9571

• UCREFRP Catalog Number: 9571
• Author: Miller Ecological Consultants Inc.
• Title: Fryingpan-Roaring Fork Literature Review.
• USFW Year: 2002.
• USFW - Doc Type: Fort Collins, CO.
• Copyright Material: NO

recommendations were made fora 1 brown trout and 1 rainbow trout bag limit and
additional stocking of rainbow trout fingerlings in the reach below the dam (Grieb, 1983).
Most studies during the 1980's indicated that the implementation of fishing regulations
and stocking programs had resulted in an overall improvement in health and biomass of
trout populations (Nehring and Anderson 1984; Nehring and Anderson 1985); however,
declines observed specifically in rainbow trout populations caused further protections to
' be recommended (Nehring 1986).
Instream flow studies found poor correlations between Ruedi Dam flow regimes and trout
' population dynamics (Nehring 1988a). Minimum and optimum flows determined for
various life stages of all species of trout ranged from 50 to 250 cfs (Nehring 1988b).
' During the 1980's the Fryingpan River had become famous and was subject to heavy
fishing pressures (Nehring 1987). The opossum shrimp, Mysis relicta, had been found to
commonly occur in releases from the dam and had altered the normal trophic flow in the
' river (Nehring 1988a). The release of Mysis relicta from the dam was found to have a
significant positive effect on the growth rate of rainbow trout in the Fryingpan River
(Nehring 1991). Although Mysis relicta was found to cause increases in trout population
' and biomass below the dam in a favorable year. Years of poor shrimp production were
found to cause severe declines in trout biomass below the dam. The rest of the river
remained relatively unaffected (Nehring and Thompson 1994).
' Durin the 1990's trout o ulation studies continued in the F 'n k
g p p Dn gpan River. The broo
trout population was found to be declining while brown trout were found to be increasing
(Nehring and Thompson 1996). It was speculated that brown trout predation was at least
partially responsible for the brook trout decline.
' Whirling disease was first detected in the Fryingpan River in 1995 though no population
level affects on trout populations were detected (Nehring and Thompson 1996). In 1997,
' a slight decline in recruitment of juvenile rainbow and brown trout at the Seven Castles
area was noticed in the Fryingpan River (Nehring 1998). Nehring, (1999) described
several point sources of whirling disease in the Fryingpan River and its tributaries. In
' general, brown trout and rainbow trout fiy showed no overt signs of whirling disease in
the Fryingpan River except for a decline in numbers at the Taylor Creek site. Though
whirling disease was present in several ponds that spill into the Fryingpan River,
' filtration studies found extremely low levels of spores in the main river. Whirling disease
spores were mostly found in the downstream reaches (Nehring 1999).
' ROARING FORK RIVER
The Roaring Fork River has been the subject of far fewer studies than the Fryingpan
River. Nehring, (1980) described self-sustaining trout populations in the upper reaches of
the Roaring Fork River. The upper reach had distinctly better trout habitat and greater
habitat diversity, whereas less habitat diversity and limited spawning was described in the
Fryingpan-Roaring Fork Literature Review February 27, 2002
Miller Ecological Consultants, Inc. Page 3