Juvenile growth performance and associated genetic parameters in common carp,

The degraded soils unfit for primary agricultural crops can be utilised for inland saline aquaculture of saline-tolerant species. In India, a genetic improvement program for developing a faster-growing, saline-tolerant strain of common carp has been initiated. The present study reports juvenile growth performance and genetic parameters for common carp reared at 8-9 ppt salinity. The population comprised 5075 individuals belonging to 86 full-sib families generated by single-pair mating. Until 30 days post hatch (dph) (mean body weight 1.8 g) the families were reared in separate hapas in freshwater, and thereafter until 75 dph (5.3 g) in separate hapas at 8 ppt salinity until attaining a suitable body size for PIT-tagging at 150 dph (28.1 g). Thereafter, they were reared communally in two ponds until 195 dph (55.0 g). The body weight and body length at 30, 75, 150, and 195 dph, and weight gain (WG150-195) and specific growth coefficient (SGR150-195) were analysed. The effect of stock and pond on the traits was non-significant at 30 and 75 dph, whereas pond had a significant effect on the traits at 150 and 195dph. The heritability estimates for body weight at 30 dph and body weight and length at 75 dph were medium to high (0.52-0.68), and those at 150 and 195 dph and WG150-195, and SGR150-195 were moderate (0.29-0.43). The genetic correlation of BW150 and BW195 with WG150-195 was high (0.67 ± 0.09 to 0.90 ± 0.04), whereas that of BW150 and BW195 with SGR was negative (–0.41 ± 0.14 to –0.60 ± 0.10). The genetic parameters for juvenile traits are likely to be inflated due to the full-sib family structure and their separate early rearing in hapas. A follow-up study is required to estimate genetic parameters for body weight at the desired market size in carp reared in saline earthen ponds.