9689

• UCREFRP Catalog Number: 9689
• Author: Recovery Implementation Program.
• Title: Recovery Implementation Program For Endangered Fish Species In The Upper Colorado And San Juan River Basins - 27th Annual Recovery Program Researchers Meeting Program.
• USFW Year: 2006.
• USFW - Doc Type: Moab, UT.
• Copyright Material: NO

less than 2.5 miles and the other 29% moved between 2.5 and 7 miles. Most (71 %) of the
roundtail chub that moved over 2.5 miles were recaptured in a spawning aggregation.
Percentage of roundtail chub that exhibited pike bites was low (1 %) in LP-
Treatment and high in L YC-Control (13%) and L YC-Treatment (20%). The low pike-
bite percentage observed in LP- Treatment may be due to higher predation success rates
by northern pike due to smaller length classes and therefore lower escape rates of
roundtail chub. Conversely, the high pike-bite percentage observed in L YC-Control and
L YC- Treatment may be due to lower predation success by northern pike on larger
roundtail chub and therefore higher escape rates. Some of the differences we observed in
roundtail chub attributes among study sites were may be attributed to densities and sizes
of nonnative predators. Continued monitoring of roundtail chub abundance and size
structure in these reaches will give insights into response of native fish to removal of
piscivorous nonnative fishes.

15. Trial and error: Efforts to improve retention of stocked Colorado pikeminnow
in the San Juan River

Authors: M.E. GOLDEN and P.B. HOLDEN - BIO-WEST, Inc.; D. L. PROPST and S.
CARMEN - New Mexico Department of Game and Fish; W.H. BRANDENBURG and
M.A. FARRINGTON, University of New Mexico, Museum of Southwestern Biology;
J.K. JACKSON - Utah Division of Wildlife Resources.

Abstract: Since November 2002, the San Juan River Recovery Implementation Program
(SJRIP) has funded a cooperative effort to monitor the retention, growth, and survival of
hatchery-reared young-of-the year (YOY) Colorado pikeminnow (Ptychocheilus lucius)
stocked into the San Juan River. One of the ancillary goals of this effort is to provide
insights and recommendations to the SJRIP on what can be done to increase the retention
and survival of stocked Colorado pikeminnow in order to facilitate achieving the goals of
the SJRIP's Augmentation Plan for Colorado pikeminnow. When monitoring after the
initial 2002 stocking yielded what we perceived to be poor retention, when compared to
similar stockings in the mid- to late 1990s, the cooperating agencies recommended a
series of stocking protocol changes and experiments designed to increase the retention of
stocked YOY Colorado pikeminnow. The changes included, stocking Colorado
pikeminnow directly into preferred habitats, acclimation experiments, and habitat
manipulations.
Short-term habitat manipulations near the time of stocking in 2003 and 2004
appeared to have little impact on Colorado pikeminnow retention, primarily because
relatively small flow fluctuations had dramatic impacts on the suitability of low-velocity
habitats. Beginning in 2003, the U.S. Fish and Wildlife Service's Grand Junction Field
Office began stocking Colorado pikeminnow directly into backwaters and other low
velocity habitats, instead of en masse at one or two locations in the main river. While
habitat availability and other environmental factors have clouded the interpretation of our
results, we believe that part of the observed increase in retention and survival seen from
2003 -2005, versus what was seen in 2002, is attributable to this change in stocking
protocols.
From 2003-2005, we have also attempted to acclimate a marked subset of 20,000
Colorado pikeminnow to river conditions by holding them in low velocity areas with net

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