In terms of the United Nations Convention on the Law of the Sea (UNCLOS) of 1982, and in particular according to Article 76, coastal states have the potential to extend the maritime area under their jurisdiction, beyond the 200 nautical miles that currently constitutes their Exclusive Economic Zone (EEZ).
These extensions towards the high seas can be claimed for the continental shelf (on and below the seafloor) bordering their landmass, if certain geological, geomorphological and geophysical criteria are met. The claims are examined by a specialized commission of the United Nations (the Commission on the Limits of the Continental Shelf, or CLCS), and most coastal states were required to submit their claims before the 13th of May 2009.
In the extended continental shelf area, coastal states will have sovereign rights over the exploitation of its natural resources (mineral and hydrocarbon resources, and living species of on and below the seafloor, excluding fish stock).

Following the work of several expert commissions of the United Nations, instructed to reflect upon the problem of the outer limits of the continental shelf, a number of technical and scientific guidelines were formulated and adopted on the 13th of May, 1999 (CLCS/11).

The extension of the continental shelf is constrained by the outermost of two limits:

• A line drawn at 350 nautical miles from the base lines, and
• a limit determined as 100 miles beyond the 2500 m isobath.
• Within this combined maximum limit (constraint line), coastal states can claim an extended shelf by using the maximum of two distinct distances measured seawards from the foot of the slope (the foot of the slope (FOS) being defined as the maximum change in gradient at its base):
• either a distance of 60 nautical miles, or
• a distance, "d", beyond the FOS where the thickness of the sedimentary cover equals 1 % of that distance.

Ultimately, the outer limit is determined by a combination of the two last criteria, but it can never exceed the previously defined constraint.

Following the ratification of the UN Convention on the Law of the Sea, many coastal states mounted national programs to conduct the theoretical studies and acquisition activities needed to claim an extended continental shelf. As of today, more than 65 submissions have been lodged at the CLCS. In addition, more than 40 preliminary information files have been submitted to the Secretary General of the UN, giving coastal states additional time to finalise their submission.
Here we describe the national program related to the extended continental shelf for South Africa and its joint project with France.

South Africa ratified the Convention on 23 December 1997 and had until 13 May 2009 to submit its claim to the expert commission of the United Nations.
It has two main areas of interest: - the continental shelf around the South African mainland, - and that around its island territories, Marion and Prince Edward Islands. In October 2002, South Africa's Extended Continental Shelf Project began officially when the Minister of Minerals and Energy directed Petroleum Agency SA to manage the project to determine the potential for South Africa to extend its continental shelf beyond its current Exclusive Economic Zone (EEZ).
The South African Shelf Claim Project comprises a Steering Committee and a technical Working Group. The Steering Committee consists of senior representatives from:

• Department of Minerals and Energy
• Department of Foreign Affairs
• Petroleum Agency SA
• Council for Geoscience
• South African Navy and
• Hydrographic Office

This committee was later extended to include representatives from:

• Department of Environmental Affairs (Marine Coastal Management)
• Department of Science and Technology and
• South African Maritime Safety

The Working Group comprises technical representatives from:

• Petroleum Agency SA
• Council for Geoscience
• Institute for Maritime Technology (IMT) and
• South African Navy Hydrographic Office

The group is tasked with carrying out the project under the chairmanship of the Petroleum Agency. The underlying philosophy of the Project was the thorough investigation of all possible potential claims within South African waters. The guiding principles have been firstly, to ensure that all existing knowledge in the form of academic research and data is studied and that the claim parameters are fully understood before committing itself to acquiring new data and secondly, that the project shall liaise and cooperate with South Africa's maritime neighbours in joint endeavours to harmonize interpretations and submissions across mutual boundaries.
Preliminary scoping studies had identified seven potential claim areas for South Africa. Four of these are located around mainland South Africa and three around the Prince Edward Islands. An optimistic assessment of South Africa's total potential claim is approximately 940,000 square kilometers, of which one third is made up by potential claims around the island territories. The three potential claim areas around the Prince Edward Islands include the Del Cano Rise claim, the Discovery II Ridge, and the Southwest Indian Ridge (SWIR) claim.

With an area of about 576 000 km2, the EEZ of the Crozet Archipelago does not have any international boundaries. Similarly, the Prince Edward Islands, located some 500 miles West of Crozet, have an EEZ of about 475 000 km² and no international boundaries (Fig. 2). The 350 mile constraint lines of both countries overlap.
For practical reasons, the area of potential extension was divided along a median line between the two island groups, without prejudice to any future boundary negotiations. France and South Africa decided to undertake a collaborative exploration of the area in order to define the extended continental shelf. As such both States decided to optimize and harmonize claim limits and to present a joint submission to the CLCS. This may also have the benefit of making the claim more acceptable to the CLCS as it has expressed its approval of such joint approaches.

The Extended Continental Shelf : A New Marine Frontier Opens for South Africa!