As the water temps get closer to 60F you'll start seeing better numbers. But you're best chance to go after the big girls was directly after ice out. The water will warm considerably during a hot day so I'd definately be fishing that 5:30-8:30pm window that Dilli was talking about. Jerkbaits are by far your best bait this time of year but I'd be throwing big plastic swimbaits too. Keep a close eye for followups and have another rod rigged ready to drop in front of them if they don't take the first bait.