It will not be long, I have fished Murray many times over the years, not much here of late, but historically speaking the second week in March has always been good for me as a starting date. Water temps are important for spawning to begin, but length of day light hours is what triggers the fishes migration to the creeks and flats. One must trust his electronics, or have the experience to know when the fish are going to be where. Crappie are river fish by trait, so the upper part of the lakes are always a good place to start. If muddy conditions are present, move down lake until suitable stain is present. If your not seeing fish on the sonar, they either aren't present, or they are on the bottom. Focus on fish that are visible on the sonar, crappie are notorious suspenders. If you see groups of fish that are suspended in 20 to 30 feet of water, 10 to 15 feet down, these are catchable fish. Alter baits and boat speeds until you find something to their liking. If no takers, move to another location and repeat the process. I will guarantee that someone on that lake is, or has been catching some nice fish for a while now. You just got to know some of the primary starting points. Little Saluda, Bush river, in and around SCE&G #4, Hawleek, Rocky, and back in Buffalo around the creek fork are well known starting points.