I do think they spawn over a couple months and not all of them at one time. I also believe each female will go in and out several times and not put all her eggs in one nest. I feel that on a normal year here they can start in late Feb and not stop for a good while.
Our fish this year I believe spawned out in 9'-10' of water for most of them. Conditions from cold and the Sabine River Authority's lake level dropping at the worst time made for a very strange year on T- Bend.