201
The determination of some rights of Mauritius as a coastal State under the
UNCLOS, in itself, could hardly be seen as not relating to the interpretation and
application of the Convention. The fact that, as will be seen below, the source of
Mauritius’ rights was not only the UNCLOS, but the specific undertakings that the
United Kingdom had made, was a matter of applicable law, which should be kept
distinct from the definition of the scope of jurisdiction.
46
In any event, the need to consider the United Kingdom’s undertakings to determine Mauritius’ rights would have not prevented the majority from finding that it
had jurisdiction in relation to Mauritius’s second submission, because it is on the
basis of those undertakings that the Tribunal assessed the compatibility of the
Chagos Marine Protected Area with the UNCLOS under Mauritius’ fourth submission. Indeed, in assessing the merits of Mauritius’ fourth submission, the Tribunal
admitted that the determination of the nature of the United Kingdom’s undertakings
was also central for “Mauritius’ First and Second Submissions, sovereignty, and the
identity of the coastal State”.
47
Yet, as regards Mauritius’ fourth submission, it is
only in assessing the merits that the Tribunal took into account the United Kingdom’s
undertakings,
48
whereas, as regards Mauritius’ first and second submissions, it is in
the determination of the scope of jurisdiction that the majority concerned itself with
the need to apply rules of international law falling outside the international law of
the sea.
49
Secondly, the adoption of a factual approach would have prevented any risk of
fragmentation of the notion of coastal State, which the Tribunal seemingly raised in
alluding to a distinction to be drawn between cases of disputed sovereignty and
cases of undisputed sovereignty. On the one hand, in the absence of any definition
in the UNCLOS, the Tribunal assumed a factual definition of the term ‘coastal
State’ in deducing that it “was intended to denote a State having a sea coast, as distinct from a land-locked State”.
50
On the other hand, in the presence of a land sovereignty dispute, the factual notion of the ‘coastal State’ as the State having a sea
coast should be ignored. The Tribunal observed that no guidance could be found in
the UNCLOS “on the identification of the ‘coastal state’ in cases where sovereignty
over the land territory fronting a coast is disputed”
51
: in the event, it would be necessary for courts and tribunals convened pursuant to Part XV UNCLOS to apply rules
of international law other than the international law of the sea and address the land
sovereignty dispute, provided they had jurisdiction.
52
considering the assumption of the United Kingdom’ sovereignty underlying Mauritius’ second
submission in ascertaining its jurisdiction in relation thereto.
46 See also infra, note 56.
47 Chagos Marine Protected Area Arbitration, para. 418.
48 Ibidem, para. 419.
49 Ibidem, para. 203.
50 Ibidem.
51 Ibidem.
52 Ibidem.
The Interpretation of the United Nations Convention on the Law of the Sea…
The determination of some rights of Mauritius as a coastal State under the
UNCLOS, in itself, could hardly be seen as not relating to the interpretation and
application of the Convention. The fact that, as will be seen below, the source of
Mauritius’ rights was not only the UNCLOS, but the specific undertakings that the
United Kingdom had made, was a matter of applicable law, which should be kept
distinct from the definition of the scope of jurisdiction.
46
In any event, the need to consider the United Kingdom’s undertakings to determine Mauritius’ rights would have not prevented the majority from finding that it
had jurisdiction in relation to Mauritius’s second submission, because it is on the
basis of those undertakings that the Tribunal assessed the compatibility of the
Chagos Marine Protected Area with the UNCLOS under Mauritius’ fourth submission. Indeed, in assessing the merits of Mauritius’ fourth submission, the Tribunal
admitted that the determination of the nature of the United Kingdom’s undertakings
was also central for “Mauritius’ First and Second Submissions, sovereignty, and the
identity of the coastal State”.
47
Yet, as regards Mauritius’ fourth submission, it is
only in assessing the merits that the Tribunal took into account the United Kingdom’s
undertakings,
48
whereas, as regards Mauritius’ first and second submissions, it is in
the determination of the scope of jurisdiction that the majority concerned itself with
the need to apply rules of international law falling outside the international law of
the sea.
49
Secondly, the adoption of a factual approach would have prevented any risk of
fragmentation of the notion of coastal State, which the Tribunal seemingly raised in
alluding to a distinction to be drawn between cases of disputed sovereignty and
cases of undisputed sovereignty. On the one hand, in the absence of any definition
in the UNCLOS, the Tribunal assumed a factual definition of the term ‘coastal
State’ in deducing that it “was intended to denote a State having a sea coast, as distinct from a land-locked State”.
50
On the other hand, in the presence of a land sovereignty dispute, the factual notion of the ‘coastal State’ as the State having a sea
coast should be ignored. The Tribunal observed that no guidance could be found in
the UNCLOS “on the identification of the ‘coastal state’ in cases where sovereignty
over the land territory fronting a coast is disputed”
51
: in the event, it would be necessary for courts and tribunals convened pursuant to Part XV UNCLOS to apply rules
of international law other than the international law of the sea and address the land
sovereignty dispute, provided they had jurisdiction.
52
considering the assumption of the United Kingdom’ sovereignty underlying Mauritius’ second
submission in ascertaining its jurisdiction in relation thereto.
46 See also infra, note 56.
47 Chagos Marine Protected Area Arbitration, para. 418.
48 Ibidem, para. 419.
49 Ibidem, para. 203.
50 Ibidem.
51 Ibidem.
52 Ibidem.
The Interpretation of the United Nations Convention on the Law of the Sea…