1. WATER IN AQUACULTURE SYSTEMS
To a great extent water quality determines the success or failure of a fish farming operation 3

2. WATER IN AQUACULTURE SYSTEMS
Fish perform all
bodily functions in water
Eat
Breathe
Take in and lose salts 4

3. Water Balance in Freshwater Fish
Salts
Ammonia
Large quantities
of dilute urine 19

4. Water Balance in Saltwater Fish
Drinks
sea water
Ammonia
Small quantities of
concentrated urine 20

5. Inadequate water quality causes more losses than any other problem!
Water Resources
Water quality
Water quantity
Water sources
Inadequate water quality causes more losses than any other problem!

6. WATER IN AQUACULTURE SYSTEMS
Physical
Temperature
Chemical (“No effect” limits)

7. Physical Characteristics of Water
WATER IN AQUACULTURE SYSTEMS
Physical Characteristics of Water
“Universal solvent” 5

8. Dissolved Oxygen Importance Solubility Safe levels
highest cause of mortality
Solubility
variables
Safe levels
> 5mg/l

9. Projected Dissolved Oxygen
Levels for Ponds 7
Measured values 6 5
mg/l 4
Projected values 3 2 1
5 pm
10 pm
5 am 24

10. Uniform dissolved O in pond2 29

11. High dissolved oxygen (warm) Low dissolved oxygen (cool) Decomposing
materials 30

12. Turnover
Turnover
Low dissolved oxygen -
possible fish kill 31

13. Relationships

14. Percent of Total Ammonia in the Un-Ionized Form at
Various Temperatures and pH
Percent Ammonia
Temperature (F) (pH) 25

15. Nitrification NH3 NO2- NO3-
nitrosomonas
nitrobacter
NO2-
Requires 3 moles oxygen to convert one mole of ammonia to nitrate

16. Dissolved Gasses Problem gasses Problem sources Nitrogen (primarily)
Popeye/exophthalmia
dorsal view
Problem gasses
Nitrogen (primarily)
Problem sources
Wells and Springs
leaky pipe

17. WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
Requirements are based on temperature-dependent and size-dependent standard metabolic rates for fish

18. WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
Suggested replacement times
Linear
Noncirculating –
Circulating
Suggested water velocity rates
Circulating -

19. WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
Flow measuring techniques
Flow meters
Pond filling time – not very accurate

20. WATER IN AQUACULTURE SYSTEMS
Water quantity parameters
  Weir gauges
Sharp-crested – if outfall consists of dam boards
V-notch
Trapezoidal   

21. WATER IN AQUACULTURE SYSTEMS
Pre-Use treatment
Sediment removal
  Settling basin/pond –
  Filtration –
Gas stabilization (O2 and/or N2)
  Slatted inflow boards 3

22. WATER IN AQUACULTURE SYSTEMS
Pre-Use treatment
Sterilization
  Ultraviolet –
  Chlorination-de-chlorination –
Temperature control
Heating
  Chilling 3

23. WATER IN AQUACULTURE SYSTEMS
Water utilization
Open water systems
  Flow-through
Water enters pond or series of ponds and exits with/without treatment 3

24. Water Sources
Rivers, lakes and streams
Surface

25. Springs
Advantages
few or no predators
no pathogens
Disadvantages

26. Wells
Types
Advantages
no predators
no pathogens
Disadvantages
low O2

27. Rivers, Lakes and Streams
Advantages
large volumes
inexpensive
Disadvantages
excessive nutrients

28. Surface Advantages inexpensive Disadvantages contaminates
5-7 acre watershed per surface acre of water

29. Groundwater
Advantages
Disadvantages
hard to drain
removal of fish

30. Municipal Advantages no predators Disadvantages disinfectants
chloramines

31. Water Quantity
Ponds
Raceways
Cages
Recirculating aquaculture systems

32. Ponds Minimum requirement 13 gal/min or 50L/min per acre Rational
to replace evaporation

33. Raceways
Minimum requirement
500 gal/min. or 1900L/min
Rational

34. Recirculating Aquaculture Systems
Minimum requirement
varies depending on size of system
Rational
needed to backflush filters
during harvesting

35. for Bio-Filter to Mature
Time Required
for Bio-Filter to Mature
0.8 8 NO 3
0.6 NO 6 2 NH 3
Nitrites &
Nitrates
(mg/l)
Ammonia
(mg/l)
0.4 4
0.2 2
0.0 2 6 10 14 18 22
Time in Days 22