Fishery experts agreed at a February conference that there's no practical way to eliminate the illegally planted lake trout that are killing native cutthroat trout in Yellowstone Lake. "There isn't a fix, there isn't a silver bullet - even suppression is a forever commitment," federal biologist Lynn Kaeding told the Billings Gazette. A draft report issued after the conference says broad-scale poisoning or blowing up the lake trout could hurt other fish or wildlife. At the same time, introducing sterile lamprey eels, successful in controlling alien trout populations in the Great Lakes, might further disrupt nature's balance. Fisheries experts say the only long-term hope is for inbreeding to weaken the population. "That's a long shot, but it's one of the only promising ideas," says Kaeding. If nothing is done, biologists predict that half the cutthroat in Yellowstone Lake will disappear within 20 years. Biologists fear that grizzly bears, ospreys, pelicans and eagles, who feed on the shallow-dwelling cutthroat, will also suffer from the native fish's demise (HCN, 9/19/94). For a copy of the report, contact U.S. Fish and Wildlife Service, 307/344-2281.