When I think of the OP's lake my greatest interest is how the prior owners managed (or not) a great northern MI trophy fishery in water more than 100 years of age. Whatever they were doing ... encouraged the growth and ultimate weight of the predators. So I do wonder why returning to similar harvest regime wouldn't return the water to its former condition?
Bill, I like your idea of determining standing weights. But I will add that if owned the property, I would be most interested in what the predator standing weights are. Whatever it is, it represents a biomass that is supported by a niche. IOWs the lake produces whatever it takes to support it as well as the growth required to replace natural mortality. So I wonder why this niche cannot be managed solely by manipulation of the number of predators exploiting the niche? The niche being fish prey of all of species reproducing to include prey sizes of the own kind. If I owned the lake, I would be very interested in whether the standing weight of the predators was acceptable to provide good fishing. I'd also like to know the proportion of predator weight to the total because I think that would help to guide whether the predator niche could be expanded.
Knowing that the predator niche could be expanded, I would give very deep consideration to whether I wanted to do that. The main reason I may abstain is that I think that forage numbers cannot be expanded without also recruiting at a higher level the predators that I know I am behind the curve in culling. I would fear that increasing production of forage fish would delay my goal of trophy predators. This concern would probably cause me to reject advice that I needed to expand prey production unless I was reasonably persuaded that the predator biomass was just to low to provide good fishing.
I've always considered the predator growth problem as forage per predator problem. If we make it prey problem, then how much can we increase the weight of predators? For example, if we double the production of prey what's the expectation for predator growth? It's probably similar reducing the predator population to 1/2 . Neither of these are minor adjustments but both can only increase an average predator length of 12" to 15". We all under appreciate just how restricted predator numbers must be to produce trophy predators. So to me the question of whether to increase production of prey depends solely on whether I want more predators. If I owned the lake, I would want to make decisions of whether I needed more predators after I had returned the water to trophy status by culling predator numbers so I could have an sense of how manipulating prey might affect my culling requirements. Surely more predators will need to culled if the lake can support a greater standing weight of predators.
