Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA


Teng Yang1,* and Hye-Ji Kim1

1 Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907

* Current address: School of Applied and Interdisciplinary Studies, Kansas State University, Olathe, KS 66061,


Aquaponics is a form of aquaculture that integrates soilless crop production (hydroponics) to raise edible plants and fish. The fish are fed and excrete waste, which is broken down by bacteria into nutrients. Plants utilize some of these nutrients and in the process filter the water in the system. According to former study, we found that initial nutrient levels may make a big influence on crop growth rate, so during this study fish were fed once per day under two feeding scheme (daily uniform feeding (DUF) and daily increasing feeding (DIF) by 1% fish FW) in order to figure out initial nutrient requirement for aquaponics crops. Two feeding schemes had the same total monthly feeding amount, so initial nutrient level (60 g and 40 g/day) and nutrient accumulation rate (0 g and 5 g increment/day) were the only variances. Ten different vegetable crops (pac choi, mizuna, mustard, amaranth, bekana, Swiss chard, chia, basil, lettuce, and tomato) were planted under cultivation of Blue tilapia (Oreochromis aureus) in recirculating aquaponics systems over a 30-day trial. The mean feed conversion ratio (FCR) values for two feeding schemes were 1.08±0.65 and 0.92±0.26, respectively. The electrical conductivity (EC) values of two feeding schemes increased over time. DUF showed higher EC values although there was no significant difference compared to DIF. Orthophosphate, total ammonium nitrogen (TAN), nitrate, pH and dissolved oxygen (DO) levels were not significantly different between treatments. Data showed that DUF resulted in a significant lower water consumption than DIF after 15 days of transplant, which may a result of lower Gs (transpiration rate) values.  There were no significant differences in weekly growth rate (height, leaf length, leaf number, SPAD) and harvest fresh weight between treatments. The instantaneous photosynthetic rate of pac Choi, swiss chard, lettuce, and amaranth in DUF increased over time and showed significant higher values than DIF by the end of study. Results of this study showed the potential effect of initial nutrient level on the aquaponics production of vegetable crops.