5" day - Central Institute of Brackishwater Aquaculture

hydroxyl ions which in ~ ms incruv thc pH H~gh pli WI dnmuhull! rrduce thc
mv~aia ionintian ccmtmt inmasing X of thc mxic unicmized pmion
As a medium for shrimp cuhw. bmckishwater has nun) ads-anyycr. It
oontainr a high caKIcnmtion of nutrient nhs .nd is prfcrcl) buffed medium
ag.lrm h p c chmpn in pH. Naxtheb It can flucrrvter bcrwrcn 7 5-9 5 with thc
accumulation of midual feed. dad alp and cxcm over a 24 hour pricd with
lomr pH occurring nar dam d the highen pH occurring in the aRcmmn Low
variation in pH wdws will indiuw smbk phyzopMrton blooms T k ptl should k
in optimum kvel oi7.5 m 8.3. It should M* vary mow ~hn 0.5 in a d.y
-l* The tcnn ralinic). refers to thc toul conccnmtion ofall dissolved lons in grams
contained in I kg of ua water. Following major ions connihute to the saline nature of
wrw. SaliniI) as a single factor play m Important role in prawn farmtng as it a
responsible for many functions such as mctnhol~sm. gnnrlh, osmot~c beha\lour.
reproduction etc. Rams haw an optimal range ol' ulrnlt? for better gmulh and
survival. depending on the rpcin. If thc ulmrr) is allowed to go beyond Ihc opt~m*
limit rhc pntrru refrain From laking nomul food and htacc vc muiued and
became rurocptlbls m dimme.
In pond Mndition. the tiger pmm PCNIJU momdon can tolerate n.ide range of
rshniry from ru low as 5 ppt lo a hlgh of 40 pp, but whik pmwn P idtcur and
banana pnm P mcrp~cnrir pmall~ prefer brackishu,akr (Salinity . J to 25 ppt).
Sallnit~ above 45 to MI ppt can k lethal. Mon rpocles will pmu ben rt wlrnltlcs of
151030ppt.
'
1 1 W)
I Chlorides j
/ Sodium
1
1 Sulphak 1
Slangnassiurn 1
Seawater j ~ ~
19000 1 12090
I05W 7745
27W
I yv5
13%-.G ____-.-..-_.,_-.. 125
I
P~hwater ~ I
6
4
8 I
16 .-j
..-fi_-_ . -;
~
I Caicrum
j ponurium
Biwborutc
/(M
[ Total
I
1
1
I
I
400
380
142
86
345%
1
;
308
75
156
35
?I!:u
i
I
I
1
42
2
174
263
i
:
__] _
Due to high evapwation mtc In summer, salt conccntratlun In pondr gradurll)
increase. Winity may increase to be)ond 40 ppt whrch un affect the pwlh of
pnmr. Wua should b cxshnged fitqucnrly either by pump or *ugh tidal
ordunpc. The puundwuor with low ulinity (2.3 pp) can b uUlLsd for radwina
the Ylinlty. wwua (35 pp) mired with pandwaM can be urd for prrpuln8
wuu with required alinity fw uw or exchange. Sudden fluctuat~onr In chc lollnlty
associared with thc huq. rains result in huv? morUllt)
Ram I.IY.c arc produced In wakn HI& ul~n~tles of 18-35 ppt but advanced
pas L.Nd sage onen uc naked In ponds where wlln~ty
IS much lower At the trmc
oiaocktng they should be awllmstcd gndually to the allnlty of pond waler sa as to