Freshwater (pre-smoltification/juvenile fish)
RSPCA welfare standards for farmed Atlantic salmon 24 September 2015
* indicates an amendment
FW 1.7 Flow rates must be such that fish can comfortably maintain their position in the water column.
A representative water quality table for a recirculation system:
Parameter Ova Alevins Fry Parr/Smolt
Oxygen (O2) mg/l 7.0 7.0 7.0 7.0
Oxygen (O2) saturation
% in the exit water
>90 >90 >70 >80
Free Ammonia (NH3)
(mg/l)
n/a 0.025 0.025 0.025
Total Ammonia N (mg/l) n/a <1 <1 <1
Carbon dioxide (CO2)
(mg/l)
<10 <15 <12 <15
Max temp oC 8 10 14 16
Min temp
oC 1 1 1 1
pH 6.8-8.0 6.8-8.0 6.8-8.0 6.8-8.0
Alkalinity
(as CaCO3)
50-300 50-300 50-300 50-300
Suspended solids <25 <25 <25 <25
Nitrite (NO2) (mg/l) <0.2 <0.2 <0.2 <0.2
Nitrate (NO3) (mg/l) n/a n/a 150max 150max
* Ova
FW 2.1 All equipment must be:
a) maintained in full working order
b) serviced and repaired as required.
FW 2.2 Records must be kept of equipment services.
FW 2.3 The hatching environment must minimise movement of the eggs.
FW 2.4 Flow and/or oxygen alarms must be fitted to all water intakes to the unit.
FW 2.5 All alarms must be checked weekly and records kept.
FW 2.6 There must be a screen to prevent the blocking of inlet valves.
FW 2.6.1 Inlet valves must be regularly checked (at least daily).
FW 2.7 * All eggs must be disinfected prior to entry to any new facility.
FW 2.8 Eggs must be water-hardened before being exposed to disinfectant or transportation.
FW 2.9 Eggs being transported must be carried with twice the volume of water than eggs.
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