Early Growth and Survival Rate of Hybrids from Male Meagre (Argyrosomus regius) x Female Shi Drum (Umbrina cirrosa) Compared to their Parent Species

Growth performance and survival rates of hybrid meagre x shi drum and purebred offspring of their parents were compared. Hybrids were produced from eggs of hormone-induced shi drum females (Umbrina cirrosa), artificially fertilized by frozen meagre (Argyrosomus regius) sperm. For comparison, purebred offspring were obtained from both species by natural spawning from hormone-manipulated breeders. Growth and survival were observed for 120 days after hatching. The hybrid offspring grew significantly faster than the purebred. On day 120, the mean weights were 12 +/- 1 g for the meagre, 5 +/- 0.5 g for the shi drum, and 22 +/- 1 g for the hybrid juveniles. The mean daily growth coefficients were 1.9 for the meagre, 1.3 for the shi drum, and 2.1 for the hybrids. Estimations of growth heterosis, the extent to which the hybrids outperformed their parent species, showed high hybrid vigor: heterosis for mean weight was 159% and for daily growth coefficient was 31%. The hybrids also had better survival rates than either of the purebred juvenile populations: 49 +/- 0.03% for the meagre, 34 +/- 0.02% for the shi drum, and 78 +/- 0.02% for the hybrids. Therefore, heterosis for survival rate was 86%. According to the growth performance and survival rate, crossing of these two species is strongly suggested.