Edexcel iGCSE Biology- 6.9B Fish Farming- Study Notes- New Syllabus

Fish Farming (Aquaculture) for Protein Production

🌱 Introduction

Fish farming (aquaculture) is the controlled breeding and rearing of fish to provide a reliable source of protein for humans.
Key goal: maximize growth and yield while maintaining healthy fish.

⚡ Methods and Practices in Fish Farming

• Maintaining Water Quality:
  Clean water is essential for healthy fish growth.
  Factors to monitor:
  – Oxygen levels → fish need dissolved O₂
  – pH → suitable for species
  – Temperature → ideal for metabolism
  – Ammonia & waste levels → too high → toxic
• Controlling Intraspecific & Interspecific Predation:
  Intraspecific predation: Fish eating smaller individuals of same species
  Interspecific predation: Fish eaten by other species
  Solutions:
  – Separate species or size classes
  – Use nets and enclosures to protect fish
• Controlling Disease:
  Disease can spread rapidly in dense populations
  Methods:
  – Quarantine new fish
  – Regular monitoring
  – Medicated feed or treatments if needed
  – Maintain hygiene in tanks/ponds
• Removing Waste Products:
  Uneaten food and excretory products → pollute water
  Methods:
  – Filtration systems
  – Pumps for water circulation
  – Frequent water changes
• Controlling Quality & Frequency of Feeding:
  Fish need balanced diet with proteins, vitamins, minerals
  – Overfeeding → waste, pollution
  – Underfeeding → slow growth, weak fish
  Feed small amounts frequently for optimum growth
• Selective Breeding:
  Choosing fast-growing, disease-resistant fish for breeding
  Produces healthy offspring with high yield
  Improves overall productivity over generations

📊 Summary Table

💡 Quick Recap
Fish farming → controlled rearing for protein
Key practices: Water, predation, disease, waste, feeding, selective breeding
Goal → healthy fish + maximum yield
🧠 Mnemonic: “Wet Ponds Don’t Waste Selectively” (Water, Predation, Disease, Waste, Feeding, Selective breeding)