Perhaps the problem is an increase in the Muskie population
Nature.
The problem is you can't micro control the fishing industry, and to their credit, the respective state DNR's have done a fine job in enhancing the walleye, the salmon, and the steelhead fishing in their respective states.
If one species is diminishing it's due to the predatory influences of the others.
Despite their goals, there is no way man (aka the DNR) can control the outcomes of their good intentions......