Production of Freshwater Prawns
in the Mekong Delta
C. KWEI LIN
CHRISTOPHER LEE
Natural Production
The Mekong River flows through
southern Vietnam in Iwomajorbranchcs,
encompassing a 39,550-
km2 delta with 14.2
million inhabitants. With
open access to vast
estuaries, extensively
interconnected rivers
and canals constitute
most of the aquatic
environment in the Mekong Delta: an
ideal habitat for the native freshwater
prawn (Macrobrachium rosenbergii) (Fig.
1). The prawns arc harvested primarily
by a common small-scale method using
shelter traps. The shelter traps installed
along the edges of rivers and canals arc
square or rectangular enclosures
surrounded with bamboo or wooden
frames, within which pilcsof tree branches
and aquatic vegetation (water hyacinth)
arc placed to attract prawns from the
open water. Periodically, fishers surround
MEKONG R.
Thu Duc
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N TRt
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South China Sea
Fig. 1. Mekong Delta
waterways.
predict
24
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the shelters with seine nets and remove
prawns from within them. Prawns arc
harvested all усаг-round and the larger
ones arc sold al more than USS4∕kg,
Currently, there are two sources of freshwater prawn
(Macrobrachium rosenbergii) production in Vietnam:
natural production from the rivers and canals, and
aquaculture production from ponds and ricefields.
either to local markets or government
processing plants. Smaller prawns and
juveniles arc kept alive and sold to
prawn farmers al around USS1.5∕kg,
which comprises 200 Io 300 individuals.
The total annual freshwater prawn
production in Vietnam during 1985-90
was reported to vary from 5,000 to
8,0001, most of it from natural fisheries.
Unless the harvest of wild juveniles is
managed, it may undermine the
sustainability of the natural fisheries.
There have been few efforts to estimate
the standing slock of prawns in any
given river or habitat. Nor is
there information on catch/
effort and rale of natural
recruitment for the prawn
population. Without such
data, it will be difficult,
ifnol impossible, to assess
their present status and
the future trend of the
prawn fisheries.
Aquaculture Production
Although there arc no official statistics
on the production of farmed prawns, the
amount is believed to be relatively small.
The growout system includes intensive
monospccics pond culture, and scmi-
intcnsivc Orcxlcnsivc integrated ricc-
⅛ prawn or vegetable-prawn culture.
Intensive prawn culture is rare and
requires large capital investment for
pond construction, high protein feed,
large labor and energy inputs, as well
as sophisticated farm
management skills. The
major impediment to
large commercial farm
development in Vietnam
is lack of reliable market
demand. Although the
potential yields of
intensive farming arc up to 1,500 to
2,000 kg∕ha∕ycar, the risks arc also great.
Most prawn cul turc systems practised
in Vietnam arc semi-intensive, found
predominantly in An Giang, Hau Giang,
Cuu Long and Ticn Giang provinces.
This type of farm requires modest capital
input and less management know-how
and has lower risks. The prawns feed
on natural food, supplemented with raw
farm products, and the yields arc usually
low at 200-500 kg∕ha∕ycar.
NAGA, THE ICLARM QUARTERLY