CHARACTERIZATION OF GROWTH AND SEXUAL MATURITY IN BASE POPULATION OF GIANT FRESHWATER PRAWN (Macrobrachium rosenbergii)

Selective breeding is basic tool for improving commercially important traits of aquaculture species. The main objectives of selective breeding programs are faster growth. Heritability for growth trait of females Giant Freshwater Prawn (GFP) was higher than those of males for carapace length, body weight, body length, total length and claw length.  Late sexual maturity allows aquaculture species to reach commercial size more rapidly since fish invest energy in growth instead of gametogenesis.  There are five main types of females GFP which are immature females (IF), Mature Female (MF), orange egg carrying females (OE), grey egg carrying females (GE) and open brood chamber (spent) females (OP).  The present study aims to characterize the standard body length and sexual maturity in base population as an effort to develop a new strain characterized by improved growth and delayed sexual maturation.  Juvenile prawns, with a mean weight of 0.27±0.19 g, were stocked at a density of 10 prawns/m². Prawns were fed twice daily (early morning and evening) with a formulated diet at 7% body weight per day during the first months, 5% during second months and 4% thereafter. Total harvest was made at the end of the 4-month grow-out cycle. Total female prawn size at six months ages varied from 65 t0 83 mm (75.78±4.82 mm) Standard Length and 12 to 26 g (19.74±3.67 g) Body Weight. The frequency of IF and OE were very low in the 4^rd month grow-out (8% and 4%), and frequency of OP and MF were more high than others (42% and 34%).  Female Body weight was significantly (P<0.05) higher in orange egg carrying females (23.17±4,22 g) in comparison to other females types.  The sexual maturity of females were heterogenous (coefficient of variation (CV) = 44.69%).  Our results show that selection for both growth and late sexual maturation in GFP could be done with selected superior female and then lower type of sexual maturity to generate the next generation.