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  • Fishing
    • Pelagic fish
      • Live in upper parts of the water
      • Caught by drift netting
        • Suspending a net from floats stretched between two boats so that fish swim into it
    • Bottom feeders
      • Caught by trawling
        • Dragging a large net through the water
    • Measures to reduce overfishing
      • Quotas on catches
      • Restricting net mesh size (large mesh nets allow juvenile fish through)
      • International agreements limiting catches
      • Enforcing closed seasons for fishing
      • Enforcing exclusion zones
    • Fish farming
      • The growth of phytoplankton can be aided by the addition of artificial fertilisers
      • Fish grow rapidly reared in warm waters discharged from factories
      • Disease spreads rapidly
        • Huge amounts of pesticides used
          • Can harm marine invertebrates
        • Can spread to wild fish
      • Eutrophication
        • Fish excreta, waste food and fertiliser are carried in the water to the wider community around rearing pens
      • Escaped fish
        • Interbreed with wild fish weakening wild stocks
      • Farmed salmon eat 3X their body weight of fish food (other fish) so this is not the best use of resources


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