International Journal of Aquaculture, 2013, Vol.3, No.21, 117
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feed given was10.5 g and the highest was 379.323 g.
The lowest weight gain was 0.4 g and the highest was
13.93
g. The number of fish survived during the
period was calculated and percentage recorded. Solar
had the highest mean weight of 20.7±10.61 while the
electric powered fish pond had the fish weight of
19.46
±1.17. The initial number of fish was 500, at 4
weeks was 480 and in 6 weeks 375 and final number
was 375. Feed ration (g) given at 5 % body weight
were 1.5, 24.72 and 110.625, 364.875. Total biomass
(
g) were from week 2 to 8 were 30494.4, 2212.5 and
7297.5.
Solar had the highest biomass of 7586.46 g
while the electric powered fish pond had the total
biomass of 7 297 g. Total Weight gain (g) was 0.97,
4.87
and 13.56. Survival (%), 1 009 675 (Table 3). Food
conversion ratio were (FCR) for solar powered system
were, 1.0, 1.34 and 1.01, while the electric powered for
week 4, 6 and 8, were 1.38, 1.17 and 1.00%. FCR is one
of the most important benchmarks for measuring the
efficiency of an operation; FCR alone does not give a
true measure of production. Survival % was high for the
both system.
Conductivity of the electric and solar powered system
is shown on the Table 4. For electric powered system
conductivity was (35±5.00) µS/m and the solar
powered was 45 µS/m, inlet water was (10±0.58) µS/m
while the treated water was (85±15) µS/m.
Table 4 Conductivity and Total dissolve solids of water recirculating system
Parameters
Inlet water Electric pump
Pump
Solar pump treated
Water
Conductivity (µS/m)
10 .0
±0.58
35.00
±5.00
45 .00
±2.89
85.00
±15
Total Dissolved Solids (ppm)
6.7
±0.70
23.45
±2.55
30.15
±9.85
56.95
±6.05
Total dissolved solids (ppm) for electric powered
pump was (23.45 ± 2.55) ppm while solar powered are
30.15
± 9.85. Total dissolve solids for Inlet water was
(6.7
±0.70) ppm and treated water was (56.95± 6.05)
ppm. Solid wastes or particulate matter, consisted
mainly of feaces and uneaten feed.
Table 5 shows the biochemical oxygen demand for
recirculation system. Electric powered pump had the
highest BOD which was (4.80±0.70) mg/L. The water
from the solar powered pump had biochemical oxygen
demand of (3.20±0.20) mg/L; the inlet water had
nothing while the treated water had (1.60±0.40) mg/L.
Table 5 Biochemical oxygen demand of recirculating system
Water types
BOD
Water from Fish pond connected to Solar Pump 3.20 ±0.20
Water from Fish pond connected to Electric Pump 4.80± 0.70
Inlet Water
Nil
Treated Water
1.60
± 0.40
3
Discussion
In this work oxygen values were for inlet, solar
powered pond, electric powered pond and UV treated
water between 5.7 to 9.4 mg/L which are within the
acceptable levels. Tookwinas and Charearnrid (2008)
obtained dissolve oxygen range 4.0-8.0 mg/L during
their experiment with recirculating system, the range
which was a little difference with the range obtained
in this work. Syarikat (2008) obtained dissolved
oxygen 6.5 mg which was within the range in this
work. Pada (2007) obtained the oxygen range of
10.5
mg/L during his work with recirculating system.
Dissolved oxygen supply is usually the first process
applied to prepare water for further use, because
dissolved oxygen is often the first water quality
parameter to limit production in intensive culture
systems (Colt et al., 1991). Even though the
availability of dissolved oxygen could be increased by
movement of water from a depth to a height as was
achieved during the conduct of this experiment and
the use of aerator, other fish wastes can begin to
accumulate to concentrations that must be reduced
to maintain a healthy fish culture environment (Colt
et al., 1991). Hence several complementary water
treatment processes are required to reduce waste
accumulations to maintain a healthy fish culture
environment. Water treatment processes are used to
change the physio-chemical conditions or characteristics
of the water that pass through the process. Sometimes
water treatment processes can change more than one
characteristic of the water. For example, water
flowing through a trickling biofilter can gain dissolved
oxygen and nitrate, while dissolved carbon dioxide
and un-ionised ammonia are removed (Wheaton et al., 1991;