Integrated cultivation of tambaqui (Colossoma macropomum) with coriander (Coriandrum sativum L.) grown at different plant density

The present study aimed to evaluate an aquaponic bioeconomic model integrating the cultivation of tambaqui (Colossoma macropomum) with coriander (Coriandrum sativum) at different densities of 32, 72, 128, and 512 cells m(-2) for 19 days. The hydroponic bed was configured on a bench with a capacity of 100 L (1.62 m-long, 0.72 m-width, and 0.1 m-depth) and was coupled to a plastic tank with the fish. The coriander seeds were irrigated for four days until germination, when they were transferred to the hydroponic beds. Two hundred forty tambaqui juveniles (113.5 +/- 0.15 g and 19.6 +/- 0.20 cm) were distributed in 12 tanks (1000-L capacity) in aquaponic units, totaling 20 fish per unit. The fish were fed commercial feed (36% protein and 7% lipids), and water quality variables were monitored daily. At 5, 10, and 15 days after transplanting to the hydroponic bed, the leaf number (LN) and plant height (PH, in cm) of the coriander were determined. Additionally, total fresh mass (TFM, in g), leaf fresh mass (LFM, in g), root fresh mass (RFM, in g), total dry mass (TDM, in g), leaf dry mass (LDM, in g), root dry mass (RDM, in g), leaf length (LL, in cm), root length (RL, in cm), yield of total fresh mass (YTFM, in kg m(-2)), and the nutritional composition of macro and micronutrients were determined, as well as fish growth performance. A density of 512 cells m(-2) reduced the electrical conductivity (0.097 +/- 0.001 dS m(-1)) of the water. The pH, dissolved oxygen, and temperature did not differ significantly between the densities. The total ammonia nitrogen (28.81 +/- 2.26 mg L-1) and nitrate (51.07 +/- 0.81 mg L-1) concentrations were greater at a density of 32 cells m(-2). At the end of the 19-day period, the fish growth indices did not significantly differ (p > 0.05) as a function of coriander cultivation density. Density significantly influenced coriander growth. All variables (PH with root, LL, RL, LFM, TFM, LDM, TDM, RFM, RDM, and YTFM) were significantly influenced (p < 0.05) as a function of cultivation density. YTFM (1.82 +/- 0.45 kg m(-2)), PH (30.39 +/- 0.61 cm), and LL (16.62 +/- 0.53 cm) were significantly higher (p < 0.05) at a density of 512 cells m(-2). RL was significantly higher (p < 0.05) at densities of 72 and 32 cells m(-2), of the order of 15.98 +/- 0.43 and 18.79 +/- 1.01 cm, respectively. Boron was significantly greater at a density of 512 cells m(-2) (39.70 +/- 1.04 mg kg(-1)) than at 32 cells m(-2) (29.93 +/- 4.66 mg kg(-1)). Similarly, sodium was significantly more abundant at a density of 512 cells m(-2) (5975.54 +/- 783.82 mg kg(-1)) when compared to the densities of 128 and 72 cells m(-2), which were 4179.97 +/- 287.31 and 3760.60 +/- 224.31 mg kg(-1), respectively. Aquaponic production in the equatorial Amazon region accelerated, and the optimal density for coriander integrated with tambaqui without compromising plant growth performance was 128 cells m(-2).