aw ter in aquaculture systems - universitas...

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


• 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!


Physical

Temperature

••

Chemical (“No effect” limits)

Physical

Temperature

••

Chemical (“No effect” limits)

Physical Characteristicsof Water

•

• “Universal solvent”

–


•

• “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 quantity parameters

• Requirements are based on temperature-dependent and size-dependent standardmetabolic rates for fish

•


• Requirements are based on temperature-dependent and size-dependent standardmetabolic rates for fish

•



Suggested replacement times

Linear• Noncirculating –• Circulating

Suggested water velocity rates• Noncirculating –• Circulating -


Suggested replacement times

Linear• Noncirculating –• Circulating

Suggested water velocity rates• Noncirculating –• Circulating -



Flow measuring techniques

Flow meters••

Pond filling time – not very accurate


Flow measuring techniques

Flow meters••

Pond filling time – not very accurate



Weir gauges• Sharp-crested – if outfall consists of damboards

• V-notch

• Trapezoidal••


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••


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


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 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

aw ter in aquaculture systems - universitas...

Documents