John,

Al Zale, Leader of the Montana Cooperative Fishery Research Unit at Montana State University in Bozeman, suggested the use of ultrasound, microwaves, electroshocking and Jello to help protect the native cutthroat trout in Yellowstone Lake from the illegally introduced, non-native lake trout. The Jello, presumably unflavored, would be spread over eggs (location of the spawning areas had been determined by previous studies) to smother them. I haven't heard anything lately on this project; wonder if they'd consider testing it on Flathead Lake, too? Seems a little less indiscriminent than gill-netting. Of course, Flathead Lake is a poster child for resource mismanagement over the years; for example, the introduction of mysis shrimp in the 80s inadvertantly helped wipe out the kokanee salmon population (they competed for the same plankton foodsource) which, in turn led the lakers to turn to other species as prey including cutthroat and bull trout, depleting their numbers, too.
I've caught a few lakers on Whitefish Lake on a fly and have heard that at times in the spring they're available to the fly angler on Flathead, but for the most part I found that to be a game for trollers with outriggers/cannonballs/planerboards.

Regards,
Scott