Remember what happened in 1989, the Wis. commercial fishing fleet went to a Quota System. Quota was a problem.

"Total prey fish biomass in Lake Michigan has trended downward since 1989. This decline was largely driven by the dramatic decrease in bloater biomass". Source USGS page 9 .
And
“Yellow perch populations declined precipitously during the mid-1990s, due to minimal recruitment after 1988." Great Lakes Fishery Commission 2006
And
"Because Wisconsin first implemented a commercial quota for yellow perch in the summer of 1989, there had been less incentive for commercial fishermen to underreport before then. For observed commercial yield in Wisconsin during 1989–1992, we added the reported commercial yield and the verified illegal yield and multiplied the sum by two." Dr. Wilberg.

Might underreporting chart something like this? 2.25 times as much net, twice as many trips to catch only 72% as many Perch, when perch numbers were at a record high? Strange how much poorer fishing efficiency becomes for some, after the quota system is in place?
I wonder if the same trouble shows up with some other fishers trying for chubs? It would appear so, why didn't the WDNR didn't just ask their computer to check on anyone having such a bad run of luck on so many extra trips?

What happened to the yellow perch, the estimated Wisconsin illegal harvest was 170% on average, this dispite the extra WI wardens and USFWS personal running the CanAm sting at the time. How much damage can one fisher do?
So what of the other commercial species of fish, if you look at the post quota data, the same pattern of more trips, more nets to catch the same or fewer fish is present on the commercial harvest database. Does anyone think only the perch were the target of overfishing and underreporting? So here are the harvest numbers for Bloater Chubs. Here is Smelt. Remember, Alewives had to be closed in 1991 as were perch in 1996.

Please note that if illegal Chub harvest was as great as with perch illegal harvests could have amounted to 3 - 8 million pounds per year. Is that so far fetched as so many game wardens were working on perch violations. Was the DNR checking for Chub violations? What of Smelt?

Another problem being that the same size nets catch both perch and chubs. See in the chart, how after perch numbers drop to almost zero, commercials switch to chubs, bringing even more pressure on them. In both the 1960's and 2000's, chub harvest soon bottom after the perch are gone.

Since the estimated total biomass of chubs in Lake Michigan is only 15 million pounds, why is the Wisconsin commercial limit still 3.6 million pounds per year?