Lots of good discussion here - hope some of it makes it to the meetings on Jan 30 and/or Feb 1
It may be contentious, but Indiana should not write off “pulling a Wisconsin” now or in the future. “Pulling a Wisconsin” is defined by listening to its stakeholders, reviewing the same “science” that all states fisheries managers look at, and making an informed decision to do the best it can do for its stakeholders. It doesn't appear to be a complete disregard for "science" at all. I may be wrong, but I have yet to see or hear a single biologist from Wisconsin come out in opposition to its decision to stock more than the LMC agreed to. Are their hands tied? Is there a gag order? I dont know, but I have not heard it. Michigan has come out in opposition, but no one else...not even Indiana. Not even the tribes in Michigan.
Well the entire lake committee (which includes a biologist from WI) made a recommendation which was ignored. I think you'd be hard pressed at any job to have employees publicly opposing a decision made by their superiors...especially one that was political. I'll just say I have not personally spoken to any biologist in any state that supports what happened in Wisconsin. I'll leave it at that because I don't want to speak for anybody, particularly if it would get them in trouble
For myself, I certainly do not agree with breaking 50+ years of consensus based management and have no intention of operating outside the lake committee structure and the joint strategic plan that everybody signed onto via the GLFC. It's not a perfect system, but no system is. I don't always agree with what comes out of it, but having all the states go it alone has pretty good potential for disastrous downsides.
In terms of lake trout biomass and abundance on the south end, it's pretty high and rising and I have some concerns with the same thing happening with wild lake trout that happened with wild chinooks. The ability to detect wild lake trout is worse than chinooks in terms of management, because they typically are 3-5 years old before they start showing up in angler catch, compared to 1 and 2 for chinooks. So it's a delayed detection ability. If And that gobies could experience the same issue affecting alewife - overpredation. Diet is a real nuanced thing to talk about - depending on when, where, and how fish were collected there are all sorts of different numbers. And obviously diet changes over time, as prey fish populations fluctuate, move around, etc. So any study is a snapshot. There's also significant regional variation in lake trout diet. But in any case, Austin Happel's 2017 diet study (physical study contents, collected from netting surveys) showed about 50% of the diet was gobies in southern Michigan waters, about 30% in Indiana, and 20% in Illinois. Purdue's 2016 study, using angler captured fish, showed western half of the lake's lakers ate about 90% alewife (probably what you're thinking of above) and the eastern half only about 40% alewife. That study also showed the significant seasonal change, as lake trout ate almost 100% gobies in April, 60% gobies in May, dwindling under 20% during the summer, then jumping back up in the fall. Lakers basically eat whatever is available, and they are overlapping with gobies fall, winter and spring, and mostly only overlapping with alewife in summer. I think that's the source of a lot of disconnect about what lake trout eat - you are entirely correct in saying they eat mostly alewife, or mostly gobies, depending on what season and where. Both things are true.
Ironically I think the policy of stocking more and more kings to get the alewife before the lakers can get to them would be a boon to lake trout long term, as that strategy would have a decent chance of depressing the alewife population so much that lake trout natural reproduction would increase even more as they shifted to a diet of fish without thiaminase, and long-term would probably crater the chinook population if the alewife were depressed beyond the point of population rebound
Also a good point about the harvest of lake trout as well - if anglers don't want to target and harvest them, it doesn't really matter how high the limit is. I didn't expect Wisconsin's 5 fish limit to affect much since their anglers are the least likely to harvest lakers in the first place. Harvest-driven strategies only work if the willingness and ability to harvest significantly exists.
In terms of Indiana lake trout harvest, probably 80% of the lakers harvested by boats launching out of Indiana are not caught in our waters, as the thermal habitat is not there once summer sets in. And when the cold water is there, most anglers are hammering silver fish in the spring rather than targeting lakers. So changing our limit to 5 would have almost zero real-world impact. And we like it to align with Michigan's to avoid burden on our anglers and to reduce the need for enforcement action on anglers that might be crossing state lines and fishing in both Indiana and Michigan. In fact, we changed our limit from 2 to 3 at the request of our anglers that it match Michigan's