I'd go with what dleurquin says. In the Lake Erie-Niagara river-Lake Ontario part of N.Y. which seems like your part of Wisconsin, you'll see them around that time before and after April 1st. You might want to scout around a few nights earlier than that.

Suckers spawn at the same time the Walleye females start dropping eggs. Off western lake Erie and tributaries that is the the last week of march first week of april. Water temp has got to be 43 degrees for them to start spawning in the rivers. The jacks will be in a week earlier in 37deg waters stacking up waiting for the females. Red house suckers will be in the second week of walleye spawning. Smaller inland lakes warm faster so keep that in mind. It goes Ice out,pike out,walleye in,the suckers,shad and white bass, carp and catfish come in and the walleyes are done,followed by the rest depending on how fast the water temp reached the mid 50's and peak spawning usually into late may early june before it stops

In Maine it's just after ice out, starting in southern Maine and working it's way north. There's still usually snow Baka in the shade. We use them for lobster bait.