Fig. 10

Comparison of the developmental process between free and embedded embryos. a Comparison of the developmental progress of newly hatched embryos (NHE) and unhatched embryos that still remain in the envelope (UE) at the same age. Twelve criteria were evaluated at the date of hatching. Observations have been done on embryos from four spawn, n correspond to the total number of embryos that hatched at a particular date and were used for this study. One embryo from one spawn begun to hatch at 8 dpf, while the others begun at 9 or at 11 dpf. Numbers correspond to the criteria as follows: 1 circulation in the yolk, 2 embryo straightening, 3 urinary bladder, 4 eye pigmentation, 5 ventral circulation, 6 bile, 7 melanophores on the body, 8 peristaltic undulations, 9 mouth open, 10 coordinated pectoral fins movement, 11 jaw movements and 12 first oral feeding. b The total length of newly hatched embryos (NHE) were measured and compared to the ones of embryos of the same age that remained in the envelope (UE) (n = 3 group UE or NHE/date of hatching/spawn, three spawn were used). Data correspond to the mean value of the three different spawns ± SD. Significant differences were observed according to the hatching date (different letters) but not the status hatched or unhatched embryos p < 0.05. c From the day after hatching, embryos were considered as free embryos (FE) their total length was measured daily and compared to unhatched embryos (UE) of the same age. (n = 3 group UE or FE/date of hatching/spawn, three spawn were used). Data correspond to the mean value of the three different spawns ± SD. Significant differences were observed according to the hatching date (different letters) but not the status hatched or unhatched embryos p < 0.05