studies on improved practices of prawn farming for higher ...

[larvest methods
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Pond harvesting, apart from its construction is the most
labour-intensive operation in an aquaculture farm.
Shrimps can be harvested by a variety of methods including
draining, seining, trawling, cast netting, trapping and hand picking
depending upon the species cultured. The most efficient method was
found to be drain harvesting provided the pond is a well designed one
as it can capture more than 95% of the shrimp with virtually no
attached mud and less labour. As soon as more than 50% water was
drained, shrimps begin to swim towards the water flow. Using a
recessed impeller pump these shrimps from the drain net can be
continuously lifted without damage as is practised in advanced
countries.
In shrimp ponds in Asia, long bag nets are set in the sluice
gates to catch the shrimps as they swim out from the pond with the out
flow of water at low tide. The best time for total harvest is during
the full/new moon periods as at this time the shrimps are more active.
Catches are best at night and a light placed at the sluice gate will
serve to lure shrimps to swim towards it. Penaeus monodon often do not
swim out of the pond easily and so repeated draining is necessary in
order to harvest a good percentage of the stock.
It will be worthwhile to examine the traditional fishing methods
being practised in India. The indigeneous gears employed for the
exploitation of fishery resources of our country are many and numerous.
An outline of some of them is given by Panikkar and Menon (1956). Some
of the commonly used gears in various parts of the country are the cast
nets, drag nets, stake nets and wall nets. Gill nets of suitable
meshes are also set for the capture of shrimps.
Traditional traps made of bamboo and fabricated in the shape of
V or W with suitable openings are usually anployed in front of sluice