Cutthroat Trout lay their eggs during spring. Their color changes during
this reproduction period. The female trout seeks out a spot in the stream
were the current is slow moving. She lies on her side and begins moving
her tail back and forth in order to clear material away from the streambed
and create a shallow nest for the eggs. This nest is called a redd. Once
the redd is four to six inches deep, she will swim over the top of it
while waiting for a male trout. Once he arrives, the female's eggs and the
males milt are deposited in the redd. The female then swims not to far
downstream and begins to build another redd. It may or may not be used,
but the female is capable of building and laying eggs for multiple redds.
After a period of about three weeks the infant trout hatch. At this time they are still very dependent on their yolk sac for nourishment. As the new hatchlings age and grow larger, the yolk sacs slowly disappear.