Inside the egg
Cell division begins before the body axis and organs take shape. Yolk supplies energy to the embryo. Temperature, salinity and oxygen affect its development, and currents carry pelagic eggs through the water. This transport is known as advection.
The first meal
As yolk reserves run out, a larva needs prey it can catch and swallow. The match–mismatch hypothesis proposes that recruitment depends partly on whether suitable prey is abundant at that critical stage.
Finding shelter in an unfamiliar habitat
At settlement, the young fish enters a different habitat and faces different risks. In flatfish, one eye moves as the skull is remodelled. A larva that swims upright in open water becomes a juvenile that rests on one side on the seabed.
