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To a great extentwater qualitydetermines thesuccess or failureof a fish farmingoperation
WATER IN AQUACULTURE SYSTEMS
To a great extentwater qualitydetermines thesuccess or failureof a fish farmingoperation
Fish perform allbodily functions in water
• Eat
• Breathe
••• Take in and lose salts
WATER IN AQUACULTURE SYSTEMS
• Eat
• Breathe
••• Take in and lose salts
Water Balance in Freshwater Fish
Salts
Water
Large quantitiesof dilute urine
Ammonia
Water Balance in Saltwater Fish
Water
Drinkssea water
Small quantities ofconcentrated urine
Ammonia
Water Resources
• Water quality
• Water quantity
• Water sources
• Water quality
• Water quantity
• Water sources
Inadequate water quality causes moreInadequate water quality causes morelosses than any other problem!losses than any other problem!
WATER IN AQUACULTURE SYSTEMS
Physical
Temperature
••
Chemical (“No effect” limits)
Physical
Temperature
••
Chemical (“No effect” limits)
Physical Characteristicsof Water
•
• “Universal solvent”
–
WATER IN AQUACULTURE SYSTEMS
•
• “Universal solvent”
–
Dissolved Oxygen
• Importance– highest cause of mortality
• Solubility– variables
•••
• Safe levels– > 5mg/l
• Importance– highest cause of mortality
• Solubility– variables
•••
• Safe levels– > 5mg/l
7
6
5
Measured values
Projected Dissolved OxygenLevels for Ponds
5
4
3
2
1
05 pm 10 pm 5 am
Projected values
mg/l
Uniform dissolved O in pond2
High dissolvedoxygen (warm)
Decomposingmaterials
Low dissolvedoxygen (cool)
TurnoverTurnover
Low dissolved oxygen -possible fish kill
Relationships
Temperature (F) (pH) 7.0 8.0 9.0
50 0.19 1.83 15.7
68 0.40 3.82 28.4
86 0.80 7.46 44.6
Percent Ammonia
Percent of Total Ammoniain the Un-Ionized Form at
Various Temperatures and pH
Temperature (F) (pH) 7.0 8.0 9.0
50 0.19 1.83 15.7
68 0.40 3.82 28.4
86 0.80 7.46 44.6
Nitrification
NONO33--NHNH33
1½ O1½ O22
nitrosomonasnitrosomonas nitrobacternitrobacter
1½ O1½ O22NONO22--
• Requires 3 moles oxygen to convert one mole ofammonia to nitrate
•
Dissolved Gasses
• Problem gasses– Nitrogen (primarily)
•
• Problem sources– Wells and Springs
––
dorsal viewdorsal view• Problem gasses
– Nitrogen (primarily)•
• Problem sources– Wells and Springs
–– leaky pipeleaky pipe
Popeye/exophthalmiaPopeye/exophthalmia
WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
• Requirements are based on temperature-dependent and size-dependent standardmetabolic rates for fish
•
Water quantity parameters
• Requirements are based on temperature-dependent and size-dependent standardmetabolic rates for fish
•
WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
Suggested replacement times
Linear• Noncirculating –• Circulating
Suggested water velocity rates• Noncirculating –• Circulating -
Water quantity parameters
Suggested replacement times
Linear• Noncirculating –• Circulating
Suggested water velocity rates• Noncirculating –• Circulating -
WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
Flow measuring techniques
Flow meters••
Pond filling time – not very accurate
Water quantity parameters
Flow measuring techniques
Flow meters••
Pond filling time – not very accurate
WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
Weir gauges• Sharp-crested – if outfall consists of damboards
• V-notch
• Trapezoidal••
Water quantity parameters
Weir gauges• Sharp-crested – if outfall consists of damboards
• V-notch
• Trapezoidal••
Pre-Use treatment
Sediment removal• Settling basin/pond –
• Filtration –
Gas stabilization (O2 and/or N2)• Slatted inflow boards••
WATER IN AQUACULTURE SYSTEMS
Pre-Use treatment
Sediment removal• Settling basin/pond –
• Filtration –
Gas stabilization (O2 and/or N2)• Slatted inflow boards••
Pre-Use treatmentSterilization
• Ultraviolet –•• Chlorination-de-chlorination –•
Temperature control• Heating• Chilling
WATER IN AQUACULTURE SYSTEMS
Pre-Use treatmentSterilization
• Ultraviolet –•• Chlorination-de-chlorination –•
Temperature control• Heating• Chilling
Water utilization• Open water systems
• Flow-through-Water enters pond or series of ponds andexits with/without treatment
-
-
WATER IN AQUACULTURE SYSTEMS
Water utilization• Open water systems
• Flow-through-Water enters pond or series of ponds andexits with/without treatment
-
-
Water Sources
••• Rivers, lakes and streams
• Surface
••
••• Rivers, lakes and streams
• Surface
••
Springs
• Advantages
–– few or no predators
– no pathogens
• Disadvantages
–
• Advantages
–– few or no predators
– no pathogens
• Disadvantages
–
Wells• Types
––
• Advantages– no predators– no pathogens
• Disadvantages–– low O2
• Types––
• Advantages– no predators– no pathogens
• Disadvantages–– low O2
Rivers, Lakes and Streams
• Advantages
– large volumes
– inexpensive
• Disadvantages
–– excessive nutrients
• Advantages
– large volumes
– inexpensive
• Disadvantages
–– excessive nutrients
Surface
• Advantages
– inexpensive
• Disadvantages
– contaminates
–– 5-7 acre watershed
per surface acre ofwater
• Advantages
– inexpensive
• Disadvantages
– contaminates
–– 5-7 acre watershed
per surface acre ofwater
Groundwater
• Advantages
–• Disadvantages
– hard to drain
•
• removal of fish
• Advantages
–• Disadvantages
– hard to drain
•
• removal of fish
Municipal
• Advantages–– no predators–
• Disadvantages– disinfectants
•• chloramines
–
• Advantages–– no predators–
• Disadvantages– disinfectants
•• chloramines
–
Water Quantity
• Ponds
• Raceways
• Cages
• Recirculating aquaculture systems
• Ponds
• Raceways
• Cages
• Recirculating aquaculture systems
Ponds• Minimum requirement
– 13 gal/min or 50L/min peracre
• Rational
–– to replace evaporation
–
• Minimum requirement
– 13 gal/min or 50L/min peracre
• Rational
–– to replace evaporation
–
Raceways• Minimum requirement
– 500 gal/min. or 1900L/min
• Rational
––
• Minimum requirement
– 500 gal/min. or 1900L/min
• Rational
––
Recirculating Aquaculture Systems
• Minimum requirement– varies depending on size
of system–
• Rational– needed to backflush filtersduring harvesting–
–
• Minimum requirement– varies depending on size
of system–
• Rational– needed to backflush filtersduring harvesting–
–
0.8
0.6
8
6NH
NO
NO
2
3
Time Requiredfor Bio-Filter to Mature
0.6
0.4
0.2
0.02 6 10 14 18 22
6
4
2
0
Ammonia(mg/l)
Nitrites &Nitrates(mg/l)
NHNO2
3
Time in Days