Aquaculture Feed and Fertilizer Resources Information System
 

Giant river prawn - Growth

Growth can be expressed as the increase in length, volume or weight against time (Hartnoll, 1982). In aquaculture growth is measured by weight gain. Some authors have developed equations to relate data on length and weight for M. rosenbergii raised in tropical and sub-tropical pond (Sampaio and Valenti, 1996 and Valenti and Sampaio, 1996). As an example, the equation presented by Sampaio and Valenti (1996) based on data obtained in four experimental ponds was as: W = 1.21 x 10-6 L 3.43, where W = weight (g) and L = length (mm).

Growth curve facilitate forecasting and may be used in the determination of production models. Some authors reported using von Bertalonffy equations (Bertalanffy, 1938) to represent the growth of M. rosenbergii under batch conditions (Valenti, Mello and Castagnoll, 1993; Faria and Valenti, 1995; Sampaio and Valenti, 1996 and Valenti and Sampaio, 1996). Figure 2 shows an example of these curves, which indicate that growth rate is high during the first month after stocking and decrease later.

Males grow faster than females (Holthuis, 1980; Hartnoll, 1982). Within populations growth is heterogenous (Malecha et al., 1981). Two distinct types of juveniles are defined on the basis of their relative growth rates: ‘Jumpers’ and ‘Laggards’. Jumpers are exceptionally fast growing individuals and laggards are the slow growing ones.

Growth of M. rosenbergii is asymptotic. The length – weight relationship for male and female M. rosenbergii under natural conditions is described by the equation Log W = -5.57 +3.19 log L (r = 0.99) (Rao, 1967) and under experimental pond culture conditions by W = 1.21 x 10-6 L 3.43 where W = weight (g) & L = Length (mm) (Menasveta and Piyatiratitivokul, 1982; Sampaio and Valenti, 1996). The total length (TL) - carapace length (CL) relationship is described by Log CL= -0.92760 + 1.13787 Log TL  (r = 0.97235) and Log TL = 0.88675 + 0.83088 Log CL (r = 0.97235) (Rao, 1967). The growth rate of immature females prior to sexual maturation is exponential, where after it slows down considerably (Ra’anan et al., 1991).