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Aquaponics: Questions and Answers Brian Nerrie and Chris Mullins

Virginia State University

Hydroponics

S Growing plants without soil

S Usually in a greenhouse

S Potential for building with grow lights

Aquaculture

S Farming in water

S In ponds, cages, raceways, indoor tanks, etc.

S Intensive aquaculture: high food input

Aquaponics

S Combination of intensive aquaculture (fish farming) and

hydroponics (growing plants without soil)

So how does it work?

S Uneaten food and excreted waste

S Ammonia directly from gills and waste turned into usable nitrogen form through by bacterial mineralization

S This ammonia is in a form toxic to fish

S Conversion of ammonia to nitrite and then nitrate

S Plants take up nitrates and other nutrients

S Water goes back to

the fish cleaner

S Ecosystem

sustained: fish,

plant, and bacteria Solid waste captured by filters

and discharged from system

System Requirements

S Location

S Fish

S Source

S System Design

S Health

S Post-Harvest

S Plant

S Seed Source

S Systems Design

S Insect and Disease Management

S Back-up Power

S Greenhouse

S Cooler

S Freezer

S Material Storage

S Biosecurity

S Processing

Fish Tank

S Aquaria

S Wood Tank

S Fiberglass

S Drums

S Polyethylene

Biofilter

Ammonia

Nitrite

Nitrate

Nitrosomonas

Nitrobacter

TOXIC

PLANT USABLE

Solids Filter

S Mechanical

S Clarifier

Pump

S Sump

S Centrifugal

S Air Lift

Fish/Plant Guidelines

S Media Bed System

S Example 2 ft3 pea gravel per 1ft3 of fish production area

S Float Bed System

S 7 times plant area than fish production area

S 60-80 grams of feed/m3 of float area/day

S Stock density for fish

S 0.25 – 0.50 lbs finished biomass per gallon water

MARKETS

ETHNIC MARKETS

LOCAL MARKETS

SOURCES of FISH

S Reliable hatcheries

STOCKING

• Water quality testing

• Acclimate

DENSITY

S One pound of fish per 5-10 gallons of water

S Upper limit one pound per three gallons

S Key factor: Feeding Rate recommendations

S Raft system: 60 – 100 g/m2/day

S NFT system: 25% of raft system

FEEDING

S Feed size and quality depend on species

S Commercially Available Fish Food (28-50% Protein)

S Floating (for observation)

S Pellet size (mouth size of fish)

S Feed Conversion: <2:1

S Limit: Provide the amount consumed in 5 min.; Do not overfeed

S If feed is not consumed, stop feeding

S There is no USDA certified organic fish

TILAPIA

S Optimum Temperature: 82-86oF; (eating slows at 75°F and die

at 50°F)

S Positive characteristics: Omnivorous, Palatable, Hardy

S Temperature: 80-100°F, 85°F is optimal

S Dissolved Oxygen: 5-7 ppm (parts per million)

S pH: 7-7.5

Other Fish

S Rainbow Trout

S Koi

S Bluegill

S Goldfish

S Catfish

S *Freshwater Shrimp

TILAPIA FEEDING

S Higher protein level for fry

S Adults do well on 32% crude protein

S Floating pellet

(Wing-Keong Ng)

Stomach with pH <2

Anal opening

Very long intestine

(affnansquaponics.com , Malaysia)

MONO-SEX PRODUCTION

Tilapia males grow faster than females

Systems for producing all-male populations

1. Selecting only males from normal

populations

2. Hormonal Sex-reversal

3. Genetic all-male production

RACOCY’S RULES +

S Follow feeding rate calculations

S Raft system: 60-100 g/m2/day

S NFT system: 25% of raft system

S Keep feed input constant

S Supplement with calcium, potassium

and iron

S Remove solids: 25% of feed ends up as

waste

S Oversize pipe system

S Be careful with aggregates

S Water Quality

S Temperature

S Dissolved Oxygen (use excess aeration)

S Ammonia

S Control pH

S Have adequate biofiltration; NFT has less surface area than raft system so NFT needs biofilter

S Use only one pump at system low point for efficiency and have back up system

Harvesting and Handling

S With care

S Ice

S Clean

S HACCP

Greenhouse

S Single

S Gutter Connected

S Plastic

S Glass

S Hard Panel

Grow Bed

S Float

S NFT

S Media Bed

S Bag

What crops can be grown?

S Lettuce

S Herbs

S Tomato

S Pepper

S Cucumber

S Cut flowers

Lettuce

S Plant varieties

Bibb types - Rex, Ostinata

Red Oak leaf, Romaine

S Substrate

Rockwool

Oasis

S Crop time – approximately 35-40 days seed to harvest, 9 to 11 crops/year

What types of systems?

S Nutrient Film Technique (NFT)

S Float Bed or Raft System

S Ebb and Flood

NFT System

NFT Lettuce

Float/Raft

Media Bed

Tips for Growers

S Use a feeding rate ratio for design calculations

S Keep feed input relatively constant

S Supplement with calcium, potassium and iron

S Use oversize pipes

S Use biological control

S Control pH

pH

S Adjust slowly

S Keep around pH = 5 (for

plant, fish and bacteria)

S pH will drop due to

respiration forming

carbonic acid- add KOH or

CaOH

pH

S Nitrification most efficient at pH >7.5

S Nitrification ends at pH <6.0

S Nitrification is an acid producing process

S Monitor daily and add base as needed: CaOH or KOH

S Nutrient solubility optimum at pH <6.5

S Therefore, compromise to pH = 7.0

Post-Harvest

S Lettuce – root off-on, clamshell,

vacuum cool 32° F

S Tomato – room cooling, 50°F

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Good Agricultural Practices (GAP)

S Key Areas S Human sanitation

S Safe produce harvest

S Managing warm-blooded animal feces

S Water source

S Prevention of zoonosis

S Waste water disposal

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Zoonosis Prevention

Human Sanitation

S Cover wounds before handling fish or fish system water

S Wash hands after contact with system water

S Wear gloves when handling or other personal protective equipment as appropriate

S Be mindful of what you have touched before harvesting

S Wash hands with liquid soap, rinse, use potable water, dry with single use paper towels

S Glove use

S Wash after every time after using bathroom, eating, smoking, changing diapers, handling fish, touching head (mouth, nose, ear, hair)

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Harvesting Produce Safely

S Keep harvest bins, cutting utensils, produce-contact surfaces clean

S Examples S Toilet within 5 minute walk

S Sink with potable water and single use towels

S Covered trash can

S Rinse produce in potable water

S Labeling produce containers with farm name, address, phone number, product name, date, and location of harvest

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Managing Warm-Blooded Animal Feces

S Keep animals (birds, dogs, rats, sheep, goats, ducks, cattle,

pigs, etc.) from you commercial produce area

S Tanks off the ground will help

S Remove all contaminated produce and dispose of after

harvested product has been removed

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Food Safety Modernization Act

S Small farm exemption - $25,000, compliance dates ramp in

S Qualified exemption

S Agriculture Water with covered produce

S Agriculture water that does not or is not intended to come in

contact with harvested portion of produce is not considered

agriculture water.

S Otherwise must meet the applicable water standards for

agriculture water.

S Growth media – Subpart F

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Resources

S https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/105/

S ATTRA: Aquaponics: Integration of Hydroponics with Aquaculture

S http://www.ctahr.hawaii.edu/oc/freepubs/pdf/FST-38.pdf

S https://aquaponics.com/

S http://www.aquaticeco.com/

S http://www.growingpower.org/aquaponics.htm

S http://www.youtube.com/watch?v=jV9CCxdkOng

S http://aquaponics.com/media/docs/articles/Ten-Guidelines-for-Aquaponics.pdf

S

Thanks

Questions?