LUMINESCENT
BACTERIA IN SHRIMP HATCHERY
From :
Gopa Kumar gopakumar14@hotmail.com
Date:
18 Dec 2000
Question:
A hatchery
working in South India faces an acute problem of luminescent bacteria (LB).
The water used in the hatchery is treated with 20ppm chlorine as the source
water contains LB. In spite of the treatment the presence of LB is found in
the rearing tanks in lesser numbers. The tank with 100 nauplii/litre
contains more numbers than the tanks with half the stocking density.
Please suggest remedial measures, chemical doses
etc.. to destroy LB in the rearing tanks.
Gopakumar
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COMMENTS
1:
You do not mention specific problems associated with your luminescent bacteria – are you actually experiencing mortalities or other negative impacts on your shrimp? You may have seen in other postings on this list that the presence of luminescent organisms does not always correlate with any undesirable effects on the shrimp. Can you have the luminescent organism identified precisely?
It
would be normal to have higher bacterial counts with higher shrimp stocking
densities; there is more food for the bacteria from leftover feed, shrimp
excretions, etc.
As
to chlorine treatments, one rule that is commonly applied is that you must
supply enough initial chlorine so that there will be 1 ppm residue after 24
hours. The amount of organic matter in your water will influence how much
chlorine is “used up”. If you have high organic matter, perhaps your
filtering system can be upgraded at reasonable cost, and that may prove just
as effective by itself as the chlorine treatment. Thorough
cleaning/disinfection of rearing tanks before refilling is also important.
Assuming a 1-hour generation time, just one viable bacterium will give rise
to 16 million in 24 hours and 256 billion (256 x 1012) in 48
hours.
Julio Estrada
E-mail: julioe@speed.net.ec
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COMMENTS
2:
Which bacteria from
probiotics can control Vibrio?
I am told that Bacillus subtilis can control luminescent bacteria from
pond water.What is your experience ?
How to boost the non-specific immune system of PL?
Ajitsinha
E-mail: pancham@bom3.vsnl.net.in
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COMMENTS
3:
Try
ozone, it works and we can give you the names of several farms using it all
over the world. Look at www.trio3.com
Clarence
Marsden
E-mail:
triogen@gate.net
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COMMENTS
4:
Bacteria
like Pseudomonas and Bacillus (e.g. subtilis, licheniformis) have the
ability to control the Vibrio. I have used bacteria in my farm and hatchery
as well and so far very seldom vibrio problems occur. I isolated bacteria
from our own environment and do the mass culture; the results are very good.
You
can boost the immunity by using the bacteria (peptidoglycan cell wall) and
also by a good feeding regime, with high nutritional value. On the other
hand, by using bacteria you can have better water quality.
Dr. Farshad Shishehchian
Ph.D. Aquatic Ecology- Shrimp Culture Pond Management
Technical Manager
J.W Farm
Malaysia
E-mail: farshadshrimp@hotmail.com