maritime zone. Chile claims that although its ratification of the 1954 Special Maritime Frontier
Zone Agreement came some time after its signature, the boundary whose existence was
acknowledged and acted upon was already in place throughout the period leading to its ratification.
89. According to Peru, the aim of the 1954 Special Maritime Frontier Zone Agreement “was
narrow and specific”, establishing a “zone of tolerance” for small and ill-equipped fishing vessels.
Defining that zone by reference to a parallel of latitude was a practical approach for the crew of
such vessels. The 1954 Special Maritime Frontier Zone Agreement did not have a larger purpose,
such as establishing a comprehensive régime for the exploitation of fisheries or adding to the
content of the 200-nautical-mile zones or setting out their limits and borders. Peru also maintains
that “the 1954 Agreement was a practical arrangement, of a technical nature, and of limited
geographical scope, not one dealing in any sense with political matters”.
90. In the view of the Court, the operative terms and purpose of the 1954 Special Maritime
Frontier Zone Agreement are indeed narrow and specific. That is not however the matter under
consideration by the Court at this stage. Rather, its focus is on one central issue, namely, the
existence of a maritime boundary. On that issue the terms of the 1954 Special Maritime Frontier
Zone Agreement, especially Article 1 read with the preambular paragraphs, are clear. They
acknowledge in a binding international agreement that a maritime boundary already exists. The
Parties did not see any difference in this context between the expression “límite marítimo” in
Article 1 and the expression “frontera marítima” in the Preamble, nor does the Court.
91. The 1954 Special Maritime Frontier Zone Agreement does not indicate when and by
what means that boundary was agreed upon. The Parties’ express acknowledgment of its existence
can only reflect a tacit agreement which they had reached earlier. In this connection, the Court has
- 39 -
99. The Court is of the opinion that the purpose and geographical scope of the arrangements
were limited, as indeed the Parties recognize. The Court also observes that the record of the
process leading to the arrangements and the building of the lighthouses does not refer to any
pre-existent delimitation agreement. What is important in the Court’s view, however, is that the
arrangements proceed on the basis that a maritime boundary extending along the parallel beyond
12 nautical miles already exists. Along with the 1954 Special Maritime Frontier Zone Agreement,
the arrangements acknowledge that fact. Also, like that Agreement, they do not indicate the extent
and nature of that maritime boundary. The arrangements seek to give effect to it for a specific
purpose.
5. The nature of the agreed maritime boundary
100. As the Court has just said, it is the case that the 1954 Special Maritime Frontier Zone
Agreement refers to the existing boundary for a particular purpose; that is also true of the
1968-1969 arrangements for the lighthouses. The Court must now determine the nature of the
maritime boundary, the existence of which was acknowledged in the 1954 Agreement, that is,
whether it is a single maritime boundary applicable to the water column, the sea-bed and its
subsoil, or a boundary applicable only to the water column.
101. Chile contends that the boundary is an all-purpose one, applying to the sea-bed and
subsoil as well as to the waters above them with rights to their resources in accordance with
customary law as reflected in the United Nations Convention on the Law of the Sea (UNCLOS).
Peru submits that the line to which the 1954 Special Maritime Frontier Zone Agreement refers is
related only to aspects of the policing of coastal fisheries and facilitating safe shipping and fishing
in near-shore areas.
102. The Court is concerned at this stage with the 1954 Special Maritime Frontier Zone
Agreement only to the extent that it acknowledged the existence of a maritime boundary. The tacit
agreement, acknowledged in the 1954 Agreement, must be understood in the context of the
1947 Proclamations and the 1952 Santiago Declaration. These instruments expressed claims to the
sea-bed and to waters above the sea-bed and their resources. In this regard the Parties drew no
distinction, at that time or subsequently, between these spaces. The Court concludes that the
boundary is an all-purpose one.
6. The extent of the agreed maritime boundary
103. The Court now turns to consider the extent of the agreed maritime boundary. It recalls
that the purpose of the 1954 Agreement was narrow and specific (see paragraph 90 above): it
refers to the existing maritime boundary for a particular purpose, namely to establish a zone of
tolerance for fishing activity operated by small vessels. Consequently, it must be considered that
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the maritime boundary whose existence it recognizes, along a parallel, necessarily extends at least
to the distance up to which, at the time considered, such activity took place. That activity is one
element of the Parties’ relevant practice which the Court will consider, but it is not the only
element warranting consideration. The Court will examine other relevant practice of the Parties in
the early and mid-1950s, as well as the wider context including developments in the law of the sea
at that time. It will also assess the practice of the two Parties subsequent to 1954. This analysis
could contribute to the determination of the content of the tacit agreement which the Parties
reached concerning the extent of their maritime boundary.
A. Fishing potential and activity
104. The Court will begin with the geography and biology in the area of the maritime
boundary. Peru described Ilo as its principal port along this part of the coast. It is about 120 km
north-west of the land boundary. On the Chilean side, the port city of Arica lies 15 km to the south
of the land boundary and Iquique about 200 km further south (see sketch-map No. 1: Geographical
context).
105. Peru, in submissions not challenged by Chile, emphasizes that the areas lying off the
coasts of Peru and Chile are rich in marine resources, pointing out that the area in dispute is located
in the Humboldt Current Large Maritime Ecosystem. That Current, according to Peru, supports an
abundance of marine life, with approximately 18 to 20 per cent of the world’s fish catch coming
from this ecosystem. The Peruvian representative at the 1958 United Nations Conference on the
Law of the Sea (paragraph 106 below) referred to the opinion of a Peruvian expert (writing
in a book published in 1947), according to which the “biological limit” of the Current was to be
found at a distance of 80 to 100 nautical miles from the shore in the summer, and 200 to
250 nautical miles in the winter.
Peru recalls that it was the “enormous whaling and fishing potential” of the areas situated off
their coasts which led the three States to proclaim 200-nautical-mile zones in 1952. Industrial
fishing is carried out nowadays at significant levels in southern areas of Peru, notably from the
ports of Ilo and Matarani: the former is “one of Peru’s main fishing ports and the most important
fishing centre in southern Peru”.
106. Chilean and Peruvian representatives emphasized the richness and value of the fish
stocks as preparations were being made for the first United Nations Conference on the Law of the
Sea and at that Conference itself. In 1956 the Chilean delegate in the Sixth (Legal) Committee of
the United Nations General Assembly, declaring that it was tragic to see large foreign fishing fleets
exhausting resources necessary for the livelihood of coastal populations and expressing the hope
that the rules established by the three States, including Ecuador, would be endorsed by international
law, observed that “[t]he distance of 200 miles was explained by the need to protect all the marine
flora and fauna living in the Humboldt current, as all the various species depended on one another
for their existence and have constituted a biological unit which had to be preserved”. At the
1958 Conference, the Peruvian representative (who was the Foreign Minister at the time of the
1947 Declaration), in supporting the 200-nautical-mile limit, stated that what the countries had
proclaimed was a biological limit: - 41 -
“Species such as tunny and barrilete were mostly caught 20 to 80 miles from the
coast; the same anchovetas of the coastal waters sometimes went 60 or more miles
away; and the cachalot and whales were usually to be found more than 100 miles
off.”
He then continued:
“The requests formulated by Peru met the conditions necessary for their
recognition as legally binding and applicable since first, they were the expression of
principles recognized by law; secondly, they had a scientific basis; and thirdly, they
responded to national vital necessities.”
107. Chile referred the Court to statistics produced by the Food and Agricultural
Organization of the United Nations (FAO) to demonstrate the extent of the fishery activities of
Chile and Peru in the early 1950s and later years for the purpose of showing, as Chile saw the
matter, the benefits of the 1952 Santiago Declaration to Peru. Those statistics reveal two facts
which the Court sees as helpful in identifying the maritime areas with which the Parties were
concerned in the period when they acknowledged the existence of their maritime boundary. The
first is the relatively limited fishing activity by both Chile and Peru in the early 1950s. In 1950,
Chile’s catch at about 90,000 tonnes was slightly larger than Peru’s at 74,000 tonnes. In the early
1950s, the Parties’ catches of anchovy were exceeded by the catch of other species. In 1950, for
instance, Peru’s take of anchovy was 500 tonnes, while its catch of tuna and bonito was
44,600 tonnes; Chile caught 600 tonnes of anchovy that year, and 3,300 tonnes of tuna and bonito.
Second, in the years leading up to 1954, the Parties’ respective catches in the Pacific Ocean
included large amounts of bonito/barrilete and tuna. While it is true that through the 1950s the take
of anchovy, especially by Peru, increased very rapidly, the catch of the other species continued at a
high and increasing level. In 1954 the Peruvian catch of tuna and bonito was 65,900, and of
anchovy 43,100, while Chile caught 5,200 and 1,300 tonnes of those species, respectively.
The Parties also referred to the hunting of whales by their fleets and by foreign fleets as one
of the factors leading to the adoption of the 1947 and 1952 instruments. The FAO statistics provide
some information about the extent of whale catches by the Parties; there is no indication of where
those catches occurred.
108. The above information shows that the species which were being taken in the early
1950s were generally to be found within a range of 60 nautical miles from the coast. In that
context, the Court takes note of the orientation of the coast in this region, and the location of the
most important relevant ports of the Parties at the time. Ilo, situated about 120 km north-west of
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the seaward terminus of the land boundary, is described by Peru as “one of [its] main fishing ports
and the most important fishing centre in Southern Peru”. On the Chilean side, the port of Arica lies
just 15 km to the south of the seaward terminus of the land boundary. According to Chile, “[a]
significant proportion of the country’s small and medium-sized fishing vessels, of crucial
importance to the economy of the region, are registered at Arica”, while the next significant port is
at Iquique, 200 km further south.
The purpose of the 1954 Special Maritime Frontier Zone Agreement was to establish a zone
of tolerance along the parallel for small fishing boats, which were not sufficiently equipped (see
paragraphs 88 to 90 and 103). Boats departing from Arica to catch the above-mentioned species, in
a west-north-west direction, in the range of 60 nautical miles from the coast, which runs essentially
from north to south at this point, would not cross the parallel beyond a point approximately
57 nautical miles from the starting-point of the maritime boundary. The orientation of the coast
turns sharply to the north-west in this region (see sketch-maps Nos. 1 and 2), such that, on the
Peruvian side, fishing boats departing seaward from Ilo, in a south-west direction, to the range of
those same species would cross the parallel of latitude at a point up to approximately 100 nautical
miles from the starting-point of the maritime boundary.
109. The Court, in assessing the extent of the lateral maritime boundary which the Parties
acknowledged existed in 1954, is aware of the importance that fishing has had for the coastal
populations of both Parties. It does not see as of great significance their knowledge of the likely or
possible extent of the resources out to 200 nautical miles nor the extent of their fishing in later
years. The catch figures indicate that the principal maritime activity in the early 1950s was fishing
undertaken by small vessels, such as those specifically mentioned in the 1954 Special Maritime
Frontier Zone Agreement and which were also to benefit from the 1968-1969 arrangements relating
to the lighthouses.
110. A central concern of the three States in the early 1950s was with long-distance foreign
fishing, which they wanted to bring to an end. That concern, and the Parties’ growing
understanding of the extent of the fish stocks in the Humboldt Current off their coasts, were major
factors in the decisions made by Chile and Peru to declare, unilaterally, their 200-nautical-mile
zones in 1947, and, with Ecuador, to adopt the 1952 Santiago Declaration and other texts in
1952 and to take the further measures in 1954 and 1955. To repeat, the emphasis in this period,
especially in respect of the more distant waters, was, as Chile asserts, on “[t]he exclusion of
unauthorized foreign fleets . . . to facilitate the development of the fishing industries of [the three
States]”.
111. The Court recalls that the all-purpose nature of the maritime boundary (see
paragraph 102 above) means that evidence concerning fisheries activity, in itself, cannot be
determinative of the extent of that boundary. Nevertheless, the fisheries activity provides some
support for the view that the Parties, at the time when they acknowledged the existence of an
agreed maritime boundary between them, were unlikely to have considered that it extended all the
way to the 200-nautical-mile limit. - 43 -
B. Contemporaneous developments in the law of the sea
112. The Court now moves from the specific, regional context to the broader context as it
existed in the 1950s, at the time of the acknowledgment by the Parties of the existence of the
maritime boundary. That context is provided by the State practice and related studies in, and
proposals coming from, the International Law Commission and reactions by States or groups of
States to those proposals concerning the establishment of maritime zones beyond the territorial sea
and the delimitation of those zones. By the 1950s that practice included several unilateral State
declarations.
113. Those declarations, all adopted between 1945 and 1956, may be divided into two
categories. The first category is limited to claims in respect of the sea-bed and its subsoil, the
continental shelf, and their resources. They include declarations made by the United States
(28 September 1945), Mexico (29 October 1945), Argentina (11 October 1946), Saudi Arabia
(28 May 1949), Philippines (18 June 1949), Pakistan (9 March 1950), Brazil (8 November 1950),
Israel (3 August 1952), Australia (11 September 1953), India (30 August 1955), Portugal
(21 March 1956) and those made in respect of several territories then under United Kingdom
authority: Jamaica (26 November 1948), Bahamas (26 November 1948), British Honduras
(9 October 1950), North Borneo (1953), British Guiana (1954), Brunei (1954) and Sarawak (1954),
as well as nine Arab States then under the protection of the United Kingdom (Abu Dhabi
(10 June 1949), Ajman (20 June 1949), Bahrain (5 June 1949), Dubai (14 June 1949), Kuwait
(12 June 1949), Qatar (8 June 1949), Ras al Khaimah (17 June 1949), Sharjah (16 June 1949), and
Umm al Qaiwain (20 June 1949)). Other declarations, the second category, also claim the waters
above the shelf or sea-bed or make claims in respect of the resources of those waters. In addition to
the three claims in issue in this case, those claims include those made by the United States of
America (28 September 1945), Panama (17 December 1946), Iceland (5 April 1948), Costa Rica
(5 November 1949), Honduras (7 March 1950), El Salvador (7 September 1950) and Nicaragua
(1 November 1950). The above-mentioned acts are reproduced in the United Nations collection,
Laws and Regulations on the High Seas, Vol. I, 1951, Part 1, Chap. 1, and Supplement, 1959,
Part 1, Chap. 1, and in the Parties’ Pleadings.
114. Some of the declarations did address the issue of establishing maritime boundaries. The
first was the continental shelf declaration of the United States, which provided that, whenever the
continental shelf extends to the shores of another State, or is shared with an adjacent State, the
boundary shall be determined by the United States and the State concerned in accordance with
equitable principles. Those of Mexico and Costa Rica (like that of Chile, see paragraph 37 above)
stated that the particular declaration each had made did not mean that that Government sought to
disregard the lawful rights of other States, based on reciprocity. The wording in the Argentinean
decree accorded conditional recognition to the right of each nation to the same entitlements as it
claimed. Proclamations made by the Arab States then under United Kingdom protection all
provided in similar terms that their exclusive jurisdiction and control of the sea-bed and subsoil
extended to boundaries to be determined more precisely, as occasion arises, on equitable or, in one
case, just principles, after consultation with the neighbouring States. - 44 -
115. Those declarations were part of the background against which the International Law
Commission worked in preparing its 1956 draft articles for the United Nations Conference on the
Law of the Sea, held in 1958. On the basis, among other things, of the material summarized above,
the report of a committee of experts, and comments by a significant range of States, the
Commission proposed that, in the absence of an agreement or special circumstances, an
equidistance line be used for delimitation of both the territorial sea and the continental shelf. The
Commission in particular rejected, in the absence of an agreement, as a basis for the line the
geographical parallel passing through the point at which the land frontier meets the coast. Chile
and Ecuador in their observations submitted to the Commission contended that the rights of the
coastal State over its continental shelf went beyond just “control” and “jurisdiction”; Chile, in
addition, called for “sovereignty” over both the continental shelf and superjacent waters. However,
neither State made any comment on the matter of delimitation. Peru made no comment of any
kind. This further supports the view that the chief concern of the three States in this period was
defending their 200-nautical-mile claims as against third States. The Commission’s proposals were
adopted by the 1958 Conference and incorporated, with drafting amendments, in the Convention on
the Territorial Sea and Contiguous Zone (Art. 12) and the Convention on the Continental Shelf
(Art. 6). The territorial sea was not seen by the International Law Commission, and would not
have been seen at that time by most nations, as extending beyond 6 nautical miles and the
continental shelf line was for the sea-bed and subsoil, extending to a 200-metre depth or beyond to
the limit of exploitability, and not for the resources of the water above the shelf.
116. The Court observes that, during the period under consideration, the proposal in respect
of the rights of a State over its waters which came nearest to general international acceptance was
for a 6-nautical-mile territorial sea with a further fishing zone of 6 nautical miles and some
reservation of established fishing rights. As the Court has noted previously, in this period the
concept of an exclusive economic zone of 200 nautical miles was “still some long years away”
(Maritime Delimitation in the Black Sea (Romania v. Ukraine), Judgment, I.C.J. Reports 2009,
p. 87, para. 70), while its general acceptance in practice and in the 1982 United Nations Convention
on the Law of the Sea was about 30 years into the future. In answering a question from a Member
