Fluctuating water levels and water temperature are both important during the spawning period, even more importantly is there timing. The ideal water temp which puts crappie in spawn mode is the mid 50's. When water temp reaches the upper 50's to low 60's the crappie will really start moving shallow to spawn. So last year we had high water, but the timing was off with water temp. The past several years we have had mid winters and early spring weather (warmer water temp earlier in the year). Last year water temps reached the upper 50's near the last week of March. This was just about the time there was a fast water level rise.

So, crappie move shallow to spawn. Why shallow... a few reasons, habitat such as button ball bushes and water willow. Crappie eggs are adhesive, and will be deposited on root hairs of the vegetation. As compared to bluegill which just make a bowl shape bed and lays their eggs in the middle of it. In the shallower water they also can reduce predation by other fish on the eggs. Up shallow they have less water behind them to protect the nest.

So, the males go in first to find a nest site, and fans it off to expose root hairs. Then he moves back out to find and entice a female to follow him back to the nest site. However the water has risen and the nest area is no longer shallow. Maybe he aborts the nest and starts a new nest up shallow. Maybe he tries to us that nest, but due to the deeper water other fish eat the eggs.

The eggs in a female are ripened by water temp, when they are ready - they are ready. If conditions change for nesting more of the eggs may over ripen - rotten eggs.

So ideally there should not be any water level fluctuations during spawning. There is probably a worst spawn when the water is falling during spawn. Or the water temp reached the ideal range, and then a cold front moves in for a week, and water temp drop out of range. But a quick water rise can also hurt.

There are other factors that affect the spawn. But that is my educated guess about water levels. There is some research that shows no matter what, crappie populations are cyclic and every few years there will be a good spawn, followed by a few years of poorer spawn. Some research indicates a 3 to 5 year cycle.

One last note, last year during May while doing some bass population sampling (electrofishing), we noted many crappie in water less than 18". The area we were in was Jacks Branch (Blood River). The crappie were in the middle of a large water willow bed that was under water. The water was so clear we could see the backs of fish as our boat slowly moved toward them. We shocked that area just for a moment to prove what we thought we were seeing, and an unbelievable number of crappie were there still spawning. Most likely males still guarding the nest. So this is where you get another factor that affects a spawn. Fish spawning late, means the young fish will be smaller going into the winter months. Smaller fish often have higher winter mortality. We have seen this with largemouth bass at KY Lake, so I would only assume it would hold true for crappie also.

Hope that helps.