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. They are then transferred with buckets to another tank where first-feeding begins. . The stumbling block for farming halibut was that they are notoriously difficult to feed. This problem has been largely solved biologically. The larvae are subjected to intensive feeding for 30-45 days on live prey.