It is my experience in Central Indiana, most of the medium or less rivers and creeks have bass on beds right now. A good time to leave the bass alone. It will save you a lot of frustration on why your lures aren't consistently bitten. The best reason to leave smallmouth alone is to help ensure a good year's recruitment class after last year's cold winter. Catching a spawning smallmouth can cause it to abandon the nest and allow the eggs to be eaten.