Maternal and genetic effects on individual variation during early development in Japanese flounder Paralichthys olivaceus

To investigate the changes in maternal effects during early development in Japanese flounder Paralichthys olivaceus, four-by-four factorial mating by artificial fertilization was performed to produce 16 families. Larvae and juveniles of each family were reared under common environmental conditions until completion of metamorphosis. The magnitude of maternal effects was estimated as the differences between sire and dam variance. Maternal effects were highest at hatching, and then disappeared at 30 days after hatching. During early development, larval size at hatching was largely affected by egg size, but this effect decreased as larvae grew. Estimated mean heritability during early development was nearly constant (0.14 +/- 0.06 for total length and 0.10 +/- 0.05 for body depth). Therefore, it is suggested that early development in Japanese flounder is affected by both maternal effect and genetic factors.