I talked with the Warden I work with and law in Wisconsin and as it is illegal to keep targeting that species once yu have a limit, it is extremely hard for him to present a case for the local D.A. to prosecute as how do you prove you weren’t targeting northern (assuming you have a limit of eyes). That being said, he looks at intent. If you are taking a picture of every walleye, holding it out of the water, measuring, etc. he would make contact with you and push it further (looking for self incrimination). he said if you simply caught another walleye, immediately unhook and threw back he would most likely look the other way.
I’d like to see in the regs where it states this. I can’t find it anywhere. What I can see in the WI regs is (per pg 16):
The total daily bag limit is the maximum number of fish that an angler may reduce to his/her possession in one day from all waters fished for that day.