VANNAMEI....!!
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ABSTRACT
The present study is the report on the culture of L. vannamei in the brackish water shrimp farm
in Bhimavaram, west Godavari district, Andhra Pradesh, India. The study was conducted in four
culture ponds at different stocking densities. Crab fencing and bird netting was done before
pumping water to prevent th
e autoentrants. The average pH reading for the AM was 7.9 to 8.8,
while a pH of 8.2 to 9.1 was recorded in the PM. After 110th days of pond culture, the mean
average weights of the shrimp at harvest were 21.2, 18.9, 19.6, and 17.5; survivals were 82, 92,
81, and 80 %; FCR was 1.4, 1.34, 1.38, and 1.35. The average production was 8750, 9813,
8138, and 8591 kg/ha for P1, P2, P5, and P6, respectively. Two way ANOVA was attempted
between stocking density and Average body weight (ABW). The calculated p value was 0.0017. Its shows the relationship between stocking density and average body weight is highly
significant. So ABW increases with less stocking density and vice versa. The present
investigation it was concluded that L.vannamei culture is successful in brackish water
environment and the growth is directly related to stocking density. Keywords: Litopenaeus vannamei, Growth performance, Stocking densities, Water quality,
statistical analysis.
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INTRODUCTION
During the last few years, white spot disease (WSD) has spread worldwide and caused largescale
mortalities and severe damage to shrimp culture, particularly in Asia leading to massive
economic losses [1,2]. Due to continues outbreak of WSSV in of P.monodon culture leads to
shattering of shrimp culture in India. So the farmers are seriously looking for alternative species
for culture. At right time the Coastal Aquaculture Authority of India (CAA) introduced a new
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species (Litopenaeus vannamei) in India. At the same time CAA is very keen in the bio security
and approval for culture of L.vannamei. The shrimp has been introduced and farmed in Asia since the mid 1990s, with production in
Mainland China being particularly significant. However, beginning in 1996, L. vannamei was
introduced into Asia on a commercial scale. Total production of L.vannamei in Asia was
approximately 316 000 mt in 2002. In some countries, L. vannamei culture has been promoted
by some private sector suppliers as being tolerant or resistant to WSSV, leading to introductions
based on a mistaken belief that they are safe. It is now evident that L. vannamei is farmed and established in several countries in East,
Southeast and South Asia and is playing a major significant role in shrimp aquaculture
production. There is very limited research works were done on the culture and growth
performance of L.vannamei with different stocking densities in brackish water ponds in India. So
the present study was attempted to evaluate the survival, growth, and FCR of L. vannamei
culture in the brackish water with different stocking densities. MATERIALS AND METHODS
The present study was undertaken at a shrimp farm in Bhimavaram, west Godavari district,
Andhrapradesh, India. The study was conducted in four shrimp culture ponds. Three ponds (1, 2,
and 5) were 0.8ha and pond 6 was 0.9ha in area. Besides the above there was a reservoir pond in
the size of 2ha, a sedimentation pond and a chlorination pond are in the size of 0.6 ha. Water
recirculation method followed to avoid cross contamination during the culture period. All the
experimental ponds were 1.2 – 1.5m deep. The soil type was sandy clay. Ponds were initially
prepared by drying, tilting (to remove the pests and predators and oxidize bottom soil) and
liming to correct the pH of the soil. Inorganic fertilizers such as urea and triple superphosphate
were applied to enrich the natural food organisms in the water. Crab fencing and bird netting was done before pumping water to prevent the autoentrants. The
filter bags were checked properly, which was fitted in the inlet and outlet pipe, then the pumping
was done to the entire ponds. After filling water kept stand one day with out any disturbance for
sedimentation. Subsequently the water was chlorinated (60 ppm/ha) after that excess chlorine
was neutralized by dechlorination process which took 72 hours. After dechlorination, the water
enriched with probiotic for the good beneficial bacterial environment. The algal bloom was
noticed slowly in the ponds. The L.vannamei seeds ( post larval stage 14, that had been acclimated to a salinity level of 17 ppt
and confirmed negative for the white spot syndrome virus(WSSV) and Taura syndrome
virus(TSV) by the polymerase chain reaction(PCR assay), were purchased from CP Aquaculture
India Private Ltd , hatchery Gudur. The seeds were transported in oxygenated double-layered
polythene bags with crushed ice packs between inner and outer covers of the bag to maintain
optimum temperature in turn to keep less stress to the shrimps and the entire set up was packed
in a carton. The seeds were brought to the farm site and bags were kept in the pond water for
some time to adjust the temperature. Then the pond water was added slowly into the seed bag to
adjust the salinity and pH. Subsequently the seeds were released slowly in to the ponds. The
stocking densities were 50/ m², 56/m², 51/m² and 61/m² for ponds 1, 2, 5 and 6 respectively. Blanca feed pellets (CP Aquaculture India Pvt Ltd) were fed to the stocked post larvae for four
times daily at 7am, 10am, 3pm and 9pm respectively. No water exchange was done for the entire
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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 of time
the pond water was not pumped out side of the farm as a bio secure measures. From the 55th
days of culture (DOC) onwards cast net (sampling) was used every seven days for monitoring
shrimp health and growth. The water level was measured by using a standard scale with cm marking. The water quality
parameters like salinity, pH, temperature, dissolved oxygen and light transparency were
measured by using hand refractometer, pH pen, thermometer, and dissolved oxygen meter and
secchi disc, respectively. Aeration was given to the entire culture period for all ponds. Totally 16
hp aerator was fixed for each culture pond. The aerators were placed in such a way that it could
dissolve maximum dissolved oxygen (DO) into the pond water and makes the culture
environment friendly. Feed conversion ratio (FCR) and Average daily growth (ADG) were
calculated by the given formula below
FCR = Total weight of the harvested shrimps / total feed used
ADG = Total weight gained by the shrimps / Total days of culture
STATISTICAL ANALYSIS
Two way ANOVA analysis was applied to know the statistical significance between growth and
stocking densities of the shrimp. Data were expressed in the mean ± standard error. RESULTS
Water quality analyses for the culture ponds are summarized in Tables 1&2. Pond water pH,
temperature and DO readings are recorded in early mornings (AM) and late evenings (PM). For
the four culture ponds an overall, average fluctuation of pH reading was between 7.9 and 8.8 in
the early morning, while fluctuation of pH value was between 8.2 and 9.1 in the evening. DO
values fluctuated varied between 5.5 mg/l and 3.5 mg/l in the morning and between 4.5 mg/l and
10.2 mg/l in the evening (Table 2). In general, AM readings became lower as the cycle
progressed and the standing crop 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 with temperatures 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 19ppt and minimum salinity was recorded 15ppt in all the
ponds. Table 1 Average water quality parameters
parameters Range
Salinity (ppt) 15 – 19
Temperature °C 22 – 29
pH AM 7.9 - 8.8
pH PM 8.2 - 9.1
Weekly averages of shrimp weights are presented in Table.3 .After 110th days of pond culture,
the mean average weights of the shrimp at harvest were 21.2g, 18.9g, 19.6g, and 17.5g (Table 3);
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survivals were 82, 92, 81, and 80 %; FCR was 1.4, 1.34, 1.38, and 1.35. The average production
was 8750, 9813, 8138, and 8591 kg/ha for P1, P2, P5, and P6, respectively (Table 4). Table 2 Average Dissolve Oxygen concentration
Days of culture (DOC) 1 10 20 30 40 50 60 70 80 90 100 110 120
MORNING (mg/l) 4 4.5 3.5 3.9 4.5 5.3 5.3 5.5 5.3 5.2 4.4 4.3 4.3
EVENING (mg/l) 4.5 6.5 7.8 7.8 7.2 9 8.2 8.9 8.6 10.2 10.1 7.3 7
Table 3 Weekly growth performances (g)
Ponds
Days Of Culture (DOC)
55 62 69 76 83 90 97 104 111
P 1 8.9 11.1 12.5 13.5 14.5 16.4 17.5 18.7 21.2
P 2 7.4 9.43 10.7 11 13.2 13.8 16.4 17.3 18.9
P 5 8.3 9.96 11.6 12.8 13.7 15.3 17.9 17.99 19.6
P 6 8.4 9.2 10.8 12.7 13.6 15.3 16.7 16.85 17.5
Table 4 Pond performance details
Details Pond 1 Pond 2 Pond 5 Pond 6
Area (Ha) 0.8 0.8 0.8 0.9
Initial Stocking (Numbers) 400000 450000 410000 550000
Density (Numbers/m²) 50 56 51 61
Stocking Date 2-Nov-09 2-Nov-09 3-Nov-09 3-Nov-09
Harvest Date 4-Mar-10 3-Mar-10 2-Mar-10 1-Mar-10
Culture Period 122 121 119 118
Harvest Size (g) 21.2 18.9 19.6 17.5
Count (numbers/Kg) 47 53 51 57
Shrimp Harvest (Kg) 7000 7850 6510 7732
Survival percentage 82 92 81 80
Total Feed Used (Kg) 9800 10500 9000 10400
FCR 1.4 1.34 1.38 1.35
ADG 0.17 0.16 0.16 0.15
Production( Kg/Ha) 8750 9813 8138 8591
For each pond cost analysis was worked out. Production cost for 1kg shrimp (19.2 gram, 52
counts) was calculated as Rs 121.44. The feed cost was Rs 61.2/kg, followed by seed cost Rs
18.6/kg. The over all production was 29.092 metric tons. Totally 39.700 metric ton feed was
used. The average FCR was 1.36, average ABW was 19.2g and average density was
54numbers/m². Profit /kg shrimp was Rs 78.56 and overall total profit was Rs 22, 85,468 (Table
5). Two way ANOVA was attempted between stocking density and Average body weight (ABW). Its shows the relationship between stocking density and
average body weight is highly significant. So ABW increases with less stocking density and vice
versa. Gunalan Balakrishnan et al Adv. Res., 2011, 2 (3):107-113
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Table 5 Average Cost Analysis
Area (ha) 3.3
Density (Numbers/m²) 54
Harvest size (g) 19.2
Count (numbers/kg) 52
Doc 119
Survival (%) 84
FCR 1.36
Production (kg) 29092
Total feed (kg) 39700
Seed cost/kg shrimp Rs18.6
Feed cost/kg shrimp Rs 61.2
Pond preparation cost/kg Rs 1
Water treatment cost/ kg Rs 3.6
Feed probiotic cost/ kg Rs 0.2
Water probiotic cost/kg Rs 0
Bottom probiotic cost /kg Rs 2.3
Carbon source cost/ kg Rs 0.2
Minerals cost /kg 2.37
Chemicals cost/kg 2.6
Feed supplement cost/kg 0.26
Diesel cost/kg 4.45
Electricity cost/kg 16.25
Labour cost/kg 3.85
Farm lease cost/kg 2.06
Maintenance & repair/kg 1
Other expenses/kg 1.5
Total production cost (Rs)/kg of shrimp 121.44
Material price (Rs) 200
Profit / kg 78.56
Total profit (Rs) 2285468
DISCUSSION
The present study is the report on the culture of L. vannamei in the brackish water shrimp farm in
Bhimavaram, west Godavari district, Andhrapradesh, India. This study shows that stocking
density affects growth of L. vannamei .Several authors have reported on the growth and survival
of L. vannamei in different salinities and densities [3, 4, 5, and 6].The maintenance of good
water quality is essential for optimum growth and survival of shrimp. Good water quality
characterized by adequate dissolved oxygen, temperature, pH and salinity. Excess feed, faecal
matter and metabolites will exert tremendous influence on the water quality of the shrimp farm
[7]. In the present study the salinity was maintained 15 – 19 ppt in all ponds. However, the white
leg shrimp, L. vannamei, is widely cultured in Central and South America [8] and tolerates the
salinities of 2-45 ppt [9, 10]. Several authors have reported good growth and survival of L. vannamei in brackish water of 1.7-2.3 ppt [11- 13, 5, and 6]. [14, 15] recommended a salinity
range of 10 – 35 ppt was ideal for shrimp culture. [16, 17] reported that growth is higher in low
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saline (2 ppt) water than in sea water. In the present study pH value was ranging between 7.9 –
8.8 in the morning and 8.2-9.1 in the evening. The pH of pond water is influenced by many
factors, including pH of source water, acidity of bottom soil and shrimp culture inputs and
biological activity. [18] recommended the favorable pH range of 7.6-8.6 for L. The
concentrations of DO in all ponds are ranged from 3.5- 5.5 mg/l in the morning and 4.5-10.2
mg/l in the evening during the culture period. The values of water quality parameters reveal that
all these are in the acceptable range for survival and growth for L.vannamei [19, 20]. The growth of the shrimps depends on the quality of feed. In the present study CP feed was used
for all the ponds and the amount was followed as per feed chat. The maximum feed was used in
pond P2 followed by P6, P1 and P5. In the present study the average FCR was 1.36 for all ponds. Similar results were recorded by [21, 22, and 7]. even though the stocking densities was quiet
high could able to achieve the better FCR in all the ponds because of quality of the feed, feed
management, water quality, pond bottom management and other effective farm management. Weekly sampling is very important to know the shrimp health, growth and survival. In the
present study first sampling was carried out in all ponds at the 55th DOC of the culture. During
sampling the growth of the shrimps varied depends on the density. At the time of harvest in P1
pond the shrimps harvested at the size of 21.2 grams, inP2 pond 18.9 grams, in P5 pond
19.6grams and in P6 pond 17.5 grams. The higher survival (92%) was recorded in the pond P2
and lowest survival (80%) was recorded in pond P6. [11] was observed similar finding in their
research. Shrimp survival was quit well considering the dimension of the pond and the sanitary
risks of outdoor-reared shrimp [23, 24]. The appreciable feed conversion ratio indicates good
rearing procedures combined with a suitable environment and a good shrimp biological
responsiveness. From the present investigation it was concluded that L.vannamei culture is
successful in brackish water environment and the growth is directly related to stocking density.
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