The production of the freshwater prawn Macrobrachium rosenbergii in Israel: the effect of added substrates on yields in a monoculture system.

Intensive monoculture of Macrobrachium rosenbergii in temperate zones is dependent on the ability to bring maximum prawns to a minimal size of 25 gram in 6-7 months. Since increased density per area causes a decrease in average weight, the addition of surface area, in the form of net substrates, into the water column in effect reduces the density per surface area correspondingly. Nursed juveniles (0.5g) were stocked in ponds with improved substrates at a density of 15m^-2 for a growout period of 184 days. Yields of marketable prawns were 24% higher in ponds with substrates. While the effect of the added substrates on average weight was insignificant, the percentage of marketable prawns was 17.7% higher in the treatment with substrates. Overall survival also increased by about 10%. -from Authors