Lake fertilezation projects have been used since the early 80's in SE Alaska most have been successful.
The first to embark on this program were the commercial fisherman funded Aqua culture assoc. in Ketchikan and Sitka. Most of the projects were on isolated lakes with no anadromous stocks due to high waterfalls etc.
The U.S. Forrest Service got involved in funding and The State and Fed. did several enhancement projects on depleted Sockeye systems. The runs in most of these project areas appear to have increased and in most instances not only Sockeye but Coho too.
One problem that is an off shoot of all man made projects is that the indegenous populations often get left behind and the increased harvest of the enhanced run always hurts the Native stocks. No different in Ak. than any where else, so far the managers have done a good job of allowing for escapement in this regard. But as you may or may not know the Fed has taken over the managment of Fisheries in Ak. and only time will tell how they will perform, I am nervous.