Figure 1.
Maximum, mean, and minimum air temperature data were monitored in the city during a study with Penaeus vannamei post-larvae in a low salinity biofloc system in winter in northeastern Brazil
Table 1.
Mean ± standard deviation of water parameters for 75 days of study with Penaeus vannamei post-larvae cultured under different stocking densities (75, 150, and 301 shrimp m−2) in a low salinity biofloc system during winter in northeastern Brazil, with four replicates
| 75 shrimp m−2 | 150 shrimp m−2 | 301 shrimp m−2 | |
|---|---|---|---|
| Temperature (°C) | 22.12±0.37 | 22.09±0.35 | 22.17±0.35 |
| Dissolved oxygen (mg L−1) | 6.38±0.78 | 6.37±0.83 | 6.26±0.81 |
| Salinity (g L−1) | 1.67±0.08 | 1.68±0.05 | 1.67±0.06 |
| pH | 7.60±0.10 | 7.57±0.09 | 7.55±0.09 |
| Total alkalinity (mg CaCO3 L−1) | 166.67±28.65 | 160.81±25.62 | 164.06±23.89 |
| Total hardness (mg CaCO3 L−1) | 454.79±80.34 | 441.25±72.69 | 447.71±72.97 |
| Electrical conductivity (mS cm−1) | 2.93±0.46 | 3.02±0.48 | 2.90±0.47 |
| Total ammonia nitrogen (mg L−1) | 0.26±0.05 b | 0.30±0.09 ab | 0.44±0.28 a |
| Nitrite-N (mg L−1) | 0.08±0.02 | 0.09±0.02 | 0.09±0.03 |
| Nitrate-N (mg L−1) | 31.40±5.92 | 31.80±6.37 | 31.89±7.37 |
| Orthophosphate (mg L−1) | 6.26±1.37 | 6.43±1.29 | 6.40±1.50 |
| Total suspended solids (mg L−1) | 604.15±235.33 | 654.81±269.33 | 680.62±281.50 |
| Settleable solids (mL L−1) | 16.66±6.58 b | 20.04±7.72 a | 20.78±8.40 a |
Figure 2.
Total ammonia nitrogen (TAN, a), nitrite nitrogen (NO2−-N, b), and nitrate nitrogen (NO3−-N, c) variation during a Penaeus vannamei post-larvae cultured under different stocking densities (75, 150, and 301 shrimp m−2) in a low salinity biofloc system in winter in northeastern Brazil, with four replicates
Figure 3.
Total suspended solids (TSS, a) and settleable solids (SS, b) variation during a Penaeus vannamei post-larvae cultured under different stocking densities (75, 150, and 301 shrimp m−2) in a low salinity biofloc system in winter in northeastern Brazil, with four replicates
Table 2.
Mean ± standard deviation of growth performance for 75 days of study with Penaeus vannamei post-larvae cultured in a low salinity biofloc system under different stocking densities (75, 150, and 301 shrimp m−2) during winter in northeastern Brazil, with four replicates
| 75 shrimp m−2 | 150 shrimp m−2 | 301 shrimp m−2 | |
|---|---|---|---|
| Initial mean weight (g) | 0.04±0.08 | 0.04±0.08 | 0.04±0.08 |
| Final mean weight (g) | 2.46±0.22 a | 1.90±0.21 b | 1.54±0.13 c |
| Weekly growth (g week−1) | 0.23±0.02 a | 0.17±0.01 b | 0.14±0.01 c |
| Specific growth rate (% day−1) | 5.55±0.12 a | 5.21±0.15 b | 4.93±0.11 c |
| Final biomass (g) | 129.72±9.34 b | 143.43±4.23 b | 225.78±37.36 a |
| Feed conversion ratio | 1.32±0.10 b | 1.81±0.20 a | 1.81±0.33 a |
| Survival (%) | 82.81±6.12 a | 59.57±7.50 b | 57.52±10.08 b |