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Capture fisheries

IB Environmental Systems and Societies • Unit 4

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Capture fisheries

Big idea: Capture fisheries involve catching wild fish from oceans and freshwater. They have fed humanity for millennia, but many stocks are now overfished and at risk of collapse.

The overfishing problem

  • ~35% of global fish stocks are overfished (FAO)
  • Modern technology makes fishing too efficient (sonar, GPS, huge nets)
  • Bycatch kills millions of non-target species
  • Bottom trawling destroys seafloor habitats
  • Illegal, unreported, and unregulated (IUU) fishing evades quotas

Impacts of overfishing

  • Stock collapse — populations fall below recovery point
  • Ecosystem disruption — removes key species from food webs
  • Economic loss — fishing communities lose livelihoods
  • Food insecurity — 3 billion people depend on fish for protein
  • Trophic cascades — removing predators affects entire ecosystem
In extended answers about sustainable aquatic food production, link renewable natural capital to management. Include several distinct strategies (MSY, quotas, protected areas, closed seasons, gear restrictions, reducing bycatch) and briefly explain how each protects fish stocks and ecosystems.

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