Key Idea: Topic 8.4 is the last part of Option B (Oceans & coastal margins) — how the future of the oceans is managed, both as a resource to share sustainably and as a space states compete over. It pulls together two ideas: 8.4.1 — sustainable fisheries & marine protection: how overfishing shrinks stocks, and how quotas, aquaculture, closed seasons, mesh rules, surveillance and Marine Protected Areas bring catches back below the breeding rate. 8.4.2 — ocean geopolitics & resource conflict: how UNCLOS divides the sea into a 12-mile territorial sea and a 200-mile EEZ, and how competition over abiotic resources (oil, gas, minerals) and strategic chokepoints drives disputes. This is an option, examined on Paper 1 (SL answers 2 options, HL answers 3 — same questions). Each option is a structured question off a stimulus plus a [10] extended-answer (Examine / Evaluate / Discuss).
🐟 8.4.1 — Sustainable fisheries & marine protection
A fishery is sustainable when fish are caught no faster than they breed and replace themselves (the sustainable yield). Overfishing — catching above that rate — shrinks the stock and can collapse it. Management either restricts the catch (quotas, mesh rules, closed seasons) or takes pressure off wild stock (aquaculture, Marine Protected Areas). The skill examiners test is reading an aquaculture-production chart or MPA map, then explaining a strategy and weighing it in the [10] essay.
Strategies to manage a fishery
| Strategy | How it works | Limitation |
|---|---|---|
| Fishing quotas | A legal cap on the tonnage of each species, keeping catches below the replacement rate | Only works if enforced; can be evaded |
| Aquaculture | Farming fish in pens/cages takes pressure off wild stock to meet demand | Can pollute and need wild fish for feed |
| Closed areas / seasons | Banning fishing in nursery grounds or breeding seasons lets fish spawn | Hard to police; displaces effort elsewhere |
| Larger mesh size | Bigger net holes let juveniles escape so they breed before being caught | Reduces the legal catch in the short term |
| Marine Protected Area (MPA) | A no-take or restricted zone where habitats and stocks recover and spill over | A 'paper park' if not patrolled; displaces fishers |
Key terms — fisheries & protection
- Sustainable yield — the catch each year that equals what the stock replaces (so the stock survives).
- Overfishing — catching faster than fish can breed, so the stock declines and may collapse.
- Fishing quota — a legal limit on how much of a species may be caught.
- Aquaculture — farming fish or shellfish instead of catching wild stock.
- Marine Protected Area (MPA) — a zone of ocean where activities are restricted to let life recover (e.g. the Galápagos Marine Reserve).
- Spillover — fish bred inside an MPA grow and move out, restocking the fishery nearby.
A favourite ocean stimulus: read the axis first, then rank the bars (China 1st, India 2nd, Indonesia 3rd) and quote the units — millions of tonnes.
🔒 Interactive diagram
Explore the labelled diagram, charts and maps for this topic in study mode.
Tip: An Explain of a strategy needs its mechanism: larger mesh → juveniles escape → they breed → stock replaced. A bare list of names scores the low marks only. For a chart or map, read the value off the axis or scale and always quote the units.
🌊 8.4.2 — Ocean geopolitics & resource conflict
The oceans are a global commons, but states still claim sovereignty over the sea near their coast under UNCLOS — a 12-mile territorial sea and a 200-mile Exclusive Economic Zone (EEZ) where they own the resources. Conflict flares where EEZs overlap, where the sea holds abiotic resources (oil, gas, minerals), or where it controls a strategic chokepoint. The skill tested is reading a flow map of oil chokepoints, then explaining EEZ rights and weighing resolvability in the [10] essay.
Maritime zones under UNCLOS (from the coast)
| Zone | Limit from coast | What the state controls |
|---|---|---|
| Territorial sea | 12 nautical miles | Near-full sovereignty — its own laws, ships and airspace |
| Exclusive Economic Zone (EEZ) | 200 nautical miles | All resources: fishing, oil, gas and seabed minerals |
| Continental shelf | up to ~350 nautical miles | Seabed and sub-soil resources (oil, gas, minerals) |
| High seas | beyond the EEZ | No state owns it — a shared global commons |
Key terms — geopolitics & conflict
- Sovereignty — a state's legal right to control its own territory, including the sea near its coast.
- UNCLOS — the UN treaty that sets out maritime zones and the rights states have in each.
- Exclusive Economic Zone (EEZ) — the sea out to 200 nautical miles, where the state owns the resources.
- Abiotic resources — non-living ocean resources (oil, gas, seabed minerals) — the focus of resource conflict.
- Chokepoint — a narrow strait a large share of world shipping must pass (e.g. Hormuz carries ~21 million barrels/day).
- Contested sea — an area whose ownership is disputed (e.g. the South China Sea and the Spratly Islands).
Example: South China Sea — China, Vietnam, the Philippines and others claim the Spratly/Paracel islands, which sit on oil, gas and rich fishing astride a major shipping route; overlapping EEZs make it contested. Arctic Ocean — as ice melts, Russia, Canada, the USA, Norway and Denmark submit rival continental-shelf claims to seabed oil, gas and new lanes. Strait of Hormuz — about 21 million barrels of oil a day pass through, so threats to close it become political leverage.
✍️ IB-style questions
Explain two strategies, other than marine reserves, that can reduce overfishing.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
"Marine Protected Areas are the most effective way to manage the future of the oceans." Evaluate this statement.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
✅ Quick self-check
Tap each card to reveal the answer.
What makes a fishery sustainable? Fish are caught no faster than they breed and replace themselves (the sustainable yield), so the stock survives for the future.
Name two non-MPA ways to cut overfishing. Quotas (legal catch caps) and larger mesh sizes (juveniles escape to breed). Also aquaculture, closed seasons and surveillance.
How far does a state's EEZ extend, and what does it own? Out to 200 nautical miles from the coast; the state owns all the resources there — fishing, oil, gas and seabed minerals.
Why is the South China Sea contested? Several states' EEZs overlap around the Spratly/Paracel islands, which hold oil, gas and rich fishing on a major shipping route — so owning the islands means owning the resources.
What does a top [10] ocean essay need? Both sides, accurate terms (sustainable yield, EEZ, UNCLOS), named cases (Galápagos, South China Sea, Hormuz), and a clear justified judgement.
🎯 Highest-yield exam reminders
Exam Tips
- Sustainable = catch at or below the replacement rate (the sustainable yield).
- Explain a fishery strategy with its MECHANISM (mesh → juveniles escape → breed → stock replaced) — a bare list scores low.
- For a chart or flow map: read the value off the axis or scale and ALWAYS quote the units (million tonnes, million barrels/day).
- EEZ = 200 nautical miles; the state owns the resources (fish, oil, gas, minerals). UNCLOS sets the zones.
- Keep ABIOTIC (oil/gas/minerals) in focus for resource-conflict questions — drifting to fishing (biotic) caps the mark.
- On the Paper 1 [10] Evaluate/Examine/Discuss: argue BOTH sides, use a NAMED case (Galápagos, South China Sea, Arctic, Hormuz), and finish with a justified judgement.