Sometimes, it’s trout that have to be killed
Chubs compete with trout. They are what our elders taught us to toss in the bushes. They were "trash fish." No longer. Could it be that American anglers are showing early symptoms of an ecological conscience?
Forty years ago, in an effort to eliminate humpbacks, the U.S. Fish and Wildlife Service dumped 20,000 gallons of emulsified rotenone into 445 miles of the Green River system, which feeds the Colorado.
"Everybody was tickled to death," effused one local angler. "There was so much chub and trash fish, (but) there was no trout." That’s because trout can’t live in warm, silty, wildly fluctuating streams. Desert fish, however, evolved adaptations. The humpback’s small eyes protect against swirling sand. Huge fins enable it to negotiate fierce currents. So sensitive is it to vibrations that it can feed on floating insects when water visibility is under one inch. It has silver flanks tinged with subtle shades of violet, a pencil-thin "wrist" before the tail, and, as its name suggests, a Quasimodo-like hump.
Giant dams on the Green and Colorado created trout habitat by trapping silt and belching cold water, but they were death on humpbacks. Now, when humpback fry sweep out of the Little Colorado River into the main Colorado, they go into cold shock and are picked off by alien trout. Only about 2,000 humpbacks survive in the entire system below Glen Canyon Dam.
In the 15 miles below the dam known as the Lees Ferry reach, the U.S. Geological Survey's Grand Canyon Monitoring and Research Center and the Bureau of Reclamation are curtailing rainbow trout reproduction by fluctuating flows from the dam. In a 9.4-mile stretch above and below the mouth of the Little Colorado, 76 miles downstream from the dam, they’re electro-shocking browns and rainbows and giving them to local Indians for fertilizer. At Bright Angel Creek, 103 miles below the dam, they’re using a weir to block spawning brown trout.
University of British Columbia fisheries professor Carl Walters, a consultant to the Grand Canyon Monitoring and Research Center, expects the cessation of the regular flows that have been in place since 1991, to improve the trout fishery.
"At Lees Ferry, we went from a trophy fishery to your standard jillions of 12-inch rainbows," he declares. "I've worked on rainbow trout for 50 years, and I've never seen densities this high. For 12 miles they're lined up like cordwood…. Even if there weren't a native-fish issue, I think we'd recommend fluctuating flows to kill some of the eggs and try to get better sizes on trout."
How are anglers reacting to the idea of killing alien trout on the Colorado and elsewhere? Since I’ve been advocating it in Fly Rod & Reel magazine, we’ve been getting some predictable responses. The editor of Outdoors Magazine, James Ehlers, is scandalized by the concept.
"It is notable that Mr. Williams has aligned himself with individuals that believe frogs have the same intrinsic value as African Americans and Holocaust victims," he writes on his internet list-serve. "It is also interesting that Mr. Williams, while claiming to be an environmentalist, advocates the poisoning of streams to kill rainbow trout." But the vast majority of readers we’re hearing from are supportive, some passionately so.
The nation’s pre-eminent trout defender, Trout Unlimited president Charles Gauvin, scolds anglers who oppose the project: "If we fight this, what will we say to Walleyes Unlimited when they complain about some coho salmon recovery program in Oregon? Let's grow up….If the science is good, what business have we to be complaining about efforts to save a native species?"
The effort to save this native species will be a test for anglers, and, while they’re doing well on this one, there will be many more. "I have no illusions about the speed…with which an ecological conscience can become functional," Aldo Leopold said 56 years ago. "It has required 19 centuries to define decent man-to-man conduct and the process is only half done; it may take as long to evolve a code of decency for man-to-land conduct."