44 MARCH 2023 • WORLD AQUACULTURE • WWW.WAS.ORG TABLE 4. Environmental indicators and the three-score thresholds. Indicator name Score Grow-out and finish ponds Temperature (°C) 1 25-32 2 20-24 OR 33-37 3 ≤19 OR ≥38 pH 1 6.0-8.5 2 5.5-5.9 OR 8.6-9.0 3 ≤5.4 OR ≥9.1 Transparency (cm) 1 41-65 2 25-40 OR ≥66 3 ≤ 24 Oxygen saturation (%) 1 70-95 2 40-69 3 ≤39 OR ≥96 Un-ionized ammonia (NH3) (mg/L) 1 0.00-0.05 2 0.051-0.10 3 ≥0.11 Nitrite (NO2) (mg/L) 1 0.00-0.50 2 0.51-1.00 3 ≥1.01 Alkalinity (mg/L as CaCO3) 1 30-100 2 20-29 OR 101-200 3 ≤19 OR ≥201 Photoperiod L (light) : D (dark) 1 Only for hatcheries 2 3 Terrestrial predators (birds, otter) 1 No, they are absent 2 Controlled presence 3 Uncontrolled presence Non specific inhabitants 1 Absence (avoided by mechanical barriers) (Aquatic competitors/predators) 2 Controlled presence 3 Uncontrolled presence TABLE 3. Nutrition indicators and the three-score thresholds. Indicator name Score Grow-out and finish ponds Grow-out and finish cages Feeding frequency (times/day) 1 2-3 or continuous 3-4 or continuous 2 1 1-2 3 ≤1 ≤1 Amount of feed (% of biomass/day) 1 2.0-3.0 1.5-3.0 2 1.5-1.9 or 3.1-5.0 1.0-1.4 or 3.1-5.0 3 ≤1.4 or ≥5.1 ≤0.9 or ≥5.1 Feed distribution area 1 ≥75 % of the surface (% of the water surface area covered) 2 50-74% of the surface 3 ≤49% of the surface Crude protein (%) 1 28-35 32-35 2 25-27 24-31 3 ≤24 or ≥36 ≤23or ≥36 Condition factor (K) 1 1.6-1.9 2 1.1-1.5 or 2.0-2.3 3 ≤1.0 or ≥2.4 Feed Conversion Ratio (FCR) 1 ≤2 2 2.1–2.5 3 ≥2.6
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