fish farming

• open system = outdoors - free movement of water and waste in large bodies of water
• closed system = indoor tanks - managed to maintain optimum temperature, O2 levels and pH for fish growth
• maintenance of water quality:

  • water needs enough O2 and clean for good growth
  • build up of faecal or food waste = bacterial growth - disease, r3educe oxygen levels, eutrophication
• control of predation:

  • fish protected from birds and mammals by netted cages and nets
  • keep fish in smaller numbers and separate by age = stop intraspecific predation
• control of disease:

  • close together so easy for disease transfer
  • treat with antibiotics - not too much or become immune
  • only in closed systems
• selective breeding:

  • create fish eggs with desired characteristics
  • when hatched and grown, pick fittest fish to breed