Effects of larval stocking density and feeding regime on larval rearing of giant freshwater prawn (Macrobrachium rosenbergii)

A series of larval rearing experiments were conducted to investigate the effect of larval stocking density and feeding regime on larval development, survival, and larval quality of Macrobrachium rosenbergii (de Man). For larval density, fixed initial stocking densities (50,100,150 and 200 larvae l(-1)), as well as treatments where larval density changed during the rearing period (in function of the rearing volume), were tested. In the latter trial, initial densities ranged between 100 and 400 larvae l(-1). For the factor feeding regime (based on Artemia nauplii), the effect of both feed ration (1.5, 2, 3 and 4 times the standard feed ration) and feeding frequency (2 or 6 times per day) on larval performance was tested. The results of the experiments showed that larval stocking density and feeding regime strongly affected larval development, survival, and duration of the rearing cycle, as well as larval quality. The best initial larval stocking density when using a constant water volume was 100-150 l(-1), which could be increased up to 400 l(-1) if the water volume was increased during culture. A feeding frequency of 6 times per day using first-stage Artemia nauplii, was more effective than feeding only twice daily. Production efficiency in terms of the number of postlarvae produced per unit rearing volume, and the number of Artemia nauplii used per postlarva produced in the different treatments is discussed. These optimized larval stocking densities and feeding regimes are expected to render freshwater prawn larval rearing more profitable and improve larval quality. (C) 2009 Elsevier B.V. All rights reserved.