I was just down that way today Pat. Took the NC route to get to the Northwest River in Chesapeake. The only reason I mention this, is that the bluegill, perch and bass we caught, were also very dark and not in a spawning mode. We saw one guy catch a good sized gar, and it was "dark" too.
Looked very dry down that way, and with a cypress/tupelo swamp system, the water might become acidic. Just a theory.