International Journal of Aquaculture 2015, Vol.5, No.34, 1-7
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3.2.1 Temperature
During the experimental period the overall range of
water temperature were 15.5±0.46 to 16.7±0.55,
20.5±0.56 to 22.2±0.80 and 25.4±0.65 to 27.1±0.27°C
in P1, P2 and P3, respectively (Table 5). The
minimum average values were recorded during
October and maximum in all the ponds. Statistical
analysis showed significant differences (P<0.05) for
temperature among the ponds during the experimental
period.
3.2.2 Nitrate and phosphate
Nitrate concentration in all the ponds showed gradual
increase in all the three ponds. The pond at the lowest
altitude (1,710 msl) showed maximum value (6.9
mg/l) followed by 5.3mg/l (2,100 msl) and 2.8 mg/l
(1,710 msl). The phosphate level was found to be
minimu in P1 and maximum in P3(Table6). A wide
range of variation in phosphate found in P3 compared
to P1 at the end of the experiment. There was a
statistically significant difference (P <0.05) for total
nitrate and total phosphate among all the treatments
(table 6)
3.2.3 Plankton
Phytoplankton belonging to Chlorophyceae,
Bacillariophyceae,
Cyanophyceae
and
Euglenophyceae were identified in all the ponds
(figure 1). Cyanophyceae was the dominant group in
pond 1 while this was the least abundant group in the
other ponds (Fig3&4). The chlorophyceae members
are the most abundant in pond P2and P3.
Bacillariophyceae and Euglenophyceae were
relatively less abundant in pond1than the P2 and P3.
3.2.4 Zooplankton abundance
The zooplankton was represented by Rotifers,
Copepods and Cladocerans. Rotifers were more
dominant in P2 and P3 followed by Copepods
(Figure5, 6, 7). The highest number of Rotifers and
Copepods were recorded in February in P3. But the
higher number of Cladocera was recorded in P1.
(Figure 5). The species of Rotifers identified during
the experimental period were,
Brachionus, Horaella,
Testudinella and Keratella
.
Keratella
was the most
dominant in P2 and P3 and
Brachionus
in P3.
Horaella was absent in P1 and rare in P2. Cyclopoid
and Calanoid were the most abundant groups of
copepods. However, copepods were less abundant in
the higher altitude pond. Calanoids were the most
dominant in P3 (Figure 7). Daphnia was the only
genus among Cladocera found in P1 than the other
ponds.
Figure 2 Percentage composition of Phytoplankton in Pond1
Figure 3 Percentage composition of Phytoplankton in Pond 2
Figure 4 Percentage composition of Phytoplankton in Pond 3
Figure 5 Zooplankton abundance in P1
