Lesson 3 - Water Quality Flashcards
It determines the success or failure of fish culture
Water quality
Importance of water quality
- Fishes live in water
- Fishes are supported by water
- Fishes receive oxygen from water
- Fishes exercise in water
- Its factors influence and interact with each other
- What may cause problem in one situation may be harmless in another
- It influences effectiveness/toxicity of treatments
- Most disease problems can be avoided with proper management of water quality
- It includes maintaining water quality at a level that provides an environment conducive to fish health and growth
Water quality variables
- Temperature
- Dissolved oxygen
- Total ammonia-nitrogen
- Alkalinity
- Hardness
- pH
- Carbon dioxide
It controls the reaction rate of chemicals
Temperature
Influences the solubility of gases in water
Temperature
Influences toxicity of ammonia and therapeutants
Temperature
Optimum temperature for tilapia growth
85-88 F
For each _____ rise in temperature, the metabolic rate doubles
10C
First limiting factor for growth and fish health
Oxygen
Solubility decrease with increasing temperature and elevation
Oxygen
Respiratory rate increases with increasing temperature, activity and feeding
Oxygen
In general, the minimum _____ should be>60% of saturation or > 5ppm
DO
2 ppm in biofilter effluent
Oxygen
Usually the second limiting factor-nitrogenous waste:feces and feed
Total ammonia-nitrogen
It includes ammonium ion and ammonia
TAN
The proportion of NH3 increases with increasing temperature and pH
Total Ammonia-Nitrogen
Is the buffering capacity of water - absorbs acids and/or bases
Alkalinity
Prevents with all fluctuatons
High alkalinity
Hardness (water quality variable)
50-100 mg/L
pH (water quality variable)
7-8
Carbon dioxide (water quality variable)
<20 mg/L
Total dissolved gasses, supersaturation caused by:
- Leaking water lines
- Air leak on low pressure side of pump
- Sources of water
- Mixing cold and hot water
Recommended total dissolved gas pressure
<104%
Stressors:
- Poor water quality
- Environmental conditions
- Improper handling
Most fish disease are
Stressed mediated
Is a physiological state caused by a procedure, environmental condition or other factor which interferes with he ability to maintain a “normal” state.
Stress
It extends the adaptive responses beyond the normal range or which disturbs the normal functioning
Stress
The first sign of water quality/environmental problems
Low level mortality
Loading effects
- DO level
- Metabolic rate of fish
- Amount being fed
- Pathogen load
- Water exchange rate
