                     316

                          DÉCLARATION DE M. LE JUGE YUSUF, VICE-PRÉSIDENT

                     [Texte original français]

                        1. Selon le paragraphe 1 de l’article 80 du Règlement, deux conditions
                     doivent être réunies pour que la Cour puisse connaître d’une demande
                     reconventionnelle en même temps que de la demande principale : il faut
                     que la demande reconventionnelle « relève de sa compétence » et qu’elle
                     « [soit] en connexité directe avec l’objet de la demande de la partie adverse ».
                        2. La Cour a analysé cette seconde exigence — la condition de
                     connexité directe — dans les précédentes affaires où il lui a fallu statuer
                     sur la recevabilité de demandes reconventionnelles. En revanche, elle n’a
                     pas précisé ce que recouvre la première — la nécessité pour la demande
                     reconventionnelle de « rel[ever] de sa compétence » — dans le contexte de
                     l’article 80. Ce flou entourant l’élément juridictionnel peut laisser à penser
                     que la Cour doit, en tout état de cause, se reposer la question de sa com-
                     pétence pour chaque demande reconventionnelle. Or, si cette démarche
                     est bien sûr nécessaire dès lors que le titre de compétence invoqué dans le
                     cadre des demandes reconventionnelles diffère de celui sur lequel le requé-
                     rant s’appuie dans le cadre de la demande principale, je m’emploierai
                     dans la présente déclaration à expliquer qu’elle ne s’impose pas lorsque le
                     titre de compétence est le même. En conséquence, il n’y avait pas non plus
                     lieu pour la Cour de chercher à déterminer s’il existait un différend entre
                     les Parties en l’espèce.

                             I. Compétence en vertu du paragraphe 1 de l’article 80
                                                 du Règlement

                        3. L’un des principaux points de désaccord entre les Parties, en l’es-
                     pèce, a trait à la condition de compétence énoncée à l’article 80. Pour la
                     Colombie, la compétence visée à l’article 80 s’entend de la compétence de
                     la Cour pour connaître de la demande principale. Selon elle, « [l]a Cour
                     ayant estimé avoir compétence à l’égard de la procédure principale, sa
                     compétence est également établie pour ce qui est des demandes reconven-
                     tionnelles ». Le Nicaragua, lui, avance que les demandes reconvention-
                     nelles sont des actes juridiques autonomes pour lesquels la compétence
                     doit s’apprécier de nouveau.
                        4. Le Nicaragua a raison de relever que la Cour a qualifié ce type de
                     demandes d’« acte[s] juridique[s] autonome[s] ayant pour objet de sou-
                     mettre une prétention nouvelle au juge … [et] ainsi d’élargir l’objet initial
                     du litige en poursuivant des avantages autres que le simple rejet de la
                     prétention du demandeur à l’action » (Application de la convention pour la
                     prévention et la répression du crime de génocide (Bosnie-     Herzégovine

                     31

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                     317 	    droits souverains et espaces maritimes (décl. yusuf)

                     c. Yougoslavie), demandes reconventionnelles, ordonnance du 17 décembre
                     1997, C.I.J. Recueil 1997, p. 256, par. 27).
                        5. Toutefois, cette nature autonome n’est que l’une des caractéristiques
                     de pareilles demandes. Comme l’a souligné la Cour dans son ordonnance
                     sur les demandes reconventionnelles en l’affaire relative à l’Application
                     de la convention pour la prévention et la répression du crime de génocide
                     (Bosnie‑Herzégovine c. Yougoslavie), elles sont aussi intimement liées à la
                     procédure découlant de la demande principale :
                             « [Une demande reconventionnelle] s[e] rattache [à la demande
                          principale], dans la mesure où, formulée à titre « reconventionnel »,
                          elle [y] riposte … ; … il s’agit essentiellement de réaliser une écono-
                          mie de procès tout en permettant au juge d’avoir une vue d’ensemble
                          des prétentions respectives des deux parties et de statuer de façon
                          plus cohérente ; … la recevabilité des demandes reconventionnelles
                          est nécessairement fonction des buts ainsi poursuivis et sujette à des
                          conditions propres à prévenir les abus. » (Ibid., p. 256-257, par. 27
                          et 30.)
                            6. C’est cette seconde caractéristique — le lien étroit qui rattache la
                         demande reconventionnelle à la demande principale — qui permet au juge
                         de réaliser une économie de procès en lui offrant une vue d’ensemble plus
                         précise et détaillée de l’ensemble des faits intéressant le différend dont il est
                         saisi. Ainsi, la demande reconventionnelle vient se greffer à la procédure
                         découlant de la demande principale. Les demandes reconventionnelles
                         sont, pourrait-on dire, à la fois autonomes d’un point de vue fonctionnel,
                         en ce qu’elles sont traitées séparément de la demande principale, et inci-
                      dentes, en ce qu’elles doivent s’ajouter à la procédure principale.
                            7. Au paragraphe 67 de la présente ordonnance, la Cour affirme que,
                      une fois « établi[e] sa compétence pour connaître d’une affaire, elle a com-
                      pétence pour en examiner toutes les phases », en ce compris les procédures
                      incidentes, dont relèvent les demandes reconventionnelles. Elle précise
                      qu’elle ne saurait être privée d’une compétence déjà établie au motif que
                      celle-ci serait ultérieurement devenue caduque. Elle examine ensuite la
                       question de savoir si les troisième et quatrième demandes reconvention-
                       nelles présentées par la Colombie entrent dans le champ de la compétence
                       que lui a conférée l’article XXXI du pacte de Bogotá.
                            8. Je souscris de manière générale au raisonnement suivi. L’étendue de
                       la compétence de la Cour pour connaître d’un différend est strictement
                       fonction des limites fixées dans l’instrument dont elle tire cette compé-
                       tence. Il est donc impératif que la Cour, lorsqu’elle se penche sur la
                       recevabilité de demandes reconventionnelles présentées sur la base du
                        même titre de compétence que la demande principale, s’assure que
                        lesdites demandes entrent bien dans le champ de la compétence que ce
                         titre lui confère (Immunités juridictionnelles de l’Etat (Allemagne c.
                         Italie), demandes reconventionnelles, ordonnance du 6 juillet 2010,
                         C.I.J. Recueil 2010 (I), p. 316, par. 17-31). Elle n’a pas, cependant, à
                     établir de nouveau sa compétence pour connaître de ces demandes.

                     32

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                     318 	   droits souverains et espaces maritimes (décl. yusuf)

                                             II. Examen par la Cour
                                           de l’existence d’un différend

                         9. La Cour, à mon sens, n’a pas poussé ce raisonnement jusqu’à sa
                     conclusion logique. Dans son arrêt sur les exceptions préliminaires, elle
                     avait déjà conclu à sa compétence, ce qui supposait, nécessairement,
                     l’existence d’un différend. Il n’y avait donc pas lieu qu’elle revînt sur la
                     question de savoir si un « différend » existait entre les Parties, comme elle
                     l’a fait dans le cadre de l’examen des troisième et quatrième demandes
                     reconventionnelles. L’existence d’un différend est déjà avérée et cela suffit
                     à établir la compétence de la Cour. A ce stade de la procédure, la Cour
                     devrait se contenter de vérifier si les demandes reconventionnelles qui lui
                     ont été soumises, d’une part, s’inscrivent dans les limites de la compétence
                     qu’elle s’était déjà déclarée posséder au titre du pacte de Bogotá, et,
                     d’autre part, présentent un lien de connexité directe, en droit et en fait,
                     avec les demandes principales.
                         10. Une telle conclusion n’est pas seulement logique, elle est aussi judi-
                     cieuse. La condition selon laquelle une demande reconventionnelle doit
                     être en connexité directe avec la demande principale offre à la Cour la
                     possibilité de prendre connaissance d’arguments se rapportant à un autre
                     aspect du différend à l’égard duquel elle s’est déclarée compétente.
                     Elle peut ainsi statuer sur ce différend en en ayant une compréhension
                     plus globale. C’est notamment sous ce rapport que les demandes
                     reconventionnelles permettent de réaliser l’économie de procès visée

                     dans l’ordonnance rendue en l’affaire relative à l’Application de la
                     convention pour la prévention et la répression du crime de génocide

                     (Bosnie-Herzégovine c. Yougoslavie), citée plus haut au paragraphe 5.
                     Point n’est besoin pour la Cour d’établir de nouveau l’existence d’un
                     différend.
                         11. Jusqu’ici, la Cour a essentiellement été amenée à examiner des
                      demandes reconventionnelles présentées sur la base du même titre de
                      compétence que la demande principale (voir, par exemple, Immunités juri-
                      dictionnelles de l’Etat (Allemagne c. Italie), demandes reconventionnelles,
                      ordonnance du 6 juillet 2010, C.I.J. Recueil 2010 (I), p. 316 ; Activités
                      armées sur le territoire du Congo (République démocratique du Congo
                      c. Ouganda), demandes reconventionnelles, ordonnance du 29 novembre
                      2001, C.I.J. Recueil 2001, p. 678 ; Plates‑formes pétrolières (République
                      islamique d’Iran c. Etats‑Unis d’Amérique), demande reconventionnelle,
                      ordonnance du 10 mars 1998, C.I.J. Recueil 1998, p. 203 ; et Application de
                      la convention pour la prévention et la répression du crime de génocide (Bos-
                      nie‑Herzégovine c. Yougoslavie), demandes reconventionnelles, ordonnance
                      du 17 décembre 1997, C.I.J. Recueil 1997, p. 256). Pour autant, l’article 80
                      n’exclut pas la possibilité d’invoquer un titre de compétence autre. C’est
                      dans ce type de circonstances, et dans cette hypothèse seulement, que la
                      Cour devra examiner la question de sa compétence pour connaître d’une
                      demande reconventionnelle séparément de celle de sa compétence à
                      l’égard de la demande principale. Sa compétence pour connaître de la

                     33

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                     319 	   droits souverains et espaces maritimes (décl. yusuf)

                     demande principale ne déterminera pas alors sa compétence pour
                     connaître d’une demande reconventionnelle présentée en vertu d’un autre
                     titre, et la validité de la base de compétence invoquée dans le cas de la
                     demande reconventionnelle devra s’apprécier à la date de la présentation
                     de celle-ci.

                     (Signé) Abdulqawi A. Yusuf.

                     34

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      SEPARATE OPINION OF JUDGE SEPÚLVEDA-AMOR

  I find myself in full agreement with most of the reasoning of the Court
 n the present Judgment. The same is true of almost all the conclusions
reached by the Court in the operative clause of the Judgment. However,
as regards the legality of Nicaragua’s imposition of visa requirements, the
Court has, in my opinion, failed to take account of Nicaragua’s legiti-
mate interest in border and immigration control and to clarify accord-
 ngly the extent of Nicaragua’s regulatory powers to that effect. I further
consider that the Court’s reasoning as regards Costa Rica’s claim relating
 o subsistence fishing is based on a weak legal foundation which might
undermine the acceptance of the Court’s finding by the Parties.

             I. BORDER CONTROL AS A LEGITIMATE PURPOSE

   1. The Court has concluded that “Nicaragua has the power to regulate
 he exercise by Costa Rica of its right to freedom of navigation under the
1858 Treaty”. It adds an important qualification : such right “is not
unlimited”; it is subject to the “rights and obligations of the Parties”
 Judgment, para. 87).
   2. According to the Court, the exercise of Nicaragua’s regulatory
power must meet certain requirements. Obviously, it must be consistent
with the terms of the Treaty. It further has to be non-discriminatory and
reasonable. The purpose of the regulation must be legitimate and “it
must only subject the activity to certain rules without rendering impossi-
ble or substantially impeding the exercise of the right of free navigation”
 ibid. ; emphasis added).

  3. As regards the burden of proof in respect of Costa Rica’s claims of
unlawful action based on the alleged unreasonableness of Nicaragua’s
exercise of its regulatory power, the Court has clearly stated that it is for
Costa Rica to establish points of facts supporting such claims :

        “The Court notes that Costa Rica, in support of its claim of un-
     lawful action, advances points of fact about unreasonableness by
     referring to the allegedly disproportionate impact of the regulations.
     The Court recalls that in terms of well established general principle it
     is for Costa Rica to establish those points (cf. Maritime Delimitation
     in the Black Sea (Romania v. Ukraine), Judgment, I.C.J. Reports
     2009, p. 86, para. 68, and cases cited there). Further, a court exam-

64

     ining the reasonableness of a regulation must recognize that the
     regulator, in this case the State with sovereignty over the river, has
     the primary responsibility for assessing the need for regulation and
     for choosing, on the basis of its knowledge of the situation, the
     measure that it deems most appropriate to meet that need. It will not
     be enough in a challenge to a regulation simply to assert in a general
     way that it is unreasonable. Concrete and specific facts will be
     required to persuade a court to come to that conclusion.” (Judg-
     ment, para. 101.)

   4. Nicaragua, as the State entitled to exercise sovereignty over the San
Juan River, has the “primary responsibility for assessing the need for
regulation and for choosing . . . the measure that it deems most appro-
priate to meet that need”. This is a principle which the Court itself has
stated that it must respect when examining the reasonableness of Nica-
ragua’s regulations, taking into account “[c]oncrete and specific facts”
 ibid.). All these issues become particularly relevant for the Judgment at
 he section where the Court considers the visa requirement and the power
of Nicaragua to impose immigration controls.

  5. On the requirement to stop and identify, the Court has indicated
 hat “Nicaragua, as sovereign, has the right to know the identity of those
entering its territory and also to know that they have left” (Judgment,
para. 104). The Court also considers that “it has been established that the
number of tourists on the river has increased over the years the require-
ment [to stop and identify] has been in force” (ibid., para. 106). The
Court concludes that the requirement is lawful and that Costa Rica did
not show that it was unreasonable.

   6. According to the Court, Nicaragua’s requirement to obtain depar-
 ure clearance certificates serves a legitimate purpose. Additionally, it
“does not appear to have imposed any significant impediment on the
exercise of Costa Rica’s freedom of navigation” ; Costa Rica has not
shown “a single case where navigation has been impeded by an arbitrary
refusal of a certificate” (ibid., para. 109).
   7. The requirement to fly Nicaragua’s flag under certain circumstances
“cannot in any respect be considered an impediment to the exercise of the
 reedom of navigation of Costa Rican vessels”. Moreover, the Court
notes that it “has not been presented with any evidence that Costa Rican
vessels have been prevented from navigation on the San Juan River as a
result of Nicaragua’s flag requirement” (ibid., para. 132).

  8. From the preceding paragraphs it becomes clear that the Court has
consistently adopted a line of reasoning which closely follows the general
principles outlined in paragraph 101 of the Judgment, i.e., in all of these

65

cases the Court has examined whether a requirement imposed by Nica-
ragua entails a substantial impediment to the exercise of Costa Rica’s
right of free navigation, and whether the burden of proof has been met
by Costa Rica. The Court answers both questions in the negative. But
 hen there is a sudden inconsistency when the Court examines the imposi-
 ion of a visa requirement on those persons who may benefit from Costa
Rica’s right of free navigation.
   9. First, the Court recognizes that “[t]he power of a State to issue or
refuse visas is a practical expression of the prerogative which each State
has to control entry by non-nationals into its territory” (Judgment,
para. 113).
   10. Then the Court itself recalls the “[c]oncrete and specific facts”, that
are “required to persuade a court to come to [the] conclusion” that a
specific regulation is unreasonable (ibid., para. 101). These concrete and
specific facts indicate, according to the Court,
     “that in fact the number of tourists travelling on the river in Costa
     Rican vessels has increased in the period these requirements have
     been in force (see paragraph 99 above). Further, Costa Rica has
     provided no evidence of arbitrary refusals of visas to tourists and
     Nicaragua points out that it does not require nationals from coun-
     tries which are the source of most of the tourists visiting the San
     Juan to obtain visas. Furthermore, it makes exceptions for residents
     of Costa Rican riparian communities and Costa Rican merchants
     who regularly use the river.” (Ibid., para. 116.)

   11. It is clear that, in the light of what the Court has stated, these
“[c]oncrete and specific facts” cannot lead to the conclusion that, by
 mposing a visa requirement, Nicaragua is rendering impossible or is sub-
stantially impeding the exercise of Costa Rica’s right of free navigation.
The requirement serves a legitimate purpose, notably the purpose of bor-
der and immigration control, and it is not discriminatory. Costa Rica has
not produced any evidence establishing the unreasonable or discrimina-
 ory character of Nicaragua’s visa requirement nor does the Court rely
on such evidence in the Judgment.

  12. Surprisingly enough, the Court, recalling that “the power of a
State to issue or refuse a visa entails discretion”, reaches the conclusion
 hat
     “Nicaragua may not impose a visa requirement on those persons
     who . . . may benefit from Costa Rica’s right of free navigation. If
     that benefit is denied, the freedom of navigation would be hindered.
     In these circumstances, an imposition of a visa requirement is a
     breach of the Treaty right.” (Ibid., para. 115.)

66

   No explanation is provided by the Court as to why the freedom of
navigation will be hindered if a person benefiting from Costa Rica’s enti-
 lement to free navigation is required to obtain a visa from the State
which has sovereignty over the waters of the San Juan River.
   13. The Judgment does not specify why non-Costa Ricans are also
entitled to benefit from free navigation (Judgment, para. 114) without
complying with the requirements established by the State which has
exclusive dominion and full sovereignty over the waters of the San Juan
River. To attribute the benefit of the right of free navigation to all foreign
nationals, whatever may be the purpose of their voyage on the waters of
 he San Juan River and whatever may be their State of origin, must be
considered as contrary to the principle the Court itself has established in
 he Judgment : “The power of a State to issue or refuse visas is a practical
expression of the prerogative which each State has to control entry by
non-nationals into its territory.” (Ibid., para. 113.) Surely Nicaragua can-
not be barred from exercising its power to regulate the entry of foreign
nationals into its territory.
   14. The prohibition to enact any visa requirements for foreign nation-
als traversing the waters of the San Juan River may involve a risk for the
public safety of Nicaragua, since there would be no immigration control
when entering the land territory of Nicaragua from the waters of the San
Juan River.
   15. A consequence of extending the right of free navigation to all for-
eign nationals travelling on the San Juan River, without any further
requirements, would be to force Nicaragua to establish a number of
 mmigration posts all along the left bank of the San Juan River in the
area where Costa Rica exercises its right of free navigation, although
even that measure will not necessarily prevent illegal entries from the
river into Nicaragua’s land territory by non-Costa Ricans benefiting
 rom a right legally attributed only to Costa Rica and to Costa Rican
nationals.
   16. From the Court’s perspective, “Nicaragua may not impose a visa
requirement on those persons who . . . may benefit from Costa Rica’s
right of free navigation. If that benefit is denied, the freedom of naviga-
 ion would be hindered.” (Ibid., para. 115.) This finding is not consistent
with the Court’s reasoning in previous paragraphs of the Judgment and it
 s certainly not based on the “[c]oncrete and specific facts” which, accord-
 ng to the Court, are required to persuade a court to reach such conclu-
sion. The reasoning of the Court does not provide any hard facts which
could endorse its argument that Nicaragua would prohibit free naviga-
 ion by exercising its discretionary power to issue visas. In this respect,
 he Court should have taken into account that, in its written or oral pro-
ceedings, Costa Rica has not submitted any evidence of cases where free
navigation had been impeded by an arbitrary refusal to grant a visa. Evi-
dence provided by Nicaragua and not contradicted by Costa Rica shows
 hat

67

     “Costa Rica’s tourism traffic on the San Juan River increased by
     more than 350 per cent between 1998, when Costa Rica says Nica-
     ragua first began to systematically deny her rights on the San Juan
     River, and 2004, the year before this lawsuit began” [CR 2009/7,
     pp. 45-46, para. 21 (Reichler) ; see also CR 2009/5, p. 25, para. 44
     (Reichler) ; Rejoinder of Nicaragua, para. 4.33, table 1 ; and Vol. II,
     Ann. 71].
  Costa Rica’s allegation that the visa requirement has “practically
destroyed Costa Rican commercial transportation of tourists” on the San
Juan River (Reply of Costa Rica, p. 159, para. 4.12 (iii)) has not been
proven.
  17. The Court concludes in its Judgment that Nicaragua “may not
require persons travelling on Costa Rican vessels which are exercising
 heir freedom of navigation on the river to obtain visas” (Judgment,
para. 117). But Nicaragua can invoke certain conventional rights,
enshrined in regional and multilateral treaties, which provide a legal basis
 or the imposition of visa requirements and which will enable Nicaragua
 o regulate immigration and border control on the waters of the San Juan
River under certain clearly defined circumstances.

  18. The American Convention on Human Rights (1969) and the Inter-
national Covenant on Civil and Political Rights (1966), to which both
Costa Rica and Nicaragua are parties, provide a similar language in
regulating freedom of movement and residence : “Every person lawfully
 n the territory of a State party has the right to move about it and to
reside in it subject to the provisions of the law.” These rights may be

     “restricted only pursuant to a law to the extent necessary . . . to pre-
     vent crime or to protect national security, public safety, public
     order, public morals, public health, or the rights or freedoms of
     others” (American Convention, Article 22, see also Article 12 of the
     Covenant on Civil and Political Rights).

Any of these conditions could give rise to a justified imposition of visas
by Nicaragua.
   19. If Nicaragua strictly follows the terms prescribed in the Conven-
 ion and in the Covenant, by enacting in a legal instrument the require-
ments for foreign nationals to obtain a visa, determining in which cir-
cumstances it will impose restrictions on the issuing of a visa (national
security, public safety, public order, public morals, public health, etc.), it
will not be in breach of any international obligation.

68

                II. LEGAL BASIS OF SUBSISTENCE FISHING

  20. The Court concludes in its Judgment that Costa Rica has a cus-
 omary right to subsistence fishing. The Court’s reasoning in the present
case is not in accordance with its previous findings on the recognition of
rules of customary international law. It will be difficult to find a pre-
cedent which corresponds with what the Court has determined in the
present case. In paragraph 141 of the Judgment, the Court provides as
 ollows :
        “The Court observes that the practice [of subsistence fishing], by
     its very nature, especially given the remoteness of the area and the
     small, thinly spread population, is not likely to be documented in
     any formal way in any official record. For the Court, the failure of
     Nicaragua to deny the existence of a right arising from the practice
     which had continued undisturbed and unquestioned over a very long
     period, is particularly significant.”

   These are the grounds on which the Court concludes that there is a
customary right. An undocumented practice by a community of fisher-
men in a remote area. A practice which in previous times has not been
claimed by Costa Rica as a right to which it is entitled. A practice which
has not been objected to by Nicaragua — “the failure of Nicaragua to
deny the existence of a right” — in circumstances where the existence of
a right has not been claimed, let alone proven.
   21. Costa Rica has not presented to the Court, at any time previous to
 he submission of its Memorial, evidence of a legal claim by which it
would consider subsistence fishing on the right bank of the San Juan
River as a right appertaining to it. Even Costa Rica’s Application insti-
 uting these proceedings does not include such a claim.
   22. Costa Rica is not conclusive in its assertions that there is a cus-
 omary right of subsistence fishing. It says that the practice “has taken on
a patina of custom”, unless the opposite can be shown conclusively
 Reply of Costa Rica, p. 84, para. 3.117). It further argues that the prac-
 ice of subsistence fishing “coupled with complete lack of application of
 nternal regulations with respect to it and the complete absence of any
negative response from Nicaragua, has given rise to a customary local
rule” [CR 2009/3, p. 62, para. 41 (Kohen)]. No need for State practice ;
no need for opinio juris, only the lack of protest of Nicaragua to a prac-
 ice not previously claimed as a right. However, given the absence of such
a claim, there is little ground to impose on Nicaragua the duty to protest
against the contents of an inexistent claim and, consequently, Costa Rica
 s not in a position to provide evidence that Nicaragua accepted subsist-
ence fishing as part of its legal obligations.

  23. It may well be that Costa Rica itself is not convinced of its argu-

69

ment that the practice of subsistence fishing amounts to a customary rule.
Costa Rica alleges that “it is of little consequence whether we talk about
a local custom, acquiescence, tacit agreement, a territorial régime or even
 he survival of a traditional right dating back to the colonial era which
has never been curtailed” [CR 2009/3, p. 62, para. 41 (Kohen)]. It is clear
 hat Costa Rica’s aim is to obtain recognition from the Court that there
 s a right to subsistence fishing, with not too much of a concern as to the
 egal basis which supports such a right. It is regrettable that the Court did
not resort to a more solid legal foundation when examining Costa Rica’s
claim to subsistence fishing.

  24. Following the Asylum case precedent, Costa Rica must prove that
 he customary right of subsistence fishing is established in such a manner
 hat it has become binding on the other Party and that the practice of
subsistence fishing is the expression of a right appertaining to Costa Rica
and a duty incumbent on Nicaragua (Asylum (Colombia/Peru), Judg-
ment, I.C.J. Reports 1950, pp. 276-277). The principle that the States
concerned must act with the conviction that they are conforming to what
amounts to a legal obligation has been reiterated by the Court on a
number of occasions, one example being the North Sea Continental Shelf
cases ((Federal Republic of Germany/Denmark ; Federal Republic of Ger-
many/Netherlands), Judgment, I.C.J. Reports 1969, p. 44).
  25. Time is another important element in the process of creation of
customary international law. In the present case, Costa Rica’s claim
regarding the existence of a customary right of subsistence fishing for the
 ocal riparian community on the Costa Rican bank of the San Juan River
was made for the first time in its Memorial submitted to the Court on
29 August 2006, i.e., less than three years before the delivery of the
Court’s Judgment. To claim the existence of a customary right, created in
such a short span of time, clearly contradicts the Court’s previous juris-
prudence on the matter ; in the Right of Passage case, the Court found :

        “This practice having continued over a period extending beyond a
     century and a quarter . . . the Court is, in view of all the circum-
     stances of the case, satisfied that that practice was accepted as law by
     the Parties and has given rise to a right and a correlative obligation.”
     (Right of Passage over Indian Territory (Portugal v. India), Merits,
     Judgment, I.C.J. Reports 1960, p. 40 ; emphasis added.)

   26. Similarly, in the Nicaragua case, the Court reiterated that in order
 o establish a rule of customary international law, it “has to direct its
attention to the practice and opinio juris of States” (Military and Para-
military Activities in and against Nicaragua (Nicaragua v. United States
of America), Merits, Judgment, I.C.J. Reports 1986, p. 97, para. 183). In
 he present case, the practice of a local community of Costa Rican ripar-

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ans cannot be equated with the practice of the Costa Rican State as
nvoked by Costa Rica (Judgment, para. 132). The Court has repeatedly
ndicated the nature of acts which it will take into account in order to
determine whether a practice exists, acts which may lead to the creation
of a customary right. These acts include administrative measures, legisla-
 ion, acts of the judiciary and treaties.

  27. As regards the requirements of State practice and opinio juris, the
Court has been subject to criticism in cases where it recognized the exist-
ence of such a practice in its findings without providing sufficient support
 or its claim. In the Arrest Warrant case, the Court indicated that it had
“carefully examined State practice, including national legislation and
 hose few decisions of national higher courts” (Arrest Warrant of 11 April
2000 (Democratic Republic of the Congo v. Belgium), Judgment, I.C.J.
Reports 2002, p. 24, para. 58). In her dissenting opinion, Judge ad hoc
Van Den Wyngaert was of the view that
     “the International Court of Justice, by deciding that incumbent For-
     eign Ministers enjoy full immunity from foreign criminal jurisdiction
     (Judgment, para. 54), has reached a conclusion which has no basis in
     positive international law. Before reaching this conclusion, the Court
     should have satisfied itself of the existence of usus and of opinio juris.
     There is neither State practice nor opinio juris establishing an inter-
     national custom to this effect.” (Ibid., p. 151, para. 23 ; emphasis
     added).
   28. It follows from the foregoing that subsistence fishing, based on a
customary right as determined by the Court, has no support in law.
Costa Rica’s claim might however be based on other legal foundations
which could provide a better ground for the findings of the Court on this
matter, namely the principle of acquired or vested rights. Already the
Permanent Court had determined that “the principle of respect for vested
rights” is “a principle which . . . forms part of generally accepted inter-
national law” (Certain German Interests in Polish Upper Silesia, Merits,
Judgment No. 7, 1926, P.C.I.J., Series A, No. 7, p. 42).

   29. In the Land, Island and Maritime Frontier Dispute case, the Cham-
ber also referred to the concept of acquired rights in the context of the
particular situation that it expected to arise following the delimitation of
 he land boundary in some areas where nationals of one Party would,
 ollowing the delimitation, find themselves living in the territory of the
other, and property rights established under the laws of the one Party
would be found to have been granted over land which is part of the ter-
ritory of the other. The Chamber indicated that it was confident that
both Parties would carry out the necessary measures “in full respect for
acquired rights, and in a humane and orderly manner” (Land, Island and
Maritime Frontier Dispute (El Salvador/Honduras ; Nicaragua interven-
 ng), Judgment, I.C.J. Reports 1992, pp. 400-401, para. 66).

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   30. Similarly, in the Cameroon v. Nigeria case, the Court determined
 hat it is up to the Parties to find a solution when a village previously
situated on one side of the boundary has spread beyond it, “with a view
 o respecting the rights and interests of the local population” (Land and
Maritime Boundary between Cameroon and Nigeria (Cameroon v.
Nigeria : Equatorial Guinea intervening), Judgment, I.C.J. Reports 2002,
p. 374, para. 123 and p. 370, para. 107).
   31. In the present case, the existence of vested rights or acquired rights
by Costa Rican riparians has not been claimed by Costa Rica. Surely the
Court could have taken the initiative to explore this legal avenue, explain-
 ng the reasons why it regards the argument of acquired rights founded or
unfounded. Furthermore, other legal options should have also been
 aken into account by the Court, in accordance with the express petitions
and commitments of the Parties.
   32. In the oral proceedings, Costa Rica required the following :

     “we ask the Court, in its dispositif, respectfully, to record and
     give effect to Nicaragua’s stated position that subsistence fishing
     by riparians, whether from the Costa Rican bank or from boats
     on the river, will not be impeded” [CR 2009/6, p. 63, para. 30
     (Crawford)].

  33. Nicaragua replied to this petition by indicating that while it “does
not agree that there is a customary right to fish in her territorial waters,
she has absolutely no intention of preventing Costa Rican residents from
engaging in subsistence fishing activities” [CR 2009/5, p. 27, para. 48
 Reichler)].
  34. The undertaking made by Nicaragua before the Court must be
regarded as a legal commitment with a binding character. In the Nuclear
Tests Judgment, the Court found that
     “[w]hen it is the intention of the State making the declaration that it
     should become bound according to its terms, that intention confers
     on the declaration the character of a legal undertaking, the State
     being henceforth legally required to follow a course of conduct con-
     sistent with the declaration. An undertaking of this kind, if given
     publicly, and with an intent to be bound . . . is binding.” (Nuclear
     Tests (Australia v. France), Judgment, I.C.J. Reports 1974, p. 267,
     para. 43.)
 35. Similarly, the Court found in a very recent case (Belgium v. Senegal)
hat
     “Senegal, both proprio motu and in response to a question put by a
     Member of the Court, gave a formal assurance on several occasions
     during the hearings that it will not allow Mr. Habré to leave its ter-
     ritory before the Court has given its final decision”.

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   Belgium indicated that such a solemn declaration “could be sufficient
 or Belgium to consider that its Request for the indication of provisional
measures no longer had any object, provided that certain conditions were
 ulfilled”. In the light of these statements, the Court decided that there
was no risk of irreparable prejudice to the rights claimed by Belgium
 Questions relating to the Obligation to Prosecute or Extradite (Belgium
v. Senegal), Provisional Measures, Order of 28 May 2009, I.C.J. Reports
2009, pp. 155-156, paras. 69, 71, 72 and 76).

   36. In the present case, the Court could thus have followed its pre-
vious jurisprudence by taking note, in the reasoning and in the operative
clause of the Judgment, of the legal commitment undertaken by Nicara-
gua during the oral proceedings. By following this legal option, by which
 t would determine the binding character of the commitment made pub-
 icly by Nicaragua before the Court, the Court could have avoided devi-
ating from its own precedents on the nature and substance of customary
 nternational law. But it chose a different route, one that will subject the
decisions of the Court to disagreement and objections.

                                 (Signed) Bernardo SEPÚLVEDA-AMOR.

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