Aquaponics Animal Side: Stocking Densities, Water Exchange, and Food Safety

D. Allen Pattillo Aquaculture Extension Specialist Iowa State University

MOST IMPORTANT Humans Eat A COMPONENTS: Lot of • CARBS Food • PROTEINS • LIPIDS Protein Sustains Life

A 200 lb person needs 74 grams of protein daily to maintain adequate health Animal Protein Content

Fish is an excellent source of Protein !

Protein Animal Content

Beef 36%

Pork 25%

Poultry 30%

Fish 20-26%

Protein to Calorie Ratio 1g protein per 4.5 calories

Ramioverfishing.blogspot.com Young fish

Fish harvest from a cage

Fish feed pellets Harvesting fish from a pond Declineof theempire.org

U. S. Balance of edible seafood trade in 2010 The US imports 91% of its Seafood, about half from Aquaculture.

www.fishwatch.gov • Each aquaculture job creates 4 other industry-related jobs

• $1 aquaculture farm gate value creates $6 in the overall economy

According to the National Aquaculture Association

Types of Aquaculture • Food • Bait • Ornamentals • Stock Enhancement • Sport • Fee Fishing Species Options • Yellow Perch • Catfish • Trout • Tilapia • Bluegill/Hybrids • Largemouth Bass • Hybrid Striped Bass • Freshwater Prawn • Paddlefish • Ornamentals

Aquaculture is Limited

• Water quality and quantity • Growing Season • Effluent mitigation • Energy inputs • Markets • Feed Costs • Fry/fingerling availability • Labor What is Aquaponics?

Aquaculture Hydroponics  90% Less water consumption  Nutrient management/ effluent mitigation  Soil pathogens eliminated  Plants grow 2x as fast  Plants can be grown at desired height  Year round production possible  No weeding!!!!  75% smaller footprint  Less space required per plant  Vertical production allows more efficient use of space  Prolonged individual plant life Where is aquaponics done? Recommended Water Temperatures

• Channel catfish • 25-30 °C • Largemouth Bass • 17-27 °C • Striped bass • 17-24 °C • Walleye • 9-25 °C • Rainbow Trout • 10-17 °C 0.25 - 1.0 kg 0.35 – 1.38 kg Oxygen CO2

0.25 - 0.5 kg 1 kg Feed Waste Solids

0.18 - 0.4 kg 0.025 - 0.055 kg Alkalinity NH3 & NH4

15 NO3

NO2

TAN

0 40 time (days) • Biofiltration is critical for the conversion of toxic ammonia to the nitrate plant fertilizer • Best to over-size the biofilter • Options: • Trickling biofilter • Fluidized bed • Rotating contact biofilter Tanks Tons of choices! • Choose the most appropriate tank for the scale of your operation • Tank size and shape is dependent on fish and plant species and harvest style • 40-gal square tanks are 20% of system volume at ISU Pumps • Efficiency is key! • Use one pump and let gravity do the rest • Always have a backup pump!!! • Impeller pumps • Inline • Submersible • Mag-drive • Airlift pumps • Blower • Compressor • See “Paradigm shift with Airlift” https://learn.extension.org/events/1064 Water

• Water is heavy! • ~8.35 lb/gal • 1 kg/L • Take advantage of gravity flow whenever possible • Put tanks on the ground or support them adequately with good construction materials • Can be sold as fertilizer or fish emulsion Water Quality Requirements

• Critically important to the survival of fish • Different for fish of different size and species • Should be monitored on a daily or weekly basis Dissolved Oxygen

• Importance • highest cause of mortality • Solubility • variables • temperature (-) • elevation (-) • salinity (-) • Safe levels • greater than 5 mg/L • Varies w/ species Dissolved Oxygen Depletion

• Overstocking • Overfeeding • Equipment failure • Signs • Fish go off feed. • Fish gasping for air at the surface. • Large fish die first. Treatment for D.O. Depletion

• Monitor DO levels = Key! • Use emergency aeration. • Flush with fresh oxygenated water. • Stop feeding until levels increase. Excess Carbon Dioxide

• Causes • High stocking densities • Chemically produced with low pH • Symptoms • Listless or lazy fish at surface of water. • Similar to low DO. • Treatment • Aeration • Add carbonate buffers. pH

• Measure of the hydrogen ion concentration • 1-14 scale • less than 7 acidic • greater than 7 basic • Optimal for aquaponics is 6.5 - 7 Causes of Ammonia Toxicity

• Nitrification • Decomposition of fish waste • Decomposition of uneaten food • Decomposition of bacteria • Breakdown of chloramines Symptoms of Ammonia Toxicity • Symptoms • Fish swim erratically. • Fish may quiver when netted. • Treatment • Reduce pH. • Reduce temperature. • Decrease stocking density. • Use biological filtration • Flush in fresh water. Nitrite

- • Nitrite (NO2 ) is the intermediate product in the breakdown of ammonia to nitrate (nitrification) • Nitrite levels greater than 0.60 mg/L toxic to fish Symptoms of Nitrite Toxicity

• Symptoms • Brown blood and gills • Listless or lazy fish • High mortality • Treatment • Use biological filtration. • Increase chloride levels to greater than 7:1 ration. Nitrate

- • Nitrate (NO3 ) is the final breakdown product in the oxidation of ammonia • Nitrate is relatively nontoxic to fish at concentrations up to 300 mg/L Alkalinity/Hardness

• Alkalinity • Buffers against pH swings

• Desirable range – 50-150 mg/L CaCo3 • Hardness • Measure of divalent cations • Calcium, magnesium • Essential to metabolism of aquatic animals • Ca important to shrimp molting • Recommended hardness levels

• 75-250 mg/L CaCo3 Water Quality Testing • Daily or weekly tests • Semi-annually or annually

SOP Considerations for Recirculating Aquaculture • Fish Husbandry • Biosecurity • Fish Health • Feeding • Water Source • Water Quality • Effluent Management • Infrastructure Management • Labor Fish Husbandry • Fish Husbandry is the overall process for care given to the fish in aquaculture • Good fish husbandry practices reduce stress and allow for maximum growth rates • Handling should be • Avoid dropping fish gentle • Acclimate fish to avoid • Avoid sharp edges on sudden changes in equipment temperature and pH • Wear protective gloves • Maintain optimal water quality for the fish Biosecurity • Preventions is best! • No foreign water, soil, fish, plants, nets, hands, etc. • Regular sterilization of surfaces and equipment • Maintaining healthy water • Regular solids removal • Ultraviolet light sterilization • O-Zone sterilization Disinfection Tools Ozone Ultraviolet Irradiation Fish Health Check Early & Check Often • Monitor and record fish behavior daily – Monitor fish for lesions or erratic swimming behavior – Inform a fish health professional immediately regarding abnormal fish behavior Common Disease Issues Feeding Don’t Be Impressed by Fish at High Densities

Fish can be held at high density with low feed even in a poorly designed system Be Impressed by High Feed Rates Per Day!

Remember it Takes Feed to Grow Fish

Daily Weight Gain = Daily Feed Rate / FCR Water Source HAVE YOUR WATER TESTED BEFORE SETTING UP A SYSTEM!!! Municipal Water – De-chlorinate • May contain chlorine or chloramine – TOXIC to fish • Chloramine must be broken up with a sulfur compound • Sodium sulfite or Sodium thiosulfate Well Water - Aerate • May contain pesticides, contaminants, or toxins

• Will likely be low DO and high CO2 Rain Water – Re-mineralize • Low hardness and may be affected by acid rain • May need to add ocean salt for fish osmotic balance (0.25 – 1 ppt) Surface Water - Disinfect • May contain pesticides, contaminants, or toxins • May contain diseases, algae, fungi, fecal coliforms, etc. Water Quality Daily Testing • Dissolved oxygen (DO) • Temperature • pH • Total ammonia nitrogen (TAN) Weekly Testing • Nitrite • Nitrate • Alkalinity • Carbon Dioxide Management of Bio-Filters • Live bacteria need time and resources to establish • ~ 1 month • Ammonia 15 • Nitrite NO3 • Alkalinity

• Easy to kill NO2

TAN

0 time (days) 40 Solid Waste Removal • Solids must be removed quickly for optimal water quality • Tank design is critical - Double stand- pipe design helps remove waste in round tanks Effluent Management Wastewater Treatment Discharge is regulated by the Iowa Department of Natural Resources (IA DNR)

Land Application Check with your state natural resource agency or extension service for details Infrastructure Management Tanks

• Check tanks daily to ensure proper function • Leaks or clogs can cause water loss and dead fish Infrastructure Management Mechanical Filters

• Make sure the filter screen removes the particles desired without clogging • Have a regular schedule of backwashing to prevent clogging Infrastructure Management Biofilters

• Ensure the biofilter maintains water and air movement • Clean clogged biofilter media to enhance Biofiltration capacity Infrastructure Management Aerators • Have a backup aerator in place and ready to go • Airstones may clog, and can be cleaned by soaking in acid Infrastructure Management Pumps Always have a backup pump! • Impeller pumps – Inline – Submersible • Airlift pumps – Blower – Compressor Infrastructure Management Feeders

• Check and clean automatic feeders often • Moldy feeds contain mycotoxins that affect fish health and growth • Make sure feeders deliver the correct amount of feed Infrastructure Management Emergency Water • Power outages or water quality emergencies may kill fish quickly • Maintain enough water to perform one full water exchange Labor • Train employees for their designated task • All employees should be trained in biosecurity practices and on critical tasks for emergencies • Have copies of standard operating procedures available for employees to reference • Have workers regularly record observations and report those to the facility supervisor • Weekly business meetings should be held to inform all employees of current issues Fillet Species Protein Tuna 26% Salmon 26% Halibut 26% Snapper 26% Perch 25% Flounder 25% Cod 24% Tilapia 20%

Feed Requirements

• Feedings should be given in 2-5 equal rations throughout the day • Fingerlings 10-15% of biomass • Adults 2-3% of biomass • Ensure the proper feed is given for the age and species of fish Tilapia Feed • Floating • 3.0 MM Diameter • 35% Protein • 5.0% Fat • 4.5% Fiber Effects of Feed on Water & Nutrients • 60 to 100 grams of 35% protein feed per day is needed to support 1 square meter of plant growing area in floating raft culture • Feed inputs must be kept constant to supply the needs of the plants in continuous culture Effects of Water Exchange

Water exchange decreases: • Turbidity • Organics • Bacteria & Pathogens • Biological Oxygen Demand • Toxins • Plant Nutrients • Water Temperature (typically) Winter Water Consumption (gal)

Treatment 19 Days 27 Days Rockwool Blocks 84 146 Floating Raft 77 145 Pea Gravel 74 128

Typical RAS Culture 285 405 *10% Exchange Daily

* Assuming 150 gallons per system Cumulative Water Usage 400

350

300

250

200 Green 10% Exchange White 150 5% - Exchange

Blue 0% - Exchange CumulativeWater Usage (gal) 100

50

0

Date Species Grown

Nile Tilapia, Oreochromis niloticus

Buttercrunch Bibb Lettuce Italian Largeleaf Basil Fish Growout

Start Weight (g) 110.3 ± 30.5 Start Length (mm) 182.6 ± 15.9 Growout Period (weeks) 16 Sex All Male Density (kg/m3) 23.0 ± 6.2 Individual Harvest Weight Goal (kg) 0.680 – 0.908 Fillet Yield 32-35% Fresh Fillet Retail Price ($/kg) $15.36 (on sale) Fish Growth

Individual Wt Daily Growth Biomass Treatment %Growth Gain (g) (g/day) Gain (kg) FCR Floating Raft 67.6 1.83 61 2.01 1.35 Pea Gravel 73.7 1.99 64 2.20 1.24

Rock-wool 69.1 1.87 65 2.17 1.23

~Survival 100% throughout~ No real differences in growth Basil Preferred1,2 Pea Gravel Floating Raft Rockwool Requirements Nutrient Concentration (mg/L)

+ Ammonia (NH4 ) 2.2 0.0 - 4.97 0.128 - 2.04 0.088 – 0.856

Nitrate (NO3) 0.4-82.2 20.2 – 24.2 35 - 111 25.3 - 110

Nitrite (NO2) 0.7 0.08 – 7.54 0.0-2.14 0.084 – 1.42

Alkalinity (CO3) 113.2 42 - 96 43 - 240 26 - 93

Calcium (Ca) 10.7-82.1 491 – 726* 150 – 780* 452 – 727*

Phosphorus (P) 0.4–15.3 0.807 – 4.97 1.68 – 40.1 1.05 – 6.05

Iron (Fe) 0.13–4.3 0.04 – 0.536 0.145 - 0.688 0.21 – 0.509 pH 7.1 - 7.4 6.53 - 8.12 5.43 – 7.9 6.39 – 8.04

Dissolved Oxygen (DO) 4.0 - 5.0 3.29 – 8.15 2.55 – 8.01 5.0 - 8.2

Temperature (°C) 29 - 31 19.4 – 27.6 21.2 – 28.8 17.4 - 26.9

* Total Hardness measured 1 – Rakocy, J., Shultz, R.C., Bailey, D.S. and Thoman, E.S. 2004. AQUAPONIC PRODUCTION OF TILAPIA AND BASIL: COMPARING A BATCH AND STAGGERED CROPPING SYSTEM. Acta Hort. (ISHS) 648:63-69 2 – Rakocy, J. 2011. Aquaponics Q and A. Nelson and Pade, Inc. Tilapia Harvest Tilapia Harvest Size and Value

Retail Production Average Biomass % Fillet Treatment Value Value weight (g) (kg/m^3) Yield ($/kg) ($/m^3) Pea 345.2 39.3 35% $15.36 $211.42 Gravel Rockwool 376.5 43.3 35% $15.36 $232.56 Cubes Floating 390.7 44.5 35% $15.36 $239.28 Raft

Food Safety Aspects

• E. coli – not considered to be a problem because fish are cold blooded and cannot harbor the bacteria in their gut • Salmonella spp. – potential issue and can be found on plant surfaces because of splashing water • Aeromonas spp. – common fish disease that can transfer in humans. Is found commonly in aquaponics Food Safety Practices

• Wear disposable gloves when handling fish and produce • Keep fish and plants separated by a physical barrier like a wall or curtain • Avoid lifting floating rafts and dripping water on other plants • Disinfection methods for water being investigated • Solids removal is critical because the dissolved organics provide food for the bacteria Questions?