There are more than 300,000 lake trout in Yellowstone Lake, and there’s a serious effort to eliminate them: they prey on and crowd out native cutthroat trout, severely impacting their numbers. While it’s unlikely the lake trout can ever be totally eliminated (they’re exceedingly hearty), efforts like this can certainly bring the numbers down. If you’re fishing in Yellowstone Lake, it’s mandatory you kill a lake trout if you catch one.
The transmitters, partially purchased by Trout Unlimited, send a signal every one to three minutes to the 28 receivers located on the lake buoys. The data is that analyzed to parse the trout’s movement, with the goal being a map of where the trout are spawning. That area can then be targeted by biologists: it can be electrocuted or the eggs can be removed, according to AP.