The numbers of lakers and the size of them being caught is probably a function of many things such as: they may represent strong year classes in the past (many years ago in the case of the big ones) where the survival rate was very good in given years for whatever reason. Lake trout do not spawn in the streams as many trout species do so they may be less susceptible to the various predation forces operating there as well as diseases and chemical contaminants etc.. They also have a varied diet....much more so than some of the other varieties such as salmon and rainbows. I've found small sunfish, perch, and smallmouth bass inside them along with various bugs etc. over the years in addition to alewives and shiners (and in the past smelt). Once they are up to size they can compete with larger predators in the shallows also (especially in the Spring) without fear. They may be stronger genetically. When you add these things to those already mentioned it could add up to greater general populations of them avaailable. The thing I wonder about is are juveniles being caught frequently too? If not it could be a bad omen for the future because these big ones are the spawners....