Nobody owns the open ocean, which is exactly why it is so hard to protect. This page covers how the sea is legally divided, who gets to decide what happens in each part, and the genuinely difficult ethical arguments about hunting marine mammals.
📘 What you need to know
UNCLOS, created in 1982, is the law governing all oceans and their resources.
It divides the sea into five zones: internal waters, territorial sea, contiguous zone, exclusive economic zone and high seas.
The EEZ extends 200 nautical miles from the baseline, and the coastal state has exclusive rights to its resources.
Selling EEZ access to foreign fleets raises equity and justice issues for local communities.
The high seas cover nearly 60% of the world’s oceans and are lightly governed; a UN High Seas Treaty was signed in 2023.
Hunting marine mammals raises conflicting animal rights and Indigenous rights perspectives; the IWC regulates whaling.
How the ocean is divided
Marine harvesting means collecting resources from the sea, including fish and marine mammals. Where you are determines whose rules apply.
Read it as a gradient of authority. Total control near shore, resource rights out to 200 nautical miles, then nothing but voluntary international agreement.
The five zones
Internal waters. On the landward side of the baseline. The coastal state has full sovereignty.
Territorial sea. Out to 12 nautical miles. Sovereignty is similar to that over land, though foreign ships have a right of innocent passage.
Contiguous zone. From 12 to 24 nautical miles. The state can enforce customs, immigration and pollution law, but does not have full sovereignty.
Exclusive economic zone. Out to 200 nautical miles. Exclusive rights to explore and use marine resources, including fishing and oil. Other nations may pass through and lay cables, but must respect resource rules.
High seas. Everything beyond the EEZ. No state has sovereignty, and all nations may fish, ship and conduct research.
The EEZ and who benefits from it
Inside its EEZ, a government decides how many fish can be caught, who may fish, and which species can be targeted. That is real economic power, and how it is used raises fairness questions.
Some countries sell access to foreign nations or fishing companies instead of managing the resource for their own people.
Poorer nations may sell rights to wealthy foreign fleets for immediate revenue.
The result can be overfishing that deprives local communities of the fish they depend on.
Local fishers, using smaller boats, cannot compete with industrial fleets, so fish availability falls and coastal ecosystems suffer.
The equity argument in one line. The revenue from selling access goes to a national government now; the cost of a depleted stock falls on coastal communities for decades. That mismatch is what makes it a justice issue and not just an economic one.
The high seas problem
The high seas cover nearly 60% of the world’s oceans, and until recently there was very little governance there. International bodies including the United Nations have developed treaties to protect these waters and regulate fishing, shipping and seabed mining.
In 2023 the UN signed an International Treaty on the High Seas, intended to allow marine protected areas to be created beyond national jurisdiction and to improve regulation of fishing and other activities there.
Ethics: hunting marine mammals
Marine harvesting includes seals, whales and dolphins, and this is where the topic stops being technical. Two well-argued positions genuinely conflict, and an exam answer is expected to present both fairly.
The most useful distinction in this debate is between subsistence hunting by a small community and commercial hunting for sale. Many people who oppose one accept the other.
The animal rights perspective
Whales, dolphins and seals are intelligent and highly social, which many people believe gives them a strong claim to protection.
Campaigners argue the killing is inhumane and unnecessary, particularly where substitutes for the products exist.
The hunting of pilot whales in the Faroe Islands, known as the grindadráp, draws international criticism on both welfare and sustainability grounds.
The Indigenous rights perspective
Indigenous groups have hunted marine mammals for food and cultural reasons over very long periods.
For communities such as the Inuit, hunting supplies food and materials and sustains a connection to ancestral tradition.
Many argue their practices are sustainable and should be protected as part of their cultural rights. The Inuit continue to hunt narwhal and seal on this basis.
The International Whaling Commission
The IWC regulates whaling: it sets limits on how many whales may be hunted and lists which species are protected. Commercial whaling has largely been banned. Some countries, notably Japan, have continued to hunt whales for stated scientific purposes, and critics describe this as a loophole for commercial whaling.
On ethical questions, your job is to lay out the arguments clearly and fairly, not to announce a personal verdict. If a question asks you to discuss, give both perspectives and the criteria — scale, purpose, species status, consent — that people use to judge between them.
Worked examples
WORKED EXAMPLE 1
How big is an island’s EEZ?
A small island nation claims an EEZ extending 200 nautical miles in all directions. Taking 1 nautical mile as 1.852 km, estimate the area of ocean it controls.
Step 1: convert the radius200 × 1.852 = 370.4 kmStep 2: treat it as a circleA = πr2 = π × 370.42Step 3: calculateA = 431 000 km2 (3 s.f.)About 4.3 × 105 km2 of oceanbigger than many countries — which is why selling access rights is such a significant economic decision for small island states
WORKED EXAMPLE 2
Discuss the sale of fishing rights within an EEZ [6]
How to build a balanced answer.
Case for
Brings immediate revenue to a government that may lack the fleet or capital to harvest the resource itself; can fund schools, health care and infrastructure
Case against
Industrial fleets can overfish, local fishers cannot compete, and food security falls in coastal communities
Equity dimension
Benefits are national and short term; costs are local and long termConditions that change the verdict
Enforceable catch limits, observers on foreign vessels, and a share of the catch landed locally
Defensible if properly regulated; damaging if it is simply a sale of accessa discuss question wants both sides plus the conditions, not a verdict announced in the first line
WORKED EXAMPLE 3
Why is the high seas so hard to regulate? [4]
Explain using UNCLOS.
Link 1
The high seas lie beyond every EEZ, so no state has sovereignty there
Link 2
They are open to all nations for fishing, shipping and research, and cover nearly 60% of the oceansLink 3
Rules depend on voluntary international agreement and are difficult to enforce so far from any coast
Link 4
The 2023 High Seas Treaty is a response, allowing MPAs beyond national jurisdiction
A shared resource with no single owner is the classic commons problemthe phrase “tragedy of the commons” fits perfectly here and links to systems theory
💡 Exam tip
Learn the five zones and their distances: 12, 24 and 200 nautical miles.
Quote UNCLOS 1982 and the 2023 High Seas Treaty with their dates.
Use nearly 60% for the high seas share of the ocean.
On ethics, present both perspectives with named examples before any judgement.
Distinguish subsistence from commercial hunting — it is the distinction the whole debate turns on.
Link EEZ access sales to equity and justice, not just economics.
⚠ Common mix-up
Confusing the contiguous zone with the EEZ. The contiguous zone is about customs and pollution enforcement, not resources.
Thinking the EEZ gives full sovereignty. It gives resource rights; ships may still pass through.
Assuming the high seas are unregulated entirely. Treaties exist, but enforcement is weak.
Treating all marine mammal hunting as one issue. Scale, species status and purpose all differ.
Dismissing the Indigenous perspective, or presenting it as the only legitimate one. Both views need fair treatment.
Mixing up nautical miles with kilometres. One nautical mile is about 1.85 km.
That completes 4.3 Aquatic Food Production Systems. Up next: Water Pollution — what we put into aquatic systems, and what it does to everything covered in these ten pages.
Want this explained one-to-one?
Book a free session with an experienced IB ESS tutor and get your trickiest topics made simple.
