Aquaponics: Comparing Walleye & Tilapia Production

Chris Hartleb Department of Biology

Northern Aquaculture Demonstration Facility Aquaponics Innovation Center

Aquaponics

• Aquaponics is an integrated, soilless system for raising fish and plants.

• Benefits: • Sustainable and natural • Free of pesticides, herbicides and chemical

fertilizers • Highly efficient • Conservative uses of resources, water, space and

labor • Produces both a protein and a vegetable crop

from one integrated system • Continuous production of food 365 days per year

Aquaponics Future

“There is a lack of scientific literature when it comes to aquaponic experiments on large-scale and during long-time sequences. Moreover, many experimental setups published are small-scale without replicates. Experiments covering bigger production systems exist, but they are performed by private research centers or companies, whereby confidential findings are not always made accessible to third parties.”

Economic Considerations

• Tilapia fillet: $2 - $4 per pound (retail) • Walleye fillet: $9 - $16 per pound (retail)

Aquaponics Innovation Center Montello, WI

UWSP-Aquaponics Innovation Center

Nelson and Pade, Inc.® Demonstration

Greenhouse

Aquaponic Systems

Fish tanks

Clarifier (solids filter)

Mineralization tanks

Raft tank Water pump

Degassing tank

Air pump

Overview of Systems

Fish Culture

Clarifier, Mineralization, Bioreactor & Degassing

Plant Culture

Tilapia Culture factor Range

Temperature 64 - 90oF (17 - 32oC)

Dissolved oxygen 3 – 10 mg/L

pH 7 – 8

Ammonia-N 0 – 0.04 mg/L

Nitrite-N 0 – 0.8 mg/L

Hardness 50 - 350 mg/L

CO2 0 – 30 mg/L

Walleye Culture factor Range

Temperature 68 - 75oF (20 - 24oC)

Dissolved oxygen 5 – 6 mg/L

pH 6 – 9

Ammonia-N 0 – 0.02 mg/L

Nitrite-N 0 – 0.2 mg/L

Hardness 50 - 350 mg/L

CO2 0 – 10 mg/L

Why it Works • Optimal ratio between fish and plants

– Balance between fish nutrient production and plant uptake – Feeding rate ratio

• 60-100 g/day/m2 for leafy greens grown on rafts • Right balance is needed based on:

– Type of fish – Plant growth platform – Type of plant (leafy vs fruiting) – Chemical composition of water

• Controlled environment agriculture = year-round production

Fish Plants

Phosphorus Phosphorus

Manganese Manganese

Copper Copper

Iron Iron

Potassium Potassium

Calcium Calcium

Magnesium Magnesium

Zinc Zinc

Cobalt Boron*

Selenium Molybdenum*

Iodine Sulfur*

Protein Nitrogen

Tilapia Growth

Market size

Walleye Growth

Variability in Growth

Market Considerations

• Tilapia, 1½ pounds = 680 grams – Projected fry to market = 297 days (10 months)

• Walleye, 1 pound = 454 grams – Projected fry to market = 1 year 10 months

Tilapia Walleye

Stocked (Harvest goal)

164/system (0.5 lb/gallon, Total 492)

166/system (0.42 lb/gallon, Total 498)

Survival 99% 81%

% Fillet size 41% 1½ pounds

14% ½ pound

Pounds of fillet 80 20

Price/pound of fillet $4/lb $9/lb

Actual value $320 $180

Estimated value 193 lb of fillet = $773 116 lb of fillet = $1,044

Plant Production (Yield)

0200400600800

1000120014001600

Tota

l yie

ld (g

)

Kale

Tilapia Walleye

0.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

Tota

l yie

ld (g

)

Broccoli

Tilapia Walleye

0.001000.002000.003000.004000.005000.006000.007000.008000.00

Tota

l Yie

ld (g

)

Romaine lettuce

0.001000.002000.003000.004000.005000.006000.007000.00

Tota

l yie

ld (g

)

Pac Choi

Average Plant Biomass

0

5

10

15

20

25

Aver

age

plan

t bio

mas

s (g)

Kale TilapiaWalleye

05

101520253035404550

Aver

age

plan

t bio

mas

s (g)

Broccoli

-20

0

20

40

60

80

100

120

140

Aver

age

plan

t bio

mas

s (g)

Romaine lettuce

-10

0

10

20

30

40

50

60

70

80

90

Aver

age

plan

t bio

mas

s (g)

Pac Choi

Root:Shoot Ratio

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016

Root

:Sho

ot R

atio

Kale

Tilapia Walleye

0

0.05

0.1

0.15

0.2

0.25

8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016

Root

:Sho

ot R

atio

Broccoli

Tilapia Walleye

0

0.05

0.1

0.15

0.2

0.25

8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016

Root

:Sho

ot R

atio

Romaine lettuce

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016

Root

:Sho

ot R

atio

Pac Choi

Plant Harvest

• Plant yield did not significantly differ between tilapia and walleye systems • Nor did it differ for plant biomass and root:shoot ratio

Nutrient Differences No differences • Micronutrients

– Iron – Molybdenum – Copper – Nickel

• Macronutrients – Calcium – Sulfur – Magnesium

Water quality • Alkalinity

– Similar: 188 – 184 mg/L • Hardness

– Similar: 260 – 244 mg/L • pH

– Similar: 7.6 – 7.8 • Temperature

– Similar: 23 – 21oC (73 – 70oF)

0

10

20

30

40

50

60

Phos

phor

us (m

g/L

PO4-3

P

Phosphorus (T) Phosphorus (W)

0

20

40

60

80

100

120

140

160

Pota

ssiu

m (m

g/L

K+

Potassium (T) Potassium (W)

Nutrient Differences

00.10.20.30.40.50.60.70.8

NH 3

-N (m

g/L)

Ammonia (T) Ammonia (W)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

NO

2-N

(mg/

L)

Nitrite (T) Nitrite (W)

0

5

10

15

20

25

30

NO

3-N

(mg/

L)

Nitrate (T) Nitrate (W)

Summary • Differences in nutrients in tilapia and walleye aquaponic systems related

to composition of feed and fish absorption efficiency. – Levels within acceptable limits for both.

• Plant production did not differ between systems. • Tilapia production to market-size accomplished in 10-12 months. • Walleye production to market-size accomplished in >1 year 10 months.

Hybrid Walleye

Harvest in 307 days (10 months)

Harvest in 462 days (1 year 3 months)

Harvest in 392 days (1 year 1 month)

Aquaponics as a Commercial Industry Status - • Small but rapidly growing industry –

experiencing exponential growth. • Driven by:

• Food security & Food quality • Locavore movement • Limited fresh water and land

Industry Needs - • Aquaponic education

• Enthusiasm > Knowledge

• Employment opportunities

• Currently have:

• Large commercial ventures

• Students pursuing careers in aquaponics

• Research in crop diversity, system efficiency & economics

Aquaponics survey respondents by zip code (Love et al. 2014. PLoS ONE 9(7).)

Education/Outreach

Summary / Contacts

• UW-Stevens Point Aquaponics Innovation Center – Professional aquaponics certificate – Three college courses (semester long) – Internship opportunities – Collaborative research – http://www.uwsp.edu/aquaponics