Lake trout (Salvelinus namaycush) have caused a near-disaster in Yellowstone Lake, starting more than two decades ago.
The new edition of Yellowstone Treasures says: “Although some larger lakes of southern Yellowstone were intentionally stocked with lake trout long ago, these large predator trout, illegally introduced into Yellowstone Lake in 1994, have caused a drastic reduction in the lake’s cutthroat trout that may never be reversed. However, the combined NPS/Yellowstone Park Foundation aggressive efforts—gillnetting and electrofishing—had begun to pay off by 2012, and lake trout numbers are now declining each year, while cutthroat trout numbers are increasing. Researchers now know where the lake trout spawn, and some eggs can be killed. Meanwhile, anglers must kill all lake trout and either eat them or puncture the air bladder and dispose of the carcass in deep water.”
Ted Koel and his team are now using “Judas fish” to lead them to schools of lake trout, and they employ aircraft to locate the tagged lake trout. As this year’s fishing season opens in Yellowstone, you can read all about it in this recent Powell Tribune article by Mark Davis.