In Yellowstone, Killing One Kind of Trout to Save Another

As the Biblically inspired name suggests, the fish — surgically altered lake trout, implanted last week with tiny radio transmitters on a gently rocking open boat by a team of scientists here — are intended to betray. The goal: annihilation.

“Finding where they spawn would be the golden egg,” said Bob Gresswell, a research biologist at the United States Geological Survey, and leader of the Judas team, a strike force in the biggest lake-trout-killing program in the nation. The idea is that the electronic chirps will lead trout hunters into the cold, deep corners of Yellowstone Lake, where the fish might be killed in volume. “The eggs could be killed before they hatch, maybe with electricity, or suction,” Dr. Gresswell said.

That millions of dollars would be spent to eradicate a fish that many people love, and love to eat, is only the beginning of a paradoxical new chapter for trout, long a silvery symbol of America’s wide-open spaces.

States in the Great Lakes region, by contrast, where lake trout are a native species, dream of rebuilding the stocks that were overfished, and only about 100 miles south of here, Wyoming state wildlife officials are in fact still breeding lake trout in a hatchery and happily releasing them into local waters.

Motivation is where it starts, since the goal here in Yellowstone is not the killing itself, but rather the saving of another trout species entirely, the cutthroat, which grizzly bears, egrets, eagles and martens, among others, depend upon for food. Lake trout, which park officials believe were introduced by fishermen a few decades ago, gobble up the cutthroats (named for the slash of red under their jaws). And lake trout, unlike the cuts, as they are called, hide in the deep and do not venture into streams and tributaries to spawn, where bears and other animals can catch and eat them.

So death to the lake trout is the rallying cry. And come death does, to hundreds of thousands of fish in recent years, through an entanglement of gill nets, or a quick slice of the fillet knife and now, through the Judas fish program, at the scientific frontier.

Americans have tried in varying ways to manage fish and nature. Back in the late 1800s, for example, industrialization and settlement were wiping out many species, and a politically powerful new constituency of recreational fishermen, many of whom patterned themselves after leisure-class titans like the steel baron Andrew Carnegie (whose treasured rod and reel were handed down to his heirs), arose in force to demand that streams and lakes be teeming with fish, and especially trout.

But hands-on management in the name of wildness itself rather than human appetite or aesthetics — the core distinction of what is happening here — is a change in how people relate to nature in set-apart corners of the world like Yellowstone.

The theme is echoed elsewhere, in worries over the Asian carp or sea lamprey in the Great Lakes, or even the rainbow trout, a species native to the Pacific coast, which was spread all over the world by hatcheries, especially after World War II and often to the detriment of native fish.

The decline of recreational fishing in the United States since its peak in the late 1970s is adding its own twist, scientists, environmentalists and anglers say. Between 1991 and 2006, according to the most recent figures from the United States Fish and Wildlife Service, the percentage of Americans 16 and older who fish declined to 13 percent from 21 percent.

At the same time, the environmental movement, which in its earlier years was closely aligned with the hunting and fishing communities, became more urban and less connected to the idea that nature should be harvested or consumed.

Here at Yellowstone, that has led to a coalition of partners standing shoulder to shoulder for killing the lake trout, of which visitors are of course encouraged to catch and eat as much as they like, on behalf of a protected fish, the cutthroat, that is strictly catch and release. Eco-system watchdog groups like the Greater Yellowstone Coalition, and the national clean-waters angler group, Trout Unlimited, for example, are raising money to help Yellowstone kill its lake trout.

“The whole population is more urban, and urban folks tend to be more mutualist — looking at humans and animals coexisting, as opposed to animals being there for utilitarian use,” said Steve L. McMullin, an associate professor in the department of fish and wildlife conservation at Virginia Tech, in Blacksburg, Va., who studies fishing demographics.