The effect of oxygen saturation on growth and metabolic rate of Arctic charr, Salvelinus alpinus 1,2 Beuvard ,
3,4 Imsland ,
2 Thorarensen
Christian Albert K. Helgi (1) University of Iceland, (2) Hólar University College, (3) Akvaplan-niva Iceland, (4) University of Bergen Contact :
[email protected]
Arctic images
Background Oxygen levels in water affect the growth performance of aquaculture fish. Recent studies have indicated that 100% O2 saturation (relative to water in equilibrium with air) is required to support the maximum growth of fish. At severe levels, hypoxia can result in mortality. Water use in aquaculture can be reduced when O2 is added to the rearing water. However, excessive levels of O2 can also limit the growth of fish and increase the cost of production. Therefore, it is important to know the minimum O2 level that maximizes the growth and welfare of each species of fish. The objective of this study was to examine the effects of O2 saturation on growth, feed conversion ratio (FCR) and metabolic rate of Arctic charr (Salvelinus alpinus).
Experimental design
Results
• Five levels of oxygen saturation in water were tested: 60%, 80%, 100%, 120%, 140% • Each treatment was applied in four replicate tanks (110 fish per tank) • The fish were hand-fed with automatic feeders • Duration of experiment: 61 days
Oxygen saturation over 60% does not affect growth performance
180
Body mass (g)
160 140 120 100 80 60
60% OSW
80%OSW
100%OSW
120%OSW
140%OSW
40 0
10
20
30
40
50
60
Days 1.22
FCR increases with increased O2 saturation
1.20 1.18
a ab
FCR
1.16 1.14
bc abc
1.12 1.10
F.K
c
1.08
Measurements of oxygen consumption
1.06 1.04 40%
• Active Metabolic Rate (AMR) was measured at maximum level of activity while fish were chased in the tank Oxygen consumtion (mg.min-1 .kg-1)
1. Water inlet off for 30 min 2. Measurements of O2 levels in the water
100%
120%
Both AMR and RMR increase with increasing O2 saturation
12.00 10.00
140%
160%
e
AMR d
c
8.00 b 6.00
a
b
b
b
RMR
ab
4.00
a
2.00 40%
a
80%
Oxygen saturation in water (%)
14.00
• Routine Metabolic Rate (RMR) was measured in fed and undisturbed fish
60%
60%
80%
100%
120%
140%
160%
Oxygen saturation (%)
Tank : 800L
Conclusions
- Excel sheet after 30 min of measurement
- AMR and RMR were calculated from the slope
• Oxygen saturation over 60% does not increase growth. This contrasts with results from studies on other species of fish where 100% saturation is required to support maximum growth. • Oxygen consumption and FCR increase with oxygen saturation levels. This may be caused by increased activity levels at higher oxygen saturation. • All together these results suggest that Arctic charr should be reared at oxygen saturation levels of 60-80%.
