There is another way to look at MSY similar to LL's.

MSY is not a biological model but an economic one. What is the minimum investment I need to make in order to maximize returns to me? This works if your $10 investment pays a fixed (say) 30% per year. But, say it doesn't. It pays only 25, but you still take your 30.

Alternatively, say I offer you a million dollars ( you can't touch it) but guarantee that you can have 10% annual return. Or, ten million but you are only guaranteed 1.5%.

Which do you want?

A friend modeled coho one time and showed that, if the coho carcasses actually benefitted coho production-as studies show, that fishing the run at 40% actually resulted in more fish in the catch than fishing at 60%. It's published in Restoring Nutrients in Salmonid Ecosystems..