International Journal of Aquaculture, 2013, Vol.3, No.21, 117
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125
http://ija.sophiapublisher.com
119
treated water respectively, dissolved oxygen was
between 5.7 mg/L to 9.4 mg/L. and temperature was
between 26.2
℃～
26.5
℃
.
NH
3
(
mg/L) were for inlet,
solar powered pond, electric powered pond and UV
treated water respectively the least was 0±0 in the
inlet water. Nitrate values were for inlet, solar
powered pond, electric powered pond and UV treated
water respectively. NO
2
(
mg/L) were for inlet, solar
powered pond, electric powered pond and UV treated
water respectively.
Table 2 Mean values of physicochemical properties of the water samples in the recirculating system of solar and electric powered fish pond
Water Samples
Dissolved Oxygen (mg/L) pH
CaCO
3
(
mg/L) NO
3
(
mg/L) NO
2
(
mg/L) NH
3
(
mg/L) Temperature (
℃
)
Borehole (inlet
water)
9.4
±1.6
6.4
±0.8 20±0.05
5.0
±0.28
0
0
26.5
±0.20
Solar powered
pump water
6.2
±0.20
6.9
±0.17 20±0.05
10
±0.08
0.3
±0.28
0.6
±0.64
26.2
±0.15
Electric powered
pump water
5.7
±0.20
6.2
±0.01 20±0.29
10
±0.26
0.3
±0.01
0.6
±0.20
26.3
±0.05
UV Treated (Outlet
water)
7.2
±0.15
8.0
±0.01 20±0.28
10
±0.26
0.3
±0.03
0.3
±0.07
26.4
±0.057
The inlet water had the highest quantity of dissolved
oxygen which is more favourable for aquatic life,
followed by the UV treated water, solar powered
pump water and then electric powered pump water.
All the treated samples affected by the fish activities
had the same concentration of calcium carbonate,
nitrate and nitrite, which were higher than the
concentration for that of inlet water. However the
concentration of ammonia in the UV treated water was
much lower than that of the solar powered pump water
and then electric powered pump water. This shows
that UV disinfection as stipulated by other authors is
really a good method of disinfection.
Growth performance of
Clarias gariepinus
fry in
recirculating system powered by solar photovoltaics
and electricity showed that the average length and
weight of fish in solar pump of recirculation system
were 11.058±0.84 and 19.46±1.17, respectively after
eight weeks of rearing in recirculating system while
those powered with electricity were 15.7±0.30 and
20.7
±10.61 (Table 3). Weight gained for solar powered
recirculating system were recorded and the electricity
powered ones were also recorded as well throughout
the period of rearing.
Table 3: Growth performance of
Clarias gariepinus
fry in recirculating system powered with solar photovoltaic and electricity
Power
source
Wk Length (cm)
Weight (g) No.
of
fish
Total Biomass
(
g)
Quantity of
feed given (g)
Total Weight
gain (g)
Weight gain
per day(g)
Survival
(%)
FCR
Photo
voltaic
2
1.400
±0.07
0.06
±50.0 500
30.00
10.500
-
-
10.0
-
4
3.790
±0.53
0.46
±0.24 482
2210.72
110.086
0.40
0.020
96.4
1.00
6
4.300
±0.23
6.14
±0.44 378
2320.92
1160.046
50.68
0.410
75.6
1.34
8
15.700
±0.3073 20.7±10.61 378
7586.46
379.323
130.93
0.995
100.0
1.01
Gene
rator
2
1.400
±0.7
0.06
±0.02
500
30.00
1.500
-
-
100.0
4
3.290
±0.68
1.03
±2.0
480
494.40
24.720
0.97
0.069
96.0
1.38
6
3.790
±0.24
5.90
± 0.7 375
2212.50
110.625
4.87
0.347
75.0
1.17
8
11.058
±0.84
19.46
±1.17 375
7297.50
364.875
13.56
0.968
100.0
1.00
Length and weights of solar powered systems were
stated as follows: the lowest lengths from 2 weeks to 8
weeks was 1.4±0.07, and 15.7±0.30.73 was the highest;
the lowest weights was 0.06±50 and the highest was
20.7
±10.61. The number of fish stocked reduced from
500, 482,
to 378. The lowest biomass was 30 g while
the highest was 7586.46 g. Quantity of feed given (g)
was as presented in the Table 1; the lowest quantity of