7858

• UCREFRP Catalog Number: 7858
• Author: U.S. Fish and Wildlife Service.
• Title: Draft Greenback Cutthroat Trout Recovery Plan.
• USFW Year: 1995.
• USFW - Doc Type: \
• Copyright Material: NO

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Heavy Metals
Bard Creek was a fishless montane stream that was known to have elevated
levels of heavy metals due to past mining activity. Experimental stocking of
greenbacks into the fishleas habitat of Bard Creek indicated that greenbacks
stocked at over 25 mm in length will survive to maturity and spawn despite
elevated concentrations of heavy metals. However, eggs from mature fish
deposited by late June did not to survive to the fall in Bard Creek. As
Woodward found with low pH and elevated aluminum levels, the swim-up and
alevin stages may be the moat sensitive to elevated levels of heavy metals.
Maaaaement Practices
Fish Culture
Although the stocking of cultured nonnative salmonids almost resulted in the
extinction of the greenback, the greenback was one of the earliest fish to be
reared in Federal hatcheries. In 1889, the Leadville National Fish Hatchery
was established near Leadville Colorado, and some of its original objectives
were to rear greenbacks and yellowfins. Both subspecies were obtained from
waters adjacent to the hatchery and moved by wagon to the hatchery to be used
as broodstock. Eggs of both subspecies were taken from Twin Lakes. However,
the greenback and yellowfin cutthroat trout did not adapt well to captive
rearing, and local citizens were so displeased with the hatchery spawning
traps in Twin Lakes that they were "blown out with dynamite" (Tulian 1896).
The availability of other species (brook and rainbow trout) more adaptable to
hatchery rearing, and the large scale availability of Yellowstone cutthroat
(O. c. bouvieri) from Yellowstone Lake, led to the abandonment of the

greenback by early fish culturists as a source of trout for stocking purposes. '
A second attempt to rear greenbacks at the Leadville National Fish Hatchery
was attempted in 1957 and 1958 using 50 slightly hybridized greenbacks from
the Big Thompson River in Forest Canyon, RMNP, and 26 pure greenbac s from the
now extirpated Albion Creek population. This project was abandoned due to
fish mortality in the hatchery and asynchronous maturation of the r maining
males and females. The project terminated with the stocking of the surviving
broodstock into Florence Creek, Uinta and ouray Indian Reservation, Utah. The
greenbacks in Florence Creek were almost totally displaced by brook trout by
1978.
South Platte Drainage Broodstock. Aa part of the Recovery Plan, an they '
attempt to rear South Platte drainage greenbacks was initiated in 1 77, with
the transfer of 64 Como Creek greenbacks to the USFWS, Fish Culture
Development Center, Bozeman Montana. This broodstock initially enc untered '
the same problems with asynchronous maturation of males and females, the lose
of males due to fungus, and the failure to accept feed in a captive situation.
In 1978, males produced milt in April and May, but the females matu ed in July
and August. Asynchronous maturation problems were overcome by allowing water '
temperatures to decline to near 2 C, then allowing the temperature to rise
again in the spring. Fungus was controlled with malachite green. The use of
variable temperatures and malachite green allowed
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