In the raised position, personnel can easily strip the females that are ready. The best female brooders are ones that have been in service for several years. They were all caught in the wild and are now domesticated. The gamete harvesting work is very labour intensive, since each egg batch must be stripped near the time of ovulation. The eggs are stored about 12 days in small upstream incubators.
Hatching is controlled by light.
Exposure to light can delay hatching. At a temperature of about 6 C, the yolk sac period is quite long. It lasts about 42 days. Researchers collect the larvae when most of the yolk sac has been absorbed. It is easy to collect them because they are phototactic at this time.