Southern Regional Aquaculture Center
AQUAPONICS
- An Integrated Fish and Plant Production System-
Jason Danaher
University of the Virgin Islands
Agricultural Experiment Station
RR 1 Box 10,000
Kingshill, U.S. Virgin Islands 00850
Southern Regional Aquaculture Center
What is Aquaponics
 Combined culture of fish and hydroponic plants in a
recirculating aquaculture system
– Aquaculture + Hydroponics = Aquaponics
– Advantages
• Plants use nutrients from fish waste to produce a marketable
product
– Hydroponic plants act as biofilter
• Integrated systems reuse nutrients, conserve water and share
infrastructure/operational cost
– Disadvantages
• Management requires knowledge of fish and plant husbandry
• Requires commercial fish diet and reliable energy source
• Moderate initial capital costs for system construction
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Overhead View of Aquaponic System
Base addition
Fish production tanks
Hydroponic tanks
Degassing
Sump
Clarifier
Net tanks
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Fish Production Tanks
 Four tanks per commercial system
 Round tank with central drain
– Water turnover rate once every 80 minutes
http://srac.tamu.edu/
Southern Regional Aquaculture Center
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Tilapia production
 Stocking and Harvesting
– Stock 600, sex reversed, male Nile
tilapia fingerlings/tank
• Average weight 50-75 grams/fish
 Tilapia Diet
– Feed a floating diet with
32% protein 3 times/day
• Feed ad libitum
• Expect FCR of 1.5 – 1.7
– Drain and harvest tank 24 weeks later  Achieve daily feeding rate of
60 – 100 grams of diet/m2 of
• Average weight 700 – 750 grams/fish
• Survival greater than 95%
hydroponic growing area/day
 Staggered production
– Allows a tilapia harvest every 6 weeks
– A total of 2 harvests from each
tank/year
– Approximately 28 – 47 lbs of
feed/day/aquaponic system
– This is optimal amount for plant
production, balances the system,
and minimizes water quality
problems
 Aeration
– 22 airstones/tank
– One, 1.5 horsepower
regenerative blower
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Staggered Production
Tank 1
Tank 2
Tank 3
Tank 4
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Harvesting a Tilapia Tank
Tank 1
Tank 2
Tank 3
Clarifier 1
Tank 4
Sump
Clarifier 2
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Tilapia Production
Marketable Nile tilapia
Feeding a Fish Tank
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Cylindro-conical Clarifier
 Function




– Primary method for solids
removal and discharge
– Baffled walls slow water
velocity
Two units per commercial
system
– Each unit receives effluent
from two fish tanks
Size
– 1,000 gallons/unit
Water turnover rate
– Once every 20 minutes =
50 gallons/minute
Sludge removed 2-3 times
daily
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Cross Sectional View of Clarifier Removing Solids
Baffled Wall
Effluent Entering Clarifier from Fish Tank
45o – 60o slope
Effluent moving to Net Tanks
to filter particulate matter
Area of concentrated settled
solids for discharge
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Effluent discharged from clarifier
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Net Tanks
 Function
– Capture suspended
solids escaping clarifier
– Allows solid matter to
leach dissolved
nutrients
 Four units per commercial
system
 Need to be cleaned 1-2
times weekly
– Cleaning affects nitrate
concentrations and
thus plant production
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Cross Sectional View of Net Tank Filtering
Suspended Solids
NO3-
Mn+
S+
Mg+2
NO3
NO3-
-
Ca+2
NO3-
NO3-
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Orchard netting in Net Tank getting
washed
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Degassing Tank
 Heavy aeration blows off nitrogen gas and hydrogen sulfide
produced in anaerobic environment of net tanks
 Distributes water to hydroponic raceways
 Nets seen prevent tilapia fry from entering hydroponic raceways
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Hydroponic Raceways
 Total of six raceways; 3 pairs
• Each raceway is 100 ft x 4 ft x 1.3 ft
• Lined with LDPE food grade liner
 Total of 72 polystyrene rafts per system; 12 rafts per
raceway
• Each raft is 8 ft x 4 ft x 1.5 in
 One, 1.0 Hp regenerative blower supplies oxygen
for plants in all six raceways
– 25 airstones per raceway with 4-foot spacing
 Water turnover rate once every 180 minutes for
each pair of raceways
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Hydroponic raceways
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Plastic Net Pots
 Net Pots
– Support seedling on
floating rafts allowing
roots to contact water
– Net pot size can vary
depending on plant
 Seedlings
– Started in greenhouse
– Grown in soilless media
and transplanted into net
pot
• Remain until harvested
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Sump
 Lowest point in system
– Water flows by gravity from fish tanks until it reaches the sump
 The sump collects water from the hydroponic raceways
before the water is pumped back to fish culture tanks
 Site for water make up due to evaporation, transpiration
and waste removal
– Float valve allows
make-up water to enter
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Base Addition Tank and Pump
 Base Addition Tank
– Function
• Site for chemical base
addition to maintain
optimum pH
• Slowly adds base to sump
via vigorous aeration
• Site for nutrient
supplementation
 Pump
• Returns water from
sump to fish culture
tanks
– Pumps 100
gallons/minute
http://srac.tamu.edu/
Southern Regional Aquaculture Center
pH and base addition
 Must compromise pH for fish, plants and
biofiltration
– Fish prefer 7.5 – 8.5
– Plants prefer 6.0 – 6.5
– Nitrifying bacteria prefer 7.0 – 8.0
• Maintain aquaponic system pH at 7.0
– Calcium hydroxide [Ca(OH)2] and potassium hydroxide
(KOH) increase pH when it falls below 7.0
» Calcium hydroxide and potassium hydroxide added on
alternate basis until pH returns to 7.0
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Base used to supplement nutrients
and neutralize pH
Calcium Hydroxide
Powder
Potassium Hydroxide
Prills/Flakes
http://srac.tamu.edu/
Southern Regional Aquaculture Center
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Regenerative Blowers
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Fish tank
Fish tank
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Net Tanks
Net Tanks
Clarifier
Clarifier
Sump
Effluent
Storage
Fish Tank
Fish Tank
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Plant Requirements
 Light
 Oxygen
 Temperature
– Indoor production is climate controlled
– Outdoor production is dependent on the season
 Adequate Spacing
– Dependent on the crop
 Protection
– Wind protection
– Control of pests
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Plant Requirements
 There are 16 essential macronutrients and
micronutrients for plant growth
– Macronutrients
• N, P, K, Ca, S, Mg
– Micronutrients
• B, Cl, Cu, Fe, Mo, Mn, Z
 There are recommended ranges for aquaponic
and hydroponic vegetable production
– Typically aquaponic nutrient levels are lower
than recommended hydroponic nutrient levels
• Possible because fish are always creating effluent
that passes through hydroponic raceways
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Nutrient concentration
Aquaponics vs Hydroponics
Nutrient
Aquaponics (mg/L)
Hydroponics (mg/L)
Calcium
10.0 – 82.0
150.0
Magnesium
0.7 – 13.0
50.0
Potassium
0.3 – 192.0
150.0
Nitrate
0.4 – 82.0
115.0
Phosphate
0.4 – 15.0
50.0
Sulfate
0.1 – 23.0
113.0
Iron
0.03 - 4.3
5.0
Manganese
0.01-0.20
0.5
Copper
0.01-0.11
3.0
Zinc
0.11-0.80
0.05
Molybdenum
0.01-0.23
0.05
Boron
0.01-0.17
0.5
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Nutrient Supplementation
 Tilapia effluent provides adequate levels of
macronutrients and micronutrients, but
supplementation of calcium, potassium and iron
required
 Calcium supplemented with addition of calcium
hydroxide
 Potassium supplemented with addition of potassium
hydroxide
 Iron supplemented with the addition of chelated iron to
maintain concentration of 2 mg/L
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Plant Production Methods
 Batch Culture
– One planting and one harvest of aquaponic
system during plant production period
• Can quickly deplete nutrients as plants mature
 Staggered Production
– Multiple plantings and harvests on a rotational
basis
• Prevents quick nutrient depletion
• Allows uniform nutrient uptake
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Staggered Plant Production
Hydroponic Raceways
Fish Tanks
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Harvesting a Staggered Crop
Push to end of raceway
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Lettuce Production
 Seedlings require four weeks in the greenhouse before
transplant into aquaponic system
 Harvest after four weeks in the aquaponic system
 Leaf lettuce
– Sierra 156 g/plant
– 60 seedlings/raft
 Crisphead
– Montello 149 g/plant
– 60 seedlings/raft
 Romaine
– Parris Island 204 g/plant
– 48 seedlings/raft
 Bibb
– Boston bibb 88 g/plant
– 88 seedlings/raft
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Basil Production
 Seedlings require three weeks in the greenhouse
before transplant into aquaponic system
 Harvest is dependent on management strategy
 Staggered production
– Cut and come again
– Cut at 4 week intervals
– 3 months production
• Cut 3 times then remove
 48 plants/raft
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Potential Crops
Mint
Chives
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Potential Crops
Cucumbers
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Potential Crops
Collard Greens
Pak Choi
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Potential Crops
Water Spinach
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Potential Crops
Cut Flowers & Melons
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Plant Pest Management and Control
 No Synthetic Chemical Pesticides
– Will harm fish and nitrifying bacteria
 Biological Controls Used to Control Insects
 BotaniGard
 Armicarb
 Dipel


Bacteria
Controls caterpillars


Fungus
Controls soft bodied
insects
 White flies, Aphids



Potassium bicarbonate
Controls fungus
 Powdery Mildew
Changes pH of leaf surface
making it unsuitable for fungus
growth
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Soaps and Oils
 Coats or contacts insect
causing death.
 Broad-spectrum
– Careful with beneficial insects
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Best Management Practices for Pests
 Integrated Pest Management
 Operation and Maintenance for Pesticide
Management
Environment
Disease
Pathogen
Host
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Pythium sp.
 Root fungus
– No biological control
– Low temperature reduces its growth and impact on
crop
• Not usually a factor in temperatures less than 28oC
• Like any crop there are better seasons of the year to grow
than others
– Effect is also dependent on crop variety and resistance
 Want to see clean, white roots = healthy plant
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Snails
 Not necessarily harmful to plants or fish but snails
will graze on nitrifying bacterial film under rafts
reducing biofiltration capability of system
 Red ear sunfish/Shell crackers used to control
snails in hydroponic raceways
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Principles to Remember
 Staggered fish and plant production maintains a
balanced nutrient concentration in the system
 Optimum fish feeding rate, 60 - 100 g/m2 plant
area/day prevents nutrient accumulation or
deficiency
 Frequency of net tank cleaning controls
nitrate levels through denitrification
 Base addition maintains optimal pH and
supplements nutrients
 Be vigilant in preventing, recognizing and treating
plant pests/disease
http://srac.tamu.edu/
Southern Regional Aquaculture Center
http://srac.tamu.edu/
Southern Regional Aquaculture Center
ADDITIONAL INFORMATION
•
Southern Regional Aquaculture Center (SRAC)
• SRAC Fact Sheets
• Aquaponics
• https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/105/
• Tilapia Production
• Life History and Biology
•https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/53/
• Tank Culture
•https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/52/
• Recirculating Systems and Management
• https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/103/
•
University of the Virgin Islands Aquaculture Program
• Aquaculture - International Aquaponics and Tilapia Aquaculture Course
http://srac.tamu.edu/
Southern Regional Aquaculture Center
Additional Information
http://srac.tamu.edu/
Southern Regional Aquaculture Center
ACKNOWLEDGEMENTS

University of the Virgin Islands Aquaculture Program
• Dr. James Rakocy
• Donald Bailey
• R. Charlie Shultz
• Rodolfo Castillo
• Use of the aquaponic computer-aided designs
• Owner of AQUAPONICOS de EL SALVADOR
• Located in La Libertad, El Salvador
http://srac.tamu.edu/
Southern Regional Aquaculture Center
NOTE
 SRAC fact sheets are reviewed annually by the Publications, Videos
and Computer Software Steering Committee. Fact sheets are revised
as new knowledge becomes available. Fact sheets that have not
been revised are considered to reflect the current state of knowledge.
 The work reported in this publication was supported in part by the
Southern Regional Aquaculture Center through Grant No. 200238500-11805 from the United States Department of Agriculture,
Cooperative State Research, Education, and Extension Service.
http://srac.tamu.edu/