International Journal of Aquaculture, 2015, Vol.5, No.24 1
-
5
4
Low stocking densities can also prove profitable if
fingerlings get out of the production system as soon as
they attain a good stocking size of 3 g.
Water Quality Parameters
To assess the effect of environmental factors on growth;
water temperature, dissolved oxygen (DO) and pH
were taken in the rearing facilities during the experimental
period and are presented in Table 3.
Findings observed in this study show that tilapia grow
successfully at temperature range of 20-30°C and this
allowed better feeding of the cultured tilapia species at
a favourable temperature, hence better fry growth.
These results have been reported in several earlier
studies such as El-Sayed (2006), El Naggar et al. (2000),
Popma and Masser (1999) and Balarin & Haller
(1982). The ideal DO level for tilapia culture is 4-5
mg/l (Frank, 2000; Marjani et al., 2009; Chakraborty
and Banerjee, 2010) and the present study showed
higher DO values in the two rearing facilities
irrespective of the stocking densities thereby
attributing good environment for tilapia culture. The
pH values of the two rearing facilities in all the
density classes were within the permissible optimum
range of 6.5 to 11.0 for tilapia culture as stated by
(Frank, 2000; Marjani et al., 2009; Chakraborty and
Banerjee, 2010). Generally, all the water quality
parameters were within the acceptable ranges as
recommended for tropical aquaculture (Boyd, 1982;
Beveridge, 1996).
Table 3: Mean water quality parameters for the rearing facilities
Rearing facility
Temp (
℃
)
DO (mg/l)
pH
Min
Max
Min
Max
Min
Max
Tank
25.65±1.95
28.51±2.19
6.74±0.30
7.08±0.22
7.29±0.43
7.55±0.33
Hapa
26.49±1.10
29.88±0.78
7.32±0.38
7.40±0.33
7.20±0.18
6.88±0.15
Conclusion and Recommendations
T. rendalli
is an economically important fish species
whose production is mostly hampered by unavailability
of fingerlings. The research findings in this present
study have demonstrated that
T. rendalli
fry reared in
hapas mounted in pond is a more productive and
favourable rearing system than tanks. This therefore
calls for the promotion of hapas mounted in pond
system of fry rearing for
T. rendalli
fingerling production.
For production of good quality fingerlings, stocking
densities of 30 fry/m
3
have proven to be more effective as
fish grows faster than the other stocking densities of
60 and 90 fry/m
3
. In terms of economic profitability,
the present study has found that no rearing facility had
a superior economic potential over the other.
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