White bass will bite on St. Croix from usually the first/second week of April and onwards.
Problem is people tend to fish community spots and those spots will be hot usually in about two/three weeks later onwards. That's usually when the fish schools much more together. It's also when the baitfish congregate much closer to shorelines too.
As usually I just only play with my fishing pole and lures, so no fish pictures to show. Everyone has already seen pictures of fish already.
If one fishes the Mississippi like on some of the southern MM/WI, fish would've been caught around last two weeks of March timeframe onward. One can even still catch trout while the water is still cold.