Bill
I don't know anything about Ohio ,I live in south Louisiana. I have three ponds only four years old & the LMB seem the be shrinking in size.My ponds are 17-20 feet deep . Yours being that old & deep you should have some "HAWGS" in there.I have all kinds of fish,my biggest problem is that we catch & release so much I think the fish are too smart now, but I'm starting to thin them out. I have alot to learn also. Try using "live" native to the pond bait,I've been catching some nice ones doing that lately.Seems like they just don't want artificial as well as they used to. GOOD LUCK !!
