The males may fan the eggs while they are growing after they are fertilized. They fan the eggs or the nest to bring in fresh oxygenated water and to remove any waste products from the nest area. Having 30,000 to 200,000 tiny eggs are dividing and growing, respiring, and producing waste can cause a local depletion of oxygen around the eggs and a build up of toxic waste products. By fanning the next the male crappie is moving the toxins away from the nest and bring in freshly oxygenated water. He also will stay there to guard the next from predators. Many criters will dine on fish eggs. Not just fish but many aquatic insects would love to have an fish eggs supper.
Remember that a lot of the time the crappie will be spawning in very shallow waters in the very back of a bay. There may not be a lot of water movement, current, in those areas.
The crappie may spawn in deeper water if the lake water is clear and the sunlight can penetrate deeper. But if the water is stained or muddy then the sunlight can't penetrate that deep into the water column so the crappie will be spawning in shallower water.
The eggs need warm clean water with lots of oxygen and sunlight to develop and hatch. Actually they need the warmth of the sunlight to grow. Live is a chemical reaction and we all know that chemical reactions go faster when it's warmer. Heat speeds up life's chemical reactions.
Originally Posted by papasage