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The Monsoon River prawn, Macrobrachium malcolmsonii (Milne-Edwards, 1844), is one of the dominant benthic species in the Ganges River. Our study describes some biological parameters including sex ratio, length-frequency distributions (LFD), length-weight relationships (LWR), and relative-condition (Kn) factor of M. malcolmsonii in the lower part of the Ganges River, northwestern Bangladesh. A total of 502 specimens of the ranges 3.54-11.76cm total length and 0.50-15.20g body weight were analyzed in this study. Sampling was done using traditional fishing traps (Kara) during the period from March to October 2010. The overall sex ratio showed no significant differences from the expected value 1:1 χ² = 0.20, p = 0.157), and there was no significant difference in the LFD between the sexes (p=0.460). The allometric coefficient b for the LWR indicated isometric growth (∼ 3.00) in males and negative allometric growth (< 3.00) in females. Kn, showed significant variation (p < 0.01) between the sexes, with better performance by females (1.027 ± 0.107) than males (0.968 ± 0.130). To our knowledge, this study presents the first comprehensive description of life-history traits for M. malcolmsonii from Bangladeshi waters. Our data should be useful for the sustainable management of this prawn fishery in the Ganges River basin of Bangladesh and neighboring countries. [ABSTRACT FROM AUTHOR]

The Ganges is one of the three major rivers in Bangladesh. It is a sediment laden, wide, meandering river. This paper deals with the stochastic modelling and prediction of sediment loads of the Lower Ganges river in Bangladesh. The annual variability of sediment loads has been examined. The annual sediment load series is trend free at 5% significance level. The means and standard deviations of monthly sediment load data show periodicity. Monthly sediment load data have been modelled and predicted using the Thomas-Fiering model for the dependent stochastic component and by taking variable month-to-month correlation structures into account. The statistical parameters of observed and predicted data fit very well and hence the predicted sediment load data may be used for future planning of water resource projects in Bangladesh. The limitations of the model have also been discussed. [ABSTRACT FROM AUTHOR]