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 Nelson and Pade, Inc. Demonstration Greenhouse UWSP-Aquaponics Innovation Center
Aquaponic Systems Fish tanks Water pump Raft tank Air pump Clarifier (solids filter) Mineralization tanks Degassing tank
Overview of Systems
Fish Culture
Clarifier, Mineralization, Bioreactor & Degassing
Plant Culture
Tilapia Culture factor Range Temperature 64-90 o F (17-32 o C) Dissolved oxygen 3 10 mg/l ph 7 8 Ammonia-N Nitrite-N Hardness CO 2 0 0.04 mg/l 0 0.8 mg/l 50-350 mg/l 0 30 mg/l
Walleye Culture factor Range Temperature 68-75 o F (20-24 o C) Dissolved oxygen 5 6 mg/l ph 6 9 Ammonia-N Nitrite-N Hardness CO 2 0 0.02 mg/l 0 0.2 mg/l 50-350 mg/l 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/m 2 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 Phosphorus Manganese Copper Iron Potassium Calcium Magnesium Zinc Cobalt Selenium Iodine Protein Plants Phosphorus Manganese Copper Iron Potassium Calcium Magnesium Zinc Boron* Molybdenum* Sulfur* 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 Stocked (Harvest goal) Tilapia 164/system (0.5 lb/gallon, Total 492) Walleye 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) Kale Broccoli Total yield (g) 1600 1400 1200 1000 800 600 400 200 0 Total yield (g) 3000.00 2500.00 2000.00 1500.00 1000.00 500.00 0.00 Tilapia Walleye Tilapia Walleye Romaine lettuce Pac Choi Total Yield (g) 8000.00 7000.00 6000.00 5000.00 4000.00 3000.00 2000.00 1000.00 0.00 Total yield (g) 7000.00 6000.00 5000.00 4000.00 3000.00 2000.00 1000.00 0.00
Average Plant Biomass Average plant biomass (g) 25 20 15 10 5 0 Kale Tilapia Walleye Average plant biomass (g) 50 45 40 35 30 25 20 15 10 5 0 Broccoli Average plant biomass (g) 140 120 100 80 60 40 20 0-20 Romaine lettuce Average plant biomass (g) 90 80 70 60 50 40 30 20 10 0-10 Pac Choi
Root:Shoot Ratio Kale Broccoli 0.4 0.25 Root:Shoot Ratio 0.35 0.3 0.25 0.2 0.15 0.1 0.05 Root:Shoot Ratio 0.2 0.15 0.1 0.05 0 8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016 0 8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016 Tilapia Walleye Tilapia Walleye 0.25 Romaine lettuce 0.14 Pac Choi Root:Shoot Ratio 0.2 0.15 0.1 0.05 Root:Shoot Ratio 0.12 0.1 0.08 0.06 0.04 0.02 0 8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016 0 8/1/2015 9/1/2015 10/1/2015 11/1/2015 12/1/2015 1/1/2016 2/1/2016
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 Phosphorus (mg/l PO 4-3 P 60 50 40 30 20 10 0 Phosphorus (T) Phosphorus (W) Water quality Alkalinity Similar: 188 184 mg/l Hardness Similar: 260 244 mg/l ph Similar: 7.6 7.8 Temperature Similar: 23 21 o C (73 70 o F) Potassium (mg/l K + 160 140 120 100 80 60 40 20 0 Potassium (T) No differences Micronutrients Iron Molybdenum Copper Nickel Macronutrients Calcium Sulfur Magnesium Potassium (W)
Nutrient Differences NH 3 -N (mg/l) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 NO 2 -N (mg/l) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Ammonia (T) Ammonia (W) Nitrite (T) Nitrite (W) 30 25 NO 3 -N (mg/l) 20 15 10 5 0 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 392 days (1 year 1 month) Harvest in 462 days (1 year 3 months)
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