6. In so far as there may be any inclination to reject the assimilation to "cession" of the change in status of the area, it is appropriate to refer to the doctrine of "continuity" as stated by Judge Jessup in the North Sea : Continental Shelf case (I.C.J. Reports, p. 3, at pp. 79-80) in relation to agreed determination of continental shelf boundaries after a period of de facto exercise of rights in the divided area by a concessionaire of one or the other State: "The Court must assume that the Parties have acted in good faith. This means that Denmark and the Netherlands, in concluding their delimitation agreement on 31 March 1966, believed that their action, which was based on the equidistance method, was justified by existing international law. In my view it would not be equitable to take the position that since the Court has now held that the equidistance method has not been made obligatory by international law, any acts such as the granting of licences or concessions in the areas of the shelf claimed by Denmark or the Netherlands are to be treated as null and void ab initio. Rather, I think there should be applied the following conclusion of the Arbitral Tribunal. which, in the Grisbadarna case, on 23 October 1909, decided the delimitation of a certain part of the maritime frontier between Norway and Sweden: '... in the law of nations, it is a well established principle that it is necessary to refrain as far as possible from modifying the state of things existing in fact and for a long time; ... that principle has a very particular application when private interests are in question, which, once disregarded, can not be preserved in an effective manner even by any sacrifices of the State, to which those interested belong ...' (Wilson, The Hague Arbitration Cases, 1915, pp. 111, 129). "The Parties to the instant case have in effect recently acted upon this same principle in respecting habitual fishing practices: Fisheries Convention of 9 March 1964, Articles 3 and 4, 581 United Nations Treaty Series, pages 58, 60. That Convention provides for a transitional period in which such established rights may be phased out, a provision which would not be suitable in dealing with drilling operations already undertaken. But it may also be noted that while in the Grisbadarna case the Tribunal spoke of a state - ... of things 'existing ... for a long time', the Fisheries
