I fished lake DeGray in Arkansas last week. The oxygen levels were so bad that we could only leave our baits (shad) at 20 feet for a couple of minutes. Then we would reel them to the top and "revive" them. The shad would survive about three of these cycles before they went belly up. The hybrids we were after are apparently pretty tolerant of poor oxygen levels. This lake is loaded with hybrids, but no stripers.