15. Exclusive Economic Zones (EEZ) and shelf areasDisclaimer: Maritime limits and boundaries depicted on Sea Around Us Project maps are not to be considered as an authority on the delimitation of international maritime boundaries. These maps are drawn on the basis of the best information available to us. Where no maritime boundary has been agreed, theoretical equidistance lines have been constructed.
Where a boundary is in dispute, we attempt to show the claims of the respective parties where these are known to us and show areas of overlapping claims. In areas where a maritime boundary has yet to be agreed, it should be emphasized that our maps are not to be taken as the endorsement of one claim over another.
Historically, the oceans of the world were considered ‘free’ to anyone wanting to use them for travel, trade or resource exploitation. However, claims to territorial seas date back at least to the 1700s when the Dutch first claimed such an area based on the range of land-based cannons, which, at the time, were taken to be at most three nautical miles (nm). Thus, the three-mile territorial seas concept was born.
Countries have ever since tried to exert control over parts of the ocean that border their shores, as maritime boundaries and claims can have significant impacts on many marine activities, including ownership of living and non-living resources and fishing access (Cimino et al. 2000). The United Nations Convention on the Law of the Sea (UNCLOS), initiated in the 1960s, established a framework that permitted countries to define their claims over the ocean areas, and provided agreed upon definitions for territorial seas (now defined as 12 nm), contiguous zones (24 nm, for prevention of infringements of customs, fiscal, immigration and sanitary regulations) as well as 200 nm Exclusive Economic Zones (EEZ), which now cover most shelf areas down to the continental shelf margins at which the slope of the continental shelf merges with the deep ocean seafloor. Most countries declared EEZs right after the adoption of UNCLOS as international law in 1982. Within its EEZ, the country has the sovereign right to explore and exploit, conserve and manage living and non-living resources in the water column and on the seafloor, as defined by Part V of the Law of the Sea.
The Law of the Sea also makes allowances, through the Commission on the Limits of the Continental Shelf, for countries to claim extended jurisdiction over shelf areas beyond 200 nm, if they can demonstrate that their continental shelf extends beyond the established 200 nm EEZ. National claims for EEZs and extended jurisdiction may overlap, creating areas of disputed ownership and jurisdiction. Settlements through boundary agreements may take many years to develop and are complex, resulting in numerous disputed areas and claimed boundaries.
http://www.seaaroundus.org/doc/saup_manual.htm#15 
