From Jim Morris' Fishing Report, published by the Dayton Daily News:
Grand Lake St. Marys: Crappie fishing has slowed with some lower temperatures. Most fish have moved to deeper water, so try working brushy areas and docks 2-4 feet deep. Minnows and jigs are the best baits. Bluegills are hitting around docks and on seawalls with minnows and redworms. A few bass have been caught in the channels on a variety of spinners, crankbaits and jig-n-pig. Fish in the spillway along the west bank for walleyes and crappies. (The state is currently treating the lake with alum. Boaters should keep a safe distance from the boats and barges being used to spread the chemical.)
Source: http://www.daytondailynews.com/ohio-recreation/fishing/jim-morris-fishing-report-for-april-5-1355304.html