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

Nehring, R B. 1991. Effects of reservoir escapement of mysids on two Colorado
tailrace trout fisheries. American Fisheries Society Symposium 9:134-143.
Fryingpan River
The objective of this research was to determine the influence of the opossum shrimp
(Mysis relicta) on the rainbow trout population in the reach of the Fryingpan River below
Ruedi dam. Mysis relicta was stocked into Ruedi Reservoir in 1970, but first appeazed in
the Fryingpan River in releases below the dam in 1985. Conclusions for this study were
based on a comparison of current rainbow trout data (1986-1988) to data collected during
' premysid years (1978-1985), as well as to data collected approximately 8 km
downstream. The presence of Mysis relicta in releases from Ruedi Reservoir was found
to have a significant positive effect on rainbow trout condition, growth rate, and
' populations in the first 5 km below the reservoir outlet.
Nehring, R B. and I{. G. Thompson. 1994. Stream Fisheries Investigations.
Colorado Division of Wildlife. Federal Aid Project F-51-R Fort Collins, Colorado.
Fryingpan River
The purpose of this study was to monitor trout densities, biomass, and species
composition, and evaluate the potential harmful effects of electro-fishing. The
availability of Mysis relicta was found to be a major factor in determining the size and
structure of the fish community immediately below the dam. A five-year period with
above average precipitation resulted in releases from Ruedi Dam that were conducive to a
high rate of entrainment of Mysis relicta. This period of augmented food supply
sustained trout populations near 1000 kg/ha. The following four years produced below
normal precipitation. The subsequent decrease in releases from Ruedi Dam during the
winter months resulted in a severe decline in Mysis relicta entrainment. Rainbow trout
and bmok trout populations declined sharply during this period while brown trout became
dominant. Trout populations at lower sites on the Fryingpan River seemed to be
relatively unaffected by these events.
Trout collected at stations in the Fryingpan River were evaluated to assess the impact
from electro-fishing. Preliminary results suggested that a significant percentage of the
fish sustained some injuries due to the electro-fishing process. The percentage varied
with technique and increased with fish size.

Fryingpan-Roaring Fork Literature Review February 27, 2002
Miller Ecological Consultants, Inc. Page 19