A federal judge has ruled that the U.S. Fish and Wildlife Service ignored major threats to the westslope cutthroat trout in deciding not to list the fish as a threatened species under the Endangered Species Act. Judge Emmet Sullivan, of the United States district court in Washington D.C., found that the Service gave short shrift to extinction risks posed by interbreeding or “hybridization” with non-native fish. The judge ordered the Service to reevaluate the trout’s status in light of widespread hybridization and to issue a new listing determination within one year.

“This is a real turning point in the battle to protect native trout,” said Abigail Dillen of Earthjustice, who represented American Wildlands, the Gallatin-Madison Chapter of Trout Unlimited, Clearwater Biodiversity Project, Montana Environmental Information Center, Idaho Watersheds Project and Mr. Bud Lilly. “The Fish and Wildlife Service threw up its hands when it came to the greatest problem facing this fish. Now the agency’s finally going to have to roll up its sleeves and think about how we can actually save the westslope cutthroat trout.”

Two years ago, the U.S. Fish and Wildlife Service refused to list the westslope cutthroat trout as a threatened species. Conservation groups brought suit challenging the Service’s determination on grounds that the agency never distinguished between pure and hybrid fish when it concluded that there are still enough westslope cutthroat to ensure the species’ survival. This week, federal district court Judge Emmet Sullivan agreed, holding that: “The agency wholly fails to reconcile its recognition of hybridization as a threat to WCT’s viability with its inclusion of hybrid stock in the population assessed for listing.”

Judge Sullivan’s ruling vindicates serious concerns that the westslope cutthroat trout could be hybridized to death on the Fish and Wildlife Service’s watch. “The agency tried to play a numbers game, counting hybrids and pure strains of westslope cutthroat trout as the same. Yet, in the same document, they stated hybridization is the greatest threat to the native fish, ” said Rob Ament, Executive Director of American Wildlands. “The court said they can’t have it both ways.”

In Lewis and Clark’s time, the westslope cutthroat trout was abundant in lakes and rivers across the Northern Rockies. In fact, the fish takes its scientific name, Oncorhynchus clarki lewisi, from the explorers, who first described the “cutthroat trout” in 1805. Today, westslope cutthroat trout are just managing to survive in the few headwaters streams across Montana, Idaho, northwest Wyoming, eastern Washington, and the John Day River Basin in Oregon, where logging, mining, roading and other development have not yet taken their toll on sensitive fisheries. Like the American buffalo, these fish have become an icon of a vanished wild west – the cutthroat trout is now the state fish of both Idaho and Montana.

The prognosis for remnant westslope cutthroat trout populations is grim. There are few protections in place to protect the trout’s diminishing habitat. Given that the Clinton-era roadless initiative is not currently in place, many of the westslope cutthroat trout’s last refuges are still open to development. But the single greatest threat – and the most intractable one – is the spread of nonnative sportfish such as rainbow and brook trout that have been planted in the westslope cutthroat’s home waters. These fish can out-compete native trout, and even more problematic, species like rainbow trout readily hybridize with cutthroats. Genetic testing in Montana reveals that hybridization is now rampant, even in areas previously thought to be strongholds for pure westslope cutthroat trout.

“The state fish of Montana and Idaho is still in limbo,” stated famous fly-fishing guide Bud Lilly. “It’s time for the Fish and Wildlife Service to quit its legal wrangling and give this fish protection under the ESA. It won’t survive if there’s no coordinated recovery plan in all five states where it survives.”