I was up there last week. I fluked one and my mate had a shot in 3 days fishing. My theory is that the rising water is now rotting the grass that is now below waterline and making the water toxic. I noticed that none of the waterbirds stayed in the water for long. I've noticed this happening in Hinze Dam on the Bass a while after rising water levels. I think oxygen levels drop and the water gets acidic, but not sure about that.
We also had great showings of bait and big fish on the sounder around the Dam wall all 40 foot and deeper, but we didn't have anything to probe those depths with.
Just an idea is take something you can drop and jig or work at depths of 40 to 90 feet and give it a go.