Rights and Obligations of Coastal States Bordering Straits based on international law of the sea and customary international law

The coastal State has a right to adopt laws and regulations relating to transit passage through straits. Under Article 42(1), those laws and regulations involve:
(a) the safety of navigation and the regulation of maritime traffic, as provided in Article 41,
(b) the prevention, reduction and control of pollution, by giving effect to applicable international regulations regarding the discharge of oil, oily wastes and other noxious substances in the strait,
(c) with respect to fishing vessels, the prevention of fishing, including the stowage of fishing gear, and
(d) the loading or unloading of any commodity, currency or person in contravention of the customs, fiscal, immigration or sanitary laws and regulations of States bordering straits. States bordering straits are required to give due publicity to all such laws and regulations in accordance with Article 41(3).
Further, the coastal State bordering straits may designate sea lanes and prescribe traffic separation schemes for navigation in straits where necessary to promote the safe passage of ships pursuant to Article 41(1). Under Article 41(3), such sea lanes and traffic separation schemes shall conform to generally accepted international regulation. In this connection, Article 41(4) requires that States bordering straits refer proposals to the competent international organisation with a view to their adoption before designating or substituting sea lanes or prescribing or substituting traffic separation schemes. These provisions can help to prevent States which border straits from designating sea lanes and prescribing traffic separation schemes in ways that might be disadvantageous to international shipping.
The legislative jurisdiction of the coastal State is qualified by paragraph 2 of Article 42 in two respects. The first limitation is that the laws and regulations of the coastal State bordering international straits ‘shall not discriminate in form or in fact among foreign ships’. The second limitation is that the application of the laws and regulations shall not ‘have the practical effect of denying, hampering or impairing the right of transit passage’. In relation to this, there is the question of whether, in the case of the violation of the municipal law of the State bordering straits, that State could terminate the right of transit passage unilaterally. The cumulative effect of Articles 38(1), 42(2) and 44 seems to suggest that States bordering straits are not allowed to directly deny the right of transit passage merely on grounds of breach of their municipal law. In the case of a violation of the laws and regulations referred to in Article 42(1)(a) and (b), however, Article 233 of the LOSC explicitly allows the State bordering a strait to exercise its enforcement jurisdiction.
Coastal States bordering straits shall undertake the following duties in accordance with Article 44:
(i) not to hamper transit passage,
(ii) to give appropriate publicity to any danger to navigation or overflight within or over the strait of which they have knowledge, and
(iii) not to suspend transit passage.

Moreover, Article 43 of the LOSC requires user States and States bordering a strait to cooperate:
(a) in the establishment and maintenance in a strait of necessary navigational and safety aids or other improvements in aid of international navigation; and (b) for the prevention, reduction and control of pollution from ships.
By way of example, Japan has been promoting international cooperation in the Straits of Malacca and Singapore through the Malacca Strait Council in such fields as hydrographic survey, maintenance of aids to navigation, making nautical charts, transfer of technology and clearance of sunken ships. In September 2007, the Cooperative Mechanism on Safety of Navigation and Environmental Protection in the Straits of Malacca and Singapore was launched as a result of a series of IMO-sponsored meetings on the Straits of Malacca and Singapore. The Cooperative Mechanism aims to promote dialogue and facilitate close cooperation between the littoral States, user States and other stakeholders. The establishment of the Cooperative Mechanism can be considered as a realisation of Article 43 of the LOSC.

Finally, environmental protection of international straits should be mentioned. As international straits are often narrow, the risk of marine casualties is higher than in other marine spaces. Thus the health of waterways is a matter of serious concern for States bordering international straits. In this regard, the question arises as to whether, under Part III of the LOSC, the coastal State has a right to introduce a compulsory pilotage system in an international strait.
A case in point is the compulsory pilotage system in the Torres Strait adopted by Australia. The Torres Strait is a strait used for international navigation to which the regime of transit passage applies. The depths of the Torres Strait are shallow and there are many reefs and shoals within the strait. The strait is also subject to highly complex tidal variation. As a consequence, navigation in that strait is extremely difficult. As the Torres Strait contains a highly sensitive marine habitat, it became a Particularly Sensitive Sea Area (PSSA) by IMO Resolution MEPC.133(53) adopted on 22 July 2005. Subsequently, Australia introduced in 2006 a compulsory pilotage system for certain vessels within the Torres Strait and Great North East Channel in order to protect sensitive marine habitats.
According to Marine Notice 8/2006, the compulsory pilotage system applies to merchant ships 70 metres in length and over or oil tankers, chemical tankers and liquefied gas carriers, irrespective of size, when navigating the Torres Strait and the Great North East Channel. According to Marine Notice 16/2006, the Australian authorities will not suspend or deny transit passage and will not stop, arrest or board ships that do not take on a pilot while transiting the Strait. However, the owner, master, and/or operator of the ship may be prosecuted on the next entry into an Australian port, for both ships on voyages to Australian ports and ships transiting the Torres Strait en route to other destinations. Australia’s compulsory pilotage system was protested by the United States and Singapore.
The controversy relating to the compulsory pilotage system in the Torres Strait seems to signal a growing tension between the navigational interest of the user States and the environmental interest of States bordering an international strait. Later, Australia changed its position and effectively exempted vessels from compulsory pilotage if they do not intend to call at an Australian port. Australia’s experience seems to suggest that unilateral action to implement compulsory pilotage could not win support from user States.139 In this respect, Article 43 of the LOSC merits particular attention with a view to reconciling such contrasting interests through international cooperation.

Customary Law Character of the Right of Transit Passage
Some States, notably the United States and Thailand, are of the view that the right of transit passage is a codification of customary law. However, it must be recalled that the regime of transit passage of the LOSC is a result of compromise and significantly beyond the rules of the 1958 TSC and traditional customary law in this matter. In this respect, the closing statement by the President of UNCLOS III bears quoting:
The argument that, except for Part XI, the Convention [LOSC] codifies customary law or reflects existing international practice is factually incorrect and legally insupportable. The regime of transit passage through straits used for international navigation and the regime of archipelagic sea lanes passage are only two examples of the many new concepts in the Convention.
At present, there appears to be little evidence to prove that ‘extensive and virtually uniform’ State practice and opinio juris exist with regard to the right of transit passage. It seems reasonable to conclude, therefore, that the right of transit passage is a new regime established by the LOSC, and has yet to become a part of customary international law.

Non-suspendable Innocent Passage
Under Article 45(1) of the LOSC, the right of innocent passage applies to straits used for international navigation excluded from the application of Article 38(1), or between a part of the high seas or an EEZ and the territorial sea of a foreign State. Unlike the right of innocent passage through the territorial sea, there shall be no suspension of innocent passage through international straits by virtue of Article 45(2). As with innocent passage through the territorial sea, aircraft do not enjoy the freedom of overflight. Further, submarines and other underwater vehicles are required to navigate on the surface and to show their flag in the exercise of the right of non-suspendable innocent passage.

Legality of Creation of Bridges in International Straits
A debatable issue is the legality of the creation of bridges in international straits. This question was raised in the 1991 Great Belt case between Finland and Denmark before the ICJ. On 10 June 1987, the Danish Parliament passed a law on the construction of a fixed link across the Great Belt Strait and, in 1989, the Danish authorities adopted the final version of the form of the link. The Danish project involved the construction over the West Channel of the Great Belt of a low-level bridge for road and rail traffic, and over the East Channel of a high-level suspension bridge for road traffic, with clearance for passage of 65 metres above mean sea level. As a result, the East Channel Bridge would permanently close the Baltic Sea for deep draught vessels over 65 metres in height.
Since the early 1970s, Finland, or strictly speaking, more than ten mobile offshore drilling units (MODUs, i.e. drill ships and drill rigs) built in Finland had used the Great Belt. Some of the Finnish MODUs reached a height of close to 150 metres. Once the fixed link was created across the Great Belt, these MODUs would no longer be able to pass through the Great Belt, damaging Finnish commercial activity. Thus a dispute arose between Finland and Denmark with regard to the Danish project. On 17 May 1991, the Finnish government filed an application instituting proceedings against Denmark before the ICJ. Further, on 23 May 1991, the Finnish government requested the Court to indicate provisional measures.

This dispute gave rise to several interesting questions in the law of the sea, such as the legal status of MODUs (e.g. whether drill rigs can be regarded as ships), the law applicable to the movement of MODUs, the right of coastal States to construct a fixed link in an international strait, the compatibility of the construction of a fixed bridge across the Great Belt with the right of free passage, the relevance of a comparison of interests on the basis of the equitable principles for the right of passage, the right of passage of reasonably foreseeable ships and acquiescence, etc. In essence, these questions concern the balance between the navigational interest of third States and the interest of the coastal State bordering the strait.
In its Order of 29 July 1991, the Court refused to indicate provisional measures primarily because there was no urgency justifying the indication of these measures. Later, on 3 September 1992, only one week before the oral hearings were to open before the Court, Denmark and Finland agreed to settle the dispute. Denmark agreed to pay a sum of 90 million Danish kroner (around US$15 million), and Finland agreed to withdraw its application. As a consequence, the Court did not have occasion to pronounce its view on this dispute, and the questions remain open.