Length-length, Length-weight Relationships and Condition Factor of the Giant Freshwater Prawn Macrobrachium rosenbergii (de Man 1879) Cultured in Earthen Pond at High Density

Length-length and length-weight relationships of Macrobrachium rosenbergii (de Man 1879) cultured at high density in earthen pond were investigated. The results revealed that the relationships among various length measurements: rostrum length (RL), carapace length (CL), head length (HL), abdominal length (AL), body length (BL) and total length (TL) showed significant linear correlations through regression analysis (P 0.001). The values obtained from the length-weight relationship showed that there was a significant correlation between body weight (BW) and RL, CL, HL, AL, BL and TL (P 0.001). Their regression equation confirmed a power function relationship: BW=1.5×10^-2RL^2.6572, BW=9×10^-3CL^2.9433, BW=1×10^-3HL^2.8676, BW=2×10^-5AL^3.3475, BW=9×10^-6, BL^3.2277, and BW=5×10^-6TL^3.1205. All the values of b obtained in the current study were significantly different from the isometric value (b=3). Low slopes (b) were observed in BW-RL, BW-CL and BW-HL, while high slopes (b) were observed in BW-AL, BW-BL and BW-TL. The growth type in BW-RL, BW-CL and BW-HL was negative-allometric growth (b 3) while growth type in BW-AL, BW-BL and BW-TL was postive-allometric growth (b 3). The values of Fulton’s condition factor K obtained in the present study varied from 0.70 to 1.05. A high value of K ( 1) was obtained at harvest time indicating that prawns cultured at high intensive condition were stout showing a good condition of robustness.