on the Kenyan side of the delimitation
line (“grey area”).” (Emphasis mine.)
This reasoning is a conjecture built on a surmise founded on a hypothesis  scarcely a basis for the
construction of a legal régime. Regrettably, the grey area that it identifies is not of “limited size”, but
in the circumstances of this case, may be seen as applying to the entire area beyond 200 nautical
miles. It is noted, however, that the Court decided not to address the question of the legal régime that
would be applicable to this grey area.
19. Notwithstanding that delineation of the outer limits of the continental shelf is carried out
by coastal States on the basis of the recommendations of the CLCS, and not by the Court, there must
be a concern that delimitation and delineation exercises may impact adversely on the Area, defined
in Article 1 (1) of the Convention as “the sea-bed and ocean floor and subsoil thereof, beyond the
limits of national jurisdiction”. The Area therefore begins where national jurisdiction ends.
Article 136 provides that “[t]he Area and its resources are the common heritage of mankind”;
Article 140 (1) provides that activities in the Area are to be carried out “for the benefit of mankind
as a whole . . . and taking into particular consideration the interests and needs of developing States”.
During the UNCLOS negotiations, generally, developing countries attached the greatest importance
to the establishment of a meaningful régime for the Area in the expectation that its exploration and
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exploitation would contribute to their growth and development in the interest of the common heritage
of mankind.
20. Concerns about the possible impact of delimitation on the régime for the Area were
expressed by the Arbitral Tribunal in the France-Canada Maritime Delimitation case (St. Pierre and
Miquelon), in which France had requested delimitation of the continental shelf beyond 200 nautical
miles. The Commission stated:
“Any decision by this Court recognizing or rejecting any rights of the parties over
the continental shelf beyond 200 nautical miles, would constitute a pronouncement
involving a delimitation, not ‘between the Parties’ but between each one of them and
the international community, represented by organs entrusted with the administration
and protection of the international sea-bed Area (the sea-bed beyond national
jurisdiction) that has been declared to be the common heritage of mankind.”6
While this Award, made not very long after the adoption of the Convention, may be seen as going
too far, its underlying concern should not be disregarded: where it is appropriate, the interests of the
international community in exploring and exploiting the Area is a factor that must be taken into
account in maritime delimitation in the area beyond 200 nautical miles. Moreover, in the
Bangladesh/Myanmar case the Tribunal expressly considered the possible impact of the delimitation
of the shelf beyond 200 nautical miles on the interests of the international community in the Area,
and determined in the following finding that those interests were not affected:
“In addition, as far as the Area is concerned, the Tribunal wishes to observe that,
as is evident from the Parties’ submissions to the Commission, the continental shelf
beyond 200 nm that is the subject of delimitation in the present case is situated far from
the Area. Accordingly, the Tribunal, by drawing a line of delimitation, will not prejudice
the rights of the international community.”7
A fair inference from this finding is that the Tribunal would not have carried out the delimitation
requested or, at any rate, would have given serious thought to declining that delimitation, had it found
that this delimitation was to be carried out in an area that was near to the Area in which the
international community has an interest. It would seem that, in the instant case, a statement similar
to that of the Tribunal in Bangladesh/Myanmar could not be made by the Court, because the
continental shelf that is the subject of delimitation could possibly extend to the Area. Nonetheless
the Tribunal’s dictum is instructive in that it signifies an appropriate sensitivity to the interests of the
international community in the Area.
21. Fourth, Article 83 (1) of the Convention requires that the delimitation of the continental
shelf be effected by agreement on the basis of international law in order to achieve an equitable
solution. In the delimitation of the continental shelf within 200 nautical miles, the Court quite
properly spent much time considering whether its three-stage methodology produced an equitable
solution. On the other hand, in the delimitation of the continental shelf beyond 200 nautical miles,
the Judgment is silent on the question whether the methodology the Court has used produces an
equitable solution. This is a significant omission in the Judgment and it raises serious questions as to
whether the delimitation carried out has been effected in accordance with the Convention.
6 Delimitation of Maritime Areas between Canada and France (10 June 1992), United Nations, Reports of
International Arbitral Awards (RIAA), International Legal Materials (ILM), Vol. 3, p. 1172, para. 78.
7 Delimitation of the Maritime Boundary in the Bay of Bengal (Bangladesh/Myanmar), Judgment, ITLOS
Reports 2012, p. 97, para. 368.
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Concavity
The significance of the Kenyan “concavity”
22. The best statement of the law on the relationship between a relevant circumstance, a
concavity, the median line and a cut-off effect is the finding of the ITLOS in Bangladesh/Myanmar
that
“concavity per se is not necessarily a relevant circumstance. However, when an
equidistance line drawn between two States produces a cut-off effect on the maritime
entitlement of one of those States, as a result of the concavity of the coast, then an
adjustment of that line may be necessary in order to reach an equitable result.”8
23. The question is whether the cut-off effect produced by the equidistance line must result
from a geographical feature that meets the minimum requirements for a concavity or whether it can
result from any geographical feature, such as a mere curvature or an indentation, even if that feature
does not meet the minimum requirements for a concavity. Case law is generally unhelpful in
identifying the minimum features for a concavity to result in the equidistance line producing a cut-off
effect that requires its adjustment in order to achieve an equitable solution. The comments that one
finds on this question are of a general nature; for example, in Ghana/Côte d’Ivoire, the Special
Chamber found “that the coast of Côte d’Ivoire is concave, although such concavity is not as
pronounced as in, for example, the case of the Bay of Bengal”9.
24. In the 1969 North Sea Continental Shelf cases, the Court found that the German coast was
“markedly concave”10. It is not for nothing that in considering the German concavity, the Court
referred to another coastline, that of Bangladesh, that was also markedly concave. Indeed, in
Bangladesh/Myanmar, ITLOS held that the Bangladesh coast was “manifestly concave” and that,
consequently, the equidistance line produced a cut-off effect warranting the adjustment of that line.
One may also consider the Court’s decision in Costa Rica v. Nicaragua. However, that decision is
not apposite because the Court did not examine in detail whether a concavity existed, but simply
confined itself to the conclusion that the existence of a concavity did not produce a cut-off effect
warranting an adjustment of the equidistance line. This is to be contrasted with the instant case in
which the majority has found not only that there is a concavity, but that “[w]hen the mainland coasts
of Somalia, Kenya and Tanzania are observed together, as a whole, the coastline is undoubtedly
concave” and that, consequently, the equidistance line produces a cut-off effect that warrants some
adjustment of that line. In Cameroon v. Nigeria, the Court found that there was no concavity in the
sectors of the coastline relevant to the present delimitation11. In Guinea/Guinea-Bissau, the Tribunal
found that the coastline of Guinea-Bissau, Guinea and Sierra Leone, when considered together, was
generally concave12.
8 Delimitation of the Maritime Boundary in the Bay of Bengal (Bangladesh/Myanmar), Judgment, ITLOS
Reports 2012, p. 81, para. 292.
9 Delimitation of the Maritime Boundary in the Atlantic Ocean (Ghana/Côte d’Ivoire), Judgment, ITLOS
Reports 2017, p. 120, para. 424.
10 North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of
Germany/Netherlands), Judgment, I.C.J. Reports 1969, p. 50, para 91.
11 Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria: Equatorial Guinea
intervening), Judgment, I.C.J. Reports 2002, p. 445, para. 297.
12 Delimitation of the Maritime Boundary between Guinea and Guinea-Bissau, Award of 14 February 1985,
International Law Reports (ILR), Vol. 77, pp. 634-693.
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25. In accordance with the Court’s jurisprudence therefore, an adjustment of the equidistance
line is only required when it produces a cut-off effect as a result of a coastal feature that is obviously
concave or, to use the language of the Court in North Sea Continental Shelf cases, “markedly
concave” or that of the Tribunal in Bangladesh/Myanmar, “manifestly concave”. That the Court did
not have in mind a cut-off effect resulting from a slight curvature or an indentation in a coast is clear
from its finding in Libya/Malta 16 years later, that an equidistance line “may yield a disproportionate
result where a coast is . . . markedly concave or convex”13. Here the Court was restating its finding
in the 1969 North Sea Continental Shelf cases that an equidistance line may yield disproportionate
results when a coastal feature has a concavity or convexity that would have the effect of pulling the
line inwards or outwards. What is significant is that the Court found that this outcome must be the
result of a markedly concave or convex coast.
26. The phrase, “as a consequence of a concavity” in the ITLOS dictum makes clear that the
cut-off effect must result from a concavity, that is, a geographical feature that causes an equidistance
line to produce a cut-off effect, warranting its adjustment in order to achieve an equitable result.
The phrase has special significance in that it emphasizes the very important causal role that the
concavity plays in the equidistance line producing a cut-off effect. If a geographical feature that is a
mere curvature or an indentation rather than a concavity, produces a cut-off effect, then that effect is
to be ignored, because to recognize it as capable of leading to an adjustment of the equidistance line
would be to refashion geography and an equitable solution would not be achieved. The well-known
proposition that maritime delimitation should not result in refashioning geography is reflected in
paragraph 172 of the Judgment.
27. It can be inferred from the ITLOS dictum (cited above in paragraph 26) that it is not any
and every geographical feature that will be sufficient to constitute a relevant circumstance; it is only
a geographical feature meeting the minimum requirement for a concavity and producing a cut-off
effect that will constitute a relevant circumstance requiring adjustment of the provisional
equidistance line. Regrettably, the Special Chamber’s decision in Ghana/Côte d’Ivoire is
inconsistent with the Court’s jurisprudence that an adjustment of the equidistance line is only
required when it produces a cut-off effect as a result of a coastal feature that is markedly concave.
The effect of the Special Chamber’s ruling in that case is that a coastal feature that would appear to
be nothing more than a mere curvature constituted a concavity. However, the Chamber only found
that there was a cut-off effect when the convexity of the Ghanaian coastline was also taken into
account, and in any event, it found that the cut off did not warrant an adjustment of the equidistance
line. The decision of the Arbitral Tribunal in Guinea/Guinea-Bissau is also inconsistent with the
aforementioned jurisprudence of the Court.
28. Although one cannot identify, with a fine degree of certainty, the minimum requirements
for a concavity sufficient to produce a cut-off effect that calls for an adjustment of the provisional
equidistance line, of the several coastal features considered in the previous paragraphs, it is only
those of Germany and Bangladesh that would appear to meet those requirements. It is only those
coastal features that can be said to be markedly concave. As will be seen in the sketch-maps below,
it is only those coastal features that, on their face, resemble a concavity in that they possess a shape
that is markedly hollowed or markedly rounded inward like the inside of a bowl (Merriam-Webster’s
Dictionary). The more relaxed view of what constitutes a concavity, evident in Ghana/Côte d’Ivoire
and Guinea/Guinea-Bissau, has not displaced the clear finding of the Court that it is a markedly
concave coastal feature that produces a cut-off effect, calling for an adjustment of the provisional
equidistance line.
13 Continental Shelf (Libyan Arab Jamahiriya/Malta), Judgment, I.C.J. Reports 1985, p. 44, para. 56.
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29. In the instant case, there must be a doubt as to whether the curvature in the Kenyan coast
or, for that matter, the curvature in the Somali, Kenyan and Tanzanian coasts, has the degree of
concavity sufficient to result in the equidistance line producing a cut-off effect, requiring an
adjustment of that line. Certainly, the greater part of the Kenyan coastline may fairly be described as
a slight curvature. Since, in the result, the Court has held this curvature to be a concavity, the
reasonable doubt that exists as to whether the feature constitutes a concavity means that any cut-off
resulting would only warrant the slightest adjustment of the equidistance line, because that line does
not in any significant way prevent Kenya from achieving its maximum maritime area in accordance
with international law; in fact, the better view might very well be that no adjustment is warranted
since the cut-off is neither serious nor severe.
30. In considering the curvature in the Somali, Kenyan and Tanzanian coasts as part of what
the Judgment describes as the “broader geographical configuration”, the Court has followed the
Tribunal’s decision in Guinea/Guinea-Bissau rather than its Judgment in Cameroon v. Nigeria. In
the former case, the Tribunal considered the coastline of Guinea, Guinea-Bissau and Sierra Leone
together; in the latter case, the Court was explicit in its finding that the Cameroonian concavity could
only be a relevant circumstance “when such concavity lies within the area to be delimited”14. In order
to show that the Cameroonian concavity did not meet that requirement, the Court observed that it
was not facing Nigeria, but rather, the island of Bioko, that belonged to a third State, and was not
within the area to be delimited. The Judgment has wrongly seized on this reference by the Court to
an island of a third State to conclude that “the Court’s statement thus should not be understood as
excluding in all circumstances the consideration of the concavity of a coastline in a broader
geographical configuration”. But there is nothing in the Court’s finding to suggest that it was
embracing the notion of a broader geographical configuration; rather, in order to dismiss the
Cameroonian claim that its concavity was a relevant circumstance, the Court merely observed that
the concavity was located in a third State, and that it was not a relevant circumstance since it was not
within the area to be delimited. Significantly, the Court referred to the third State, not to take its
concavity into account, but to exclude it from the maritime delimitation between Cameroon and
Nigeria on the basis that it was not within the area to be delimited. In contrast, in the instant case, the
Court refers to the “concavity” of a third State, Tanzania, not to exclude it from the maritime
delimitation between Somalia and Kenya, but to include it in that delimitation. The proposition that,
in maritime delimitation, account should be taken of a concavity that is not within the area to be
delimited but is part of a so-called broader geographical configuration, is problematic. In the first
place, the concept of a “broader geographical configuration” is itself broad and vague  where the
configuration begins and ends is a legitimate question. But the real danger is that the cut-off effect
may result more from the geographical feature of a third State  not a party to the dispute and not
in the delimitation area  than from the geographical feature on the coast of the State that is a party
to the dispute and is within the area to be delimited. This would appear to be so in the present case
because the Tanzanian “concavity”, that is not within the area to be delimited, appears more
pronounced than the Kenyan “concavity”, that is within the area to be delimited. The odd result is a
refashioning of geography whereby an adjustment is made to the equidistance line, more on account
of a “concavity” in the Tanzanian coastline than of the “concavity” in the Kenyan coastline  a
result that is wholly inconsistent with the Court’s finding in Cameroon v. Nigeria that, in order to
qualify as a relevant circumstance for the purpose of adjusting the equidistance line, the concavity
must be within the area to be delimited15. Somalia would appear to have been disadvantaged by
reason of a “concavity” that is not within the area to be delimited  an outcome that can scarcely be
described as equitable.
14 Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria: Equatorial Guinea
intervening), Judgment, I.C.J. Reports 2002, p. 445, para. 297.
15 Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria: Equatorial Guinea
intervening), Judgment, I.C.J. Reports 2002, p. 445, para. 297.
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31. In support of its decision to take into account the “concavity” in the Tanzanian coast as
part of a broader geographical configuration, the Court cites its finding in the 1969 North Sea
Continental Shelf cases that “although two separate delimitations were in question, they involved 
indeed actually g[a]ve rise to  a single situation”16. However, there is an important difference
between those cases and the instant case. In the 1969 cases, the Court joined cases brought separately
by Germany against the Netherlands and against Denmark, with the result that the maritime areas
produced by the coasts of the Netherlands, Denmark and Germany constituted the delimitation area.
Thus, there was no question of the maritime areas of the Netherlands and Denmark, between which
the German concavity lies, not being within the area to be delimited. In contrast, Tanzania is not a
party to the dispute between Somalia and Kenya, and its “concavity” is not within the area to be
delimited. The need for a concavity to be located within the area to be delimited, if it is to qualify as
a relevant factor requiring adjustment of the equidistance line, was reiterated by the Court in
Cameroon v. Nigeria.
32. There is another important distinction between the 1969 cases and the instant case. As a
result of the joinder, the Court had before it submissions from the two adjacent coastal States, the
Netherlands and Denmark. In contrast, in the instant case the Court has no submissions from
Tanzania, which is not a party to the dispute and whose “concavity” does not lie within the area to
be delimited.
33. In sum, the Court’s Judgment in the 1969 cases does not authorize the proposition that in
maritime delimitation account may be taken of a concavity that is not within the area to be delimited
merely because it falls within a so-called “broader geographical configuration”. Therefore, the
“single situation” to which the Court referred in the 1969 cases does not eliminate the need for the
concavity to fall within the area to be delimited if it is to qualify as a relevant factor warranting an
adjustment of the provisional equidistance line.
The status of the 1927/1933 treaty arrangement
34. There is a question whether the Court has interpreted and applied the 1927/1933 treaty
arrangement. In order to address this question, the following paragraphs of the Judgment must be
examined. Paragraph 109 states: “In light of the above, the Court therefore considers it unnecessary
to decide whether the 1927/1933 treaty arrangement had as an objective the delimitation of the
boundary in the territorial sea.”
Paragraph 118 states:
“The Court observes that the course of the median line as described in
paragraph 117 corresponds closely to the course of a line ‘at right angles to the general
trend of the coastline’, assuming that the 1927/1933 treaty arrangement, in using this
phrase, had as an objective to draw a line that continues into the territorial sea, a question
that the Court need not decide (see paragraph 109 above).”
Paragraph 214 (2) reads as follows:
“[The Court] . . . [d]ecides that the starting-point of the single maritime boundary
delimiting the respective maritime areas between the Federal Republic of Somalia and
the Republic of Kenya is the intersection of the straight line extending from the final
permanent boundary beacon (PB 29) at right angles to the general direction of the coast
16 North Sea Continental Shelf (Federal Republic of Germany/Denmark; Federal Republic of
Germany/Netherlands), Judgment, I.C.J. Reports 1969, p. 50, para. 11.
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with the low-water line at the point with co-ordinates 1° 39' 44.0" S and 41° 33' 34.4" E
(WGS 84)[.]”
35. An examination of paragraphs 109 and 118 reveals that the Court has interpreted the treaty
arrangement. The Court could not have concluded that there was a close correspondence between the
median line as described in paragraph 117 and the course of a line “at right angles to the general
trend of the coastline” without examining and interpreting that phrase, which is to be found in the
1927/1933 treaty arrangement. However, it might also be argued that, in this paragraph, the Court
has not only interpreted the colonial treaty but also applied it. This is not a view that I share, but it
cannot be ruled out of consideration. My own position is that paragraph 214 (2) of the dispositif
confirms that the Court has not applied the 1927/1933 treaty arrangement because the starting-point
identified  “the intersection of the straight line extending from the final permanent boundary
beacon (PB 29) at right angles to the general direction of the coast with the low-water line,”  is not
the starting-point set out in the 1927/1933 treaty arrangement. This paragraph of the dispositif does
not use the phrase “at right angles to the general trend of the coastline”, which is to be found in
paragraph 118, and placed in quotation marks to indicate that it is taken from the 1927/1933 treaty
arrangement. This paragraph, in its reference to the low-water line as the starting-point of the
boundary, reflects Article 5 of the Convention, which is the applicable law for the Parties, since both
States are parties to that Convention. Although it may be said that the formulation of this paragraph
is influenced by the 1927/1933 treaty arrangement, it cannot be concluded, that in determining the
starting-point the Court has applied the 1927/1933 treaty arrangement.
36. An interesting feature of this case is that although the part of this Judgment relating to the
territorial sea is replete with references to the 1927/1933 treaty arrangement, and although the Court
has quite plainly interpreted that treaty, there is nothing that explains how the Court is in a position
to take cognizance of this treaty.
37. The dispute brought before the Court relates to differences between Somalia and Kenya.
The 1927/1933 treaty arrangement relates to treaties between Italy and United Kingdom. By what
legal theory or jurisprudential principle does the Court have the power to interpret the treaties
between Italy and the United Kingdom? The Judgment does not explain how, in the absence of the
Parties conferring jurisdiction on it in respect of the colonial treaties, the Court takes cognizance of
these treaties. There must be an explanation as to how the colonial treaties between Italy and the
United Kingdom become relevant to the dispute between Somalia and Kenya. It cannot even be
maintained that there is a link between the treaty arrangement and the dispute on the basis that both
cover the same geographical area, because the treaties establish a land boundary while the dispute
between the Parties relates to the sea. However even if both the treaties and the dispute covered the
same geographical area, that would not provide a sufficient link with Somalia and Kenya  States
that were not parties to the 1927/1933 treaty arrangement. Indeed, in relation to Somalia and Kenya,
the treaty is res inter alios acta. The closest that the Judgment comes to discussing the relationship
between the 1927/1933 treaty arrangement and the dispute is in paragraph 32. In that paragraph, after
outlining the various instruments described as the 1927/1933 treaty arrangement between Italy and
the United Kingdom, there is a terse reference to Somalia and Kenya gaining their independence in
1960 and 1963 respectively. However, no link is made between the colonial treaties and the
attainment of independence between Somalia and Kenya.
38. There was adopted in 1978 the United Nations Convention on Succession of States in
respect of Treaties (hereinafter referred to as the “1978 Vienna Convention”). It defines a succession
of States as “the replacement of one State by another in the responsibility for the international
relations of territory”.
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39. The 1978 Vienna Convention required ratification by 15 States to enter into force.
Following its adoption, the treaty took 18 years to enter into force and today, 43 years after its
adoption, it only has 23 States parties or about 12 per cent of the membership of the United Nations.
Obviously it has not gained any significant support. The reason is explained below.
40. By virtue of that Convention a newly independent State begins its life free from any
obligation to continue or maintain the treaties of its predecessor, but with an entitlement to continue
or maintain those treaties if it so wishes. This principle is reflected in Article 16 which provides that
“[a] newly independent State is not bound to maintain in force, or to become a party to, any treaty
by reason only of the fact that at the date of the succession of States the treaty was in force in respect
of the territory to which the succession of States relates”. In my view, the provision is protective of
the sovereignty of the newly independent States because it does not impose an obligation on them to
continue the treaties of a predecessor State and at the same time it leaves those States with an
entitlement to continue those treaties if they wish.
41. Notwithstanding the apparent potential of Article 16 to attract newly independent States to
ratify the 1978 Convention, only few have done so. In the Caribbean, for example, only Dominica
and Saint Vincent and the Grenadines are parties and from Africa only Egypt, Ethiopia, Liberia,
Morocco, Seychelles and Tunisia are parties. Somalia and Kenya are not parties. There is obviously
a strong antipathy to this Convention on the part of the vast number of developing countries that
became independent after 1960. The overriding reason for this opposition is Article 11 which
provides that “[a] succession of States does not as such affect: (a) a boundary established by a treaty;
or (b) obligations and rights established by a treaty and relating to the regime of a boundary”.
Therefore, to the extent that the 1927 Agreement established a boundary, that boundary is not
affected as such by the succession of States that took place on the independence of Somalia and
Kenya. The significance of the phrase “as such” is that  as the International Law Commission’s
Commentary indicates  Article 11 “relate[s] exclusively to the effect of the succession of States
on the boundary settlement”, “leav[ing] untouched any other ground of claiming the revision [of the
treaty] or setting aside of the boundary settlement, whether self-determination or the invalidity or
termination of the treaty”17. In my view, the 1927/1933 treaty arrangement did not establish a
boundary in the territorial sea.
42. Article 11 of the 1978 Vienna Convention provides for an exception to the general rule in
Article 16 that a newly independent State is not bound to maintain the treaties of its predecessor, but
may do so if it wishes. Newly independent States did not wish to bind themselves to a treaty that
obligated them to maintain boundaries established by their predecessor States. Nonetheless the
Organization of African Unity adopted a resolution in 1964 that its members would “respect the
borders existing on their achievement of national independence”18, and many argue that there is a
customary rule of international law requiring respect for such borders.
43. The Judgment does not determine whether the 1927/1933 treaty arrangement establishes a
boundary in the territorial sea. It is patent that the Judgment seeks to adopt an approach that would
arrive at a conclusion about the delimitation of the territorial sea without any reference to the colonial
treaties. Nonetheless, as is evident in paragraphs 109 and 118, the Judgment does not seem capable
of escaping references to those treaties.
17 Yearbook of the International Law Commission, 1974, Vol. II, Part One, Commentary on Articles 11 and 12,
p. 201, para. 17.
18 Organization of African Unity, Assembly of the Heads of State and Government, First Ordinary Session, Cairo,
17-21 July 1964, AHG/Res 16 (I)-1964.
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44. If the jurisprudential basis for the Court’s interpretation of the treaty arrangement is not
the principle of a succession of States, reflected in the 1978 Vienna Convention, then in my view, it
must be that the colonial treaties between Italy and the United Kingdom become relevant to the
Court’s adjudication in the dispute between Somalia and Kenya on the basis of the right to
self-determination. When Somalia became independent in 1960, it assumed sovereignty over
territory in respect of which Italy formerly exercised sovereignty; in particular, it assumed
responsibility for the conduct of foreign relations in respect of that territory. Similarly, when Kenya
became independent in 1963, it assumed sovereignty over territory in respect of which the
United Kingdom formerly exercised sovereignty; in particular it assumed responsibility for the
conduct of foreign relations in respect of that territory. The right to self-determination reflected in
resolution 1514 (XV) of the United Nations General Assembly, enables both Somalia and Kenya to
determine the conduct of their foreign relations, including whether to maintain the treaties entered
into by Italy and the United Kingdom in respect of the territory over which they now exercise
sovereignty. This is confirmed by Article 2 of resolution 1514 (XV) which provides that “[a]ll
peoples have the right to self-determination; by virtue of that right they freely determine their
political status and freely pursue their economic, social and cultural development”. The right to
self-determination19 as reflected in resolution 1514 (XV) was already a rule of customary
international law at the time of the independence of Somalia and Kenya.
45. In response to a question by a Member of the Court, Somalia stated that “[n]either [it] nor
Kenya, since their independence and at all times thereafter, has ever claimed that the maritime
boundary in the territorial sea follows a line perpendicular to the coast at Dar es Salam, for any
distance”. It further added that neither Party accepted nor argued for the 1927 Agreement as binding
on them in regard to a maritime boundary, for any distance. In exercise of their sovereignty and
independence Somalia and Kenya had the right to determine their relationship with the colonial
treaties, that is, whether they accepted or rejected them. These two statements by Somalia, indicating
the Parties’ non-reliance and non-acceptance of the colonial treaties, classically reflect the exercise
of the right to self-determination by newly independent States. Consequently, those treaties are
inapplicable in the determination of the maritime dispute between Somalia and Kenya. Since those
treaties did not establish a boundary in the territorial sea, the question whether there is an obligation
under customary international law to respect boundaries that existed at independence does not arise.
Acquiescence
46. Acquiescence, like the kindred concept of estoppel, owes its place in international law
primarily to Anglo-American law. In international law, acquiescence applies to cases where,
although a State’s consent has not been expressly given to a course of conduct by another State, an
inference may be drawn that the State’s silence denotes its consent to that conduct, that is, its
agreement with that conduct. Thus, the primary task in acquiescence is to determine the
circumstances in which it is permissible to infer from a State’s silence its consent or agreement with
the conduct of another State. In that regard, an essential evidentiary requirement for acquiescence to
apply is that the inference of State consent from its silence may only be drawn if the circumstances
are such that a response is called for. This is the most important element in the law of acquiescence.
19 Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, Advisory Opinion,
I.C.J. Reports 2019 (I), separate opinion of Judge Patrick Robinson, p. 294.
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47. It is settled that for acquiescence to apply there must be an examination of the conduct of
the State claiming acquiescence to determine whether it is clear and consistent and, as a consequence,
calls for a response from the alleged acquiescing State. Thus, the initial focus is on the conduct of
the State claiming acquiescence with a view to deciding whether it calls for a response from the
alleged acquiescing State.
48. Kenya captures very well the meaning of acquiescence in paragraph 210 of its
Counter-Memorial when it argued that “the absence of protest when a response is called for
constitutes acquiescence”. Kenya is correct. That is the law. Kenya’s submission reflects the
requirement that it is only when a response is called for to the conduct of the State claiming
acquiescence and that response is not forthcoming, that an inference may be drawn that silence
signifies consent with the conduct of the State claiming acquiescence. It is true that in its pleadings
Kenya examines the conduct of the alleged acquiescing State, Somalia, but it carries out this
examination on the basis that, in its view, its own conduct called for a response from Somalia  a
response that, it maintains, was not given. Thus, in paragraph 208 of its Counter-Memorial, Kenya
alludes to the Kenyan proclamations of 1979 and 2005, arguing that they clearly and unambiguously
reflected Kenya’s position on a maritime boundary with Somalia at a parallel of latitude. Kenya
submits that Somalia was aware of these proclamations and, if it had an objection, it should have
protested. But Kenya’s position is not that it is necessary ab initio to examine Somalia’s conduct to
determine whether there has been acquiescence. Rather, its position, consistent with its submission
that the absence of protest when a reaction is called for constitutes acquiescence, is that its own
conduct, such as the issuance of the proclamations of 1979 and 2005, required a response from
Somalia and, since that was not forthcoming, Somalia’s silence may be taken to signify its consent
or agreement with its conduct. Thus, every submission made by Kenya that an examination of
Somalia’s conduct shows that Somalia failed to protest when a response was called for must be
considered against the background of its main proposition that its own conduct was clear and
consistent, and therefore called for a response from Somalia. In other words, Kenya’s own position
is that an examination of Somalia’s conduct is consequential and dependent on a finding that a
response was called for from Somalia  a position that is wholly consistent with the law of
acquiescence. In this regard, the Court appears to have misinterpreted Kenya’s position.
49. Kenya’s proposition that the absence of protest when a response is called for constitutes
acquiescence is consistent with the case-law of the Court. In Pedra Branca the Court found that
“silence may also speak, but only if the conduct of the other State calls for a response”20. Here the
Court reflects the strong evidentiary requirement, implicit in the words “only if”, that an inference
of consent may only be drawn if the conduct of the State claiming acquiescence calls for a response.
It may be observed that this strong evidentiary requirement is consistent with the substantive law that
the evidence of acquiescence must be compelling.
50. There is an inherent conflict between the Court’s finding in paragraph 71 and its finding
in paragraph 72. After examining the conduct of Kenya, the Judgment concludes in paragraph 71
“that Kenya has not consistently maintained its claim that the parallel of latitude constitutes the single
maritime boundary with Somalia”. In effect the Court concluded that, by virtue of the inconsistency
of Kenya’s conduct, no response was called for by Somalia; consequently, the Court should have
dismissed the claim. There was no need to move on to determine whether Somalia clearly and
consistently accepted a maritime boundary at the parallel of latitude (paragraph 72); to do so
undermines the earlier finding that Kenya’s conduct was not consistent and, consequently, no
response was called for by Somalia. The conflict between paragraphs 71 and 72 is evident because,
20 Sovereignty over Pedra Branca/Pulau Batu Puteh, Middle Rocks and South Ledge (Malaysia/Singapore),
Judgment, I.C.J. Reports 2008, p. 51, para. 121.
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if Kenya did not consistently maintain its claim, it would be impossible to identify with any certainty
what Somalia could clearly and consistently have acquiesced to. This explains why the most
important aspect of the law on acquiescence is an examination of the conduct of the State claiming
acquiescence to determine whether that conduct requires a response. In particular the Court’s
approach flies in the face of the finding in paragraph 71 that “it was reasonable for Somalia to
understand that its maritime boundary with Kenya in the territorial sea, in the exclusive economic
zone and on the continental shelf would be established by an agreement to be negotiated and
concluded in the future”. If it is reasonable for Somalia to have this understanding, it is difficult to
appreciate why the Court would go on to examine whether Somalia clearly and consistently accepted
a maritime boundary at the parallel of latitude. This is so because the Court could only have made
this finding on the basis that it had rejected Kenya’s claim of Somalia’s acquiescence to a boundary
along a parallel of latitude  all the more reason why an enquiry into Somalia’s conduct was
unnecessary.
51. Having carried out its examination of Somalia’s conduct, the Court concludes that the
conduct of Somalia between 1979 and 2014 did not demonstrate “Somalia’s clear and consistent
acceptance of a maritime boundary at the parallel of latitude” (paragraph 80). An examination of the
logic of this conclusion shows why the Court’s approach is questionable. Had the finding been that
there was evidence demonstrating Somalia’s clear and consistent acceptance of a maritime boundary
along a parallel of latitude, it would be impossible to reconcile that finding with the earlier conclusion
in paragraph 71 not only that Kenya’s conduct did not require a response from Somalia, but also that
it was reasonable for Somalia to expect that on the basis of Kenya’s conduct its maritime boundary
with that State would be established on the basis of agreement.
52. Consequently, I am unable to agree with the Court’s conclusion in paragraph 80; after its
finding in paragraph 71, the Court should have dismissed Kenya’s claim. In my view, it reflects a
wrong reading not only of the law, but also of Kenya’s own submission. Properly understood,
Kenya’s own submission proceeds on the basis that the evidentiary hurdle of a required response
must first be cleared before undertaking any examination of Somalia’s acceptance of a maritime
boundary along a parallel of latitude. Since the Court has found that no such response was required
the question of an examination of Somalia’s conduct does not arise.
(Signed) Patrick L. ROBINSON.
___________