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Abstract:
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Macrobrachium rosenbergii (de Man) and M.ide77a
(Hilgendorf) form two commercially important Palaemonid
prawns of the Vembanad lake (9 28' and 10 10’ N and 76
13' and 76 31' E). Both of them were known to have
contributed to a very lucrative fishery during the sixties,
however, in recent years these natural resources have badly
depleted owing to the impact of many man made alterations
brought about in the ecosystem such as habitat reduction,
physical obstruction imposed in the migratory pathway of
these species, pollution hazards, etc,. Changed
environmental conditions and increased fishing pressures
caused persistent alterations in the stock size of these
prawns during the past so many years, however, no serious
attempt was made to monitor the stock size from time to time
and also to bring out the resource characteristics. Though,
the morphotypic differentiation in grow out male population
of M.rosenbergii has been documented, no similar studies
were conducted with regard to natural male and female
population. Based on the data collected during fishery
cruise surveys conducted in Vembanad lake from March '94 to
February '96, population characteristics. postlarval
distribution, fishery and population dynamics of
M.rosenbergii and M.ide77a of the lake were studied in
detail. |