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
| Parameters | Treatments | ||
|---|---|---|---|
| 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 ± 0.05b | 0.30 ± 0.09ab | 0.44 ± 0.28a |
| 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 ± 6.58b | 20.04 ± 7.72a | 20.78 ± 8.40a |
Figure 3.
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 4.
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
| Parameters | Treatments | ||
|---|---|---|---|
| 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 ± 0.22a | 1.90 ± 0.21b | 1.54 ± 0.13c |
| Weekly growth (g week−1) | 0.23 ± 0.02a | 0.17 ± 0.01b | 0.14 ± 0.01c |
| Specific growth rate (% day−1) | 5.55 ± 0.12a | 5.21 ± 0.15b | 4.93 ± 0.11c |
| Final biomass (g) | 129.72 ± 9.34b | 143.43 ± 4.23b | 225.78 ± 37.36a |
| Feed conversion ratio | 1.32 ± 0.10b | 1.81 ± 0.20a | 1.81 ± 0.33a |
| Survival (%) | 82.81 ± 6.12a | 59.57 ± 7.50b | 57.52 ± 10.08b |