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Law of the sea

Law of the sea is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Law of the sea rather than just read about it. In short: Law of the sea (or ocean law) is a body of international law governing the rights and duties of states in maritime environments. It concerns matters such as navigational rights, sea mineral claims, and coastal waters jurisdiction.

Law of the sea — main illustration
Law of the sea — illustration

Key takeaways

  • Law of the sea belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Law of the sea to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Law of the sea from memory before moving on to harder problems.

Reference excerpt

Law of the sea (or ocean law) is a body of international law governing the rights and duties of states in maritime environments. It concerns matters such as navigational rights, sea mineral claims, and coastal waters jurisdiction. The connotation of ocean law is somewhat broader, but the law of the sea (anchored in the United Nations Convention on the Law of the Sea (UNCLOS)) is so comprehensive that it covers all areas of ocean law as well (e.g., marine environmental law, maritime law). While drawn from a number of international customs, treaties, and agreements, modern law of the sea derives largely from the United Nations Convention on the Law of the Sea. That convention is effective since 1994, and is generally accepted as a codification of customary international law of the sea, and is sometimes regarded as the "constitution of the oceans". Law of the sea is the public law counterpart to admiralty law (also known as maritime law), which applies to private maritime issues, such as the carriage of goods by sea, rights of salvage, ship collisions, and marine insurance.

History Among the earliest examples of legal codes concerning maritime affairs is the Byzantine Lex Rhodia, promulgated between 600 and 800 C.E. to govern trade and navigation in the Mediterranean. Maritime law codes were also created during the European Middle Ages, such as the Rolls of Oléron, which drew from Lex Rhodia, and the Laws of Wisby, enacted among the mercantile city-states of the Hanseatic League. However, the earliest known formulation of public international law of the sea was in 17th century Europe, which saw unprecedented navigation, exploration, and trade across the world's oceans. Portugal and Spain led this trend, staking claims over both the land and sea routes they discovered. Spain considered the Pacific Ocean a mare clausum—literally a "closed sea" off limits to other naval powers—in part to protect its possessions in Asia. Similarly, as the only known entrance from the Atlantic, the Strait of Magellan was periodically patrolled by Spanish fleets to prevent entrance by foreign vessels. The papal bull Romanus Pontifex (1455) recognized Portugal's exclusive right to navigation, trade, and fishing in the seas near discovered land, and on this basis the Portuguese claimed a monopoly on East Indian trade, prompting opposition and conflict from other European naval powers. Amid growing competition over sea trade, Dutch jurist and philosopher Hugo Grotius—considered the father of international law generally—wrote Mare Liberum (The Freedom of the Seas), published in 1609, which set forth the principle that the sea was international territory and that all nations were thus free to use it for trade. He premised this argument on the idea that "every nation is free to travel to every other nation, and to trade with it." Thus, there was a right to innocent passage over land and a similar right of innocent passage at sea. Grotius observed that unlike land, on which sovereigns could demarcate their jurisdiction, the sea was akin to air, a common property of all:

The air belongs to this class of things for two reasons. First, it is not susceptible of occupation; and second its common use is destined for all men. For the same reasons the sea is common to all, because it is so limitless that it cannot become a possession of any one, and because it is adapted for the use of all, whether we consider it from the point of view of navigation or of fisheries. Writing in response to Grotius, the English jurist John Selden argued in Mare Clausum that the sea was as capable of appropriation by sovereign powers as terrestrial territory. Rejecting Grotius' premise, Selden claimed there was no historical basis for the sea to be treated differently than land, nor was there anything inherent in the nature of the sea that precluded states from exercising dominion over parts of it. In essence, international law could evolve to accommodate the emerging framework of national jurisdiction over the sea.

As a growing number of nations began to expand their naval presence across the world, conflicting claims over the open sea mounted. This prompted maritime states to moderate their stance and to limit the extent of their jurisdiction towards the sea from land. This was aided by the compromise position presented by Dutch legal theorist Cornelius Bynkershoek, who in De dominio maris (1702), established the principle that maritime dominion was limited to the distance within which cannons could effectively protect it. Grotius' concept of "freedom of the seas" became virtually universal until the mid-20th century, following the global dominance of European naval powers. National rights and jurisdiction over the seas were limited to a specified belt of water extending from a nation's coastlines, usually three nautical miles (5.6 km), according to Bynkershoek's "cannon shot" rule. Under the mare liberum principle, all waters beyond national boundaries were considered international waters: Free to all nations, but belonging to none of them. In the early 20th century, some nations expressed their desire to extend national maritime claims, namely to exploit mineral resources, protect fish stocks, and enforce pollution controls. To that end, in 1930, the League of Nations called conference at The Hague, but no agreements resulted. By the mid 20th century, technological improvements in fishing and oil exploration expanded the nautical range in which countries could detect and exploit natural resources. This prompted United States President Harry S. Truman in 1945 to extend American jurisdiction to all the natural resources of its continental shelf, well beyond the territorial waters of the country. Truman's proclamation cited the customary international law principle of a nation's right to protect its natural resources. Other nations quickly followed suit: Between 1946 and 1950, Chile, Peru, and Ecuador extended their rights to a distance of 200 nautical miles (370 km) to cover their Humboldt Current fishing grounds.

UN Convention of the Law of the Sea

The first attempt to promulgate and codify a comprehensive law of the sea was in the 1950s, shortly after the Truman proclamation on the continental shelf. In 1956, the United Nations held its first Conference on the Law of the Sea (UNCLOS I) in Geneva, Switzerland, which resulted in four treaties concluded in 1958:

… excerpt ends here. Continue reading the full article.

Illustrations

Law of the sea illustration
Law of the sea: Mare Liberum (1609) by Hugo Grotius is one of the earliest works on law of the sea.
Mare Liberum (1609) by Hugo Grotius is one of the earliest works on law of the sea.
Law of the sea: "Mare clausum" in the European Age of Discovery
"Mare clausum" in the European Age of Discovery
Law of the sea: Maritime zones are a core component of modern law of the sea.
Maritime zones are a core component of modern law of the sea.
Law of the sea: UNCLOS sea areas
UNCLOS sea areas

Worked examples

Example 1 — a first encounter with Law of the sea

Start with the simplest possible case. Write down what Law of the sea claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Law of the sea before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Law of the sea ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Law of the sea

In research
Law of the sea appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Law of the sea in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Law of the sea is common in secondary-school and first-year university syllabi. It links to neighbouring topics International law, Law of the sea, Maritime history, so understanding it makes those chapters shorter.
In everyday life
Look for Law of the sea outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Law of the sea in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Law of the sea means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Law of the sea out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Law of the sea in simple terms?

Law of the sea (or ocean law) is a body of international law governing the rights and duties of states in maritime environments. It concerns matters such as navigational rights, sea mineral claims, and coastal waters jurisdiction.

Why does Law of the sea matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Law of the sea?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Law of the sea.

Tags

  • International law
  • Law of the sea
  • Maritime history

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