that KY/Barkley Lakes have become infested with Zebra Mussels !! This has helped clear the water clarity, too. And it may be a factor in the decline of the White Crappie, since the mussels filter feed on the same planktons as Crappie fry. Could it not also be possible, that Black Crappie fry have a different diet, and are not impacted as much ??
I've also heard that the lakes went thru a couple of years of drought conditions, and that may have impacted the spawns of those years.
The "grass/water weeds" are also supposed to be making a comeback, and that bodes well for the Black Crappie (which prefer weeds/clear water ... think Canadian border area and Florida )
White Crappie do prefer murky/warm waters, and Black Crappie prefer clear/cooler waters ... so maybe the changing conditions of the lakes has more to do with the domination change, than other factors ?

As to the creel limit reduction, I think it's the easiest, cheapest, and most fair way that the KDFWR knows how to use, to slow down the harvest numbers. We won't know, one way or another, for several more years, if it will help the fishery recover.

... cp