Marine Waters Legal Definition

Another challenge is the definition of islands. States are encouraged to obtain island status for their deep-sea characteristics. Unlike rocks or low water, islands project a complete territorial sea with overflight control and a complete EEZ. This problem is most common in the resource-rich South China Sea, which contains many maritime features, which may or may not be islands, which may or may not be eligible for large EEZs. Even small islands like the Spratly Islands, totaling 1.5 square miles, can project hundreds of square kilometers of exclusive economic control over the South China Sea. This issue is discussed in more detail in Chapter Ten: The South China Sea Tribunal. While territorial seas are subject to the exclusive jurisdiction of coastal States, the rights of coastal States are limited by the transit rights of other States, including innocent passage through the territorial sea and passage through international straits. This is the main distinction between internal waters and territorial seas. These rights are described in detail in Chapter Three, Freedom of Navigation. Everything from the baseline to a border that does not exceed twelve miles is considered the territorial sea of the state. Coastal seas are the simplest area. Like internal waters, coastal States have sovereignty and jurisdiction over the territorial sea.

These rights extend not only on the surface, but also on the seabed and subsoil and vertically on the airspace. The vast majority of States have established territorial waters within the 12-nautical-mile limit, but a handful have established shorter thresholds. States are not in a position to arbitrarily draw straight baselines to extend their maritime claims. The LOSC states that straight baselines must correspond to the general direction of the coast and that the sea area with the lines must be closely linked to the coast.15 Straight baselines cannot be drawn above low water levels (see definition below). Finally, they may not be used to cut off another State`s access to its territorial sea or EEZ. Straight baselines may be considered in the case of “economic interests of the region concerned” if the state establishing the baseline proves “long use”.16 Marine areas are drawn using what the LOSC calls “baselines”. Unlike inland waters, coastal waters rise and fall in tides. Instead of having mobile maritime boundaries, the baseline is set to start at the low tide line along the coast. The low tide line is derived from the coastal state`s own maps.1 To record deeply jagged coastlines and island margins along the coast, the LOSC allows for the use of straight baselines.14 These baselines, drawn between features and coastline to create straight lines, allow states to create fixed points to cope with variations in wild distance caused by these features. Any sea between the coast and the straight baseline is considered internal waters and not territorial waters.

The practical effect of straight baselines is that they move a State`s maritime boundaries outward. As a result, states ranging from Canada to China have aggressively used straight baselines in a manner not accepted by the United States. The LOSC specifically defines the different maritime zones and features. However, there is an ongoing controversy around the world over the definition of these features and the areas they should create. It is easy to understand why, depending on the type of function. The sea surface and water column beyond the EEZ are referred to as the high seas in the LOSC. The seabed beyond the EEZ and continental shelf of a coastal state is referred to as the LOSC area. The LOSC stipulates that the area is considered a “common heritage of all mankind”12 and is beyond national jurisdiction. States may carry out activities in the region as long as they serve peaceful purposes, such as transit, marine science and underwater exploration. Unlike other areas whose existence resulted from previous international law, the EEZ was a creation of the LOSC. States may claim an EEZ extending 200 nautical miles from the baseline.

In this area, a coastal State has the exclusive right to use or conserve all resources in the water, on the seabed or under the seabed. These resources include both living resources such as fish and non-living resources such as oil and natural gas.4 States also have the exclusive right to generate offshore energy from waves, currents and winds in their EEZ. Article 56 also allows States to establish and use artificial islands, installations and structures, to conduct marine scientific research, and to protect and preserve the marine environment through marine protected areas.5 Article 58 states that Articles 88 to 115 of the Convention on the Rights of the High Seas apply to the EEZ “to the extent that they are not inconsistent with this Part [V]”. 6 From the eighteenth to the mid-twentieth century, international law fixed the breadth of territorial waters at one league (three nautical miles), although practice was never entirely uniform. The United States established a three-mile territorial boundary in 1793. International law has also established the principle that foreign ships have the right to cross territorial waters for peaceful purposes. Bays are one of the most complex maritime features. In general, a bay is a large depression in a coastline. This can become a problem with straight baselines, as states may try to classify large bays as inland waters to further project maritime boundaries and control overflight access. To avoid this, the LOSC defines an array as a “well-marked indentation”. [where] its surface is as large or greater than that of a semicircle, the diameter of which is a line drawn through the mouth of this depression.

18 The extent of a State`s control over a bay depends on the distance between the low-water mark on either side of the entrance to the bay. If the inlet is equal to or less than 24 miles wide at low tide, a state can draw a straight baseline through the entrance, effectively turning the entire bay into inland waters. If the entrance is more than 24 miles wide, a state can only draw a straight baseline 24 miles across the bay to maximize the area of inland waters.