International Journal of Marine Science 2015, Vol.5, No.14, 1-5
3
The water quality parameters were recorded from culture
ponds regularly. The water level was measured by using
a standard scale with cm marking. The water salinity was
measured by using a Hand Refractometer (Erma-Japan).
The pH of the pond water was measured by using
electronic pH pen manufactured by Hanna Instrumental
Company, Japan. The dissolved oxygen was estimated
by an oxygen meter.
Blanca feed pellets (CP Aquaculture
India Pvt Ltd) were fed to the stocked post larvae for
four times daily at 7am, 11am, 2pm and 5pm respectively.
No water exchange was done for the entire culture period.
But some water from the reservoir was added at regular
intervals to compensate water loss due to evaporation or
soil seepage. During harvest all the water from culture
ponds drained to sedimentation pond and ultimately
reached to reservoir pond. At any account the pond water
was not pumped out side of the farm as a bio secure
measures. Cast net was used to measure the growth rate
of shrimps. The first sampling was taken after 40
th
days
of culture and number of individuals and the average
body weights were recorded in each sampling. Sampling
was regularly performed every ten days until harvest.
2 Results
Water quality parameters for the culture ponds are
summarized in Table 1. Pond water pH and DO
readings were recorded in early mornings (AM) and
late evenings (PM). For the two culture ponds an
overall average fluctuation of pH reading was between
7.5 and 8.0 in the early morning, while fluctuation of
pH value was between 7.9 and 8.4 in the evening. DO
values fluctuated between 4.0 mg/l and 5.0 mg/l in the
morning and between 4.5 mg/l and 6.5 mg/l in the
evening (Table 1). In general, AM readings became
lower as the cycle progressed and the standing crop
was increased. Average AM and PM pond
temperatures were 22 to 29 °C, respectively (Table 1).
In general, the temperature trend through the
production cycle started around 27.5 °C, dropped to
22 °C because of a cold front during the third and
fourth week, and then increased to a range of
28-29 °C. During the culture period the maximum
salinity was recorded, as 22 ppt and minimum
salinity was recorded as 30ppt in all the culture
ponds. Ammonia was recorded maximum 0.3 ppm
and minimum was 1ppm. Weekly shrimp growth is
presented in Table 2. After 123
th
days of pond culture,
the mean average growth of the shrimp at harvest
were 32.8g and 33g for ponds 1and 2 respectively.
Table 1 Average water quality parameters of the culture ponds
Parameters
Range
Salinity (ppt)
22–30
Temperature °C
22–29
pH AM
7.5–8.0
pH PM
7.9–8.4
Do AM
4.0–5.0
Do PM
4.5–6.5
Ammonia
0.1–0.3
Table 2 Average mean body weight
DOC 30 40 50 60
70
80
90 100 110 120
Pond 1 6 9 13.8 14.72 16.2 20.16 23.2 26.9 29.4 32.8
Pond 2 7 10.2 14 15.6 17.32 21.4 24 27.1 29.6 33
During the culture after 50
th
Doc there was a poor
growth observed in both ponds due to white gut and
white fecal matter (Figure 3, 4 &5). Immediately feed
probiotic (
Bacillus
sp) mix with the feed for three
weeks and two meals per day. The problem was
slowly rectified. During this three weeks period we
loss five grams weight gain. Survivals were 82 and 85
for ponds 1 and 2 respectively; the average FCR was
recorded 1.4 in both the ponds. The average
production was 5450 and 5660 kg/ha for ponds 1 and
2 respectively.
Figure 3 White feces with shrimp
Figure 4 White feces in the check tray
