Thanks for the update, Theeck.
I am commenting a lot in your thread because I like all of the "alternative" methods you are trying!
I believe MUCH less energy is required to run a small aeration unit compared to a heating unit. Perhaps excavate a small side pond for FHM and fill it with spring water, then shut the connector and let it warm. Running a very small aerator would probably be enough to keep your FHMs alive, even during the dog days of summer. Maybe do some tiny water exchanges as needed to maintain your water quality?
Another option is a black fly larva feeder. (There are some old posts on the topic.) Basically putting rotting meat in a mesh above the pond. The maggots fall through and feed the fish a lot of protein. (Would the bears eat carrion?) I think that would be more food than a mosquito zapper? However, you could always choose both! (I think there have been some posts on Pond Boss where people have just put a light on their dock near the water surface and the fish congregate at night to eat all of the bugs that hit the water.)
Also, I think(?) a FHM pond needs to be in sunlight to start the bottom of the food chain for them.
Finally, I think your best bet is to train the bears to perform pond management! Explain to them that if they help raise your trout from fingerlings to hefty adults, they you will split the trout harvest with them 50/50.
