Table 2.
Mean ± SD values for physicochemical parameters of pond waters in different subcounties of Kirinyaga County.
| Subcounties | Physicochemical parameter | ||||||
|---|---|---|---|---|---|---|---|
| Dissolved oxygen (mg/L) | Temperature (°C) | pH | Total ammonia (mg/L) | Nitrate (mg/L) | Nitrite (mg/L) | ||
| Kirinyaga Central | Mean ± SD | 7.1 ± 2.8 | 25.9 ± 3.7 | 7.96 ± 0.7 | 0.06 ± 0.1 | 14.4 ± 10.5 | 0.07 ± 0.05 |
| Range | 3.2–11.7c | 21.6–31.7 | 7.35–9.2 | 0.0–0.2c | 0.06–27 | 0.003–0.15 | |
|
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| Kirinyaga West | Mean ± SD | 5.8 ± 1.6 | 24.3 ± 1.1 | 7.4 ± 0.8 | 0.35 ± 0.8 | 43.0–31 | 0.15 ± 0.13 |
| Range | 3.9–7.7c | 23.3–26.0 | 6.7–8.6 | 0.0–1.7c | 12.5–84 | 0.05–0.34cc | |
|
| |||||||
| Mwea East | Mean ± SD | 6.1 ± 2.0 | 28.0 ± 3.2 | 8.07 ± 0.8 | 0.93 ± 0.9 | 38.1 ± 50.1 | 0.12 ± 0.14 |
| Range | 4.4–8.3c | 24.5–30.8 | 7.2–8.5 | 0.29–1.6cc | 12.9–113.2c | 0.03–0.33cc | |
|
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| Kirinyaga East | Mean ± SD | 6.2 ± 2.9 | 24.2 ± 2.4 | 7.46 ± 0.5 | 0.37 ± 0.6 | 22.4 ± 17.6 | 0.60 ± 1.08 |
| Range | 2.3–13.40c | 20.5–28.7 | 7–8.4 | 0–1.94c | 0.0–49.2 | 0–3.06c | |
|
| |||||||
| Mwea West | Mean ± SD | 4.4 ± 3.9 | 26.2 ± 3.2 | 7.0 ± 0.6 | 2.98 ± 4.7 | 37.7 ± 15.4 | 0.10 ± 0.04 |
| Range | 0.13–9.1b | 22.7–30.9 | 6.27a–7.7 | 0.12–9.9cc | 17.6–59.2 | 0.03b–0.14 | |
|
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| County total | Mean ± SD | 6.0 ± 2.8 | 25.3 ± 2.9 | 7.54 ± 0.7 | 0.72 ± 1.9 | 29.4 ± 24.5 | 0.27 ± 0.7 |
| Range | 0.13–13.4b | 20.5–31.7 | 6.27a–9.2 | 0–9.9c | 0.0–113.2c | 0.0–3.06c | |
The optimal ranges of water parameter for fish culture are as follows: dissolved oxygen = 1–5 mg/L; temperature = 20°C–32°C; pH = 6.5–8.5; total ammonia = 0–0.05 mg/L; nitrate = 0–100 mg/L; nitrite = 0.02–0.2 mg/L as described by Bhatnagar and Devi [46]. Note. ccBoth lower and upper values of the reported range exceeded the optimum range. aOnly lower value was below the optimum range. bLower value was below the optimum range and the upper value was above the optimum range. cOnly upper value was above the optimum range. ∗Significantly different (P < 0.001) across subcounties.