Growth Performance of Offspring from Selected Korean, Cultured Japanese and Their Reciprocal Intraspecific Hybrids of Red Sea Bream, Pagrus major

Intraspecific hybrids have been proven to be a useful tool for increase growth rate in some freshwater fish species. However the effects of intraspecific hybrids in seawater fish species is little known. To assess whether intraspecific hybrids in red sea bream was associated with growth enhancement, growth performances of offspring from two inbred lines, selected Korean line (KORDI-F4) and cultured Japanese line (IPN) and two intraspecific hybrids lines (KORDI-F4♀×JPN♂ and JPN♀×KORDI-F4♂) of red sea bream were compared. There's no significant difference in body weight between offspring groups during seed production period (until 4 months old). At seven months old (after three months rearing trials on sea cages communally), the offspring from KORDI-F4 (41.0±11.1g) and JPN♀×KORDI-F4♂ (39.3±8.1g) showed significantly better performance in body weight than that of the offspring from KORDI-F4♀×JPN♂ (37.0±8.1g) and IPN (35.7±9.7g). At 15 months old, the offspring from JPN♀×KORDI-F4♂ showed best growth performances in body weight, weight gain, specific growth rate among four offspring groups. As the results, the intraspecific hybrids between cultured Japanese line and selected Korean line showed superior growth performances than their paternal and maternal inbred lines.