on ky lake, april 15. thats tax day, nectar flow for honey bees and usually marks the beginning of the spawns for crappie and LMB give or take a week depending on weather. before that is mainly pre-spawn and after that for a month or so is still pre-spawn, spawn and post spawn up into the first 2 weeks of may, generally.
temps stated above are about right but they also need a few consecutive days of sunlight for the females to incubate the eggs before laying. if nasty weather blows in theyll move off into deeper water and wait for conditions to improve. this is what happened during the 2018 Elite series where some fish were still on beds the week before and moved out when the weather rolled in.
travel routes and points from mouths to the back of the creek bays are typical pre-spawn spots along with main lake points and travel routes post spawn. travels routes are generally under water old creek channels, ditches, humps, etc. the north to northeast sides with chunk rock, rip rap and gravel heat up quicker early on as well as creek bays that have multiple feeder creeks. birdsong creek is a good example of this. keep an analog temp thermometer to compare with your transducer and adjust it if its off. even a 1-2 degree difference in water temp can make a difference in catching fish and not catching fish.
the guys above pretty much gave the run down on baits, but dont get committed to one or two baits. youll probably get burned if you do. if they dont hit red switch to a shad color, they may just be feeding on shad instead of crawfish.
learn to read lake maps and sat images. it can make a world of difference on big lakes to find those travel routes.
here is an example. main river channel at the bottom, old creek channel through the middle that runs a few miles to the backwater. those are not islands above water in the middle. they are under water as this was shot during winter pool and the satellite image is looking through the water, kind of like looking through a piece of glass. they are also helpful for searching for logs, treetops, rock piles, etc in shallow water spawning areas. the above water islands are to the right.
the same location with c-map.