There are YP in the Potomac where I fish. The largest I have ever caught was a bit over 13" in length. From research done on shortnose sturgeon in the Potomac, they collected extensive data on water temps and DO concentrations. In the peak of summer, bottom temperatures in the Potomac top out around 88 degrees with DO levels of 5.0 mg/L. I do know that the Potomac sees its striped bass flee the river and head north up the Atlantic to New England waters. However, non migratory fish can't do that. The Potomac does have walleye up to about 8 pounds and musky up to about 30 pounds. Unless they are finding some underwater spring seeps and holding in the cooler water they release, it would appear 8 pound walleye, 30 pound musky and 13"+ YP can handle water temps to 88 degrees with DO levels of 5.0 mg/L. Albeit, these temps and DO levels may be very stressful for those large class fish. I suspect it is...
