Life history traits of the Monsoon River prawn Macrobrachium malcolmsonii (Milne-Edwards, 1844) (Palaemonidae) in the Ganges (Padma) River, northwestern Bangladesh

Abstract

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 3.54–11.76 cm total length and 0.50–15.20 g 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 (χ 2 = 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.