TIME AFTER SPAWNING
1 HOUR 30 MINUTES

Figure 2.3a, b, c, d Time 1 hour 30 minutes

Cell division is occurring rapidly. Within a sample of eggs a range of developmental stages will be seen (Fig. 2.3a, b, c). The majority will be in the 4-cell stage but will range between the 8-cell and 16-cell stage. At this time it is still possible to distinguish between fertilised and non-fertilised eggs due to the cleavage pattern on the outside edge of the egg. Fertilised eggs have an even regular pattern of cell division whereas unfertilised eggs are uneven and nonsymmetrical (Fig. 2.3d).