Not sure what the water temps were, but I've stood on the bank & fished over a large blowdown at Taylorsville in Dec & Jan and caught Crappie. Daytime temps were in the low 30's when I got there (little after sunup) and probably/maybe got to around 40deg at best by midday. Now, this was a long time ago & back when I didn't have a boat .... and that tree is no longer there. Most fish came from about 8ft deep & about midway of the tree, but I did catch several (on one occasion) right at the shoreline next to the base of the tree in less than 4fow. The only time I didn't catch anything was when the surface was covered in ice about 30ft out from that shoreline.