A project launched by the Utah Division of Wildlife Resources to protect a recently discovered population of rare native trout killed almost every fish in the stream instead. The fish, located in Parley's Creek close to Salt Lake City, were believed to be pure Bonneville cutthroat trout, one of only two varieties of trout native to Utah, and candidates for listing under the Endangered Species Act.
were attempting to rid a creek upstream of introduced rainbow trout
by poisoning the water with rotenone. Rainbows and other non-native
trout interbreed with Bonneville cutthroats and are the chief
reason the native now occupies less than 1 percent of its former
Division staffers were unaware that
anything had gone wrong until they were informed by a member of a
local fishing club. Paul Dremann, conservation chairman of the
Stonefly Society, went to the site Nov. 1 to check on the
"The whole stretch was strewn with dead
fish," says Dremann. "My reaction was dismay and tremendous anger."
Dremann then informed Charlie Thompson, a state fisheries biologist
in charge of the project.
"I feel pretty bad
about it," says Thompson. "They were really pretty fish."
Thompson says cold weather may have caused the
rotenone to maintain its toxicity longer than expected. He also
says other chemicals used to neutralize the rotenone may have
killed the fish.
"I don't know what could have
been done differently," Thompson says. Levels of the poison were
kept far below recommended doses, and monitoring stations were
carefully watched, he adds. "We worked so darn hard to make sure
everything went right."
Critics say that is
precisely the problem. Even with the best-laid plans, rotenone can
be unpredictable. "It's a crap shoot," says Dremann. "This is a
glaring example of how you can plan carefully and it can still go
Rotenone has killed the wrong fish
before. A project on Utah's Fremont River in 1991 killed aquatic
life along a 35-mile stretch of the river, including sections that
flowed through Capitol Reef National Park. In 1990, 18,000 fish
were killed in streams leading to Idaho's Salmon River. Perhaps the
most infamous case of rotenone gone wrong occurred in 1962 when 430
miles of the Green River were poisoned, including sections in
Dinosaur National Monument.
Rotenone kills fish
as well as macro invertebrate species such as caddis flies and
stoneflies. It can also kill amphibians in early stages of
development. Since the Parley's Creek fish kill, Zach Frankel,
director of the Utah Rivers Conservation Council, thinks a
moratorium on using rotenone makes sense because the poison is
unpredictable. Utah officials acknowledge the problems but say it
is the most effective tool they have to control non-native fish.
"There's no other way," says Thompson, since alternatives such as
electroshocking are ineffective, time-consuming and
Discovery of the Parley's Creek
cutthroats last year had astonished state biologists. They believed
that most of Utah's native fish were holding out in remote streams,
but the creek winds through a golf course and is not far from
Interstate 80, just a 10-minute drive from Salt Lake
Two days after the discovery of the
accident, wildlife officials found one small Bonneville cutthroat
still alive in Parley's Creek. They hope it indicates more fish may
The writer works out of
Salt Lake City, Utah.