| Naga
- The *ICLARM Quarterly
Vol.
24, No. 3 & 4 (July – December 2001)
Aquabyte
The
Half-lives of Biological Activity of some Pesticides
in Water
Kyaw
M.O.
Abstract
In the absence of analytical methods, the half-lives
of biological activity of pesticides can be estimated
by bioassays. To determine the half-lives of biological
acivity of pesticides to fish, static bioassays
were conducted in the laboratory with ten different
formulations of pesticides using Labeo rohita
as a bio-indicator. The half-lives of biological
activity for ten different pesticides in soft
water at pH 7.5 and 27°C, ranged from 4.6 days
to 11.8 days. The half-life of biological activity
of Sumithion 50% EC was only 4.6 days. In contrast,
Dimecron 50% EC degraded very slowly and its half-life
of biological activity on L. rohita was
about 11.8 days. Sumithion 50% EC, Padan 50% SP,
EPN 45% EC, Diazinon 40% EC and Diazinon 10 G
degraded in less than five to seven days indicating
that these pesticides are desirable for rice-fish
culture. Contamination by pesticides with long-term
residual toxicity in waters may eventually cause
high levels of fish mortality.
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Article (PDF 203 KB)
A
Note on Monoculture of Penaeus monodon in
a Hardwater Seasonal Pond
S. Athithan, T.
Francis, N. Ramanathan and V. Ramadhas
Abstract
A study was undertaken to assess the growth performance
of brackishwater tiger shrimp, Penaeus monodon
under monoculture in a hardwater seasonal pond
in Tamil Nadu, India. A production of 209 kg/ha/110
days was attained at a low stocking density of
1.5/m2.
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Article (PDF 185 KB)
White
Spot Viral Desease in Penaeid Shrimp - A Review
A.P.
Sangamaheswaran and M.J.P. Jeyaseelan
Abstract
The white spot viral disease in penaeid shrimp
affects the development of the global shrimp industry.
This paper reviews the viruses that cause the
disease, the transmission of the virus, diagnosis
and preventive measures.
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Article (PDF 305 KB)
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