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

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et al., 1964). The bheries are chiefly large pereminal water bodies
surrounded by earthern dykes which are constructed by borrowing earth
fro the trenches excavated inside the bheries near the toe line of the
dykes. The bheries are deeper and larger in extent than the pokkali
fields of Kerala. Usually the bheries have single sluice which serves
both the purpose of taking the tidal water during spring tide and
releasing water from bheri during ebb tide. The production system in
bheries is largely based on trapping holding and culture of wild seeds
of shrimps and fishes taken during high tide. Prawns are obtained
along with the mullets and perches. The stocking is done during
January-February and fishing is carried out in September-Decanber.
During the 10 months, fishes are inside the impoundments and feed on
the natural food provided by the habitat which gets replenished by the
animal and plant life contained in the incoming tide waters. These
farms are known to yield 168-672 kg/ha of shrimp and fish and hold
l.ITlIl'l€l'1S€ potential of development. This traditional practice is giving
way to selective stocking with desirable culture species of prawns and
fishes (Natarajan, 1985).
During scientific preparation of the field, care is given to
provide canals of various dimensions occupying about 8% area to hold
the fish in extreme situations. The height of dykes normally varied
from 1.5 m to 1.8 m and the crest width is kept at 60 cm. Two tier
system of sluices are also fixed suitably. From March onwards tidal
water is drawn into the field which brings in the seeds of commercial
species of prawns and fishes. This will be continued upto June with
all earlier precautions taken not to inundate the paddy beds with
saline tidal water. With the onset of monsoon, the entry of tidal
water is stopped and the fishes harvested when an yield of 200-400
kg/ha/4 months is obtained.
The monsoon showers thoroughly wash the paddy beds which also
raises the water level in fields. At this time required cuttings are
made in the dykes to permit the free flow of water. In due course
congenial ecological conditions are restored in the field when Kharif