Dissolved oxygen

• Essential to most aquatic organisms for their respiration.
• Is also necessary during the process of decomposition.
• If adequate amount not maintained, aquatic animals will be stressed, becoming vulnerable to diseases and parasites outbreaks, or they will die.
• The animals may refuse to eat for a period during and after oxygen depletion.
• Thus, growth rate and food conversion efficiency will suffer and feed will be wasted if prepared diets are provided.
• Solubility of oxygen in water depends on:

1. Temperature: Decrease with increasing water temperature.
2. Atmospheric pressure: Increase with increasing atmospheric pressure.
3. Salinity: Decrease with increasing salinity.