After anglers caught two of the non-native trout in the lake this summer, park officials figured the aliens were slipped into the lake by someone who wanted bigger fish to fry (well, catch: Yellowstone is a catch-and-release lake). “This was done in a very deliberate way,” says park scientist John Varley. Yellowstone has offered $10,000 for information leading to the arrest of the eco-saboteur. Meanwhile, park officials are debating whether to destroy lake-trout spawning areas or release a sterile male, ensuring that the aliens die out after this generation. Yellowstone anglers can do their bit, too: hook as many lake trout as they can. And don’t throw them back.
